CA2897081A1 - Transcritical r744 refrigeration system with gas cooler outlet vapors used as a heat source for the dehumidifying coil - Google Patents

Transcritical r744 refrigeration system with gas cooler outlet vapors used as a heat source for the dehumidifying coil Download PDF

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Publication number
CA2897081A1
CA2897081A1 CA2897081A CA2897081A CA2897081A1 CA 2897081 A1 CA2897081 A1 CA 2897081A1 CA 2897081 A CA2897081 A CA 2897081A CA 2897081 A CA2897081 A CA 2897081A CA 2897081 A1 CA2897081 A1 CA 2897081A1
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Prior art keywords
dehumidifying
gas cooler
heat
transcritical
receiver
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CA2897081A
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French (fr)
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CA2897081C (en
Inventor
Jordan Kantchev
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Evapco Systems Lmp Ulc
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SYSTEMES LMP Inc
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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00Gas cycle refrigeration machines
    • F25B2309/06Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure

Abstract

A transcritical R-744 refrigeration systems for supermarkets with dehumidifying capability where the heat of the R-744 leaving the gas cooler is used for dehumidifying. The same heat exchanger is used for heat reclaim and dehumidifying purposes.

Description

Jul 15 02:45p Equinox IP F.B. 14504823478 10.3 COOLER OUTLET VAPORS USED AS A HEAT SOURCE FOR THE
DEHUMIDIFYING COIL
FIELD OF THE INVENTION
5 [0001] The present invention relates to transcritical R-744 refrigeration systems, and more specifically to transcritical R-744 refrigeration systems for supermarkets and the like, which use multiple compressors and multiple evaporators to refrigerate and/or to maintain in frozen conditions perishable food products. The refrigeration system used is transcritical R744 system 10 having heat reclaim and dehumidifying capability.
BACKGROUND OF THE INVENTION
[0002] During some periods of the year when the ambient temperatures and humidity are elevated, it is necessary to provide, in addition to the air conditioning, a system which will reduce the relative air humidity in the supermarket. Failing to do so will result in high air relative humidity inside the store, frequent defrosts, frosting of the surface of the food products and discomfort for the customers.
[0003] The most frequently used dehumidifying method in supermarkets is to install heating coil downstream of the air conditioning coil. The air from the outlet of the air conditioning coil has low temperature and very high relative humidity. By reheating this air to a comfortable temperature level the relative humidity is lowered to acceptable level (around 40%). Most often the heat of the high pressure compressed refrigerant that vapors directly from the discharge outlet of the compressors is used as a heat source for the heating coil. This method provides sufficient heat for the dehumidification process but in the case of R744 transcritical system, having into consideration that the dehumidification process is used mainly during the summer period, does not provide increase of efficiency of the transcritical refrigeration system which PAGE 3113* RCVD AT 7/10/2015 2:58:32 PM [Eastern Daylight TImel* SVR:F00003116 DNIS:3905* CSID:14504823478* DURATION (mm-ss):04-54 Jul 15 02:46p, Equinox IP F.B. 14504823478 p.4 during the summer period is significantly lower than that of the freon refrigeration systems.
[0004] The need to improve the cycle efficiency during the warmer periods of the year is obvious.
5 [0005] Accordingly, there is a need for an improved transcritical R-744 refrigeration system.
SUMMARY OF THE INVENTION
[0006] It is therefore a general object of the present invention to provide an improved transcritical R-744 refrigeration system and method.
10 [00071 An advantage of the present invention is that the transcritical R-refrigeration system and method, instead of using the high pressure compressed refrigeration vapors directly from the discharge outlet of the compressors as a heat source for the heating coil, uses the vapors from the outlet of the gas cooler are as a heat source for the heating coil.
[0008] Another advantage of the present invention is that the transcritical R-refrigeration system and method.uses only one heat exchanger for heat reclaim and dehumidifying purposes.
[0009] A further advantage of the present invention is that the transcritical R-744 refrigeration system and method, by using the vapors from the outlet of the gas cooler as a heat source for dehumidification, a significant amount of subcooling capacity is provided thus increasing the efficiency of the system without installing additional equipment and without adding to the power consumption of the system.
[0010] Still another advantage of the present invention is that the transcritical R-744 refrigeration system and method, by feeding vapors with lower temperature through the dehumidifying heat exchanger, reduces the thermal stress to the heat exchanger thus increasing the reliability and the useful Fife of the dehumidifying system.
PAGE 4113* RCVD AT 7/10/2015 2:58:32 PM [Eastern Daylight Timel*
SVR:F00003116*DNIS:3905 CSID:14504823478* DURATION (mm-ss):04-54 Jul 15 02:46p Equinox IP F.B. 14504823478 10.5 [0011] According to an aspect of the present invention, there is provided a transcritical R-744 refrigeration system for supermarket with dehumidifying capability, the transcritical R-744 refrigeration system having a vapor of a R-refrigerant circulating from a compressor to a heat reclaim /dehumidifying heat 5 exchanger, a gas cooler, a receiver and an evaporator, and back to the compressor via a plurality of conduits and a plurality of valves, the transcntical R-744 refrigeration system comprising a modulating valve allowing heat of at least a portion of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before 10 circulating to the receiver.
[0012] In one embodiment, one of the plurality of conduits is a conduit junction located between the gas cooler and the receiver, one of the plurality of valves is a second valve located between the conduit junction and the receiver, and the modulating valve is located between the conduit junction and the heat reclaim /dehumidifying heat exchanger, wherein the modulating valve allowing heat of all of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver when the modulating valve is open and the second valve is closed.
[0013] According to another aspect of the present invention, there is provided a method of dehumidifying a heat reclaim /dehumidifying heat exchanger of a transcritical R-744 refrigeration system, the transcritical R-744 refrigeration system having a vapor of a R-744 refrigerant circulating from a compressor to a heat reclaim /dehumidifying heat exchanger, a gas cooler, a receiver and an evaporator, and back to the compressor via a plurality of conduits and a plurality of valves, the method comprising the step of: modulating a modulating valve to allow heat of at least a portion of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver.
100141 In one embodiment, one of the plurality of conduits is a conduit junction located between the gas cooler and the receiver, one of the plurality of valves is a second valve located between the conduit junction and the receiver, the modulating valve is located between the conduit junction and the heat reclaim PAGE 5113* RCVD AT 7/1012015 2:58:32 PM [Eastern Daylight Time] SVR:F00003/16*
DNIS:3905* CSID:14504823478* DURATION (mm-ss):04-54 Jul 15 02:46p Equinox IP F.B. 14504823478 p.6 /dehumidifying heat exchanger, wherein the method further comprising the step of: dosing the second valve as to allow all of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver.
5 [0015] Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Further aspects and advantages of the present invention will become 10 better understood with reference to the description in association with the following Figure, wherein:
[0017] Figure 1 is a schematic view of a transcritical R-744 refrigeration system having the gas cooler outlet vapors used as a heat source for the dehumidifying the heating coil in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] With reference to the annexed drawings the preferred embodiment of the present invention will be herein described for indicative purpose and by no means as of limitation.
[0019] Referring to Figure 1, there is schematically shown a transcritical R-refrigeration system 30 having the gas cooler outlet vapors used as a heat source for the dehumidifying the heating coil in accordance with an embodiment of the present invention.
[0020] The refrigeration system shown on Figure 1 is a simplified schematic of the transcritical R-744 system 30 with the low temperature compressors and all evaporators not being specifically shown since they are not participating directly into the dehumidifying and heat reclaim process.
PAGE 6113* RCVD AT 711012015 2:58:32 PM [Eastern Daylight Timel*
SVR:F00003116*DNIS:3905* CSID:14504823478 * DURATION (mm-ss):04-54 Jul 15 02:47p Equinox IP F.B. 14504823478 ID.7 [0021] If heat reclaim or dehumidifying are not required, the compressed refrigerant vapors from corn pressors 11 are fed through conduit 12 and conduit 18 to the gas cooler 5, and then through conduit 19 and conduit 20 to the throttling device 9 and then to the receiver (flash tank) 10. During this 5 operational configuration, valves 25 and 7 are fully open, while valves 3, 4, 6 and 8 are completely closed. Valve 7, the 'second valve', is located between the gas cooler 5 and the receiver 10, downstream of a conduit junction 26 allowing the refrigerant vapors leaving the gas cooler 5 to circulate to a heat reclaim /dehumidifying heat exchanger 1 for the dehumidification thereof, as 10 further explained herein below.
[0022] If heat reclaim is required, valve 25 is adjusted to maintain a pressure higher than the pressure maintained by valve 3. Valve 4 is completely open.
The compressed vapors from compressors 11 are fed through conduit 12, valve 4 and conduit 13 to the heat reclaim /dehumidifying heat exchanger 1 where the 15 heat of the vapors is transferred to the air flowing through the heat exchanger.
The valve 3 maintains the necessary pressure in order to provide maximum efficiency. From heat exchanger 1, the vapors are fed through valve 3, conduit 14, conduit 16, conduit 17 and conduit 18 to the gas cooler 5. Valve 6 and 8 are completely closed and valve 7 is completely open. From the gas cooler 5, the 20 vapors and/or liquid refrigerant, depending on the operation conditions, are fed through conduit 19 and conduit 20 to the throttling device 9 and from there to the receiver 10.
[0023] If dehumidifying is required, valve 25 is completely open, valves 3, 4 and
7 are completely closed and valves 6 and 8 are completely open. The 25 compressed refrigeration vapors from compressors are fed through conduit 12, valve 25 and conduit 18 to the gas cooler 5. The vapors from the outlet of the gas cooler 5 are fed through conduit 19, junction 26, valve 6, conduit 22, conduit 23, conduit 24 and conduit 13 to the heat reclaim /dehumidifying heat exchanger 1. Cooled by the air-conditioning heat exchanger 2, air is reheated 30 by the dehumidifying heat exchanger 1, using the heat of the vapors from the gas cooler 5 outlet, thus reducing its relative humidity. From heat exchanger 1, _ PAGE 7113* RCVD AT 7/10/2015 2:58:32 PM [Eastern Daylight Time]
SVR:F00003/16 DNIS:3905* CSID:14504823478* DURATION (mm-ss):04-54 Jul 15 02:47p Equinox IP F.B. 14504823478 p.8 the refrigerant is fed through conduit 14, conduit 15, conduit 21 and valve 8 to conduit 20 and then to throttling device 9 and receiver 10.
[0024] An embodiment of the present invention is a method of dehumidifying a heat reclaim /dehumidifying heat exchanger 1 of a transcritical R-744 refrigeration system 30. The method includes the step of modulating the modulating valve 6 to allow heat of at least a portion of the R-744 refrigerant leaving the gas cooler 5 to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger 1 before circulating to the receiver 10.
[0025] Preferably, the method includes the step of closing the second valve 7 10 as to allow all of the R-744 refrigerant leaving the gas cooler 5 to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger 1 before circulating to the receiver 10.
[0026] Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope of the invention as hereinabove described and hereinafter claimed.
PAGE 8113* RCVD AT 7110/2015 2:58:32 PM [Eastern Dayllaht Timel* SVR:F00003116 * DNIS:3905 CSID:14504823478 DURATION (mm-ss):04-54

Claims (4)

7I/We claim:
1. A transcritical R-744 refrigeration system for supermarket with dehumidifying capability, the transcritical R-744 refrigeration system having a vapor of a R-744 refrigerant circulating from a compressor to a heat reclaim /dehumidifying heat exchanger, a gas cooler, a receiver and an evaporator, and back to the compressor via a plurality of conduits and a plurality of valves, the transcritical R-744 refrigeration system comprising a modulating valve allowing heat of at least a portion of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver.
2. The system of claim 1, wherein one of the plurality of conduits is a conduit junction located between the gas cooler and the receiver and wherein one of the plurality of valves is a second valve located between the conduit junction and the receiver, and wherein the modulating valve is located between the conduit junction and the heat reclaim /dehumidifying heat exchanger, the modulating valve allowing heat of all of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver when the modulating valve is open and the second valve is closed.
3. A method of dehumidifying a heat reclaim /dehumidifying heat exchanger of a transcritical R-744 refrigeration system, the transcritical R-refrigeration system having a vapor of a R-744 refrigerant circulating from a compressor to a heat reclaim /dehumidifying heat exchanger, a gas cooler, a receiver and an evaporator, and back to the compressor via a plurality of conduits and a plurality of valves, the method comprising the step of:

- modulating a modulating valve to allow heat of at least a portion of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver.
4. The method of claim 3, wherein one of the plurality of conduits is a conduit junction located between the gas cooler and the receiver, wherein one of the plurality of valves is a second valve located between the conduit junction and the receiver, wherein the modulating valve is located between the conduit junction and the heat reclaim /dehumidifying heat exchanger, and wherein the method further comprising the step of:
- closing the second valve as to allow all of the R-744 refrigerant leaving the gas cooler to directly reach and dehumidify the heat reclaim /dehumidifying heat exchanger before circulating to the receiver.
CA2897081A 2014-07-10 2015-07-10 Transcritical r744 refrigeration system with gas cooler outlet vapors used as a heat source for the dehumidifying coil Active CA2897081C (en)

Applications Claiming Priority (2)

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US201462022887P 2014-07-10 2014-07-10
US62/022,887 2014-07-10

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CA2897081A1 true CA2897081A1 (en) 2016-01-10
CA2897081C CA2897081C (en) 2023-02-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115076994A (en) * 2022-06-13 2022-09-20 安徽正刚新能源科技有限公司 Waste heat recycling system of rotary dehumidification unit

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110030764A (en) * 2018-01-11 2019-07-19 开利公司 Refrigeration system and its control method
US11226144B2 (en) * 2018-05-18 2022-01-18 Systemes Lmp Inc. R-744 system with hot gas defrost by the transcritical compressors
US11137171B2 (en) * 2018-12-11 2021-10-05 Systemes Lmp Inc. Transcritical R-744 refrigeration system for supermarkets with improved efficiency and reliability
CA3156850A1 (en) 2021-04-29 2022-10-29 Flo Energy Solutions Inc. Hvac dual de-superheating/subcooling heat reclaim system for transcritical refrigeration systems

Family Cites Families (6)

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US4285205A (en) * 1979-12-20 1981-08-25 Martin Leonard I Refrigerant sub-cooling
US4621505A (en) * 1985-08-01 1986-11-11 Hussmann Corporation Flow-through surge receiver
US4711094A (en) * 1986-11-12 1987-12-08 Hussmann Corporation Reverse cycle heat reclaim coil and subcooling method
US20060130494A1 (en) * 2004-12-20 2006-06-22 Serge Dube Defrost refrigeration system
DE102006024796B4 (en) * 2006-03-17 2009-11-26 Konvekta Ag air conditioning
CA2779757A1 (en) * 2011-06-10 2012-12-10 Systemes Lmp Inc. Suction compressor temperature regulator device for transcritical and subcritical r-744 compressors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115076994A (en) * 2022-06-13 2022-09-20 安徽正刚新能源科技有限公司 Waste heat recycling system of rotary dehumidification unit

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CA2897081C (en) 2023-02-28

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