CN212274311U - Overlapping heat pump system - Google Patents
Overlapping heat pump system Download PDFInfo
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- CN212274311U CN212274311U CN202021030254.5U CN202021030254U CN212274311U CN 212274311 U CN212274311 U CN 212274311U CN 202021030254 U CN202021030254 U CN 202021030254U CN 212274311 U CN212274311 U CN 212274311U
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Abstract
The utility model discloses a cascade heat pump system, including medium circulation system and CO2 circulation system, the medium circulation system is used for cooling the liquefaction to the refrigerant in the CO2 circulation system, and the ice machine utilizes the cold volume ice-making that CO2 circulation system made; the medium heat exchanger is connected in series in the medium circulating system, and the CO2 heat exchanger is connected in series in the CO2 circulating system and is used for absorbing heat of refrigerant compressed by the compressor in the medium circulating system and the CO2 circulating system so as to raise the water temperature to generate hot water. The CO2 circulating system comprises a CO2 liquid storage device, a CO2 gas-liquid separator and a pressure relief pipeline communicated with the CO2 liquid storage device and the CO2 gas-liquid separator, and a pressure relief assembly is arranged on the pressure relief pipeline. The amount of CO2 filled into the CO2 circulating system is less than the safety value when the pressure relief assembly is in an open state and reaches the set temperature and the internal pressure value of the CO2 circulating system is smaller than the safety value.
Description
Technical Field
The utility model relates to a overlapping heat pump technical field, concretely relates to overlapping heat pump system.
Background
A heat pump unit system in the prior art generally adopts a Freon unit, the heating energy efficiency ratio of the Freon unit is poor after the outdoor temperature is lower than 0 ℃, and the heating quantity is greatly reduced. High operation cost and no energy conservation.
In order to achieve a good heating energy efficiency ratio also in environments below 0 ℃, cascade heat pump systems are now beginning to appear, for example cascade units consisting of HFC or NH3 refrigeration and CO2 refrigeration. However, in the prior art, all the cascade units consisting of HFC or NH3 refrigeration and CO2 refrigeration are large systems, and the units are large, and the cascade units need to keep low temperature and low pressure all the time, otherwise the leakage of CO2 refrigerant is easily caused, which causes safety accidents; that is, in the prior art, a cascade unit composed of HFC or NH3 refrigeration and CO2 refrigeration needs to be provided with a special refrigeration capacity maintaining unit and an uninterruptible power supply to ensure that the CO2 refrigerant in the cascade unit is constantly in a low temperature and low pressure state to ensure safe operation (for example, chinese patent document CN 204478572U).
Because a cold quantity maintaining unit and an uninterruptible power supply need to be equipped, and the cold quantity maintaining unit can be kept in a starting state at any time to maintain the low temperature and low pressure state of the CO2 refrigerant, the overall cost of the CO2 cascade refrigeration equipment in the prior art is higher, the energy consumption is high, and once the power supply is powered off, the potential safety hazard of the leakage of the CO2 refrigerant also exists.
SUMMERY OF THE UTILITY MODEL
Therefore, the to-be-solved technical problem of the present invention is to overcome the CO2 overlapping unit in the prior art, in case of power failure, the temperature and pressure of the refrigerant unit rise easily to cause the defect of CO2 refrigerant leakage, thereby providing an overlapping heat pump system that even under the power failure state, the temperature and pressure all rise to the room temperature, also can not cause the refrigerant leakage.
In order to solve the above problem, the utility model provides a cascade heat pump system, including medium circulation system and CO2 circulation system, medium circulation system is used for right cooling liquefaction is carried out to refrigerant in the CO2 circulation system, still includes:
an ice maker for making ice by using the cold energy produced by the CO2 circulation system;
a heat pump assembly comprising a medium heat exchanger in series in the medium circulation system, and a CO2 heat exchanger in series in the CO2 circulation system, the medium heat exchanger and the CO2 heat exchanger for increasing water temperature to generate hot water;
the CO2 circulating system comprises a CO2 liquid storage device, a CO2 gas-liquid separator and a pressure relief pipeline for communicating the CO2 liquid storage device with the CO2 gas-liquid separator, and a pressure relief assembly is arranged on the pressure relief pipeline;
when the pressure relief assembly is opened, the CO2 liquid storage device and the CO2 gas-liquid separator are communicated;
when the pressure relief assembly is closed, the CO2 liquid storage device and the CO2 gas-liquid separator are switched off and on;
and when the pressure relief assembly is in an open state and reaches a set maximum temperature, the internal pressure value of the CO2 circulating system is smaller than a safe pressure value by filling the amount of CO2 entering the CO2 circulating system.
Preferably, the pressure relief assembly comprises a pressure regulating valve that opens automatically when the pressure in the CO2 reservoir reaches a set point.
As a preferable scheme, the pressure relief assembly further comprises a manual bypass valve, and the manual bypass valve is connected with the pressure regulating valve in parallel.
As a preferable scheme, the CO2 circulating system comprises a CO2 gas-liquid separator, a CO2 compressor, a CO2 oil separator, a CO2 cooler, a medium condenser, the CO2 liquid accumulator, a CO2 throttling expansion valve, an ice maker, a CO2 low-temperature evaporator, a CO2 cooler and a CO2 gas-liquid separator which are connected in sequence; (ii) a
The ice maker further comprises a second pipeline which is connected with the ice maker in parallel, and a second switch valve which is arranged on the second pipeline.
As a preferred scheme, the CO2 heat exchanger is connected in series between the CO2 compressor and the CO2 oil separator;
alternatively, the CO2 heat exchanger is connected in series between the CO2 oil separator and the CO2 cooler.
As a preferable scheme, the medium circulating system comprises a medium gas-liquid separator, a medium compressor, a medium oil separator, a medium subcooler, a medium reservoir, a medium throttle expansion valve, the medium condenser, the medium subcooler and a medium gas-liquid separator which are connected in sequence.
Preferably, the medium heat exchanger is connected in series between the medium compressor and the medium oil separator,
or the medium heat exchanger is connected in series between the medium oil separator and the medium subcooler.
As a preferable scheme, the system also comprises a circulating water supply pipeline which is connected with the medium heat exchanger and the CO2 heat exchanger in series, and a pump, an automatic temperature control valve, a hot water storage tank and a water valve are also connected on the circulating water supply pipeline in series;
a water pipe is communicated between the heat storage water tank and the water valve;
and the water inlet pipe is communicated with the circulating water supply pipeline.
As a preferable scheme, the defrosting device also comprises a defrosting assembly, wherein the defrosting assembly comprises a CO2 regulating valve, a CO2 heater and a defrosting regulating valve; the CO2 regulating valve is connected in series between the CO2 oil separator and the CO2 cooler, one end of the CO2 heater is installed between the CO2 oil separator and the CO2 regulating valve, and the other end of the CO2 heater is connected with the defrosting regulating valve; the other end of the defrosting regulating valve is arranged between the CO2 low-temperature evaporator and the CO2 throttling expansion valve.
Preferably, the system further comprises a first pipeline arranged in parallel with the CO2 low-temperature evaporator, and a first switch valve arranged on the first pipeline.
The utility model discloses a cascade heat pump system, including medium circulation system and CO2 circulation system, the medium circulation system is used for cooling the liquefaction to the refrigerant in the CO2 circulation system, and the ice machine utilizes the cold volume ice-making that CO2 circulation system made; the medium heat exchanger is connected in series in the medium circulating system, and the CO2 heat exchanger is connected in series in the CO2 circulating system and is used for absorbing heat of refrigerant compressed by the compressor in the medium circulating system and the CO2 circulating system so as to raise the water temperature to generate hot water. The CO2 circulating system comprises a CO2 liquid storage device, a CO2 gas-liquid separator and a pressure relief pipeline communicated with the CO2 liquid storage device and the CO2 gas-liquid separator, and a pressure relief assembly is arranged on the pressure relief pipeline. The amount of CO2 filled into the CO2 circulating system is less than the safety value when the pressure relief assembly is in an open state and reaches the set temperature and the internal pressure value of the CO2 circulating system is smaller than the safety value.
That is to say, the utility model discloses a cascade heat pump system has adopted medium circulation system and CO2 circulation system to carry out the cascade, can be used in the region that the room temperature is higher than-45 ℃, under outdoor temperature-45 ℃ of extreme weather, also can produce the hot water more than 60 ℃. Additionally, the utility model discloses a cascade heat pump system, although CO2 has been used as the refrigerant, also need not set up special cold volume alone and maintain the unit, also be equipped with uninterrupted power supply, temperature and pressure rise in leading to CO2 reservoir when long-time outage (initiative outage or passive outage), further lead to liquid CO2 vaporization in the CO2 reservoir to change into high-pressure gaseous state CO2, through the pressure release value of the automatic pressure release subassembly of reasonable settlement, in case pressure in CO2 reservoir reaches above-mentioned pressure release value of setting for, automatic pressure release subassembly is opened, high-pressure gaseous state CO2 in the CO2 reservoir gets into and shares pressure in the CO2 vapour and liquid separator, thereby avoid the too high refrigerant leakage problem that leads to in the CO2 reservoir, and the incident that causes.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic view of a circulation structure of a cascade refrigeration system according to the present invention;
description of reference numerals:
1. a CO2 reservoir; 2. a CO2 gas-liquid separator; 3. a pressure relief pipeline; 4. a manual bypass valve; 5. a pressure regulating valve; 6. a CO2 compressor; 7. a CO2 heat exchanger; 8. a CO2 oil separator; 9. a CO2 regulating valve; 10. a CO2 cooler; 11. a medium condenser; 12. a CO2 throttle expansion valve; 13. a CO2 low temperature evaporator; 14. a CO2 heater; 15. a defrosting regulating valve; 16. an ice maker; 17. a second on-off valve; 18. a medium gas-liquid separator; 19. a medium compressor; 20. a medium oil separator; 21. a medium heat exchanger; 22. a medium subcooler; 23. a media reservoir; 24. a medium throttle expansion valve; 25. a water inlet pipe; 26. a pump; 27. an automatic temperature control valve; 28. a heat storage water tank; 29. a water pipe is used; 30. an air purifier; 31. a first safety valve; 32. a second relief valve; 33. a third relief valve; 34. a fourth relief valve; 35. a first on-off valve; 36. a water valve.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Examples
The embodiment provides a cascade heat pump system, which comprises a medium circulating system and a CO2 circulating system, wherein the medium circulating system is a high-temperature system, the CO2 circulating system is a low-temperature system, and the medium circulating system is used for cooling and liquefying refrigerant in the CO2 circulating system, is not in contact with the outside and is a single closed-loop circulating system. The filling amount of the medium refrigerant is small, and the filling amount of the common maximum unit does not exceed 200kg, so that the energy-saving effect is achieved.
When the cascade heat pump system operates, the required temperature can be set according to the working condition requirement, so that the high-temperature system liquefies the refrigerant CO2 in the low-temperature system under the optimal energy-saving operating condition, the liquefied CO2 flows into a CO2 liquid storage device by utilizing high-low pressure difference, the pressure vaporization is reduced by a CO2 throttling expansion valve to generate cold energy, and ice making cold energy is provided for an ice maker. The low-temperature system can also automatically adjust the vaporization amount of CO2 according to the requirement of the refrigeration working condition, and the external environment is cooled under the optimal energy-saving working condition, so that the high energy-saving effect can be achieved.
The cascade heat pump system of the embodiment is suitable for various working conditions with outdoor temperature of more than-45 ℃.
The following is a detailed description:
as shown in fig. 1, the present embodiment provides a cascade refrigeration system, which includes a medium circulation system and a CO2 circulation system, wherein the medium circulation system is used for refrigerating and liquefying CO2 refrigerant in the CO2 circulation system.
Specifically, the medium circulation system includes: the medium gas-liquid separator 18, the medium compressor 19, the medium oil separator 20, the medium subcooler 22, the medium reservoir 23, the medium throttle expansion valve 24, the medium condenser 11, the medium subcooler 22 and the medium gas-liquid separator 18 are connected in sequence.
The refrigeration process of the medium circulating system is as follows: the refrigeration medium is compressed by the medium compressor 19 to become a high-temperature high-pressure state, the refrigerant is subjected to oil-gas separation by the medium oil separator 20 and enters the medium subcooler 22, the liquid refrigeration medium enters the medium reservoir 23 after being cooled, the refrigerant is expanded by the medium throttle expansion valve 24 and then cooled and enters the medium condenser 11 for cooling the CO2 refrigerant in the CO2 circulating system, the refrigeration medium enters the medium subcooler 22 after passing through the medium condenser 11, the refrigeration medium passing through the cooler 22 is cooled by utilizing the residual cold energy, and finally enters the medium gas-liquid separator 18, and the gaseous refrigeration medium enters the medium compressor 19 after being subjected to gas-liquid separation, so that a refrigeration cycle is completed.
In this embodiment, the refrigeration medium in the medium circulation system is freon or ammonia. To ensure safety, a third relief valve 33 is installed in the medium gas-liquid separator 18, and a fourth relief valve 34 is installed in the medium reservoir 23.
The CO2 circulation system includes: the system comprises a CO2 gas-liquid separator 2, a CO2 compressor 6, a CO2 oil separator 8, a CO2 cooler 10, a medium condenser 11, a CO2 liquid storage tank 1, a CO2 throttle expansion valve 12, an ice maker 16, a CO2 low-temperature evaporator 13, a CO2 cooler 10 and a CO2 gas-liquid separator 2 which are connected in sequence; a second pipeline arranged in parallel with the ice maker 16 and a second on-off valve 17 arranged on the second pipeline are also included.
The refrigeration process of the CO2 circulating system is as follows: when a medium circulating system cools CO2 refrigerant in a CO2 liquid storage tank 1 to a temperature set by a program, a low-temperature-level CO2 circulating system is started, CO2 is compressed by a CO2 compressor 6 and becomes a high-temperature and high-pressure state, the high-temperature and high-pressure state is subjected to oil-gas separation by a CO2 oil separator 8 and enters a CO2 cooler 10, the cooled CO2 enters a medium condenser 11 to receive the temperature reduction of the medium circulating system, at the moment, CO2 is basically cooled to be in a liquid state, enters the CO2 liquid storage tank 1, is expanded by a CO2 throttling expansion valve 12 and enters an ice maker 16 to provide cold for the ice maker; then the gas enters a CO2 low-temperature evaporator 13 to absorb external heat, the gas enters a CO2 gas-liquid separator 2 after cold recovery through a CO2 subcooler 10, and the gas CO2 enters a CO2 compressor 6 after gas-liquid separation, so that a refrigeration cycle is completed.
In the CO2 circulating system, a pressure relief pipeline 3 is communicated between a CO2 liquid storage device 1 and a CO2 gas-liquid separator 2, an automatic pressure relief assembly is arranged on the pressure relief pipeline 3, and the automatic pressure relief assembly is automatically opened when the pressure in the CO2 liquid storage device 1 reaches a set value; when the automatic pressure relief assembly is opened, the CO2 liquid storage device 1 and the CO2 gas-liquid separator 2 are communicated; when the automatic pressure relief assembly is closed, the CO2 reservoir 1 and the CO2 gas-liquid separator 2 are switched off.
In particular, the CO2 cycle system of this embodiment is filled with an amount of incoming CO2, and when the automatic pressure relief valve is in an open state and reaches a set maximum temperature (e.g., the highest natural temperature that can be reached when the entire cascade refrigeration system is completely shut down, such as 40 degrees), the pressure is less than a safe pressure value (e.g., 3.3 MPa).
That is, the HFC (NH3)/CO2 cascade heat pump unit of this embodiment adopts a unique medium-low pressure design, and the maximum pressure of the high-pressure section does not exceed 5MPa and the maximum pressure of the low-pressure section does not exceed 3.5MPa at normal temperature (≦ 40 °) for a long time of shutdown, and refrigerant leakage cannot be caused by overpressure even if the unit is shutdown for a long time. After starting up and running, the highest pressure of the high-pressure section is not more than 4.5MPa, and the highest pressure of the low-pressure section is not more than 2.0 MPa.
A second pipeline which is arranged in parallel with the ice maker 16 and a second switch valve 17 which is arranged on the second pipeline are also included; when the ice maker 16 finishes making ice or otherwise does not need to supply cold energy to the ice maker 16, the second switch valve 17 can be opened to allow cold energy to bypass the ice maker 16.
As an improvement, a first safety valve 31 is arranged on the CO2 gas-liquid separator 2, and a second safety valve 32 is arranged on the CO2 liquid storage tank 1. In case of an accident situation causing the pressure inside the CO2 circulation system to be too high, either the first safety valve 31 or the second safety valve 32 can open for pressure relief.
As can be seen from the above description, the cascade heat pump system of this embodiment does not have to separately provide a dedicated cold quantity maintaining unit, and does not have to be equipped with an uninterruptible power supply, when a long-time power failure (active power failure or passive power failure) causes a temperature and a pressure increase in the CO2 liquid reservoir 1, and further causes the liquid CO2 in the CO2 liquid reservoir 1 to vaporize and convert into high-pressure gaseous CO2, by reasonably setting a pressure relief value of the automatic pressure relief assembly, once the pressure in the CO2 liquid reservoir 1 reaches the above set pressure relief value, the automatic pressure relief assembly is opened, and the high-pressure gaseous CO2 in the CO2 liquid reservoir 1 enters the CO2 gas-liquid separator 2 to share the pressure, thereby avoiding a refrigerant leakage problem caused by an excessively high pressure in the CO 2. Of course, the refrigerant charge to the CO2 accumulator 1 needs to be calculated in advance, and normally, the refrigerant in the CO2 accumulator 1 is smaller than the volume in the CO2 gas-liquid separator 2, so as to avoid the situation of excessive overpressure charging. Meanwhile, the first safety valve 31 and the second safety valve 32 are arranged, so that the pressure in the CO2 gas-liquid separator 2 and the CO2 liquid storage device 1 does not exceed a specified value, and an important protection effect is achieved on personal safety and equipment operation.
The automatic pressure relief assembly comprises a pressure regulating valve 5, wherein the pressure regulating valve 5 is of a spring self-supporting type and can be automatically opened when the pressure in the CO2 liquid storage device 1 reaches a set value; when the pressure regulating valve 5 is used, only the preset pressure needs to be set in advance, and the pressure regulating valve can be used without being communicated with a power supply. This embodiment employs a common commercially available spring self-contained pressure regulator valve.
As a further improvement, as shown in fig. 1, a manual bypass valve 4 is further disposed on the pressure relief pipeline 3, the manual bypass valve 4 is disposed in parallel with the pressure regulating valve 5, and when the pressure regulating valve 5 fails or the refrigeration system is not used for a long time (e.g., no people are on duty during holidays), the manual bypass valve 4 is manually opened to allow high-pressure gas of refrigerant in the CO2 accumulator 1 to enter the CO2 gas-liquid separator 2, so as to avoid the situation that the refrigerant leaks due to overhigh pressure in the CO2 accumulator 1 caused by temperature rise.
In the embodiment, the medium circulating system only has the function of cooling and liquefying the CO2 refrigerant in the CO2 circulating system, does not contact with the outside and is an independent closed-circuit circulating system, so that the charging amount of HFC or NH3 refrigerant is very small, the charging amount of the largest model is not more than 200kg, the medium circulating system is safe and environment-friendly, and the refrigerant is saved. The lowest evaporation temperature of the medium circulating system does not exceed minus 26 ℃, and the medium circulating system is in the optimal energy-saving working condition of HFC or NH3 refrigeration. The evaporation temperature of the CO2 circulating system can be set between-20 and-56 degrees according to the requirement of the refrigeration condition.
The system also comprises a circulating water supply pipeline which is connected with the medium heat exchanger 21 and the CO2 heat exchanger 7 in series, and a pump 26, an automatic temperature control valve 27, a hot water storage tank 28 and a water valve 36 are also connected on the circulating water supply pipeline in series; a water using pipe 29 is communicated between the hot water storage tank 28 and the water valve 36; and a water inlet pipe 25 communicated with the circulating water supply pipeline.
In the heat storage stage, the water inlet pipe 25 is closed, the water using pipe 29 is closed, the water valve 36 is opened, the pump 26 is opened, water is driven to circularly run along the circulating water supply pipeline, and water flows through the medium heat exchanger 21 and the CO2 heat exchanger 7 to be gradually heated until the water in the heat storage water tank 28 is heated to the target temperature, and at the moment, heating can be stopped.
When water is used, the water pipe 29 can be directly opened, and hot water is available after the water pipe is opened.
When the water in the heat storage water tank 28 is insufficient, the water using pipe 29 and the water valve 36 are closed, the water inlet pipe 25 and the pump 26 are opened, at this time, the external water flow is continuously conveyed into the heat storage water tank 28, when the water in the heat storage water tank 28 is sufficient, the water inlet pipe 25 can be closed, the water valve 36 is opened, and the water is circularly heated.
The water inlet pipe 25 can also be directly connected with the heat storage water tank 28 to directly add water to the heat storage water tank 28.
The defrosting device also comprises a defrosting assembly, wherein the defrosting assembly comprises a CO2 regulating valve 9, a CO2 heater 14 and a defrosting regulating valve 15; the CO2 regulating valve 9 is connected in series between the CO2 oil separator 8 and the CO2 cooler 10, one end of the CO2 heater 14 is installed between the CO2 oil separator 8 and the CO2 regulating valve 9, and the other end is connected with the defrosting regulating valve 15; the other end of the defrosting regulating valve 15 is installed between the CO2 low-temperature evaporator 13 and the CO2 throttling expansion valve 12.
When the ice maker 16 or the CO2 low-temperature evaporator 13 needs to be defrosted, the medium circulating system is closed, the CO2 throttling expansion valve 12 and the CO2 regulating valve 9 are closed, the CO2 compressor 6 is started, and CO2 gas is driven to circularly run along the CO2 heat exchanger 7, the CO2 oil separator 8, the defrosting regulating valve 15, the ice maker 16, the CO2 low-temperature evaporator 13, the CO2 cooler 10, the CO2 gas-liquid separator 2 and the CO2 compressor 6.
The heat source can come from the hot water storage tank 28, and the specific method is as follows: the pump 26 is started, hot water stored in the hot water storage tank 28 flows through the medium heat exchanger 21, the CO2 heat exchanger 7, the automatic temperature control valve 27 and the hot water storage tank 28 along a circulating water supply pipeline to circularly run, the high temperature of the hot water is exchanged to CO2 in a CO2 circulating system through the CO2 heat exchanger 7, and the ice maker 16 or the CO2 low-temperature evaporator 13 is defrosted by high-temperature CO2 gas.
The heat source can also come from a CO2 heater, specifically, a CO2 heater 14 is connected in series between the CO2 oil separator 8 and the defrosting regulating valve 15, the CO2 heater 14 heats CO2 in the CO2 circulating system, and the ice maker 16 or the CO2 low-temperature evaporator 13 is defrosted by high-temperature CO2 gas.
Of course, both heat sources may be activated simultaneously.
The CO2 heater 14 in the embodiment adopts an external design, and the CO2 heater 14 adopts a tube array design, so that the CO2 refrigerant is directly heated and is not in a cold storage or a CO2 evaporator, and a fire disaster and a safety accident are prevented from being caused. When the hot water in the hot water storage tank 28 is used for defrosting, the temperature can be set to be lower than the set temperature, the electric heating is started, and the electric heating is turned off when the set temperature is reached. The electric heating pipe is externally arranged and directly inserted into the tube nest of the heater, is not directly contacted with the CO2 refrigerant, and is easy to replace.
The CO2 circulation system further includes a second on-off valve 17 connected in parallel with the ice maker 16, wherein when defrosting of the ice maker 16 is required, the second on-off valve 17 is closed, and when defrosting of the ice maker 16 is not required, the second on-off valve 17 is opened.
The CO2 circulating system further comprises a first switch valve 35 which is connected in parallel with the CO2 low-temperature evaporator 13, when the defrosting treatment of the CO2 low-temperature evaporator 13 is needed, the second switch valve 17 is closed, and when the defrosting treatment of the CO2 low-temperature evaporator 13 is not needed, the second switch valve 17 is opened.
The air purifier 30 is arranged at the position of an air suction opening of the CO2 low-temperature evaporator 13, and the fan on the CO2 low-temperature evaporator 13 is used for purifying air, so that the purposes of one machine, multiple purposes, energy conservation and emission reduction are achieved.
All HFC (NH3)/CO2 superposed units which are put into use in the prior art of the same type are large systems, the units are huge, and the units can be installed only in large refrigeration houses or places needing large cooling capacity. The CO2 refrigerant of the refrigerating unit system needs refrigeration capacity to maintain the unit to keep low temperature and low pressure, an uninterruptible power supply needs to be equipped, the refrigerating unit system cannot interrupt the power supply, the refrigeration capacity maintaining unit cannot run after power failure, and the refrigerant leakage and safety accidents are easily caused by the increase of temperature and pressure. The refrigerating unit system needs a refrigerant liquid supply pump to supply liquid, the filling amount of the refrigerant is large, all equipment, pipelines and valve accessories need to be installed on site, and the occupied area of the unit system is large. The existing experimental miniaturized unit is a supercritical unit, the pressure is up to more than 10MPa, and the pressure is too high, unsafe and not suitable for popularization and application. The cascade refrigeration system of the embodiment has the advantages of small refrigerant charging amount and lower cost.
The heat pump unit of the embodiment can be installed underground, does not occupy the ground space, can be installed in underground spaces such as parking lots, public greenbelts, farmer markets and shopping malls, the ground only has an atmospheric suction inlet and a cold air outlet, and is very suitable for heating urban areas with valuable ground space, a distributed energy heat supply design is adopted, a heating area of 30-60 ten thousand square is taken as a heating range, a suitable underground space is selected, the freon/carbon dioxide overlapping heat pump unit is installed underground, the ground is provided with the atmospheric suction inlet and the cold air outlet (the atmospheric inlet and the atmospheric outlet can be respectively combined together for sharing), an ice maker and an air purification system are installed in a matching way, the air purification system is installed at the atmospheric suction inlet, each heat pump unit is matched with an ice maker to produce ice blocks while producing hot water, and the ice blocks can be wholesale to restaurants, fresh-keeping distribution, fishing boat and other customers needing fresh-keeping), one heat pump unit can heat 1 ten thousand square when the outdoor minimum temperature is more than-20 ℃, the power consumption per hour is 800kw, ice can be produced by 4.7 tons (the evaporation temperature is-30 ℃) after being used for making ice, the calculated power consumption per ton of ice is 170kw, the wholesale price per ton of ice is 260 yuan, the average electric charge is 0.7 yuan/kw, the electric charge per 170kw is 119 yuan, the water charge per 1 ton is 6 yuan, the artificial machinery cost per 1 ton is 20 yuan, the total production cost per ton of ice is 145 yuan, the gross profit is 115 yuan, if the water tank is heated and enlarged, the electric charge can be further reduced, the Freon/carbon dioxide multi-functional heat pump unit is reasonably and comprehensively utilized, the heating, hot water production, atmosphere purification and ice making can save energy and reduce emission and generate certain economic benefit, and the heat pump unit is very suitable for urban heating areas with the outdoor minimum temperature being more than-20 ℃ and places (small areas) needing a large amount of hot, Bath centers, hotels, etc.).
In the cascade refrigeration system in this embodiment, when a plurality of cascade refrigeration systems need to be modularly combined, the cold water inlet 25 is connected in parallel with the cold water inlets 25 of other cascade refrigeration systems, the hot water outlet 29 is connected in parallel with the hot water outlets 29 of the other cascade refrigeration systems, and a valve is additionally installed at the connection position and can be cut off if necessary. And a PLC automatic control system can be adopted, and heating can be automatically switched on and off according to needs.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.
Claims (10)
1. A cascade heat pump system comprises a medium circulation system and CO2A medium circulation system for supplying CO2The refrigerant in the circulating system is cooled and liquefied, and is characterized in that: further comprising:
an ice maker (16) using the CO2Making ice by using cold energy produced by the circulating system;
a heat pump assembly comprising a medium heat exchanger (21) in series in the medium circulation system, and a heat exchanger in series in the CO2CO in a circulating system2A heat exchanger (7), the medium heat exchanger (21) and the CO2The heat exchanger (7) is used for increasing the water temperature to generate hot water;
the CO is2The circulation system comprises CO2Reservoir (1), CO2A gas-liquid separator (2) and a gas-liquid separator communicating with the CO2A reservoir (1) and the CO2Gas-liquid separationA pressure relief pipeline (3) of the separator (2), wherein a pressure relief assembly is arranged on the pressure relief pipeline (3);
when the pressure relief component is opened, the CO2A reservoir (1) and the CO2The gas-liquid separator (2) is communicated;
when the pressure relief component is closed, the CO2A reservoir (1) and the CO2The gas-liquid separator (2) is switched off and on;
charging into the CO2CO in the circulating system2Amount, when the pressure relief component is in an open state and reaches a set maximum temperature, the CO2The internal pressure value of the circulating system is smaller than the safety pressure value.
2. The cascade heat pump system of claim 1, wherein: the pressure relief assembly comprises a pressure regulating valve (5), and the pressure regulating valve (5) is arranged on the CO2The pressure in the liquid storage device (1) is automatically opened when reaching a set value.
3. The cascade heat pump system of claim 2, wherein: the pressure relief assembly further comprises a manual bypass valve (4), and the manual bypass valve (4) and the pressure regulating valve (5) are connected in parallel.
4. The cascade heat pump system according to any one of claims 1-3, wherein: the CO is2The circulation system comprises sequentially connected CO2Gas-liquid separator (2), CO2Compressor (6), CO2Oil separator (8), CO2A cooler (10), a medium condenser (11), CO2Reservoir (1), CO2A throttle expansion valve (12), an ice maker (16), CO2Low temperature evaporator (13), CO2Cooler (10) and CO2A gas-liquid separator (2);
the ice maker further comprises a second pipeline arranged in parallel with the ice maker (16), and a second switch valve (17) arranged on the second pipeline.
5. The cascade heat pump system of claim 4, wherein the cascade heat pump system comprisesThe method comprises the following steps: the CO is2A heat exchanger (7) is connected in series with the CO2Compressor (6) and the CO2Between the oil separators (8);
or, the CO2A heat exchanger (7) is connected in series with the CO2An oil separator (8) and the CO2Between the coolers (10).
6. The cascade heat pump system according to any one of claims 1-3, wherein: the medium circulating system comprises a medium gas-liquid separator (18), a medium compressor (19), a medium oil separator (20), a medium subcooler (22), a medium reservoir (23), a medium throttle expansion valve (24), a medium condenser (11), a medium subcooler (22) and a medium gas-liquid separator (18) which are connected in sequence.
7. The cascade heat pump system of claim 6, wherein: the medium heat exchanger (21) is connected in series between the medium compressor (19) and the medium oil separator (20),
or the medium heat exchanger (21) is connected in series between the medium oil separator (20) and the medium subcooler (22).
8. The cascade heat pump system according to any one of claims 1-3, wherein: further comprising connecting the medium heat exchanger (21) and the CO in series2A circulating water supply pipeline of the heat exchanger (7), wherein a pump (26), an automatic temperature control valve (27), a heat storage water tank (28) and a water valve (36) are also connected in series on the circulating water supply pipeline;
a water using pipe (29) is communicated between the hot water storage tank (28) and the water valve (36);
and the water inlet pipe (25) is communicated with the circulating water supply pipeline.
9. The cascade heat pump system of claim 4, wherein: also comprises a defrosting component, wherein the defrosting component comprises CO2Regulating valve (9), CO2A heater (14) and a defrosting regulating valve (15); the CO is2A regulating valve (9) is connected in series with the CO2An oil separator (8) and the CO2Between coolers (10), the CO2One end of the heater (14) is mounted on the CO2An oil separator (8) and the CO2The other end of the regulating valve (9) is connected with the defrosting regulating valve (15); the other end of the defrosting regulating valve (15) is arranged on the CO2 low-temperature evaporator (13) and the CO2Between the throttle expansion valves (12).
10. The cascade heat pump system of claim 9, wherein: further comprising reacting with the CO2The low-temperature evaporator (13) is connected with a first pipeline in parallel, and a first switch valve (35) is arranged on the first pipeline.
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| CN202021030254.5U CN212274311U (en) | 2020-06-08 | 2020-06-08 | Overlapping heat pump system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021030254.5U CN212274311U (en) | 2020-06-08 | 2020-06-08 | Overlapping heat pump system |
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| CN212274311U true CN212274311U (en) | 2021-01-01 |
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