阅读说明：本技术 二氧化碳制冷系统和方法 (Carbon dioxide refrigeration system and method ) 是由 雒志明 于 2021-11-15 设计创作，主要内容包括：本公开提供了一种二氧化碳制冷系统和方法,涉及制冷技术领域,尤其涉及数据中心室内制冷技术。所述二氧化碳制冷系统包括：蒸发冷凝器和背板换热末端；所述背板换热末端具有第一换热器,所述第一换热器用于液态二氧化碳与室内热量进行第一次热交换；所述蒸发冷凝器具有控制装置,且表面设置有喷淋湿膜,所述控制装置用于根据预设湿球温度控制所述喷淋湿膜；所述蒸发冷凝器还具有第二换热器,所述第二换热器用于承载室内热量的气态二氧化碳与所述预设湿球温度的所述室外气体进行第二次热交换,得到液态二氧化碳。(The disclosure provides a carbon dioxide refrigeration system and method, relates to the technical field of refrigeration, and particularly relates to an indoor refrigeration technology of a data center. The carbon dioxide refrigeration system includes: the evaporative condenser and the back plate heat exchange tail end; the heat exchange tail end of the back plate is provided with a first heat exchanger, and the first heat exchanger is used for carrying out first heat exchange on liquid carbon dioxide and indoor heat; the evaporative condenser is provided with a control device, a spraying wet film is arranged on the surface of the evaporative condenser, and the control device is used for controlling the spraying wet film according to the preset wet bulb temperature; the evaporative condenser is also provided with a second heat exchanger, and the second heat exchanger is used for carrying out secondary heat exchange on the gaseous carbon dioxide of the indoor heat and the outdoor gas with the preset wet bulb temperature to obtain liquid carbon dioxide.)

1. A carbon dioxide refrigeration system, the system comprising: an evaporative condenser (8) and a back plate heat exchange end (12);

the back plate heat exchange tail end (12) is provided with a first heat exchanger, and the first heat exchanger is used for carrying out first heat exchange on liquid carbon dioxide and indoor heat to obtain gaseous carbon dioxide bearing the indoor heat;

the evaporative condenser (8) is provided with a control device, a spraying wet film (18) is arranged on the surface of the evaporative condenser, the control device is used for controlling the spraying wet film (18) according to a preset wet bulb temperature, and the spraying wet film (18) is used for humidifying outdoor gas (20) with the wet bulb temperature higher than the preset wet bulb temperature so that the temperature of the outdoor gas (20) is less than or equal to the preset wet bulb temperature;

the evaporative condenser (8) is further provided with a second heat exchanger (22), and the second heat exchanger (22) is used for carrying gaseous carbon dioxide of indoor heat and outdoor gas (20) with the temperature less than or equal to the preset wet bulb temperature to carry out secondary heat exchange to obtain liquid carbon dioxide.

2. The system of claim 1, wherein the system further comprises: a carbon dioxide liquid pump (10) and a carbon dioxide oil-free compressor (14);

the carbon dioxide oil-free compressor (14) is used for compressing the gaseous carbon dioxide carrying indoor heat; one end of the carbon dioxide oil-free compressor (14) is connected with one end of the evaporative condenser (8), and the other end of the carbon dioxide oil-free compressor (14) is connected with one end of the back plate heat exchange tail end (12) through a filter (13);

the carbon dioxide liquid pump (10) is used for outputting liquid carbon dioxide to the back plate heat exchange tail end (12); one end of the carbon dioxide liquid pump (10) is connected with the other end of the evaporative condenser (8) through a liquid storage tank (9); the other end of the carbon dioxide liquid pump (10) is connected with the other end of the back plate heat exchange tail end (12) through a first electronic expansion valve (11).

3. The system according to claim 1, wherein the evaporative condenser (8) comprises: a fan (16) and a water distributor (21);

the water distributor (21) is arranged between the spraying wet film (18) and the second heat exchanger (22) and is used for filtering the outdoor gas (20);

and the fan (16) is arranged at an exhaust outlet of the evaporative condenser (8) and is used for exhausting the gas after the second heat exchange.

4. The system of claim 1, wherein the system further comprises: a liquid supply pipe network (23), a shut-off valve (24), an air return pipe network (25), a shut-off ball valve (26), a second electronic expansion valve (27), a pressure sensor (28) and a temperature sensor (29);

each back plate heat exchange tail end (12) is provided with a shutoff ball valve (26), a second electronic expansion valve (27), a pressure sensor (28) and a temperature sensor (29);

one end of each back plate heat exchange tail end (12) is connected with the air return pipe network (25) through a shutoff ball valve (26) and a second electronic expansion valve (27);

one end of each back plate heat exchange tail end (12) is connected with the liquid supply pipe network (23) through a pressure sensor (28) and a temperature sensor (29);

the shutoff valve (24) is arranged on the liquid supply pipe network (23) and the gas return pipe network (25).

5. A carbon dioxide refrigeration process, the process comprising:

carrying out first heat exchange on the liquid carbon dioxide and indoor heat based on a first heat exchanger at the heat exchange tail end of the back plate to obtain gaseous carbon dioxide bearing the indoor heat;

in response to the outdoor gas being greater than the preset wet bulb temperature, determining that a control device controls a spray wet film to humidify the outdoor gas so that the outdoor gas is less than or equal to the preset wet bulb temperature;

and carrying out secondary heat exchange on the outdoor gas with the temperature less than or equal to the preset wet bulb temperature and the gaseous carbon dioxide bearing indoor heat according to a second heat exchanger of the evaporative condenser to obtain liquid carbon dioxide.

6. The method of claim 5, wherein the first heat exchanger based on the back plate heat exchange end performs a first heat exchange between the liquid carbon dioxide and the indoor heat to obtain gaseous carbon dioxide carrying the indoor heat, and comprises:

storing the obtained liquid carbon dioxide in a liquid storage tank;

the numerical value of liquid carbon dioxide output by the liquid storage tank is adjusted based on the electric signal obtained by the first electronic expansion valve, and the liquid carbon dioxide is output to the heat exchange tail end of the back plate by the carbon dioxide liquid pump;

performing first heat exchange between liquid carbon dioxide and indoor heat, and filtering the heat-exchanged gaseous carbon dioxide based on a filter;

outputting the filtered gaseous carbon dioxide to the evaporative condenser based on a carbon dioxide oil-free compressor to obtain the gaseous carbon dioxide bearing indoor heat.

7. The method of claim 5, wherein the second heat exchanger according to the evaporative condenser is used for performing second heat exchange on the outdoor air with the temperature less than or equal to the preset wet bulb temperature and the gaseous carbon dioxide carrying indoor heat to obtain liquid carbon dioxide, and the second heat exchanger comprises:

filtering the outdoor gas with the temperature less than or equal to the preset wet bulb temperature by using a water distributor, and carrying out secondary heat exchange on the filtered outdoor gas and gaseous carbon dioxide bearing indoor heat to obtain liquid carbon dioxide;

and exhausting the gas carrying the indoor heat to the atmosphere through a fan.

8. The method of claim 5, wherein the method further comprises:

controlling the states of a shutoff ball valve and a second electronic expansion valve which are arranged at the heat exchange tail end of each back plate based on a pressure sensor and a temperature sensor;

determining the connection or disconnection of the heat exchange tail end of the back plate and the liquid supply pipe network based on the states of the shutoff ball valve and the second electronic expansion valve;

and controlling the connection or disconnection of the heat exchange tail end of the back plate and the return pipe network based on the shutoff valve.

Technical Field

The disclosure relates to the technical field of refrigeration, in particular to a data center indoor refrigeration technology, and specifically relates to a carbon dioxide refrigeration system and a carbon dioxide refrigeration method.

Background

With the development of internet technology, the demand of data centers is increasing in recent years, and a large number of servers in a data center generate a large amount of heat when operating, so that a uniform cooling system needs to be provided for the servers operating in the data center to avoid the increase of power consumption caused by the generated large amount of heat.

Disclosure of Invention

The present disclosure provides a carbon dioxide refrigeration system and method.

According to a first aspect of the present disclosure, there is provided a carbon dioxide refrigeration system, the system comprising: the evaporative condenser and the back plate heat exchange tail end;

the heat exchange tail end of the back plate is provided with a first heat exchanger, and the first heat exchanger is used for carrying out first heat exchange on liquid carbon dioxide and indoor heat to obtain gaseous carbon dioxide bearing the indoor heat;

the evaporative condenser is provided with a control device, a spraying wet film is arranged on the surface of the evaporative condenser, the control device is used for controlling the on and off of the spraying wet film according to the preset wet bulb temperature, and the spraying wet film is used for humidifying outdoor gas with the wet bulb temperature higher than the preset wet bulb temperature so as to enable the outdoor gas to be less than or equal to the preset wet bulb temperature;

the evaporative condenser is also provided with a second heat exchanger, and the second heat exchanger is used for carrying out secondary heat exchange on gaseous carbon dioxide of indoor heat and the outdoor gas with the temperature less than or equal to the preset wet bulb temperature to obtain liquid carbon dioxide.

According to a second aspect of the present disclosure, there is provided a carbon dioxide refrigeration process, the process comprising: carrying out first heat exchange on the liquid carbon dioxide and indoor heat based on a first heat exchanger at the heat exchange tail end of the back plate to obtain gaseous carbon dioxide bearing the indoor heat; in response to the outdoor gas being greater than the preset wet bulb temperature, determining that a control device controls a spray wet film to humidify the outdoor gas so that the outdoor gas is less than or equal to the preset wet bulb temperature; and carrying out secondary heat exchange on the outdoor gas with the temperature less than or equal to the preset wet bulb temperature and the gaseous carbon dioxide bearing indoor heat according to a second heat exchanger of the evaporative condenser to obtain liquid carbon dioxide.

According to a third aspect of the present disclosure, there is provided an electronic device comprising:

at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of the second aspect.

According to a fourth aspect of the present disclosure, there is provided a non-transitory computer readable storage medium having stored thereon computer instructions for causing the computer to perform the method according to the second aspect.

It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present disclosure, nor do they limit the scope of the present disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The drawings are included to provide a better understanding of the present solution and are not to be construed as limiting the present disclosure. Wherein:

FIG. 1 is a schematic flow diagram of refrigeration with water provided by an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a carbon dioxide refrigeration system provided by an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of an evaporative condenser provided in an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a heat exchange end structure of a back plate provided in an embodiment of the present disclosure;

FIG. 5 is a schematic flow diagram of a carbon dioxide refrigeration process provided by an embodiment of the present disclosure;

wherein, 1-a cooling tower, 2-a shut-off valve, 3-a water chilling unit, 4-a water pump, 5-an air conditioner terminal, 6-a main water pump, 7-a cooling water pump, 8-an evaporative condenser, 9-a liquid storage tank, 10-a carbon dioxide liquid pump, 11-a first electronic expansion valve, 12-a back plate heat exchange terminal, 13-a filter, 14-a carbon dioxide oil-free compressor, 15-a coil, 16-a fan, 17-exhaust air, 18-a spray wet film, 19-cooling air, 20-outdoor gas, 21-a water distributor, 22-a second heat exchanger, 23-a liquid supply pipe network, 24-a shut-off valve, 25-an air return pipe network, 26-a shut-off ball valve, 27-a second electronic expansion valve and 28-a pressure sensor, 29-temperature sensor.

Detailed Description

Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings, in which various details of the embodiments of the disclosure are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

With the development of internet technology, the demand of data centers is increasing in recent years, and a large number of servers in the data centers generate a large amount of heat when operating, so that the data centers need to be cooled. In the cooling process, in order to achieve the green and energy-saving effect of the data center, water is mostly adopted as the refrigerating system secondary refrigerant in the related technology. Fig. 1 shows a schematic flow chart of refrigeration with water provided by an embodiment of the present disclosure.

As shown in fig. 1, an Operation Control Unit (OCU) cooling scheme of a data center is composed of a cooling tower 1, a water chilling Unit 3, a water pump 4 and a terminal heat exchanger of an air conditioner terminal 5, and a shut-off valve 2 can Control water flow. The principle of the system can be understood as that water resources (for example, 15 ℃) with certain water temperature in the system exchange heat with an indoor heat source through a terminal heat exchanger of an air conditioner terminal 5 to obtain water resources (for example, 21 ℃) bearing indoor heat, and the water resources at 21 ℃ are output to the water chilling unit 3 through the main water pump 6. The water chilling unit 3 obtains a water resource at a specified temperature (for example, 39 ℃) through treatment, the refrigeration cycle finally carries out heat exchange on the water resource at the temperature of 39 ℃ and the outdoor temperature through the cooling tower 1, and the heat after the heat exchange is dissipated to the atmospheric environment to obtain the water resource at the temperature of 33 ℃ for example. The cooling water pump 7 outputs the water resource with the temperature of 33 ℃ to the water chilling unit 3, and the temperature of the water resource is reduced to 15 ℃ again through the water chilling unit 3, so that the circulation is realized.

However, if water is used as the refrigerant of the refrigeration system, the cooling capacity per unit volume is limited, the power consumption of the system is large, and the outdoor cooling tower 1 of the system adopts evaporation heat exchange and consumes large amount of water, so that certain environmental protection problems exist.

In view of the above technical problems, the present disclosure provides a refrigeration system using carbon dioxide (CO2) as a refrigerant. The heat insulation phase change circulation is utilized to reduce the water consumption and energy consumption of the data center, indoor refrigeration is realized through the conversion of the CO2 state, and the CO2 is used as a natural object and cannot affect the environment. Particularly, the problems of high energy consumption and large water consumption resources of a refrigeration system adopting water as the secondary refrigerant are solved for the data center adopting water as the secondary refrigerant.

It should be noted that the present disclosure does not limit the application field, and the present disclosure is only used for illustrating the carbon dioxide refrigeration system provided by the present disclosure by taking a data center as an example.

Fig. 2 shows a schematic structural diagram of a carbon dioxide refrigeration system provided by an embodiment of the present disclosure, as shown in fig. 2, including: a carbon dioxide liquid pump 10, a carbon dioxide oil-free compressor 14, an evaporative condenser 8 and a back plate heat exchange end 12.

In the present disclosure, the evaporative condenser 8 is placed outdoors and the back plate heat exchange end 12 is placed indoors. The carbon dioxide liquid pump is used for outputting liquid carbon dioxide to the back plate heat exchange tail end 12; the carbon dioxide oil-free compressor 14 is used to compress gaseous carbon dioxide that carries heat within the chamber.

Wherein, one end of the carbon dioxide oil-free compressor 14 is connected with one end of the evaporative condenser 8, and one end of the carbon dioxide liquid pump 10 is connected with the other end of the evaporative condenser 8 through the liquid storage tank 9.

The other end of the carbon dioxide oil-free compressor 14 passes through the filter 13 and one end of the back plate heat exchange tail end 12, and the other end of the back plate heat exchange tail end 12 is connected with the other end of the carbon dioxide liquid pump 10 through the first electronic expansion valve 11. The use of the carbon dioxide oil-free compressor 14 in the present disclosure effectively avoids oil return problems.

In the embodiment of the present disclosure, the back plate heat exchange end 12 has a first heat exchanger, and the first heat exchanger is used for performing first heat exchange between liquid carbon dioxide and indoor heat to obtain gaseous carbon dioxide bearing the indoor heat.

In the disclosed embodiment, fig. 3 shows a schematic diagram of an evaporative condenser provided by the disclosed embodiment. The evaporative condenser 8 is provided with a control device, the surface of the evaporative condenser is provided with a spraying wet film 18, the control device is used for controlling the opening and closing of the spraying wet film 18 according to the preset wet bulb temperature, and the spraying wet film 18 is used for humidifying outdoor gas 20, so that the outdoor gas 20 with the wet bulb temperature higher than the preset wet bulb temperature is less than or equal to the preset wet bulb temperature. In the present disclosure, the preset wet bulb temperature may be 23 degrees celsius and the outdoor air 20 may be outdoor wind.

In the present disclosure, two operation modes for the spray wet film 18 can be realized by controlling the spray wet film 18 by the control device. In one mode of operation, the dry cooling mode may be employed if the wet bulb temperature of the outdoor air 20 is less than or equal to a predetermined wet bulb temperature. That is, the outdoor air 20 obtained in the evaporative condenser 8 does not need to be humidified and cooled by the spray wet film 18, and directly exchanges heat with the second heat exchanger 22 in the evaporative condenser 8 to perform heat exchange and cooling. In another operation mode, the wet cooling mode may be employed if the wet bulb temperature of the outdoor air 20 is higher than a preset wet bulb temperature. That is, the outdoor air 20 obtained from the evaporative condenser 8 needs to be humidified and cooled by the spray wet film 18, and when the temperature of the outdoor air 20 is less than or equal to the preset wet bulb temperature, the outdoor air exchanges heat with the second heat exchanger 22 in the evaporative condenser 8 to perform heat exchange and cooling.

In the embodiment of the present disclosure, by controlling the on/off of the spray wet film 18, the spray wet film 18 does not need to be opened at full time, so that the power consumption of the system can be reduced.

In the present disclosure, the evaporative condenser 8 further has a second heat exchanger 22, and the second heat exchanger is used for performing a second heat exchange between the gaseous carbon dioxide carrying indoor heat and the outdoor air 20 with the preset wet bulb temperature to obtain liquid carbon dioxide.

Wherein the evaporative condenser 8 may be an adiabatic evaporative condenser, as shown in fig. 2, in the present disclosure, the coil 15 may be used as the first heat exchanger of the back plate heat exchange end 12, and the coil 15 may also be used as the second heat exchanger 22 of the evaporative condenser 8.

In the evaporative condenser 8, the refrigerant in a gaseous state (i.e., gaseous carbon dioxide) in the pipe is subjected to phase-change heat exchange with the outdoor air, and then, the gaseous carbon dioxide is changed into liquid carbon dioxide. The liquid carbon dioxide is powered by a carbon dioxide liquid pump 10 and is output to a liquid inlet of each back plate heat exchange tail end 12. The liquid carbon dioxide is throttled by the first electronic expansion valve 11 and enters the heat exchange coil, namely the liquid supply pipe network 23 at the heat exchange end 12 of the back plate. The resupply pipe network 23 exchanges heat with the room return air and returns to the evaporative condenser 8, forming a circulating refrigeration system.

In the present disclosure, the evaporative condenser 8 further includes: a fan 16 and a water distributor 21.

The water distributor 21 is arranged between the spraying wet film 18 and the second heat exchanger 22 and is used for filtering outdoor air 20. The fan 16 is arranged at the exhaust outlet of the evaporative condenser 8 and is used for exhausting the gas after the secondary heat exchange, such as the exhaust 17 in fig. 3.

As shown in fig. 3, after the outdoor air (i.e., outdoor air 20) is less than or equal to the preset wet bulb temperature, the cooling air 19 is formed by entering through the water distributor 21. The cooling air 19 exchanges heat with the second heat exchanger 22 in a contact manner, and the heat is discharged through the fan 16 to obtain exhaust air 17 which is emitted to the atmosphere.

In the embodiment of the present disclosure, fig. 4 shows a schematic structural diagram of a heat exchanging end 12 of a back plate provided in the embodiment of the present disclosure. As shown in fig. 4, the carbon dioxide refrigeration system further includes: a liquid supply pipe network 23, a shut-off valve 24, an air return pipe network 25, a shut-off ball valve 26, a second electronic expansion valve 27, a pressure sensor 28 and a temperature sensor 29.

Each back plate heat exchange end 12 is fitted with a shut-off ball valve 26, a second electronic expansion valve 27, a pressure sensor 28 and a temperature sensor 29. One end of each back plate heat exchange tail end 12 is connected with the air return pipe network 25 through a shutoff ball valve 26 and a second electronic expansion valve 27; one end of each back plate heat exchange end 12 is connected to the liquid supply pipe network 23 by a pressure sensor 28 and a temperature sensor 29. A plurality of shut-off valves 24 are arranged on the liquid supply pipe network 23 and the gas return pipe network (25). For example, a shut-off valve 24 is installed between each two back plate heat exchange ends 12 connected to the liquid supply pipe network 23 and the gas return pipe network 25.

In the present disclosure, the shut-off valve 24 disposed on the liquid supply pipe network 23 can control whether the liquid carbon dioxide is input into the liquid supply pipe network 23, and control the flow direction of the liquid carbon dioxide in the liquid supply pipe network 23. The shutoff valve 24 arranged in the gas return pipe network 25 can control the gas return pipe network 25 to exhaust and also can prevent gas from flowing back, so that the shutoff valve 24 arranged on the liquid supply pipe network 23 and the gas return pipe network 25 can realize the fault isolation effect.

Fig. 5 shows a schematic flow chart of a carbon dioxide refrigeration method provided by an embodiment of the present disclosure, as shown in fig. 5, including the following steps:

in step S110, the liquid carbon dioxide and the indoor heat are subjected to first heat exchange based on the first heat exchanger at the heat exchange end of the back plate, so as to obtain gaseous carbon dioxide bearing the indoor heat.

In the embodiment of the present disclosure, based on the first heat exchanger at the back plate heat exchange end 12 of the data center, the liquid carbon dioxide and the indoor heat perform the first heat exchange, and the gaseous carbon dioxide carrying the indoor heat is obtained.

In step S120, in response to the outdoor air being greater than the preset wet bulb temperature, the determination control device controls the spray wet film to humidify the outdoor air so that the outdoor air is less than or equal to the preset wet bulb temperature.

In the embodiment of the present disclosure, the control device is configured to control the spraying wet film 18 to be turned on or off according to a preset wet bulb temperature, and the spraying wet film 18 is configured to humidify the outdoor air 20 having a wet bulb temperature higher than the preset wet bulb temperature, so as to reduce the temperature of the outdoor air 20 to be less than or equal to the preset wet bulb temperature. In the present disclosure, when the outdoor air 20 is higher than the preset wet bulb temperature, i.e., the outdoor air 20 is higher than 23 degrees celsius, the spray wet film 18 is turned on to humidify the outdoor air 20 to make its temperature less than or equal to the preset wet bulb temperature.

In step S130, according to the second heat exchanger of the evaporative condenser, performing a second heat exchange between the outdoor air at the temperature less than or equal to the preset wet bulb temperature and the gaseous carbon dioxide bearing the indoor heat to obtain liquid carbon dioxide.

In the embodiment of the present disclosure, the carbon dioxide oil-free compressor 14 outputs the gaseous carbon dioxide carrying indoor heat to the evaporative condenser 8 installed outdoors, exchanges heat between the gaseous carbon dioxide carrying indoor heat and the outdoor air 20 having a preset wet bulb temperature or less through the second heat exchanger 22 included in the evaporative condenser 8, and discharges the exchanged heat to the atmosphere. And then compressing the gaseous carbon dioxide after heat exchange to obtain liquid carbon dioxide.

Through the carbon dioxide refrigeration method provided by the embodiment of the disclosure, carbon dioxide can be recycled, no harmful substance is generated in the process of cyclic refrigeration, and no influence is caused on the environment, so that the waste of water resources can be reduced. In the process, the outdoor gas 20 with the wet bulb temperature higher than the preset wet bulb temperature is controlled to humidify and cool, so that the condition that the spraying wet film 18 is in an open state at all times can be avoided, and the power consumption is reduced.

In the disclosed embodiment, the obtained liquid carbon dioxide can also be stored in the liquid storage tank 9. And based on the electrical signal obtained by the second electronic expansion valve 27, the numerical value of the liquid carbon dioxide output by the liquid storage tank 9 is adjusted to regulate the flow, and the liquid carbon dioxide is output to the back plate heat exchange tail end 12 by the carbon dioxide liquid pump 10.

Thereafter, the liquid carbon dioxide is heat exchanged with indoor heat for the first time based on the first heat exchanger of the back plate heat exchange end 12, and the gaseous carbon dioxide of the first heat exchange is filtered based on the filter 13. The filtered gaseous carbon dioxide is compressed by the carbon dioxide oil-free compressor 14 and then output to the evaporative condenser 8, and the evaporative condenser 8 obtains the gaseous carbon dioxide carrying indoor heat.

The water distributor 21 of the evaporative condenser 8 filters the outdoor air 20 with the temperature less than or equal to the preset wet bulb temperature, and the filtered outdoor air 20 and the gaseous carbon dioxide bearing indoor heat are subjected to secondary heat exchange through the second heat exchanger 22 to obtain liquid carbon dioxide and gas bearing indoor heat. The air carrying the heat in the room after the second heat exchange is discharged to the atmosphere by the fan 16.

In the disclosed embodiment, the state of the shut-off ball valve 26 and the second electronic expansion valve 27 installed at each back plate heat exchange end 12 can also be controlled based on the pressure sensor 28 and the temperature sensor 29. And determining the connection or disconnection of the heat exchange tail end of the plate and the liquid supply pipe network 23 based on the states of the shutoff ball valve 26 and the second electronic expansion valve 27. And controlling the connection or disconnection of the back plate heat exchange tail end 12 and the return pipe network 25 based on the shutoff valve 24.

It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present disclosure may be executed in parallel or sequentially or in different orders, and are not limited herein as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved.

The above detailed description should not be construed as limiting the scope of the disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.