CN210861779U - Cold accumulation type supercooling transcritical integrated CO2Refrigeration system - Google Patents

Abstract

The utility model discloses a critical collection is striden to cold-storage supercoolingTo CO₂A refrigeration system. The utility model discloses by cold water subcooling cold-storage circulating system and transcritical integrated CO₂A refrigeration cycle system is coupled; the transcritical integrated CO₂The refrigeration cycle system comprises a low-temperature stage compressor, a medium-temperature stage compressor, a heat recovery device, a gas cooler, a throttle valve, an evaporator for an air conditioner, a gas-liquid separator, an evaporator for a refrigerating chamber and an evaporator for a freezing chamber; the cold water supercooling cold accumulation circulating system consists of a subcooler, an evaporator, a water tank, a water pump, a working medium pump, a throttle valve and a three-way valve. By cold water to CO₂And the throttling loss can be reduced by supercooling, and the overall energy efficiency of the system is improved. Meanwhile, the heat recovery is utilized to meet the domestic hot water supply and heating, and the air conditioner is integrated into CO₂In the pressurization system, the integration of air conditioning and heat supply is realized, and the equipment volume is reduced. The evaporator for the air conditioner is started to realize refrigeration in summer, and the secondary recovered heat is utilized to realize room heating in winter.

Description

Regenerative subcooling transcritical integrated CO2 refrigeration system

technical field

The utility model relates to the technical field of refrigeration, in particular to a cold storage type supercooling transcritical integrated _CO2 refrigeration system.

Background technique

With the increasingly prominent environmental problems such as global warming and the destruction of the ozone layer, in order to replace the CFCs, HCFCs, HFCs and other working fluids that have a detrimental effect on the ozone layer and produce a greenhouse effect, the search for new and friendly natural refrigerants has become the field of refrigeration and air conditioning. research focus. Among them, CO ₂ has attracted widespread attention due to its advantages of being non-toxic, non-flammable, safe and environmentally friendly.

However, due to the low critical temperature and high critical pressure of CO ₂ , the throttling loss is large and the refrigeration efficiency is low. Especially when the ambient temperature is high, the refrigeration capacity of CO ₂ drops sharply. If the _CO2 fluid at the outlet of the gas cooler is subcooled, with the increase of subcooling degree, the throttling loss decreases, the circulating cooling capacity increases, and the circulating COP is improved. The subcooling of the _CO2 refrigeration cycle can be achieved by means of internal heat exchangers, mechanical subcooling, thermoelectric subcooling, etc. The cooling load of the refrigeration system used in the supermarket field is much greater during the day than at night, and the electricity price during the day is higher than that at night. The excess cold energy is stored in the cold water of the water tank at night, and the CO ₂ refrigeration system is supercooled by the cold water during the day. It increases the cooling capacity, reduces the compressor discharge pressure, prolongs the service life of the compressor, improves the overall energy efficiency of the refrigeration system, and reduces electricity bills. For large shopping malls and supermarkets, vegetables, beverages, milk, meat and other foods in the store need to be refrigerated or frozen for freshness/preservation. In winter and summer, it is necessary to ensure proper thermal comfort inside the supermarket building. In the supermarket building, it is also necessary to provide hot water for daily life for customers and shopping mall employees. Therefore, for large-scale shopping malls and supermarket buildings, it is necessary to meet various cooling and heating requirements for freezing, refrigeration, cooling/heating, and domestic hot water. If the demand for cooling and heating is supplied independently, it will not only cause waste of cooling and heating energy, but also cause a lot of equipment and take up space.

Utility model content

The purpose of the utility model is to overcome the above-mentioned deficiencies in the prior art, and to provide a cold-storage supercooled transcritical integrated _CO2 refrigeration system.

The utility model is composed of a cold-storage subcooling transcritical integrated _CO2 refrigeration system circulation system, which is composed of a cold water subcooled cold storage circulation system and a transcritical integrated _CO2 refrigeration cycle system coupled; the transcritical integrated _CO2 refrigeration cycle system includes a low-temperature stage compression system. compressor, medium temperature compressor, heat recovery device, gas cooler, throttle valve, evaporator for air conditioner, gas-liquid separator, refrigerator evaporator, freezer evaporator; the medium temperature compressor outlet and heat recovery device The inlet is connected, the outlet of the heat recovery device is connected to the inlet of the gas cooler, the outlet of the gas cooler is connected to the inlet of the high temperature stage throttle valve, the outlet of the high temperature stage throttle valve is connected to the evaporator for air conditioning, and the outlet of the evaporator for air conditioning is first separated by gas and liquid The rear of the compressor is respectively connected with the bypass valve, the medium temperature throttle valve and the low temperature throttle valve; the outlet of the bypass valve is connected with the inlet of the medium temperature compressor; the outlet of the medium temperature throttle valve is connected with the inlet of the evaporator of the refrigerating room, and the refrigerating room evaporates The outlet of the compressor is connected to the inlet of the medium temperature compressor; the outlet of the low temperature throttle valve is connected to the inlet of the freezer chamber evaporator, the outlet of the freezer chamber evaporator is connected to the inlet of the low temperature stage compressor, and the outlet of the low temperature stage compressor is connected to the inlet of the medium temperature stage compressor;

The cold water subcooled cold storage circulation system is composed of a subcooler, an evaporator, a water tank, a water pump, a working fluid pump, a throttle valve and a three-way valve; the water tank outlet is connected to the water pump inlet, and the water pump outlet is connected to the subcooler inlet. , the outlet of the subcooler is connected with the inlet of the water tank, the outlet of the water pump is connected with the inlet of the evaporator, the outlet of the evaporator is connected with the inlet of the water tank; the outlet of the evaporator is connected with the inlet of the gas-liquid separator, and the outlet of the gas-liquid separator is connected with the working fluid pump The outlet of the working fluid pump is connected with the inlet of the throttle valve, and the outlet of the throttle valve is connected with the inlet of the evaporator.

In summer, a transcritical integrated _CO2 refrigeration cycle system is used. The low temperature stage compressor compresses the refrigerant at the outlet of the freezer evaporator to the medium temperature and medium pressure stage evaporation pressure, and the medium temperature and medium pressure saturated gas at the outlet of the freezer evaporator and the bypass refrigerant The medium temperature and medium pressure saturated gas is mixed into the medium temperature stage compressor. The gas is compressed to high temperature and high pressure gas, enters the primary heat recovery device, recovers the heat to heat the tap water to provide domestic hot water, and then enters the gas cooler to exchange heat with the air. The fluid at the outlet of the gas cooler is first throttled by the high-temperature throttle valve, and then enters the air-conditioning evaporator. The medium-temperature and medium-pressure gas-liquid two-phase fluid is evaporated in the air-conditioning evaporator to achieve room cooling, and the gas-liquid two-phase fluid enters the gas-liquid separator. Inside, the gas-liquid separation is realized in the gas-liquid separator, and the liquid is throttled to the medium-temperature and low-temperature cooling evaporators respectively through the medium-temperature and low-temperature stage throttle valves, and evaporates in the evaporators respectively. The mass becomes saturated gas and enters into the low temperature and medium temperature stage compressors for compression. The gas is bypassed into the medium temperature stage compressor to complete the transcritical integrated _CO2 refrigeration cycle for summer use.

In winter, a transcritical integrated CO ₂ refrigeration cycle system is used. The low temperature stage compressor compresses the refrigerant at the outlet of the freezer evaporator to the medium temperature and medium pressure stage evaporation pressure, and the medium temperature and medium pressure saturated gas at the outlet of the freezer evaporator and the bypassed refrigerant. The medium temperature and medium pressure saturated gas is mixed into the medium temperature stage compressor. The gas is compressed to high temperature and high pressure gas, first enters the primary heat recovery device, recovers heat to heat the tap water to provide domestic hot water, and the secondary heat recovery device is used to heat the return water of the heating system to heat the room, and then enter the gas cooler and air heat exchange. The fluid at the outlet of the gas cooler is first throttled by the high temperature throttle valve, and then the gas-liquid two-phase fluid enters the gas-liquid separator, where the gas-liquid separation is realized, and the liquid passes through the medium and low temperature throttle valves respectively. Throttle to medium temperature and low temperature stage cooling evaporators, and evaporate in the evaporators respectively. After heat absorption and evaporation, the working fluid becomes saturated gas and enters into low temperature and medium temperature stage compressors for compression. The gas is bypassed into the medium temperature stage compressor to complete the transcritical integrated _CO2 refrigeration cycle for winter use.

The advantages and positive effects that the utility model has are:

(1) The refrigerant of the CO ₂ refrigeration system is the natural working medium CO ₂ . The GWP of CO ₂ is 1, and the ODP is 0. It is safe, non-toxic, non-flammable, cheap and easy to obtain, and does not decompose to produce harmful gases under high temperature conditions. The subcooling cycle working medium is water, and the refrigerants used in the system are environmentally friendly refrigeration. agent.

(2) During the day, the ambient temperature is high and the cooling load is large, and the electricity price is high; at night, the ambient temperature is low and the cooling load is small, and the electricity price is cheap. At night, the excess cold energy can be stored in the cold water of the water tank at a small electricity cost. During the day, the CO ₂ fluid at the outlet of the gas cooler is supercooled by the cold water, which improves the overall energy efficiency of the system, reduces the high-priced electricity consumption during the day, and improves the overall overall energy efficiency and economy of the system.

(3) The rated cooling capacity of the transcritical integrated CO ₂ refrigeration system can be increased by adding the cold water storage and subcooling system, and the initial investment of the system equipment can be reduced.

(4) Subcooling the _CO2 at the outlet of the gas cooler of the _CO2 system through the cold water storage and subcooling system reduces the exhaust pressure of the compressor, prolongs the service life of the compressor, reduces the operating cost, and reduces the _CO2 temperature before entering the expansion valve, Reduce expansion losses and further reduce _CO2 operating high pressure.

(5) By using two heat recovery devices, domestic hot water supply and room heating in winter are realized, and the overall equipment is reduced, thereby reducing heating costs.

(6) By adding evaporators for air conditioners, the room can be cooled in summer, thereby reducing the cost of air conditioners.

Description of drawings

Fig. 1 is a schematic diagram of the regenerative subcooling transcritical integrated _CO2 refrigeration system of the present invention.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention includes a cold water storage and subcooling cycle system and a CO ₂ transcritical refrigeration cycle system.

Summer implementation: _CO2 transcritical refrigeration cycle low temperature stage compressor 12 absorbs low temperature and low pressure refrigerant at the outlet of freezer evaporator 11, compresses it into superheated gas at medium temperature and medium pressure, and saturated gas at the outlet of freezer evaporator 9 After mixing with the saturated gas at the outlet of the bypass valve 7, it enters the medium temperature stage compressor 1, compresses into high temperature and high pressure gas, and enters the first stage heat recovery device 2. The first stage recovered heat is used to heat domestic water, and then enters the gas cooler 4 and air heat exchange. Afterwards, the refrigerant passes through the high-temperature stage throttle valve 5, enters the air-conditioning evaporator 6 to evaporate, realizes room cooling, and then enters the gas-liquid separator 13, and passes through the bypass valve 7 all the way to become a saturated gas of medium temperature and medium pressure, and passes through the medium temperature stage all the way. After the throttle valve 8 is expanded and throttled, it absorbs the heat of the refrigerating chamber and becomes a saturated gas of medium temperature and medium pressure.

Winter implementation: _CO2 transcritical refrigeration cycle low temperature stage compressor 12 absorbs low temperature and low pressure refrigerant at the outlet of freezer evaporator 11, compresses it into superheated gas at medium temperature and medium pressure, and saturated gas at the outlet of freezer evaporator 9 After mixing with the saturated gas at the outlet of the bypass valve 7, it enters the medium temperature stage compressor 1, compresses into high temperature and high pressure gas, and enters the primary heat recovery device 2. The primary recovered heat is used to heat domestic water, and then enters the secondary heat recovery device 3. , the recovered heat is used for room heating, and then enters the gas cooler 4 to exchange heat with the air. After passing through the pipeline of the working medium three-way valve 14, the refrigerant passes through the high-temperature stage throttle valve 5, and then enters the gas-liquid separator 13, passes through the bypass valve 7 all the way to become a saturated gas of medium temperature and medium pressure, and passes through the medium-temperature stage throttle valve all the way. After expansion and throttling, the flow valve 8 absorbs the heat of the refrigerating chamber and becomes a saturated gas of medium temperature and medium pressure.

Cold water storage cycle: turn on the subcooler during the day and turn off the evaporator. The water pump 18 presses the cold water from the water tank 17 through the pipeline of the cold water three-way valve 19 to the subcooler 15, and exchanges heat with _CO2 to complete the cold water subcooling cycle during the day. Turn on the evaporator at night and turn off the subcooler. The water pump ₁₈ presses the cold water from the water tank 17 to the cold water cold storage circulation evaporator 16, and the working fluid exchanges heat with the water to complete the cold water cold storage cycle at night.

Although the preferred embodiments of the present utility model have been described above in conjunction with the accompanying drawings, the present utility model is not limited to the above-mentioned specific embodiments, which are only illustrative and not restrictive. Under the inspiration of the present utility model, those of ordinary skill can also make many forms without departing from the scope of protection of the present utility model and the claims, which all belong to the protection scope of the present utility model.

Claims (3)

1. Cold accumulation type supercooling transcritical integrated CO₂The refrigerating system is characterized in that the circulating system consists of a cold water supercooling cold accumulation circulating system and transcritical integrated CO₂Refrigeration cycle systemA system coupling component; the transcritical integrated CO₂The refrigeration cycle system comprises a low-temperature stage compressor, a medium-temperature stage compressor, a heat recovery device, a gas cooler, a throttle valve, an evaporator for an air conditioner, a gas-liquid separator, an evaporator for a refrigerating chamber and an evaporator for a freezing chamber; the outlet of the intermediate-temperature stage compressor is connected with the inlet of the heat recovery device, the outlet of the heat recovery device is connected with the inlet of the gas cooler, the outlet of the gas cooler is connected with the inlet of the high-temperature stage throttling valve, the outlet of the high-temperature stage throttling valve is connected with the evaporator for the air conditioner, and the outlet of the evaporator for the air conditioner is connected with the bypass valve, the intermediate-temperature throttling valve and the low-temperature throttling valve respectively after passing through the gas-liquid separator; the outlet of the bypass valve is connected with the inlet of the medium temperature compressor; the outlet of the refrigerating chamber evaporator is connected with the inlet of the medium-temperature compressor; the outlet of the low-temperature throttling valve is connected with the inlet of a freezing chamber evaporator, the outlet of the freezing chamber evaporator is connected with the inlet of a low-temperature stage compressor, and the outlet of the low-temperature stage compressor is connected with the inlet of a medium-temperature stage compressor;

the cold water supercooling cold accumulation circulating system consists of a subcooler, an evaporator, a water tank, a water pump, a working medium pump, a throttle valve and a three-way valve; the outlet of the water tank is connected with the inlet of the water pump, the outlet of the water pump is connected with the inlet of the subcooler, the outlet of the subcooler is connected with the inlet of the water tank, the outlet of the water pump is connected with the inlet of the evaporator, and the outlet of the evaporator is connected with the inlet of the water tank; the evaporator outlet is connected with the inlet of the gas-liquid separator, the outlet of the gas-liquid separator is connected with the working medium pump, the outlet of the working medium pump is connected with the inlet of the throttle valve, and the outlet of the throttle valve is connected with the inlet of the evaporator.

2. The cold storage subcooling transcritical integrated CO of claim 1₂The refrigerating system is characterized in that the evaporator and the subcooler are both counterflow heat exchangers.

3. The cold storage subcooling transcritical integrated CO of claim 1₂Refrigeration system characterized by transcritical integrated CO₂Natural working medium CO is used as refrigerating circulation refrigerant₂Cold water super-cooling cold-storage circulating working mediumIs cold water.

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