CN221425130U - A multi-stage cascade multi-temperature zone combined cooling and heating system - Google Patents

Abstract

A multi-stage cascade multi-temperature-zone cold and heat cogeneration system comprises 3 refrigeration loops and a heat recovery waterway, wherein the refrigeration loops comprise a low-temperature loop, a medium-temperature loop and a high-temperature loop. The low-temperature loop comprises a low-temperature compressor, a low-temperature condensing evaporator, a throttling device and a low-temperature evaporator. The medium temperature loop comprises a medium temperature compressor, a heat recoverer, an electric three-way regulating valve, a medium temperature condenser, a medium temperature condensing evaporator, a throttling device, a medium temperature evaporator and a low temperature condensing evaporator; the high-temperature loop comprises a high-temperature compressor, a high-temperature condenser, a throttling device and a medium-temperature condensing evaporator. The low-temperature loop and the medium-temperature loop share a low-temperature condensing evaporator; the medium temperature loop and the high temperature loop share a medium temperature condensation evaporator; the heat recovery waterway can respectively provide medium-temperature hot water and high-temperature hot water. The utility model can realize at least four temperature areas simultaneously: the functions of low-temperature refrigeration, medium-temperature hot water and high-temperature hot water have the advantages of high efficiency, energy conservation and low cost.

Description

A multi-stage cascade multi-temperature zone combined cooling and heating system

Technical Field

The utility model belongs to the technical field of refrigeration and air conditioning, and in particular relates to a cascade multi-temperature zone cold and hot cogeneration system.

Background technique

As people's living standards improve, the per capita meat consumption level gradually increases, and the importance of the slaughtering and processing industry in the national economy is increasing. Due to the needs of the slaughtering production process, its energy consumption has relatively distinct characteristics. In the production process, both the refrigeration system is required for cooling (food cooling, freezing, cold storage, workshop air conditioning, etc.), and process hot water is also required (slaughtering, scalding, disinfection of utensils, pasteurization, workers washing hands and showers, site cleaning, etc.). Traditionally, these cooling and heating needs are generally provided by two systems, the refrigeration room and the boiler room. According to industry surveys, the condensation heat generated by the refrigeration system in most slaughterhouses is directly discharged to the atmosphere through water or air. On the one hand, the condensation waste heat of the refrigeration system is discharged, and on the other hand, the boiler consumes energy to produce hot water or steam. From the perspective of energy utilization, the energy relationship between refrigeration and heating has not been used reasonably and effectively, and there is a disadvantage of low comprehensive energy utilization rate.

In the field of heat pumps, with the promotion of policies such as "electricity replacing coal", various high-temperature heat pump technologies have flourished, and technologies in heat exchangers, compressors, working fluid development, system control, etc. have made great progress. The energy efficiency ratio of high-temperature heat pumps has been greatly improved. Various studies at home and abroad have fully demonstrated that using heat pumps to produce hot water has great advantages over various coal-fired boilers, electric boilers, gas boilers, etc. For heat pumps, the higher the evaporation temperature, the higher the heating energy efficiency ratio; the large amount of condensation waste heat discharged by the refrigeration system can be used as a heat source for high-temperature heat pumps. At the same time, when the outlet water temperature of the heat pump remains unchanged, the higher the inlet water temperature, the less energy is consumed for heating, and therefore the total energy consumption is less. Reasonable use of the condensation waste heat of the refrigeration system, improving the heating efficiency of the heat pump, and saving the total amount of energy have obvious advantages.

In recent years, the carbon dioxide refrigeration system using natural working fluid _CO2 as refrigerant has been widely developed and applied as an efficient, energy-saving and environmentally friendly technology because of its advantages such as no pollution to the environment, GWP=1, safety and non-toxicity, and excellent heat transfer performance. Especially in large-scale industrial and commercial refrigeration systems and cold storage, including various low-temperature cascade systems and transcritical systems, it has great development potential.

Summary of the invention

The utility model aims to provide a multi-stage cascade multi-temperature zone cold and heat cogeneration system, comprising a low-temperature loop, a medium-temperature loop, and a high-temperature loop, three refrigeration loops in total, and a heat recovery water circuit.

The utility model is realized by the following technical solutions:

A multi-stage cascade multi-temperature zone cooling and heating cogeneration system, characterized by comprising three refrigeration loops, namely a low temperature loop, a medium temperature loop and a high temperature loop, and a heat recovery water circuit;

The low-temperature loop includes a low-temperature compressor, a low-temperature condenser evaporator, a low-temperature throttling device, and a low-temperature evaporator connected by pipelines;

The medium temperature loop includes a medium temperature compressor, a medium temperature heat recovery device, an electric three-way regulating valve, a medium temperature condensing evaporator, a medium temperature condenser, a low temperature heat recovery device, a medium temperature throttling device, a medium temperature evaporator, and a low temperature condensing evaporator connected by pipelines;

The high temperature loop includes a high temperature compressor, a high temperature condenser, a high temperature throttling device, and a medium temperature condenser evaporator connected by pipelines;

The low-temperature loop and the medium-temperature loop share a low-temperature condenser evaporator, in which the refrigerants of the two loops are condensed and evaporated respectively, and heat is transferred from the low-temperature loop to the medium-temperature loop;

The medium-temperature loop and the high-temperature loop share a medium-temperature condenser evaporator, in which the refrigerants of the two loops are condensed and evaporated respectively, and heat is transferred from the medium-temperature loop to the high-temperature loop.

The saturated evaporation temperature of the low-temperature compressor in the low-temperature loop is in the temperature range of -50°C to -15°C.

The saturated evaporation temperature of the medium-temperature compressor in the medium-temperature loop is in the temperature range of -15°C to +10°C.

The high-temperature compressor in the high-temperature loop is a heat pump type compressor, and its operating saturated evaporation temperature is in the temperature range of 10°C to 40°C.

The medium-temperature condensing evaporator and the medium-temperature condenser of the medium-temperature loop are connected in parallel and are respectively connected to the electric three-way regulating valve. The electric three-way regulating valve can automatically adjust the ratio of the refrigerant entering the two according to the setting to ensure the basic stability of the condensation/evaporation temperature.

The refrigerants of the three loops are not the same working fluid and can be selected according to the corresponding working conditions; preferably, the refrigerant of the low-temperature loop is carbon dioxide, a green natural working fluid suitable for low-temperature working conditions.

The low-temperature heat recovery device, medium-temperature heat recovery device, and high-temperature condenser are all refrigerant-water heat exchangers, and their water sides are connected in sequence through water pipes. The water side outlet of the medium-temperature heat recovery device is connected to a medium-temperature water storage tank, and then connected to the high-temperature condenser through a water pump. The water sides of all components form a heat recovery water circuit. The outlet water temperature of the medium-temperature heat recovery device is in the range of 30°C to 50°C, and the outlet water temperature of the high-temperature condenser is in the range of 50°C to 100°C. Furthermore, accessories such as medium-temperature water valves and high-temperature water valves are also configured in the water circuit.

Compared with the prior art, the utility model mainly has the following advantages:

The multi-stage cascade multi-temperature zone combined heating and cooling system of the utility model provides low-temperature cooling source, medium-temperature cooling source, medium-temperature hot water and high-temperature hot water at the same time, can realize the integration of cooling and heating, completely replace the traditional gas boiler or electric boiler, achieve the comprehensive utilization of cooling and heating, save gas or electricity, and reduce operating costs.

The medium temperature stage of the cascade refrigeration is used to condense the low temperature stage, thereby improving the refrigeration efficiency of the low temperature stage; the heat recovery device is used to cool the medium temperature stage refrigerant and supercool it, thereby improving the refrigeration efficiency of the medium temperature stage; the condensation waste heat of the medium temperature stage is used to produce medium temperature hot water, part of which can be directly used for production and life, and the other part can be used as the water inlet on the water supply side of the high temperature stage heat pump, thereby reducing the total energy required for producing high temperature hot water, thereby reducing the overall energy consumption for heating; the condensation waste heat of the medium temperature stage is used as the heat absorption heat source of the high temperature heat pump stage, thereby increasing the evaporation temperature of the heat pump, thereby increasing the heating efficiency of the heat pump, and compared with the use of an independent air source heat pump, it solves the problem of insufficient heat exchange in a low temperature environment in winter. The utility model better realizes the comprehensive utilization of various cooling and heat capacities, improves the comprehensive utilization efficiency of energy, and is beneficial to energy conservation and emission reduction for enterprises.

The low-temperature loop described in the utility model preferably uses pure natural working fluid _CO2 as a refrigerant, which is non-toxic, non-flammable, has an ozone depletion index ODP=0, a greenhouse effect index GWP=1, and has excellent low-temperature fluidity and heat exchange performance, and is suitable for use at lower ambient temperatures. Compared with the use of Freon refrigerants, the GWP value can be greatly reduced. Compared with the ammonia refrigerant used in the traditional slaughtering industry, the risk of toxic ammonia, leakage and injury, and explosion can be fundamentally eliminated, which can improve the reliability of enterprise safety production and reduce the additional costs required for safety and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

FIG1 is a schematic diagram of a system flow of the present utility model.

In the figure: 1—low temperature loop, 2—medium temperature loop, 3—high temperature loop, 4—heat recovery water circuit, 11—low temperature compressor, 12—low temperature condensing evaporator, 13—low temperature throttling device, 14—low temperature evaporator, 21—medium temperature compressor, 22—medium temperature heat recovery device, 23—electric three-way regulating valve, 24—medium temperature condensing evaporator, 25—medium temperature condenser, 26—low temperature heat recovery device, 27a-medium temperature throttling device, 27b-medium temperature throttling device, 28—medium temperature evaporator, 31—high temperature compressor, 32—high temperature condenser, 33—high temperature throttling device, 41—medium temperature water storage tank, 42—water pump, 43—medium temperature water valve, 44—high temperature water valve.

Detailed ways

It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs, and, unless otherwise clearly specified in the context, singular forms are intended to include plural forms.

The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

The utility model is a multi-temperature zone cold and heat cogeneration system based on a multi-stage cascade refrigeration cycle, comprising a low-temperature loop 1, a medium-temperature loop 2, and a high-temperature loop 3, a total of three refrigeration cycle loops, and a heat recovery water circuit 4.

The low-temperature loop 1 includes at least one low-temperature compressor 11, a low-temperature condenser evaporator 12, a low-temperature throttling device 13, and a low-temperature evaporator 14 connected by pipelines. The refrigerant liquid absorbs heat and evaporates in the low-temperature evaporator 14. The evaporated gaseous refrigerant enters the low-temperature compressor 11 and is compressed into a high-temperature and high-pressure superheated gas, enters the low-temperature condenser evaporator 12 to release heat and recondense into a high-pressure liquid, then enters the low-temperature throttling device 13 to throttle and reduce pressure to become a low-temperature liquid, and then enters the low-temperature evaporator 14 to absorb heat and evaporate, completing a refrigeration cycle. In the embodiment, the low-temperature loop refrigerant preferably uses green natural working fluid carbon dioxide, whose refrigeration saturated evaporation temperature is <-30°C, and can provide cooling capacity for quick freezing storage and low-temperature cold storage <-18°C.

The medium-temperature loop 2 includes at least one medium-temperature compressor 21, a medium-temperature heat recovery device 22, an electric three-way regulating valve 23, a medium-temperature condensing evaporator 24, a medium-temperature condenser 25, a low-temperature heat recovery device 26, a medium-temperature throttling device 27a and 27b, a medium-temperature evaporator 28, and a low-temperature condensing evaporator 12 connected by pipelines. The high-temperature and high-pressure refrigerant gas discharged from the medium-temperature compressor 21 enters the medium-temperature heat recovery device 22 to exchange heat with the low-temperature water on the water side, and the heat is recycled and utilized. Then, it is divided into two streams through the electric three-way regulating valve 23. One stream enters the medium-temperature condensing evaporator 24 to exchange heat with the high-temperature refrigerant and then condenses and cools down. The other stream enters the medium-temperature condenser 25 to exchange heat with the external environment and then condenses and cools down. The electric three-way regulating valve can automatically adjust and distribute the flow of the two streams according to the setting to keep the system basically stable. The refrigerant liquid after cooling and condensation merges and then enters the low-temperature heat recovery device 26 to exchange heat with the inlet water with a lower temperature (normal temperature tap water 10℃~20℃). The temperature is further reduced to a supercooled state to improve the refrigeration efficiency of the medium-temperature stage. The supercooled liquid is divided into two paths. One path passes through the medium-temperature throttling device 27a to enter the low-temperature condensing evaporator 12 to absorb CO in the low-temperature loop. ₂ exhaust gas condensation heat and evaporates; the other way enters the medium temperature evaporator 28 after passing through the medium temperature throttling device 27b, and the two evaporated gases are mixed and re-absorbed by the medium temperature compressor 21 to complete a refrigeration cycle. The low temperature condensation evaporator 12 is shared by the low temperature loop and the medium temperature loop, and heat is transferred from the low temperature loop to the medium temperature loop through it, realizing the coupling of the low temperature loop and the medium temperature loop. In the embodiment, the medium temperature loop uses R134A with a low GWP value suitable for medium and high temperature applications as a refrigerant, and the saturated evaporation temperature is <-5°C, which can provide cooling capacity for medium temperature cold storage or other refrigeration equipment.

The high temperature loop is a high temperature heat pump stage, including a high temperature compressor 31, a high temperature condenser 32, a high temperature throttling device 33 and a medium temperature condensing evaporator 24. The high temperature and high pressure gas discharged from the high temperature compressor 31 enters the high temperature condenser 32 and exchanges heat with the water side before cooling and condensing. The condensed refrigerant liquid passes through the high temperature throttling device 33 and becomes a low temperature and low pressure liquid. It then enters the medium temperature condensing evaporator 24 and exchanges heat with the refrigerant in the medium temperature loop. After absorbing heat, it evaporates into a vapor state and is sucked back into the high temperature compressor to complete a heat pump cycle. In the embodiment, the high temperature refrigerant also uses R134A, and the high temperature compressor is a screw compressor suitable for high temperature heat pump working conditions, with a saturated evaporation temperature of >10°C and a high heating efficiency.

The low-temperature heat recovery device 26, the medium-temperature heat recovery device 22, and the high-temperature condenser 32 are all refrigerant-water heat exchangers, and the water sides thereof are connected through water pipes. The water side outlet of the medium-temperature heat recovery device 22 is connected to a medium-temperature water storage tank 41, and the medium-temperature water storage tank 41 is connected to a medium-temperature water valve 43. The high-temperature condenser 32 has a high-temperature water valve 44 on the water side outlet pipe. The above water circuit components together form a heat recovery water circuit 4. The inlet water comes from normal temperature tap water (usually 10℃~20℃), and the inlet water passes through the water side of the low-temperature heat recovery device 26 and the water side of the medium-temperature heat recovery device 22 in turn, and the temperature increases step by step after absorbing heat. The outlet water temperature of the water side of the medium-temperature heat recovery device 22 reaches the medium-temperature range (30℃~50℃), and the medium-temperature hot water enters the medium-temperature water storage tank 41 for storage, and can be output to the outside through the medium-temperature water valve 43 at any time to meet the demand for medium-temperature hot water; part of the hot water in the medium-temperature water storage tank 41 is transported to the high-temperature condenser 32 through the water pump 42, and is further heated to become high-temperature hot water (50℃~100℃), which is output to the outside through the high-temperature water valve 44 and can be used in process requiring high-temperature hot water.

The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. The low temperature, medium temperature and high temperature described herein are all relative temperatures. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall be included in the protection scope of this application.

Claims (7)

1. A multistage cascade multi-temperature-zone combined heat and cold production system is characterized in that: the device comprises three refrigeration loops of a low-temperature loop (1), a medium-temperature loop (2) and a high-temperature loop (3) and a heat recovery waterway (4);

The low-temperature loop (1) comprises a low-temperature compressor (11), a low-temperature condensing evaporator (12), a low-temperature throttling device (13) and a low-temperature evaporator (14) which are connected through pipelines;

The medium temperature loop (2) comprises a medium temperature compressor (21), a medium temperature heat recoverer (22), an electric three-way regulating valve (23), a medium temperature condensing evaporator (24), a medium temperature condenser (25), a medium temperature heat recoverer (26), medium temperature throttling devices (27 a,27 b), a medium temperature evaporator (28) and a low temperature condensing evaporator (12) which are connected through pipelines;

The high-temperature loop (3) comprises a high-temperature compressor (31), a high-temperature condenser (32), a high-temperature throttling device (33) and a medium-temperature condensing evaporator (24) which are connected through pipelines;

the low-temperature loop (1) and the medium-temperature loop (2) share a low-temperature condensation evaporator (12), the refrigerants of the two loops are respectively condensed and evaporated in the low-temperature condensation evaporator, and heat is transferred from the low-temperature loop (1) to the medium-temperature loop (2);

The medium temperature loop (2) and the high temperature loop (3) share a medium temperature condensation evaporator (24), the refrigerants of the two loops are respectively condensed and evaporated in the medium temperature condensation evaporator, and heat is transferred from the medium temperature loop (2) to the high temperature loop (3);

The heat recovery waterway (4) comprises a low-temperature heat recoverer (26), a medium-temperature heat recoverer (22), a high-temperature condenser (32), a medium-temperature water storage tank (41), a water pump (42), a medium-temperature water valve (43) and a high-temperature water valve (44) which are connected through water pipes.

2. A multi-stage cascade multi-temperature zone cogeneration system according to claim 1, wherein: the saturated air suction temperature of the low-temperature compressor (11) is within the temperature range of minus 50 ℃ to minus 15 ℃.

3. A multi-stage cascade multi-temperature zone cogeneration system according to claim 1, wherein: the saturated air suction temperature of the middle temperature compressor (21) is within the temperature range of minus 15 ℃ to plus 10 ℃.

4. A multi-stage cascade multi-temperature zone cogeneration system according to claim 1, wherein: the high-temperature compressor (31) is a compressor under the working condition of a heat pump, and the saturated air suction temperature of the operation of the high-temperature compressor is within the temperature range of 10-40 ℃.

5. A multi-stage cascade multi-temperature zone cogeneration system according to claim 1, wherein: the water outlet temperature of the medium-temperature heat recoverer (22) is in the range of 30-50 ℃, and the water outlet temperature of the high-temperature condenser (32) is in the range of 50-100 ℃.

6. A multi-stage cascade multi-temperature zone cogeneration system according to claim 1, wherein: the medium temperature condensing evaporator (24) and the medium temperature condenser (25) in the medium temperature loop (2) are connected in parallel and are respectively connected with the electric three-way regulating valve (23), and the electric three-way regulating valve (23) can automatically regulate the relative proportion of the refrigerant entering the two according to the setting so as to ensure the stable operation of the refrigerating system.

7. A multi-stage cascade multi-temperature zone cogeneration system according to claim 2, wherein: the refrigerant of the low-temperature loop (1) is a refrigerant suitable for low-temperature working conditions.