JP2020525747A - Refrigeration system and method - Google Patents

Abstract

Disclosed the distributed refrigeration system, the present distributed refrigeration system is a plurality of first refrigeration circuits, each of which is provided in a refrigeration unit with a plurality of first refrigeration circuits. , A second refrigeration circuit, the second refrigeration circuit comprising a second circuit heat exchanger, and a third refrigeration circuit, each of which is a first circuit heat exchanger. Heat energy is transferred between a third refrigeration circuit, a second refrigeration circuit, and a third refrigeration circuit, which are arranged so as to transfer heat energy between the first refrigeration circuit and the second refrigeration circuit. It comprises a third circuit heat exchanger, which is arranged to transmit. [Selection diagram] Figure 2

Description

(Cross-reference of related applications)
This application is hereby incorporated by reference into US Provisional Application No. 62/522,851, filed June 21, 2017, and US provisional application, filed June 21, 2017, each of which is hereby incorporated by reference. For each of Application No. 62/522,860, we claim the benefit of their priority.

This application claims the benefit of its priority with respect to US patent application Ser. No. 16/015,145, filed June 21, 2018, which is hereby incorporated by reference.

(Field of the invention)
The present invention relates to refrigeration systems and methods, and more particularly, but not exclusively, to refrigeration systems suitable for use with low GWP refrigerants.

The refrigeration industry is under increasing pressure to replace refrigerants with a high global warming potential (GWP) such as R404A with low GWP refrigerants such as refrigerants having a GWP of less than 150, such as through changes in regulations. There is. This is especially important in commercial refrigeration systems where large amounts of refrigerant are used.

One approach is to use low GWP refrigerants such as carbon dioxide (R744) refrigerants and hydrocarbon refrigerants. However, the methods that have been used so far increase operating costs due to low system energy efficiency, high initial system costs due to high system complexity, and low maintenance due to low system availability and reliability. It can suffer significant safety and financial drawbacks such as high cost and high flammability of the system. Systems that include highly flammable refrigerants with conventional configurations may have lower levels of safety, may violate the restrictions of regulatory ordinances, and increase the liability of operators and manufacturers of refrigeration systems. This is especially inconvenient. Safety is a particular concern given that many commercial refrigeration applications such as supermarket refrigerators, freezers, and low temperature display cases are publicly available and often operate in densely populated spaces. ..

Accordingly, Applicants have realized that the refrigeration industry continues to need safe, robust, and sustainable approaches to reducing the use of high GWP refrigerants that can be used with existing technology. ..

One such approach that has been used for some time is shown in FIG. 1A. FIG. 1 shows a refrigeration system 100 commonly used for commercial refrigeration in supermarkets. System 100 is a direct expansion system that provides both medium temperature refrigeration and low temperature refrigeration via medium temperature refrigeration circuit 110 and low temperature refrigeration circuit 120.

In a typical conventional configuration, labeled 100 in FIG. 1A, medium temperature refrigeration circuit 110 has R134a as its refrigerant. The medium temperature refrigeration circuit 110 provides both medium temperature cooling and removes exhaust heat from the cooler refrigeration circuit 120 via the heat exchanger 130. The medium temperature refrigeration circuit 110 extends between the roof 140, the machine room 141, and the sales floor 142. On the other hand, the low temperature refrigeration circuit 120 has R744 as its refrigerant. The low temperature refrigeration circuit 120 extends between the machine room 141 and the sales floor 142. Usefully, as mentioned above, R744 has a low GWP.

However, while refrigeration systems of the type disclosed in FIG. 1A may be able to provide good efficiency levels, Applicants have found that this type of system has at least two major drawbacks, namely: First, such a system uses high GWP refrigerant R134a (R134a having a GWP of about 1300), and second, when the cold part of such a system uses low GWP refrigerant R744. Nevertheless, it has been found that this refrigerant exhibits a number of the above mentioned drawbacks, including significant safety and financial drawbacks.

The present invention includes a refrigeration system for providing refrigeration at cold refrigeration levels and at moderate refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a third refrigeration circuit (sometimes referred to herein as a "common refrigeration circuit" for convenience), preferably comprising transR1233zd, or preferably comprising at least about 50% by weight, or A non-flammable refrigerant (for convenience, comprising at least 50% by weight thereof, or consisting essentially of or consisting of, a non-flammable refrigerant (for convenience, sometimes referred to herein as a "common refrigerant") , Which are sometimes referred to herein as "common refrigerants"), and are arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F. And a third refrigeration circuit.

As used herein, the term "flammable" with respect to a refrigerant, under the ASHRAE 34-2016 test protocol, in which the refrigerant defines the conditions and equipment and uses the current method ASTM E681-09 annex A1, It means that it is not classified into A1. Therefore, refrigerants that define conditions and equipment and use the current practice of ASTM E681-09 annex A1, under the ASHRAE 34-2016 test protocol, and classified as A2L or more flammable than the A2L classification are Considered to be flammable.

Conversely, the term "nonflammable" with respect to a refrigerant is classified as A1 under the ASHRAE 34-2016 test protocol, where the refrigerant defines the conditions and equipment and uses the current method ASTM E681-09 annex A1. Means that.

As used herein, the term "medium temperature refrigeration" is a refrigeration in which the refrigerant circulating in the circuit evaporates at a temperature of about -5°C to about -15°C, preferably at a temperature of about -10°C. Refers to a circuit. As used herein with respect to temperature, the term “about” shall be understood to mean a variation of ±3° C. at the specified temperature. The refrigerant circulating in the medium temperature circuit can be evaporated at a temperature of -10°C ± 2°C or -10°C ± 1°C.

The medium temperature freezing of the present invention can be used, for example, to cool products such as dairy products, deli meats, and fresh foods. Individual temperature levels for different products are adjusted based on product requirements.

Cryogenic refrigeration is typically provided at evaporation levels of about -25°C. As used herein, the term "cryogenic refrigeration" refers to a refrigeration circuit in which the refrigerant circulating in the circuit evaporates at a temperature of about -20°C to about -30°C, preferably at a temperature of about -25°C. Refers to. The refrigerant circulating in the low temperature circuit can evaporate at a temperature of -25°C ± 2°C or -25°C ± 1°C.

The cryogenic freezing of the present invention can be used, for example, to cool products such as ice cream and frozen products, where again the individual temperature levels of different products are adjusted based on product requirements.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) A medium temperature heat exchanger for discharging heat from the medium temperature combustible refrigerant, wherein at least the first refrigerant or at least the second refrigerant, and preferably the first and second refrigerants. An intermediate temperature heat exchanger, wherein each of the two refrigerants is an A2L combustible refrigerant that comprises, or consists essentially of, or consists of HFO-1234fy, or at least about 50% by weight thereof. A refrigeration unit,
(C) a common refrigeration circuit, comprising a non-flammable refrigerant comprising, consisting essentially of, or consisting of at least about 50% by weight transHFO-1233zd, and at a low temperature above about 40F to about 80F. And a common refrigeration circuit arranged to receive heat discharged from each of the intermediate temperature heat exchangers.

As used herein, the term "consisting essentially of HFO-1234yf" has at least about 75% by weight HFO-1234yf and may include a co-refrigerant, but such. Refers to a refrigerant provided that the co-refrigerant does not negate the A2L flammability of the refrigerant and does not result in a refrigerant having a GWP of greater than about 150. Thus, refrigerant R455A, defined below, consists essentially of R1234yf for the purposes of this description.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO- in the above system. 1234ze, or a combination thereof, and preferably consisting essentially of HFO-1234yf, a low temperature combustible refrigerant as described above;
(Ii) A compressor having a horsepower rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant.
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant of at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO-1234ze, or a combination thereof. A medium temperature combustible refrigerant, preferably consisting essentially of HFO-1234yf, including a combination;
(Ii) a compressor having a horsepower rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature combustible refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO- in the above system. 1234ze, or a combination thereof, and preferably consisting essentially of HFO-1234yf, a low temperature combustible refrigerant as described above;
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant of at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO-1234ze, or a combination thereof. A medium temperature combustible refrigerant, preferably consisting essentially of HFO-1234yf, including a combination;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The present invention includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature refrigerant consisting essentially of HFO-1234yf in the above system,
(Ii) a compressor for compressing the low temperature refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature refrigerant,
(Iv) a low temperature refrigeration unit including a low temperature heat exchanger for discharging heat from the low temperature refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature refrigerant consisting essentially of HFO-1234yf in the above system,
(Ii) a compressor for compressing the medium temperature refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space in the medium temperature refrigeration unit containing the medium temperature refrigerant by evaporating the medium temperature refrigerant;
(Iv) a medium temperature refrigeration unit comprising: a medium temperature heat exchanger for discharging heat from the medium temperature refrigerant;
(C) A third refrigeration circuit (which may be referred to herein as a “common refrigeration circuit” for convenience), which is essentially a third refrigerant, transHFO-1233zd. (Also sometimes referred to as "common refrigerant") and is arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F. And a refrigerating circuit.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) A third refrigeration circuit (which may be referred to herein as a "common refrigeration circuit" for convenience) that consists essentially of transHFO-1233zd (for convenience, (Also referred to herein as a "common refrigerant") and is arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 60F. And a third refrigeration circuit.

The first circuit heat exchanger (preferably a low temperature circuit heat exchanger) and/or the second circuit heat exchanger (preferably a medium temperature circuit heat exchanger) may be a full liquid heat exchanger.

As used herein, the term "full heat exchanger" refers to a heat exchanger that evaporates a liquid refrigerant to produce a refrigerant vapor without substantially any overheating condition. As used herein, the term "substantially without any superheat" means that the vapor exiting the evaporator is at a temperature not exceeding 1°C above the boiling temperature of the liquid refrigerant in the heat exchanger. means.

Accordingly, the present invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a third refractory circuit which is a common refrigeration circuit, preferably comprising transHFO-1233zd, or preferably comprising at least about 50% by weight thereof, or preferably consisting essentially of, or preferably consisting of. A refrigerant and arranged to receive heat discharged from each of the low and medium temperature heat exchangers at a temperature of about 40F to about 60F, wherein each of the low temperature and medium temperature heat exchangers includes: A common refrigerant that evaporates at a temperature lower than the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, the common evaporator absorbing heat from the low temperature refrigerant or the medium temperature refrigerant. By doing so, a common refrigeration circuit, which is a liquid-filled heat exchanger, in which the common refrigerant evaporates.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. And arranged to receive heat discharged from each of the low temperature and medium temperature heat exchangers at a temperature of about 40F to about 80F, each of the low temperature and medium temperature heat exchangers having the common A common evaporator is provided, wherein the refrigerant evaporates at a temperature lower than the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, and the common evaporator absorbs heat from the low temperature refrigerant or the medium temperature refrigerant. And a common refrigeration circuit, which is a liquid-filled heat exchanger, in which the common refrigerant is evaporated.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO- in the above system. 1234ze, or a combination thereof, and preferably consisting essentially of HFO-1234yf, a low temperature combustible refrigerant as described above;
(Ii) A compressor having a horsepower rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant.
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant of at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO-1234ze, or a combination thereof. A medium temperature combustible refrigerant, preferably consisting essentially of HFO-1234yf, including a combination;
(Ii) a compressor having a horsepower rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature combustible refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, preferably comprising transHFO-1233zd, preferably comprising at least about 50% by weight thereof, or preferably consisting essentially of, or preferably consisting of, a common non-combustible refrigerant. And arranged to receive heat discharged from each of the low temperature and medium temperature heat exchangers at a temperature of about 40F to about 80F, and each of the low temperature and medium temperature heat exchangers includes a common refrigerant as described above. Evaporates at a temperature below the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, comprising a common evaporator, the common evaporator, by absorbing heat from the low temperature refrigerant or the medium temperature refrigerant. And a common refrigeration circuit, which is a liquid-filled heat exchanger in which the common refrigerant is evaporated.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO- in the above system. 1234ze, or a combination thereof, and preferably consisting essentially of HFO-1234yf, a low temperature combustible refrigerant as described above;
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant of at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight of HFO-1234yf, transHFO-1234ze, or a combination thereof. A medium temperature combustible refrigerant, preferably consisting essentially of HFO-1234yf, including a combination;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The present invention includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature refrigerant consisting essentially of HFO-1234yf in the above system,
(Ii) a compressor for compressing the low temperature refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature refrigerant,
(Iv) a low temperature refrigeration unit including a low temperature heat exchanger for discharging heat from the low temperature refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature refrigerant consisting essentially of HFO-1234yf in the above system,
(Ii) a compressor for compressing the medium temperature refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space in the medium temperature refrigeration unit containing the medium temperature refrigerant by evaporating the medium temperature refrigerant;
(Iv) a medium temperature refrigeration unit comprising: a medium temperature heat exchanger for discharging heat from the medium temperature refrigerant;
(C) A third common refrigeration circuit that includes a common refrigerant consisting essentially of transHFO-1233zd and that is discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F. Each of the low and medium temperature heat exchangers is arranged to receive a common evaporator, wherein the common refrigerant evaporates at a temperature below the low temperature refrigerant condensation temperature and the middle temperature refrigerant condensation temperature. And a common refrigeration circuit, which is a liquid-filled heat exchanger, in which the common evaporator evaporates the common refrigerant by absorbing heat from the low-temperature refrigerant or the medium-temperature refrigerant. ..

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature flammable refrigerant in the above system,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium-temperature flammable refrigerant,
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) A common refrigeration circuit that includes a common refrigerant consisting essentially of transHFO-1233zd and receives heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F. Each of said low temperature and said medium temperature heat exchangers is equipped with a common evaporator, wherein said common refrigerant evaporates at a temperature below said low temperature refrigerant condensation temperature and said medium temperature refrigerant condensation temperature, said And a common refrigeration circuit that is a liquid-filled heat exchanger in which the common refrigerant is evaporated by absorbing heat from the low-temperature refrigerant or the medium-temperature refrigerant.

Applicants have provided a flooded heat exchanger as described herein, for example between a first circuit and a second circuit, and/or a second circuit and a third circuit. It has been found to provide unexpected and greatly improved heat transfer performance with the circuit. Therefore, the preferred system described herein significantly and unexpectedly improves the efficiency of the overall refrigeration system.

The second circuit (preferably a medium temperature circuit) and the third circuit (common circuit) can be arranged substantially completely outside the first refrigeration unit (preferably a low temperature refrigeration unit) described above. As used herein, the term "substantially completely outside" refers to the first and second refrigeration circuits (or thirds, if present and appropriate in accordance with the disclosure herein). In order to provide heat exchange between the refrigerants of the circuit), transportation lines etc., which may be considered as part of the second refrigeration circuit (or the third circuit, if present), enter into the first refrigeration unit. Except for obtaining, it means that the components of the second refrigeration circuit (and/or the third circuit, if present) are not in the first refrigeration unit described above.

As used herein, the terms "first refrigeration unit" and "cryogenic refrigeration unit" refer to an at least partially closed or closable structure with cooling within at least a portion of that structure. And is structurally separate from any structure that generally surrounds or houses the common refrigeration circuit described above. In accordance with and consistent with such meaning, a preferred first refrigeration circuit of the present invention (including a preferred low temperature refrigeration unit) is housed within such a first refrigeration unit in accordance with the meaning set forth herein. When it is, it may be referred to herein as "incorporated."

As used herein, the terms "second refrigeration unit" and "medium temperature refrigeration unit" refer to an at least partially closed or closable structure that cools within at least a portion of that structure. And is structurally separate from any structure that generally surrounds or houses the common refrigeration circuit described above. In accordance with and consistent with such meaning, a preferred second refrigeration circuit of the present invention (preferably including a medium temperature refrigeration unit) is provided in such a first refrigeration unit in accordance with the meaning described herein. When contained, it may be referred to herein as "built-in."

Each first refrigeration circuit (preferably a low temperature refrigeration circuit) may be incorporated in its respective refrigeration unit.

Each first refrigeration circuit (preferably a medium temperature refrigeration circuit) may be incorporated in its respective refrigeration unit.

Each refrigeration unit may be arranged in the first area. The first area may be a shop floor. This means that each first refrigeration circuit and each second refrigeration unit may also be arranged in a first area, such as a shop floor. This may preferably eliminate the need to extend the first refrigeration circuit and the second refrigeration unit over long distances, thus significantly reducing the risk and potential severity of refrigerant leakage, and thus is preferred. It is meant to allow the use of flammable refrigerants that are also low GWP refrigerants.

Each refrigeration unit may comprise a space and/or object to be cooled, preferably that space and/or object is within the refrigeration unit.

Each first circuit and second circuit evaporator may be arranged to cool its respective space/object, preferably by cooling the air in the space to be cooled.

As mentioned above, the common refrigeration circuit may have its components extending between the first refrigeration unit and/or the second refrigeration unit and the second region. The second area may be, for example, a machine room accommodating a substantial portion of the components of the second refrigeration circuit.

The common refrigeration circuit may extend to the second and third regions.

The third area may be an area outside the building or buildings in which the first refrigeration unit and the second area are located. This allows ambient cooling to be utilized.

The third refrigeration circuit may extend between the second region and the third region. The third area may be outside a building or buildings comprising the first and second areas.

Any of the refrigerants in the first, second, or third refrigeration circuits may have a low Global Warming Potential (GWP).

Any of the refrigerants in the first, second, or third refrigeration circuit may have a GWP that is less than 150.

The common refrigerant is preferably non-flammable. This can be desirable because the common refrigeration circuit can be very long and can extend between different and distant areas within a building containing low and medium temperature refrigeration units. For example, a common refrigerant circuit may extend between the shop floor (where the medium and low temperature refrigeration units may be located) and the machine room. Therefore, both the risk of leakage and the potential severity of the leakage, in such cases, as the common refrigeration circuit covers a larger area and thus exposes more people and/or structures to the risk of fire. Having flammable refrigerant in the common refrigeration circuit may be relatively unsafe.

In a preferred embodiment, the common refrigerant can act as a flame suppressant, and the common refrigeration circuit includes the common refrigerant in a first refrigeration circuit (preferably a low temperature refrigeration unit) and/or a second refrigeration circuit (preferably a refrigeration circuit). Is placed in or near a cryogenic refrigeration unit) and arranged to act as a flame suppressant in the event of leakage of low or medium temperature refrigerants (since such refrigerants are preferably flammable). it can.

Each first and second refrigeration circuit may comprise at least one fluid expansion device. The at least one fluid expansion device may be a capillary tube or an orifice tube. This is enabled by the conditions imposed on each first and second refrigeration circuit, by virtue of its relatively constant refrigeration unit. This means that simpler flow control devices, such as capillary tubes and orifice tubes, can be, and preferably are, used to help in the first and second refrigeration circuits.

The average temperature of each of the first refrigeration circuits may be lower than the average temperature of the second refrigeration circuit and the third refrigeration circuit. The average temperature of the second refrigeration circuit may be lower than the average temperature of the third refrigeration circuit. This is because the third refrigeration circuit can cool the first and/or the second refrigeration circuit.

At least one circuit interface location may be coupled in series-parallel combination with at least one other circuit interface location. Beneficially, this is to ensure that when a defect or blockage is detected in one of the circuit interface location, the first refrigeration circuit, or the first refrigeration unit, the defect will not propagate through the system. It means that the occurring location, circuit or unit can be isolated and/or bypassed.

At least one circuit interface location may be coupled in parallel with at least one other circuit interface location.

Each circuit interface location may be coupled in parallel with each circuit interface location.

The second refrigeration circuit may comprise a plurality of cooling branches connected in parallel. Each cooling branch may include one or more circuit interface locations. The plurality of cooling branches may be connected in series with a pump and/or a further heat exchanger.

Each cooling branch may include multiple circuit interface locations.

The common refrigerant may include R1233zd(E) and/or R1234ze(Z).

The first refrigerant (preferably low temperature refrigerant) used in the first refrigerant circuit (preferably low temperature refrigeration circuit) is selected from R744, C3 to C4 hydrocarbons, R1234yf, R1234ze(E), R455A, and combinations thereof. Either may be included. The hydrocarbon may include any of R290, R600a or R1270. These refrigerants have low GWP. The first refrigerant may be one of R744, hydrocarbon, R1234yf, R1234ze(E), or R455A. The hydrocarbon may include any of R290, R600a, or R1270.

The second refrigerant (preferably medium temperature refrigeration circuit) used in the second refrigerant circuit (preferably medium temperature refrigeration circuit) is R744, C3-C4 hydrocarbon, R1234yf, R1234ze(E), R455A, and a combination thereof. Either may be included. The hydrocarbon may include any of R290, R600a or R1270. These refrigerants have low GWP.

The first refrigerant and the second refrigerant may be one of R744, hydrocarbon, R1234yf, R1234ze(E), or R455A. The hydrocarbon may include any of R290, R600a, or R1270.

The first and second refrigerants may include a mixed refrigerant. The mixed refrigerant may include a blend of A2L refrigerants. The A2L refrigerant may include a mixture of at least two of R1234ze(Z), R1234yf, and/or R455A.

The first and second refrigerants may be a mixture of HC refrigerants. The HC refrigerant may include R290 and R1270.

The third or common refrigeration circuit may comprise a heat exchanger branch with a further heat exchanger.

The common refrigeration circuit may include an ambient cooling branch. This means that the heat exchanger branch may be bypassed. The benefit of bypassing the heat exchanger branch may be that by doing so no heat is exchanged with the third refrigeration circuit. Instead, heat is exchanged with ambient air. This reduces its use because the load placed on the third refrigeration circuit is reduced.

The ambient cooling branch of the common circuit may be connected in parallel with the heat exchanger branch. The parallel configuration allows the heat exchanger branches to be bypassed by a common refrigerant and flow wholly or partially through the ambient cooling branch.

The ambient cooling branch is preferably exposed to ambient temperature outside. The ambient cooling branch may extend outside a building or buildings that include the first area and/or the second area.

The refrigerant entering the ambient cooling branch may be cooled by the ambient air temperature when the ambient air temperature is lower than the temperature of the refrigerant entering the ambient cooling branch.

A valve may be provided at one or both of the joints between the ambient cooling branch and the heat exchanger branch to control the flow of refrigerant in each of the ambient cooling branch and the heat exchanger branch. This makes it possible to control whether and how much to utilize the third heat exchanger branch and/or the ambient cooling branch.

The valve may be used to prevent the flow of refrigerant to and from the heat exchanger branch.

The pump and circuit interface locations may be located between one or more valves.

The ambient cooling branch and the heat exchanger branch may be connected in series with the pump.

The ambient cooling branch may be arranged to avoid operation of the third refrigeration circuit when the temperature of the ambient air is lower than the temperature of the refrigerant entering the ambient cooling branch.

Here, an exemplary configuration of the present disclosure will be described with reference to the drawings.
FIG. 6 shows an example of a refrigeration system previously used. FIG. 3 shows an example of a refrigeration system that is the basis for the comparative examples described herein. It is a figure which shows the four-circuit distributed refrigeration system which uses a full-fill type evaporator. It is a figure which shows the three-circuit distributed refrigeration system which uses a full-fill type evaporator. FIG. 6 shows an alternative three-circuit distributed refrigeration system that uses a flooded evaporator. FIG. 3 shows a distributed refrigeration system with and without an intake line heat exchanger. FIG. 3 shows a distributed refrigeration system with and without an intake line heat exchanger. 3 is a graph of global warming potential for refrigeration systems with R515A and R744 refrigerants. FIG. 6 is a graph of a coefficient of performance (COP) and a relative COP of a R1233zd three-circuit liquid-filled distributed refrigeration system without SLHX. FIG. 6 is a graph of a coefficient of performance (COP) and a relative COP of a R1233zd three-circuit liquid-filled distributed refrigeration system without SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd three-circuit, flooded distributed refrigeration system with SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd three-circuit, flooded distributed refrigeration system with SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd two-circuit liquid-filled distributed refrigeration system without SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd two-circuit liquid-filled distributed refrigeration system without SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd dual circuit full liquid distributed refrigeration system with SLHX. FIG. 6 is a graph of COP and relative COP of a R1233zd dual circuit full liquid distributed refrigeration system with SLHX. 3 is a graph of pressure levels and leak rates for several different refrigerants. 3 is a graph of pressure levels and leak rates for several different refrigerants. 7 is a graph of isentropic efficiency and pressure ratio for R290 and R124a refrigerants.

Like reference numerals refer to like parts throughout the specification.

Comparative Examples To assist one of ordinary skill in the art in understanding the refrigeration circuits of the present disclosure and their respective advantages, a brief description of the functioning of refrigeration systems is provided with respect to the comparative refrigeration system shown in FIGS. 1A and 1B. To do.

FIG. 1B shows an example of a refrigeration system 100 for comparison with the further systems described below. The system 100 includes a medium temperature refrigeration circuit 110 and a low temperature refrigeration circuit 120.

The low temperature refrigeration circuit 120 has a compressor 121, an interface having a heat exchanger 130 for discharging heat to ambient conditions, an expansion valve 122, and an evaporator 123. The low temperature refrigeration circuit 120 interacts with the medium temperature refrigeration circuit 110 through the inter-circuit heat exchanger 150, which removes heat from the low temperature refrigerant to the medium temperature refrigerant, thereby causing the excess refrigerant in the low temperature refrigerant cycle. It serves to generate a cooling refrigerant liquid. The evaporator 123 interacts with the space to be cooled, such as inside a freezer compartment. The components of the low temperature refrigeration circuit are connected in the order of the evaporator 123, the compressor 121, the heat exchanger 130, the inter-circuit heat exchanger 150, and the expansion valve 122. The components are connected via a pipe 124 filled with a low temperature refrigerant.

The medium temperature refrigeration circuit 110 includes a compressor 111, a condenser 113 for discharging heat to ambient conditions, and a fluid receiver 114. Liquid from the receiver 114 is manifolded to flow to each of the expansion valves 112 and 118, and thus two parallel connected branches, a subcooling cryogenic branch 117 downstream of the expansion device 118, and an expansion device. A medium temperature cooling branch 116 downstream of 112 is provided. The cold subcooling branch includes an inter-circuit heat exchanger that provides subcooling to the cold circuit as described above. The medium temperature cooling branch 116 includes a medium temperature evaporator 119 that interacts with the space to be cooled, such as the interior of a refrigeration compartment.

The medium temperature refrigerant is a high GWP refrigerant such as R134a. R134a is a hydrofluorocarbon (HFC). R134a is nonflammable and has a good coefficient of performance.

The system 100 comprises three areas of a building: a machine room in which a roof in which condensers 113 and 130 are located, compressors 111, 112, a heat exchanger 150, a receiving tank 114, and an expansion device 118 are located. , And the LT case, MT case, and sales floor 142 on which their respective expansion devices are located. Thus, the low temperature refrigeration circuit 120 and the medium temperature refrigeration circuit respectively extend between the sales floor, the machine room and the roof. During use, the medium temperature circuit 110 provides medium temperature cooling to the space cooled via the evaporator 119 and the low temperature circuit 120 provides low temperature cooling to the space cooled via the evaporator 123. The medium temperature circuit 110 also removes heat from the liquid condensate from the cold condenser 120, resulting in subcooling of the liquid entering the evaporator 123.

The individual and overall function of the various components of the cryogenic refrigeration circuit 120 will now be described. Starting with heat exchanger 150, heat exchanger 130 is a suitable device for transferring heat between a low temperature refrigerant and a medium temperature refrigerant. In one example, the heat exchanger 150 is a shell and tube heat exchanger. Other types of heat exchangers such as plate heat exchangers and other designs may also be used. During use, the medium temperature refrigerant absorbs heat from the low temperature refrigerant, thus cooling the low temperature refrigerant. The removal of heat via this heat exchanger 150 results in the supercooling of the liquid cryogenic refrigerant from the subcooling condenser 130, after which the low temperature refrigerant expands via the liquid line of the pipe 124. Flow to valve 122. The role of the expansion valve 122 is to reduce the pressure of the low temperature refrigerant. By doing so, since the pressure and the temperature are proportional, the temperature of the low-temperature refrigerant decreases accordingly. The low temperature, low pressure refrigerant then flows or is pumped to the evaporator 123. The evaporator 123 is used to transfer heat from the space to be cooled, for example a cryogenic freezer case in a supermarket, to a cryogenic refrigerant. That is, in the evaporator 123, the liquid refrigerant receives heat from the space to be cooled and, at that time, evaporates into gas. After the evaporator 123, the gas is drawn into the compressor 121 by the compressor 121 through the intake line of the pipe 124. When it reaches the compressor 121, the low-pressure low-temperature gas refrigerant is compressed. This raises the temperature of the refrigerant. Therefore, the refrigerant is converted from the low temperature and low pressure gas to the high temperature and high pressure gas. The hot high pressure gas is discharged into the exhaust pipe of pipe 124 and travels to a heat exchanger (condenser) 130, where the gas is condensed into a liquid in the manner described above. Although this illustrates the operation of the low temperature refrigeration circuit 120, the principles described herein can be generally applied to refrigeration cycles.

The individual and overall function of the various components of the medium temperature refrigeration circuit 110 will now be described. Starting with the heat exchanger 150, the medium temperature refrigerant absorbs heat from the low temperature refrigerant via the heat exchanger 150, as described above. This heat absorption causes the refrigerant in the medium temperature circuit 150, which is a cold gas and/or a mixture of gas and liquid, to enter the heat exchanger 150, transforming the liquid into a vapor phase and/or generating overheating. If it is, the temperature of the gas is raised. Upon exiting the heat exchanger 150, the gaseous refrigerant is drawn into the compressor 111 (along with the refrigerant from the evaporator 119) and is compressed by the compressor 111 into a high temperature, high pressure gas. This gas is discharged into the pipe 115 and in this example moves to the condenser 113 which is arranged on the roof of the building. In the condenser 113, the gaseous medium-temperature refrigerant radiates heat to the outside ambient air, so that it is cooled and condensed into a liquid. After the condenser 113, the liquid refrigerant collects in the fluid receiver 114. In this example, the fluid receiver 114 is a tank. Upon exiting the fluid receiver 114, the liquid refrigerant is manifolded to the medium temperature branch 116 and the subcooling branch 117 connected in parallel. In the medium temperature branch 116, the liquid refrigerant flows to the expansion valve 112 which is used to reduce the pressure and thus the temperature of the liquid refrigerant. The relatively cool liquid refrigerant then enters the heat exchanger 119 and absorbs heat from the cooling space, which is interacting with the evaporator 119f. In the subcooling branch 117, the liquid refrigerant first flows similarly to the expansion valve 118 where the pressure and temperature of the refrigerant is reduced. After valve 118, the refrigerant flows to inter-circuit heat exchanger 150, as described above. From there, the gaseous refrigerant from the heat exchanger is drawn into the compressor 111 by the compressor 111 and rejoins the refrigerant from the medium temperature cooling branch 116.

Although not mentioned above, in order to function as intended, the temperature of the refrigerant in the medium temperature circuit 110 as it enters the heat exchanger 150 is the temperature of the refrigerant in the low temperature circuit 120 as it enters the heat exchanger 150. It will be clear that it must be lower than. Otherwise, medium temperature circuit 110 will not provide the desired supercooling to the cold refrigerant in circuit 120.

The above describes the operation of a comparative example of refrigeration system 100, as illustrated in FIG. 1B. The refrigeration principles described with respect to FIG. 1B are equally well applicable to other refrigeration systems of the present disclosure.

Systems of the Invention Several refrigeration systems are described below. Each system has several refrigeration units, each refrigeration unit having at least one dedicated refrigeration circuit disposed therein. That is, each refrigeration unit includes at least one refrigeration circuit.

The refrigeration circuit included in the refrigeration unit may include at least a heat exchanger that removes heat to the refrigerant in the circuit and an evaporator that applies heat to the refrigerant.

A refrigeration circuit included in the refrigeration unit includes a compressor and at least a heat exchanger that removes heat from the refrigerant in the circuit (preferably by removing heat from the refrigerant vapor exiting the compressor), and preferably An evaporator that adds heat to the refrigerant (by cooling the cooling area of the refrigeration unit). Applicants have found that the size of the compressor used in the preferred first refrigeration circuit (and preferably the cryogenic refrigeration circuit) of the present invention is among the highly advantageous and unexpected results of the preferred embodiments of the present invention. Has been found to be important for achieving at least some of the above, and in particular that each compressor in the circuit is preferably a small compressor. As used herein, the term "small compressor" means that the compressor has a power rating of about 2 horsepower or less. As used herein with respect to compressor power rating, this value is determined by the input power rating of the compressor. When used with respect to compressor horsepower ratings, “about” means the indicated horsepower ±0.5 horsepower. The compressor size may be 0.1 horsepower to about 2 horsepower, or 0.1 horsepower to about 1 horsepower in a preferred embodiment. The compressor size may be 0.1 horsepower up to 0.75 horsepower, or 0.1 horsepower up to 0.5 horsepower.

The refrigeration unit may be an integrated physical entity, that is, an entity that is not designed to be disassembled into its components. The refrigeration unit may be, for example, a refrigerator or a freezer. It will be appreciated that more than one refrigeration circuit (especially including more than one low temperature refrigeration circuit) may be included within each refrigeration unit (preferably including each low temperature refrigeration unit).

The refrigeration circuit provided within each refrigeration unit may itself be cooled, at least in part, by a common refrigeration circuit external to the refrigeration unit. In contrast to a dedicated refrigeration circuit housed inside each refrigeration unit, the common refrigeration circuit (generally referred to herein as the second and third refrigeration circuits) has a sales floor (where the refrigeration units are located). Be installed) and a machine room and/or roof or outside area, such as between a plurality of areas of the building housing the unit.

Each refrigeration unit may include at least one compartment for storing merchandise, such as perishable merchandise. The compartment may define a space that is cooled by a refrigeration circuit housed inside the refrigeration unit.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also relates to a refrigeration system for providing cooling at low and medium temperature cooling levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) A medium temperature heat exchanger for discharging heat from the medium temperature flammable refrigerant, wherein at least the low temperature refrigerant or the medium temperature refrigerant is preferably HFO- A medium temperature heat exchanger, which is an A2L combustible refrigerant comprising 1234 fy, or comprising at least about 50% by weight thereof, or consisting essentially of, or consisting of, a medium temperature refrigeration unit;
(C) a common refrigeration circuit, comprising a non-flammable refrigerant comprising, consisting essentially of, or consisting of at least about 50% by weight transHFO-1233zd, and at a low temperature above about 40F to about 80F. And a common refrigeration circuit arranged to receive heat discharged from each of the intermediate temperature heat exchangers.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less in the above system, wherein the refrigerant is at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight. Of HFO-1234yf, transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf, and a low temperature flammable refrigerant as described above,
(Ii) A compressor having a horsepower rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant.
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a medium temperature flammable refrigerant comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf;
(Ii) a compressor having a horsepower rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature combustible refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a low temperature flammable refrigerant as described above, comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf.
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a medium temperature flammable refrigerant comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) A common refrigeration circuit, which includes a common non-combustible refrigerant consisting essentially of transHFO-1233zd and which provides heat exhausted from each of the low and medium temperature heat exchangers at temperatures of about 40F to about 80F. A common refrigeration circuit arranged to receive.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a third refractory circuit which is a common refrigeration circuit, preferably comprising transHFO-1233zd, or preferably comprising at least about 50% by weight thereof, or preferably consisting essentially of, or preferably consisting of. A refrigerant and arranged to receive heat discharged from each of the low and medium temperature heat exchangers at a temperature of about 40F to about 80F, wherein each of the low temperature and medium temperature heat exchangers includes: A common refrigerant that evaporates at a temperature lower than the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, the common evaporator absorbing heat from the low temperature refrigerant or the medium temperature refrigerant. By doing so, a common refrigeration circuit, which is a liquid-filled heat exchanger, in which the common refrigerant evaporates.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor having a power rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature flammable refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. And arranged to receive heat discharged from each of the low temperature and medium temperature heat exchangers at a temperature of about 40F to about 80F, each of the low temperature and medium temperature heat exchangers having the common Refrigerant evaporates at a temperature below the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, comprising a common evaporator, wherein the common evaporator absorbs heat from the low temperature refrigerant or the medium temperature refrigerant. And a common refrigeration circuit, which is a liquid-filled heat exchanger, in which the common refrigerant is evaporated.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a low temperature flammable refrigerant as described above, comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf.
(Ii) A compressor having a horsepower rating of about 2 horsepower or less for compressing the low temperature combustible refrigerant.
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a medium temperature flammable refrigerant comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf;
(Ii) a compressor having a horsepower rating of about 2 horsepower or less for compressing the above-mentioned medium-temperature combustible refrigerant;
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, preferably comprising transHFO-1233zd, preferably comprising at least about 50% by weight thereof, or preferably consisting essentially of, or preferably consisting of, a common non-combustible refrigerant. And arranged to receive heat discharged from each of the low temperature and medium temperature heat exchangers at a temperature of about 40F to about 80F, and each of the low temperature and medium temperature heat exchangers includes a common refrigerant as described above. Evaporates at a temperature below the low temperature refrigerant condensation temperature and the medium temperature refrigerant condensation temperature, comprising a common evaporator, the common evaporator, by absorbing heat from the low temperature refrigerant or the medium temperature refrigerant. And a common refrigeration circuit, which is a liquid-filled heat exchanger in which the common refrigerant is evaporated.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a low temperature flammable refrigerant as described above, comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf.
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less, at least about 50% by weight, or at least about 75% by weight, or at least 95% by weight, or at least 99% by weight HFO-1234yf, a medium temperature flammable refrigerant comprising transHFO-1234ze, or a combination thereof, preferably consisting essentially of HFO-1234yf;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) a common refrigeration circuit, which preferably comprises transHFO-1233zd, or preferably comprises at least about 50% by weight thereof, or preferably consists essentially of, or preferably consists of, a common non-combustible refrigerant. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 80F.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) a medium-temperature refrigeration unit comprising: a medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant;
(C) A common refrigeration circuit, which includes a common non-combustible refrigerant consisting essentially of transHFO-1233zd, and which collects the heat discharged from each of the low and medium temperature heat exchangers at temperatures of about 40F to about 60F. Each of said low temperature and said medium temperature heat exchangers arranged to receive, comprises a common evaporator, wherein said common refrigerant vaporizes at a temperature below said low temperature refrigerant condensation temperature and said medium temperature refrigerant condensation temperature. The common evaporator includes a common refrigeration circuit, which is a liquid-filled heat exchanger in which the common refrigerant is evaporated by absorbing heat from the low-temperature refrigerant or the medium-temperature refrigerant.

In a preferred embodiment, the flammable low temperature refrigerant and/or the flammable medium temperature refrigerant comprises at least 75% by weight, or at least about 95% by weight of a combination of R1234yf, difluoromethane (R-32), and CO2, or Then consists essentially of, or consists of. In a preferred embodiment, the flammable low temperature refrigerant and/or the flammable medium temperature refrigerant comprises at least 75 wt% R1234yf, difluoromethane (R-32), and CO2, the combination being R1234yf, R-32, And about 25.5% by weight of R-1234yf, about 21.5% by weight of R32, and about 3% by weight of CO2, based on the total amount of CO2, and such a combination is for convenience herein. Sometimes referred to as R455A. As used herein with respect to the weight percentages of the refrigerant components, the term "about" refers to the indicated amount of plus or minus 1%.

The invention also includes a refrigeration system for providing refrigeration at low and medium temperature refrigeration levels, the above system comprising:
(A) A low temperature refrigeration unit comprising at least one low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature combustible refrigerant having a GWP of about 150 or less,
(Ii) a compressor for compressing the low temperature combustible refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature combustible refrigerant.
(Iv) a low temperature refrigeration unit comprising a low temperature heat exchanger for discharging heat from the low temperature combustible refrigerant,
(B) A medium temperature refrigeration unit including at least one medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature combustible refrigerant having a GWP of about 150 or less;
(Ii) a compressor for compressing the above-mentioned medium-temperature combustible refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space inside the medium temperature refrigeration unit by evaporating the medium temperature combustible refrigerant.
(Iv) A medium-temperature heat exchanger for discharging heat from the medium-temperature combustible refrigerant, wherein one or both of the low-temperature combustible refrigerant and the medium-temperature combustible refrigerant is A2L combustible, and R1234yf An intermediate temperature refrigeration unit comprising: an intermediate temperature heat exchanger, and
(C) a common refrigeration circuit comprising a non-combustible refrigerant comprising transR1233zd, or preferably comprising at least 50% by weight, or preferably comprising at least 75% by weight thereof, or consisting essentially of or consisting thereof. A common refrigeration circuit, including and arranged to receive heat discharged from each of the low and medium temperature heat exchangers above at a temperature of about 40F to about 60F.

Four Circuit Filled Distributed Refrigeration System Now, a preferred distributed refrigeration system with four circuits according to the present invention will be described with reference to FIG.

FIG. 3 shows low temperature refrigeration circuits 510a and 510b (for convenience, the four shown circuits are collectively referred to as one), and medium temperature refrigeration circuits 510c and 510d (for the purpose, four shown circuits are collectively referred to as one). ), and a distributed refrigeration system 500 having four circuits including a liquid-filled common refrigeration circuit 530 and a fourth refrigeration circuit 550. The common refrigeration circuit is arranged to cool, ie remove heat from, the low and medium temperature refrigeration circuits 510a-510d. The fourth refrigeration circuit 550 is arranged to cool, ie remove heat from, the common refrigeration circuit 530. Each of the refrigeration circuits 510 is internal and provides dedicated refrigeration to their respective refrigeration unit (not shown).

More specifically, FIG. 3 has refrigeration circuits 510a, 510b, 510c, 510d, each refrigeration circuit having an evaporator 511, a compressor 512, a heat exchanger 513, an expansion valve 514, 3 illustrates a refrigeration system 500 having a. In circuits 510a, 510b, 510c, 510d, evaporators 511a, 511b, 511c, and 511d, compressors 512a, 512b, 512c, and 512d, heat exchangers 513a, 513b, 513c, and 513d, and expansion valves 514a, 514b. , 514c, and 514d are each connected in series with one another in the order listed. Each of the circuits 510a, 510b, 510c, 510d is provided and preferably contained within a respective refrigeration unit (not shown).

In this embodiment, circuits 510a and 510b are housed in a freezer-that is, a cold unit-and circuits 510c and 510b are housed in a refrigerator-that is, a medium-temperature unit. Refrigerators and freezers are examples of refrigeration units. In this way, a dedicated built-in refrigeration circuit is provided to each refrigeration unit. The refrigeration unit (not shown), and thus the refrigeration circuits 510a, 510b, 510c, 510b, are located on or near the sales floor 501 of the supermarket.

The refrigerant in the refrigeration circuits 510a, 510b, 510c, 510d is a low GWP refrigerant such as R744, hydrocarbon (R290, R600a, R1270), R1234yf, R1234ze(E), or R455A. As one of ordinary skill in the art will recognize, the refrigerant in each refrigeration circuit 510 may be the same as or different from the refrigerant in the other first refrigeration circuits 510.

The refrigeration system 500 also has a common refrigeration circuit 530. The common refrigeration circuit 530 has two branches connected in parallel: a heat exchanger branch and an ambient cooling branch. The heat exchanger branch has a heat exchanger 531 and a fluid receiver 532. The heat exchanger 531 and the fluid receiver are connected in series in the order listed. The ambient cooling branch has a chiller 533. The heat exchanger branch and the ambient cooling branch are connected in parallel by a first controllable valve 534 and a second controllable valve 535. The controllable valves 534, 535 are controllable so that the amount of refrigerant flowing through each of the heat exchanger branch and the ambient cooling branch can be controlled. Both the heat exchanger branch and the ambient cooling branch are connected in series with pump 536. The pump 536 is connected in series with the first control valve 534 and immediately downstream thereof.

The refrigeration circuit 530 connects to the refrigeration circuits 510a-510d using two further branches connected in parallel with each other, a first cooling branch 538 and a second cooling branch 537. The first cooling branch 538 and the second cooling branch 537 are connected between the pump 536 and the second controllable valve 535.

The cooling branch 537 interacts with two of the heat exchangers 513a, 513b of the refrigeration circuit 510a, 510b. The second cooling branch 538 interacts with the other two heat exchangers 513c, 513d of the refrigeration circuits 510c, 510d.

In this example, the first cooling branch 538 is a cold branch and therefore interacts with the cold first refrigeration circuit-the freezer circuit-while the second cooling branch 537 is a medium temperature branch. And thus interacts with the medium temperature refrigeration circuit-the refrigerator circuit. References to medium and low temperature cooling relate to the temperature at which energy is transferred to each system, as described above.

The first cooling branch 538 interacts with each of the heat exchangers 513a, 513b of its respective refrigeration circuit 510a, 510b at a respective circuit interface location 539a, 539b. Each of the circuit interface locations 539a, 539b on the first cooling branch 538 is associated with another circuit interface location 539a, 539b on the cooling branch 538.

The second cooling branch 537 interacts with each of the heat exchangers 513c, 513d of its respective refrigeration circuit 510c, 510d at a respective circuit interface location 539c, 539d. Each of the circuit interface locations 539c, 539d on the second cooling branch 537 is combined with another circuit interface location 539c, 539d on the second cooling branch 537.

Refrigeration system 500 according to any aspect of the invention also has an optional air conditioning loop 560. Usefully, providing such a preferred embodiment loop 560 allows for the addition of an air conditioning circuit 561 to the system 500. Beneficially, this utilizes the existing cooling infrastructure within system 500, resulting in a more efficient and much simplified air conditioning circuit 561. This is primarily because the working fluid in system 500—the refrigerant—is utilized instead, so that no additional working fluid in air conditioning circuit 561 is required.

An optional air conditioning loop 560 is connected with the second refrigeration circuit 530. More specifically, the air conditioning loop 560 is coupled to the second cooling branch 537 and is connected to the second branch 537 downstream of the circuit interface locations 539c, 539d. The air conditioning loop 560 has a circuit interface location 562 with the air conditioning circuit 561. More specifically, at circuit interface location 562, second cooling branch 537 interacts with air conditioning heat exchanger 563. The air conditioning circuit 561 additionally includes a blower 564. In use, the second cooling branch 537 removes heat from the air conditioning circuit 561 via the heat exchanger 563 in much the same manner as it removes heat from its respective first refrigeration circuit 510c, 5510d. To do. This results in an increase in the temperature of the refrigerant in the second cooling branch 537 and a decrease in the temperature of the air in the vicinity of the air conditioning heat exchanger 563. The blower 564 is used to circulate the cool air adjacent to the air conditioning heat exchanger 563 to the required location. In this example, the circuit interface location 562 with the air conditioning equipment 561 is connected to the circuit interface locations 539c, 539d of the first cooling branch 538 and the second cooling branch 537, which are included herein. Many other configurations are possible, such as simple parallel circuits and simple series connections, as one of ordinary skill in the art will appreciate based on the teachings and disclosure. As will also be appreciated by those skilled in the art, the air conditioning loop 560 and unit 561 may be equally well removed from the system 500.

Common refrigeration circuit 530 includes portions where the circuit extends between sales floor 501, machine room 502, and roof 503. The first cooling branch 538 and the second cooling branch 537 are mainly arranged on the sales floor 501. Located primarily on sales floor 501 means that circuit interface locations 539, 562 are located on or near sales floor 501. However, the junction between the first cooling branch 538 and the second cooling branch 537 and some of the first (low temperature refrigeration) circuit 538 is located in the machine room 501. A heat exchanger branch is also located in the machine room 501 with a pump 536 and a first controllable valve 534 and a second controllable valve 535. The ambient cooling branch includes the portion where the branch extends between the machine room 501 and the roof 503. The chiller 533 is arranged on the roof.

In this example, the refrigerant in the common refrigeration circuit comprises at least 75 wt% R1233zd(E). Such a refrigerant is a non-flammable low GWP refrigerant, ie, a refrigerant having a GWP of 500 or less, more preferably about 150 or less.

Referring again to FIG. 2, refrigeration system 500 also includes a refrigeration circuit 550 that cools the common refrigerant of circuit 530. The refrigeration circuit 550 has a compressor 551, a chiller 552, an expansion valve 553, and an interface with the heat exchanger 531 of the common refrigeration circuit 530. The interfaces of the compressor 551, the chiller 552, the expansion valve 553, and the common refrigeration circuit 530 with the heat exchanger 531 are connected in series in the listed order.

Refrigeration circuit 550 includes a portion where the circuit extends between machine room 502 and roof 503. The interface of the refrigeration circuit 530 with the heat exchanger 531, the compressor 551, and the expansion valve 553 are inside the machine room 502. The chiller 552 is on the roof.

In this example, the refrigerant in refrigeration circuit 550 can be an individual A2L or HC refrigerant or a mixture of A2L or HC refrigerants. Examples of the A2L refrigerant include R1234ze, R1234yf, and R455A. Examples of the HC refrigerant include R290 and R1270.

Refrigeration system 500 is preferably a system that includes a receiver in and/or on refrigeration circuit 530. Therefore, the heat exchanger 513 is filled with liquid.

During operation, the refrigeration circuit 550 extracts heat from the common refrigeration circuit 530 and the common circuit 530 extracts heat from at least the low temperature and medium temperature circuits. The advantage of this approach is that although the circuit 550 is preferably located away from areas where the public has unlimited access, such as machine rooms and roofs, the refrigerant in that circuit is flammable, That is, it can be a low GWP refrigerant. Thus, the present system allows the common refrigeration circuit to have a higher GWP (preferably up to about 500) and non-flammability because the common refrigeration circuit is the only circuit that partially extends between the sales floor 501 and the machine room 502. Being able to operate with a refrigerant can be unexpectedly effective.

The potential advantages described for filled and non-filled cascade refrigeration systems are equally sufficient for systems of the type described in this section, where the heat exchanger is full or not full. That is the case.

For convenience purposes, terms such as "full system", "full cascade system", etc., refer to the first refrigeration circuit (preferably low temperature circuit) and the first refrigeration circuit for condensing the low and medium temperature refrigerants described above. Refers to the system of the present disclosure, wherein at least one, and preferably all, heat exchangers in the two refrigeration circuits (preferably medium temperature circuits) are flooded evaporators for a common refrigerant.

A further potential advantage of the flooded distributed refrigeration system herein is that the system may further reduce the refrigerant GWP required. This occurs in part for embodiments that include a fourth, third refrigeration, such as 550, that replaces part of the common refrigeration circuit described herein. This may have the effect of shortening the common refrigeration circuit and thus reducing the volume of non-combustible but higher GWP refrigerant required in the common circuit. Instead, a fourth refrigeration circuit that replaces some of the common refrigeration circuits uses a low GWP but flammable refrigerant. Therefore, the system can be operated with a further reduced GWP.

Yet another potential advantage of the four-circuit flooded distributed refrigeration system is that it may have an air conditioning loop and a complementary air conditioning circuit. The advantage is that, as discussed in the above description, a more efficient and simplified air conditioning circuit utilizing existing systems may be provided.

4-Circuit Full Dispersion Refrigeration System-Alternative In case of flammable refrigerant leak in either or both of the low and medium temperature circuits (510 in this example) or the fourth refrigeration circuit (550 in this example) A modification of the system 500 is envisioned in which the refrigerant in the common refrigeration circuit 530 (preferably R1233zd(E)) is arranged to be released as a flame/fire suppressant. In one configuration, an extra outlet port is added to the first controllable value 536 and/or the second controllable value 536, thus allowing the refrigerant in the refrigeration circuit 530 to be controlled from the common refrigeration circuit 530. Can be released. In another configuration, an outlet port is provided immediately downstream of pump 536 so that the pump can actively pump refrigerant from refrigeration circuit 530 to act as a flame/fire suppressant.

The air conditioning loop 560 and circuit 561 may be eliminated altogether, or may be connected or placed somewhere on the refrigeration circuit 530, or indeed on one of the refrigeration circuits 510, or on the fourth refrigeration circuit 550. Further modifications of system 500 are envisioned.

Due to its preferred modular design for low and medium temperature refrigeration circuits, the refrigeration system allows the use of flammable low pressure refrigerants with low GWP in low and medium temperature refrigeration circuits. Further, due to its ambient cooling branch, the system provides reduced energy usage. Still further, due to its preferred receiver in the common circuit and the flooded design of the evaporator in the low and medium temperature refrigeration circuits, the system provides an unexpected improvement in system efficiency. Also, with its optional but preferred additional air conditioning loop, the system additionally enables a simplified complementary air conditioning circuit.

Three-Circuit Full Dispersion-Type Refrigeration System Another refrigeration system that forms part of the present disclosure will now be described with reference to FIG.

FIG. 3 illustrates two medium temperature refrigeration circuits 610a and 610b (for convenience, the three circuits shown are collectively referred to as one) and two low temperature refrigeration circuits 630a and 630b (for convenience, the three circuits are combined into one). ), and a common refrigeration circuit 650.

The common refrigeration circuit 650 is arranged to cool, ie remove heat from, both the medium temperature refrigeration circuit 610 and the low temperature refrigeration circuit 630. Each of the medium temperature refrigeration circuits 610a, 610b and the low temperature refrigeration circuits 630a, 630b is built in and provides dedicated cooling to its respective refrigeration unit (not shown).

More specifically, each of the two medium temperature refrigeration circuits 610a and 610b has evaporators 611a and 611b, compressors 612a and 612b, heat exchangers 613a and 613b, and expansion valves 614a and 614b. In each medium temperature refrigeration circuit 610a, 610b, the evaporator (611a and 611b), the compressor (612a and 612b), the heat exchanger (613a and 613b), and the expansion valve (614a and 614b) are listed in the order listed, respectively. Are connected in series with each other. Each of the medium temperature refrigeration circuits 610a and 610b is provided in a respective refrigeration unit (not shown). In this embodiment, the medium temperature refrigeration circuits 610a, 610b are housed in a refrigerator-that is, a medium temperature unit. A refrigerator is an example of a freezing unit. In this way, the built-in dedicated medium temperature refrigeration circuit 610 is provided to each refrigeration unit. The refrigeration unit (not shown), and by extension, the medium temperature refrigeration circuits 610a and 610b are arranged on or near the sales floor 601 of the supermarket.

The refrigerant in the medium temperature refrigeration circuit 610a, 610b is a flammable low GWP refrigerant such as R744, hydrocarbon (R290, R600a, R1270), R1234yf, R1234ze(E), or R455A. As one of ordinary skill in the art will recognize, the refrigerant in each of the medium temperature refrigeration circuits 610a, 610b may be the same as or different from the refrigerant in the other medium temperature refrigeration circuits 610a, 610b.

Like the middle-temperature refrigeration circuits 610a and 610b, the two low-temperature refrigeration circuits 630a and 630b each have evaporators 631a and 631b, compressors 632a and 632b, heat exchangers 633a and 633b, and expansion valves 634a and 634b. With. In each low temperature refrigeration circuit 630a, 630b, the evaporator (631a and 631b), the compressor (632a and 632b), the heat exchanger (633a and 633b), and the expansion valve (634a and 634b) are listed in the order listed, respectively. Are connected in series with each other. Each of the medium temperature refrigeration circuits 630a and 630b is provided in a respective refrigeration unit (not shown). In this embodiment, the low temperature refrigeration circuits 630a, 630b are housed in a freezer-that is, a medium temperature unit. A freezer is an example of a freezing unit. In this way, the built-in dedicated low temperature refrigeration circuit 630 is provided to each refrigeration unit. The refrigeration unit (not shown), and by extension, the low temperature refrigeration circuits 630a and 630b, are arranged on the sales floor 601 of the supermarket.

Like the medium temperature refrigeration circuit 610a, 610b, the refrigerant in the low temperature refrigeration circuit 630a, 630b is a flammable low GWP refrigerant such as R744, hydrocarbon (R290, R600a, R1270), R1234yf, R1234ze(E), or R455A. Is. As one of ordinary skill in the art will recognize, the refrigerant in each of the low temperature refrigeration circuits 6130a, 630b may be the same as or different from the refrigerant in the other low temperature refrigeration circuits 630a, 630b.

The refrigeration system 600 also has a common refrigeration circuit 650. The common refrigeration circuit 650 has a compressor branch 660 and an ambient cooling branch 670. The compressor branch 660 is connected in parallel with the ambient cooling branch 670.

The compressor branch 660 includes a compressor 661, a chiller 662, an expansion valve 663, and a receiver 664. The compressor 661, the condenser 662, and the expansion valve 663 are connected in series in a given order. The receiver 664 is connected between the compressor 661 inlet and the expansion valve 663 outlet. The ambient cooling branch 670 has a chiller 671.

The compressor branch 660 and the ambient cooling branch 670 are connected in parallel by a first controllable valve 665 and a second controllable valve 666. The controllable valves 665, 666 are controllable so that the amount of refrigerant flowing through each of the compressor branch 660 and the ambient cooling branch 670 can be controlled. The first control valve 665 is connected in series with the pump 667.

The common refrigeration circuit 650 also has two further branches connected in parallel with each other: a medium temperature cooling branch 680 and a low temperature cooling branch 685. The medium temperature cooling branch 680 and the low temperature cooling branch 685 are connected between the pump 667 and the second controllable valve 666.

In this example, the low temperature cooling branch 685 interacts with the low temperature refrigeration circuit 630-the freezer circuit- while the middle temperature cooling branch 680 interacts with the middle temperature refrigeration circuit 610-the refrigerator circuit. References to medium and low temperature cooling relate to the relative temperatures at which heat is dissipated to the area being cooled by the refrigeration circuit according to the description of such systems above.

The medium temperature cooling branch 680 interacts with each of the heat exchangers 613a, 613b of the medium temperature refrigeration circuits 610a, 610b at their respective circuit interface locations 681a, 681b. Each of the circuit interface locations 681a, 681b is a serial-parallel combination with another circuit interface location 681a, 681b.

Cryogenic cooling branch 685 interacts with heat exchangers 633a, 633b of cryogenic refrigeration circuits 630a, 630b, respectively, at respective circuit interface locations 686a, 686b. Each circuit interface location 686a, 686b is in combination with another circuit interface location 686a, 686b.

Refrigeration system 600 also has an air conditioning loop 690 in the preferred embodiment. Beneficially, the provision of loop 690 allows an air conditioning circuit 691 to be added on system 600. Beneficially, this takes advantage of the existing cooling infrastructure in system 600, thus resulting in a more efficient and much simplified air conditioning circuit 691. This is primarily because the working fluid-i.e., refrigerant-in system 600 is utilized instead, so that no additional working fluid is needed in air conditioning circuit 691.

An optional air conditioning loop 690 is associated with the second refrigeration circuit 650. More specifically, air conditioning loop 690 may be coupled to the system at one or more of several locations. In one embodiment, an optional air conditioning loop 690 is coupled to the cold cooling branch 685 and connected to the cold refrigeration circuit 630a, 630b downstream of the circuit interface location 633a, 633b of the cold cooling branch 685. The air conditioning loop 690 has a circuit interface location 692 with the air conditioning circuit 691. More specifically, at circuit interface location 692, cryocooling branch 685 interacts with air conditioning heat exchanger 693. The air conditioning circuit 691 additionally includes a blower 694. During use, the cryogenic cooling branch 685 removes heat from the air conditioning circuit 691 via the heat exchanger 693 in much the same way as it removes heat from its respective cryogenic refrigeration circuit 630a, 630b. This results in an increase in the temperature of the refrigerant in the low temperature cooling branch 685 and a decrease in the temperature of the air adjacent to the air conditioning heat exchanger 693. The blower 694 is used to circulate the cool air adjacent to the air conditioning heat exchanger 693 to the required location. In this example, the circuit interface location 692 with the air conditioning equipment 694 is connected in series parallel with the circuit interface locations 633a, 633b of the second cooling branch 537 with the low temperature cooling branch 685, but are included herein. Many other arrangements are possible, such as simple parallel circuits and simple series connections, as those skilled in the art will appreciate based on the disclosure and teachings provided. As will also be appreciated by those of skill in the art based on the disclosure and teachings contained herein, the air conditioning loop 690 and unit 691 can be equally well removed from the system 600.

Common refrigeration circuit 650 includes portions where the circuit extends between sales floor 601, machine room 602, and roof 603. The low temperature cooling branch 680 and the medium temperature cooling branch 685 are mainly arranged on or near the sales floor 601. Located primarily on or near sales floor 601 means that circuit locations 681a, 681b, 686a, 686b are located on or near sales floor 601. However, some joints between the low temperature cooling branch 680 and the middle temperature cooling branch 686, as well as the pipes of the low temperature branch 680 and the middle temperature branch 686 are located far from the sales floor, for example in the machine room 602.

Compressor branch 660 includes a portion where the branch extends between machine room 602 and roof 603. More specifically, compressor 661, expansion valve 663, and receiver 664 are located within machine room 602. The condenser 662 is located away from areas where the public has unlimited access, such as on the roof 603, and areas that provide immediate access to ambient conditions.

The perimeter cooling branch 670 includes a portion where the branch extends between the machine room 602 and the roof 603. The chiller 671 is arranged on the roof 603.

The first controllable valve 665 and the second controllable valve 666 are located within the machine room 602. The pump 667 is arranged in the machine room 602.

In this example, the refrigerant in the common refrigeration circuit 650 is R1233zd(E). This is a non-flammable refrigerant.

Although structurally different, during use, refrigeration system 600 operates in a manner similar to refrigeration system 500.

The potential advantages described for the four-circuit distributed system for both the full and non-full cases above are the two-circuit, three-circuit full and non-full distributed defrosting described in this section. It is equally well applicable to the system.

The terms used to describe full and non-full cascade cascade refrigeration systems and four-circuit full-distributed distributed refrigeration systems are commonly used to describe three-circuit full-distributed distributed systems. Equivalent to the term

Yet another potential advantage of the three-circuit flooded distributed refrigeration system is that it may have an air conditioning loop and a complementary air conditioning circuit. This advantage is discussed in the description of the loop and includes providing a more efficient and simplified air conditioning circuit that utilizes existing systems.

Overall, providing multiple low and medium temperature refrigeration circuits, one each in each refrigeration unit, reduces the leak rate, simplifies the entire refrigeration system, or is otherwise dangerous. It has the advantages of enabling the use of low GWP refrigerants, improving maintenance and installation, and reducing pressure drop, leading to improved system efficiency.

3 Circuits Filled Distributed Refrigeration Systems-Alternatives The alternatives described above for filled and non-filled distributed refrigeration systems, including 4-circuit filled distributed refrigeration systems, are described herein. Can be equally well applied to the three-circuit flooded distributed refrigeration system described.

In the event of a flammable refrigerant leak in one or more of the medium temperature refrigeration circuit 610 or the low temperature refrigeration circuit 630, the refrigerant in the common refrigeration circuit 650 (R1233zd(E) in the given example) is a flammability suppressant. Further modifications of system 600 are contemplated, which are arranged to be released as In one configuration, an extra outlet port is added to the first initial controllable value 665 and/or the second controllable value 666, thus controlling the refrigerant of the common refrigeration circuit 650 from the common refrigeration circuit 650. It can be released. In another configuration, an outlet port is provided immediately downstream of the pump 667 so that the pump can actively pump the refrigerant from the common refrigeration circuit 650 to act as a flame or fire suppressant.

The air conditioning loop 690 and circuit 691 may be eliminated altogether, or may be connected or placed somewhere on one or more of the common refrigeration circuit 630, or indeed the low temperature refrigeration circuit 630 and the medium temperature refrigeration circuit 610, Further modifications of system 600 are envisioned.

Still other modifications of system 600 are envisioned, where the ambient cooling branch can be short and simplified so that ambient cooling branch 670 bypasses only compressor 611 rather than the entire compressor branch. This configuration is shown in FIG. 3A.

FIG. 3A shows a refrigeration system 600 that is largely the same as the description for FIG. 3, except for the following.
There is no chiller 671 in FIG. 3 as it is no longer needed. This is because the ambient cooling branch 670 no longer bypasses the chiller 662 and therefore does not require a chiller dedicated to the ambient cooling branch.
There is no first controllable valve 665 as it is no longer needed. This is because the refrigerant from the ambient cooling branch 670 is simply delivered to the chiller 662 line rather than contacting the branch junction.
An ambient cooling branch 670 is connected in parallel with the compressor 661 between the second controllable valve 666 and the line between the compressor 661 and the chiller 662.

Advantageously, the shortened ambient cooling branch 670 simplifies the circuit by eliminating the need for the first, chiller 671 and first controllable valve 665, and secondly for the ambient cooling branch 670. Resulting in a lower cost circuit by reducing the amount of extra tubing and the number of components, thus reducing material costs.

In summary, due to its modular low and medium temperature refrigeration circuit design, the refrigeration system allows the use of flammable low pressure refrigerants with low GWP in low and medium temperature refrigeration circuits. Further, due to its ambient cooling branch, the system provides reduced energy usage. Still further, due to its flooded design, the system offers improved system efficiency. Thus, a refrigeration system with reduced environmental impact is provided through reduced GWP refrigerant use, reduced energy use, and improved system efficiency.

Intake Line Heat Exchanger An example of further possible modifications of any of the systems forming part of this disclosure is that any number of built-in refrigeration circuits may be equipped with an intake line heat exchanger. , SLHX).

More specifically, any of the refrigeration circuits 510a, 510b, 510c, 510d may include SLHX and any of the refrigeration circuits 630a, 630b and/or 610a, 610b temperature refrigeration circuits may be SLHX. May be included.

For comparison, FIG. 4A shows a refrigeration circuit 700 without SLHX, while FIG. 4B shows a refrigeration circuit 750 with SLHX 760.

The circuit 700 of FIG. 4A includes a compressor 710, a heat exchanger 720, an expansion valve 730, and an evaporator 740. The compressor 710, heat exchanger 720, expansion valve 730, and evaporator 740 are connected in series in the order listed. During use, refrigeration circuit 700 functions as previously described.

Circuit 750 of FIG. 4B has the same components as circuit 700, but with the addition of additional SLHX 760. SLHX provides a heat exchange interface between the line connecting the evaporator 740 and the compressor 710 and the line connecting the heat exchanger 720 and the expansion valve 730. In other words, the SLHX 760 includes a line connecting the evaporator 740 and the compressor 710 (referred to as a vapor line herein) and a line connecting the heat exchanger 720 and the expansion valve 730 (the book). (Referred to as liquid line in the specification).

In use, SLHX transfers heat from the liquid line after heat exchanger 720 to the vapor line after evaporator 740. This has two effects: firstly, the efficiency of the circuit 700 is improved, and secondly, the efficiency of the circuit 700 is reduced.

First, advantageously, on the liquid line side-ie on the high pressure side-the supercooling of the liquid refrigerant is increased. This is because the excess heat is dissipated to the liquid expansion side, which reduces the temperature of the refrigerant entering the expansion valve 730. This additional subcooling leads to a lower inlet quality in the evaporator 740 after the expansion valve 730. This increases the difference in enthalpy, which improves the ability of the refrigerant to absorb heat in the stages of the evaporator 740. Therefore, the performance of the evaporator 740 is improved.

Second, disadvantageously, on the vapor line side—the low pressure side—the refrigerant exiting the evaporator 740 receives excess heat from the liquid line, which effectively increases superheat. This results in a higher intake line temperature. The higher intake line temperature to compressor 710 results in an increased enthalpy difference in the compression process. This increases the compressor power required to compress the refrigerant. Therefore, this has a detrimental effect on system performance.

In summary, both the first and second effects of improved evaporator capacity, as well as the improved compressor power requirements, to determine if introducing SLHX would have an overall beneficial effect. It is necessary to consider. For certain refrigerants such as R717, the use of SLHX leads to an overall reduction in system efficiency. However, in contrast, the use of SLHX leads to an overall positive impact on the system of the invention.

Supporting Data Presented herein is data intended to show the technical effect of various configurations of the present disclosure and to assist one of ordinary skill in the art in practicing the various configurations.

Table 1 shows the overall GWP when the ratio of the R515A refrigerant and the R744 refrigerant in the refrigeration system is changed, and 1 is the maximum combination value, that is, 100%. According to the Fifth Intergovernmental Panel on Climate Change, R515A has a GWP of 403 and R755 has a GWP of 1. Therefore, the overall GWP of R515A with a ratio of 0 and R744 with a ratio of 1 is 1 [(1×1)=1]. Conversely, the overall GWP of R515A with a ratio of 0.05 and R755 with a ratio of 0.95 is 21.1 [(0.05×403)+(0.95×1)=21.1]. is there. Thus, Table 1 shows charge ratio limitations that take into account the GWP criteria.

FIG. 5 shows the data in Table 1 in graph form. The ratio of R515A is shown on the x-axis and the overall GWP is shown on the y-axis. From this graph, it is clear that there is a direct proportional relationship between the relative ratio of R515A and R744 and the GWP, with increasing ratio of R515A increasing the GWP of the system. This is because R515A has a much higher GWP than R744. The directly proportional relationship is shown by a straight line on the graph going from a GWP of 1 at R515A with a ratio of 0 to about 400 GWP at R515A with a ratio of 1. From this graph, it is clear that in the preferred embodiment, 150 maximum allowed system GWPs are found in R515A with a weight ratio of about 0.35.

Table 2 relates to R1233zd(E) refrigerant, a mixture of 50 wt% R1233zd(E) and 50 wt% R1234ze, and a mixture of 33 wt% R1233zd(E) and 67 wt% R1234ze. The boiling pressure temperature when the boiling temperature is changed is shown.

The test refrigeration system operates with indoor refrigerant. R1233zd(E), transHCFO-1233zd, and R1234ze are transHFO-1234ze.

The results in Table 2 show that a composition in which the amount of transHFO-1234ze is at least 50% by weight enables the indoor circuit to operate under pressure above 1 atmosphere. Such a low pressure system avoids the need for a purging system-which aids the complexity of the system-while at the same time being low enough to allow the use of relatively low cost vessels and conduits. Advantageously, it provides system pressure. Still further, the low pressure avoids refrigerant leaks that would otherwise occur in high pressure systems.

Another property of varying the ratio of R1233zd(E) and R1234ze in the mixture is the flammability of the refrigerant in the event of a leak from the refrigeration system. Table 3 shows various weight compositions of the mixture of R1233zd(E) and R1234ze, and the respective flammability of each composition. As can be seen from Table 3, formulations with greater than 67 wt% transHFO-1234ze are flammable, as measured according to American Society for Testing and Materials (ASTM) 681.

Table 4 shows a comparison of the R404A direct expansion refrigeration system of the comparative example with the four-circuit distributed refrigeration system described with respect to FIG. 2 without SLHX. In this case, the distributed refrigeration system removes R1234ze(E) in the third (common) refrigeration circuit to remove waste heat from the first and second refrigeration circuits to provide low and medium temperature cooling. And has R1233zd(E) in the fourth refrigeration circuit. For this example, the evaporation temperature of the R1234ze(E) refrigerant is varied to achieve temperatures of R1233zd(E) of 80F, 70F, 60F, 50F, and 40F. The performance of the system obtained is 54.8 kW of total power, the obtained COP is 1.82, the comparative example R404A system without mechanical subcooling, and the total power of 49.6 kW, Compare with R404A system with mechanical supercooling to 50F, COP 2.02. The cooling capacity in each case is 100 kW, with a load distribution of 67 kW MT and 33 kW LT.

As shown by the results in Table 4, with R1234yf and R455A in the low and medium temperature refrigeration circuit, more preferably at a temperature in the range of about 40F to about 80F, more preferably at a temperature in the range of about 40F to about 60F. Shows unexpected maximum performance for systems with R1233zd(E) at temperatures of about 45F to about 55F (preferably about 50F). It has been shown that the combination of these refrigerants is very advantageous and provides unexpected performance and offers the greatest improvement over the R404A system of the comparative example.

The results of Table 4 are shown graphically in FIGS. 6A and 6B. FIG. 6A shows a graph of the COP of the R1233zd(E) system with different refrigerants in the cold and medium temperature refrigeration circuit over a range of different cooling temperatures. From this graph, the R1233zd(E) system has R1234yf and/or R455A in the low/medium temperature refrigeration circuit, and the vaporization temperature of R1233zd(E) is in the range of about 40F to about 80F, more preferably about 40F. It is clear that the highest COPs are achieved at temperatures in the range of about 60 F to about 60 F, more preferably about 45 F to about 55 F (preferably about 50 F).

Table 5 shows a comparison of the comparative example R404A DX refrigeration system with the distributed refrigeration system described with respect to FIG. 2 with SLHX. In this case, the distributed refrigeration system has R1234ze(E) in the fourth refrigeration circuit to remove the exhaust heat from the low temperature and medium temperature refrigeration circuits and provide low temperature and medium temperature cooling, and a common refrigeration circuit. It has R1233zd(E) inside. In this case, the low and medium temperature refrigeration circuits provided also have SLHX. For this example, the evaporation temperature of R1234ze(E) is varied to achieve temperatures of R1233zd(E) of 80F, 70F, 60F, 50F, and 40F. The performance of the system obtained is 54.8 kW of total power, the obtained COP is 1.82, the comparative example R404A system without mechanical subcooling, and the total power of 49.6 kW, Compare with R404A system with mechanical supercooling to 50F, COP 2.02. The cooling capacity in each case is 100 kW, with a load distribution of 67 kW MT and 33 kW LT.

As shown by the results in Table 5, the R1233zd(E) system has R1234yf and/or R455A in the low/medium temperature refrigeration circuit, and the vaporization temperature of R1233zd(E) is in the range of about 40F to about 80F. It is clear that the highest COP is achieved when the temperature is more preferably in the range of about 40 F to about 60 F (evaporation temperature of 1233zd(E) is about 45 F to about 55 F (preferably about 50 F)). Shows an unexpected high when the temperature is. It has been shown that this combination of these temperatures provides the best performance and maximum improvement over the R404A system of the comparative example.

The results of Table 5 are shown graphically in FIGS. 7A and 7B. FIG. 7A shows a graph of the COP of the R1233zd(E) system with different refrigerants in the first refrigeration circuit over different cooling temperature ranges. From this graph, the R1233zd(E) system has R1234yf or R455A in the low and medium temperature refrigeration circuit, and the cooling temperature of R1233zd(E) is in the range of about 40F to about 80F, more preferably about 40F to about 80F. It is clear that the highest COP is achieved when the temperature is in the range of 60F (unexpected when the evaporation temperature of 1233zd(E) is about 45F to about 55F (preferably about 50F)). Of the highest).

Table 6 below shows a comparison of the comparative example R404A DX refrigeration system and the three-circuit, flooded distributed refrigeration circuit described with respect to FIG. 3 without SLHX. In this case, the two-circuit distributed refrigeration circuit has R1233zd(E) in the common refrigeration circuit to remove the exhaust heat from the low temperature and medium temperature refrigeration circuit and provide the low temperature and medium temperature cooling. In this example, the evaporation temperature of R1233zd(E) is varied to achieve temperatures of 80F, 70F, 60F, 50F, and 40F. The performance of the system obtained is 54.8 kW of total power, the obtained COP is 1.82, the comparative example R404A system without mechanical subcooling, and the total power of 49.6 kW, Compare with R404A system with mechanical supercooling to 50F, COP 2.02. The cooling capacity in each case is 100 kW, with a load distribution of 67 kW MT and 33 kW LT.

As shown by the results in Table 6, the R1233zd(E) system has R1234yf and/or R455A in the low/medium temperature refrigeration circuit, and the vaporization temperature of R1233zd(E) is in the range of about 50F to about 70F. It is clear that the highest COP is achieved when the temperature is more preferably in the range of about 55F to about 65F (evaporation temperature of 1233zd(E) is about 55F to about 65F (preferably about 50F). Shows an unexpected high when the temperature is. It has been shown that this combination of these temperatures provides the best performance and maximum improvement over the R404A of the comparative example.

The results of Table 6 are shown graphically in FIGS. 8A and 8B. FIG. 8A shows a graph of the COP of the R1233zd(E) system with different refrigerants in the low and medium temperature refrigeration circuit over different cooling temperature ranges.

Table 7 shows a comparison between the R404A DX refrigeration system of the comparative example and the flooded distributed refrigeration circuit described with respect to FIG. 3 with SLHX. In this case, the low and medium temperature full liquid distributed refrigeration circuit with SLHX removes waste heat from the low and medium temperature refrigeration circuit and provides R1233zd(E) in the common refrigeration circuit to provide low and medium temperature cooling. ) Has. The medium and low temperature refrigeration circuits also use SLHX. In this example, the evaporation temperature of R1233zd(E) is varied to achieve temperatures of 80F, 70F, 60F, 50F, and 40F. The performance of the system obtained is 54.8 kW of total power, the obtained COP is 1.82, the comparative example R404A system without mechanical subcooling, and the total power of 49.6 kW, Compare with R404A system with mechanical supercooling to 50F, COP 2.02. The cooling capacity in each case is 100 kW, with a load distribution of 67 kW MT and 33 kW LT.

As shown by the results in Table 7, the R1233zd(E) system has R1234yf and/or R455A in the low/medium temperature refrigeration circuit, and the evaporation temperature of R1233zd(E) is in the range of about 50F to about 70F. It is clear that the highest COP is achieved when the temperature is more preferably in the range of about 55F to about 65F (evaporation temperature of 1233zd(E) is about 55F to about 65F (preferably about 50F). Shows an unexpected high when the temperature is. This combination has been shown to provide the best performance and maximum improvement over the comparative example R404A system.

The results of Table 7 are shown graphically in FIGS. 9A and 9B. FIG. 9A shows a graph of the COP of the R1233zd(E) system with different refrigerants in the low temperature and medium temperature refrigeration circuits over different cooling temperature ranges.

Table 8 uses a three-circuit, flooded distributed refrigeration system, described with reference to FIG. 2, that requires an additional heat exchanger to provide air conditioning (AC) (“Option 3”). Show the benefits of doing. Different options of refrigerant in the first refrigeration unit are given for option 3. The results of option 3 are compared to the comparative example R404A DX refrigeration system with the R410A AC system. The preconditions of this embodiment are set as follows.
・MT load: 67,000W
・LT load: 33,000W
・AC load: 100,000W
・R1233zd temperature: 50F

The results in Table 10 show that all three variants of the four-circuit flooded distributed refrigeration system requiring an additional heat exchanger for the AC have the R404A DX refrigeration system of the comparative example with the R410A AC system. Is shown to exhibit lower power. Advantageously, this means that a three-circuit flooded distributed refrigeration system that requires an additional heat exchanger for AC uses less power (for the same cooling capacity). .. Advantageously, this leads to reduced energy usage and overall improvement in system efficiency.

As explained above, the connecting line for a flooded R1233zd system can be constructed using PVC or other low cost plastics because the pressure of R1233zd is very low. Table 9 provides material compatibility information for R1233zd with common type plastics. The sample was immersed in R1233zd for 2 weeks at room temperature between 24°C and 25°C. After exposure of the sample to R1233zd, the sample was degassed for 24 hours. The weight and volume of the samples were measured before immersion in R1233zd and after the degassing step. The results in the table show the change in average weight percent and volume for each plastic sample. The results shown in Table 11 show a change of less than 5% in average volume percent for all plastic types tested. Since all these plastics are common low cost plastics, it can therefore be concluded from the results shown in Table 9 that R1233zd(E) is compatible with many common low cost plastic materials. Beneficially, the ability to use low cost plastics to connect the lines brings down the cost of the system.

The pressure level inside the refrigeration system, and the difference in effective pressure between the inside of the system and the outside (ambient) of the system, directly affects the potential leak rate if a leak occurs. Leakage can occur for a variety of reasons, including corrosion, accidental puncture of lines and components, and improper connection of lines. The use of a lower pressure refrigerant reduces the operating pressure level inside the refrigeration system, thereby reducing the difference in effective pressure inside and outside the system. Thus, the leak rate will be reduced if a leak occurs, as compared to using a higher pressure refrigerant.

FIG. 10A shows a bar graph of pressure at kPa for various different refrigerants. From FIG. 10A, it is clear that R32 exhibits the highest pressure level.

FIG. 10B shows a bar graph of leak rates in g/year for various different refrigerants. As expected from the results shown in Figure 10A, R32 exhibits the highest leak rate (because it has the highest pressure level).

Table 10 shows vapor pressures, leak rates, and relative leak rates of the refrigerants shown in FIGS. 13A and 13B. Relative leak rate is the leak rate of a variety of different refrigerants compared to the refrigerant with the highest leak rate: R32.

Refrigerants have different safety classes based on their toxicity and combustion characteristics. Class 3 flammable refrigerants have higher flammability and therefore must comply with certain fill limits. Refrigerant charge refers to the amount of refrigerant in the system. Lower flammability classes, such as A2L, allow more refrigerant charge and provide more design opportunities for increased charge. The relationship between flammability and charge also affects the potential compressor size to be used in the system, and thus the isentropic efficiency of the compressor used in the system. FIG. 11 shows a graph of isentropic efficiency when the pressure ratio of the R290 compressor and the R134a compressor is changed. R290 is a higher flammability class refrigerant than R134a, so a smaller fill amount of R290 is used. Therefore, the R290 compressor is smaller than the R134a compressor.

Table 11 shows that greater isentropic efficiency is achieved with the larger R134a compressor than the smaller R290 compressor. Finally, Table 13 shows the isentropic efficiencies and pressure ratios of R290 and R134a on the plate, as well as varying the condensation temperature.

Where possible without apparent technical incompatibility, features of different configurations, embodiments, or aspects disclosed herein may be combined with any features that are optionally omitted.

Claims (10)

A refrigeration system for providing refrigeration at least at low and medium cooling levels, the system comprising:
(A) A low temperature refrigeration unit including a low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature refrigerant consisting essentially of HFO-1234yf,
(Ii) a compressor for compressing the low temperature refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature refrigerant,
(Iv) a low temperature refrigeration unit including a low temperature heat exchanger for discharging heat from the low temperature refrigerant,
(B) A medium temperature refrigeration unit including a medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature refrigerant consisting essentially of HFO-1234yf circulating in the system;
(Ii) a compressor for compressing the medium temperature refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space in the medium temperature refrigeration unit by evaporating the medium temperature refrigerant,
(Iv) a medium temperature refrigeration unit comprising: a medium temperature heat exchanger for discharging heat from the medium temperature refrigerant;
(C) a third refrigeration circuit, wherein the third refrigeration circuit is arranged to receive heat discharged from each of the low temperature and medium temperature heat exchangers at a temperature of about 40F to about 80F. A third refrigeration circuit, wherein the refrigerant consists essentially of transHFO-1233zd. At least one of the low-temperature heat exchanger and the medium-temperature heat exchanger is a liquid-filled heat exchanger, and the third refrigeration circuit includes a pump for circulating the common refrigerant. Refrigeration system described in. The refrigeration system of claim 1, wherein each of the low temperature and medium temperature refrigeration units is located within a first area. The refrigeration system according to claim 1, wherein each of the low-temperature refrigerant and the medium-temperature refrigerant is flammable, and the third refrigerant is non-flammable. The third refrigeration circuit is arranged to release the third refrigerant in or near the low-temperature or medium-temperature refrigerant unit when a leak of the low-temperature or medium-temperature refrigerant occurs. The refrigeration system according to claim 4. A refrigeration system for providing refrigeration at least at low and medium temperature refrigeration levels, the system comprising:
(A) A low temperature refrigeration unit including a low temperature refrigeration circuit, wherein the low temperature refrigeration circuit comprises:
(I) a low temperature refrigerant circulating in the system,
(Ii) a compressor for compressing the low temperature refrigerant,
(Iii) a low temperature evaporator for absorbing heat from the space in the low temperature refrigeration unit by evaporating the low temperature refrigerant,
(Iv) a low temperature refrigeration unit including a low temperature heat exchanger for discharging heat from the low temperature refrigerant,
(B) A medium temperature refrigeration unit including a medium temperature refrigeration circuit, wherein the medium temperature refrigeration circuit comprises:
(I) a medium temperature refrigerant circulating in the system,
(Ii) a compressor for compressing the medium temperature refrigerant,
(Iii) a medium temperature evaporator for absorbing heat from the space in the medium temperature refrigeration unit by evaporating the medium temperature refrigerant,
(Iv) a medium temperature refrigeration unit comprising: a medium temperature heat exchanger for discharging heat from the medium temperature refrigerant;
(C) A third refrigeration circuit,
(I) a third refrigerant consisting essentially of transHFO-1233zd;
(Ii) a compressor for compressing the third refrigerant,
(Iii) A full-fill type evaporator, wherein the common refrigerant is evaporated at a temperature of about 50° F. to about 70° F to remove the low temperature medium refrigerant and the medium temperature medium refrigerant in the low temperature medium temperature medium heat exchanger. A third refrigeration circuit comprising a flooded evaporator arranged to receive heat discharged from each, a refrigeration system. 7. The refrigeration system of claim 6, wherein each of the low and medium temperature refrigerants is selected from the group consisting of R744, one or more C2-C4 hydrocarbons, R1234yf, and combinations thereof. Thus, at least one of the low and medium temperature refrigerants consists essentially of HFO-1234yf. The refrigeration system according to claim 7. The third refrigeration circuit comprises at least a first branch for discharging heat by heat exchange with ambient air during operation, and a compressor branch for discharging heat to the compression refrigeration system during operation. Item 6. The refrigeration system according to Item 6. 9. The refrigeration of claim 8, wherein the compressor in the low temperature refrigeration unit has a power rating of less than about 1 horsepower and the compressor in the medium temperature refrigeration unit has a power rating of less than about 1 horsepower. system.

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