Heat pump system of underground space multi-layer film type heat exchanger and working method

Abstract

The invention relates to a heat pump system of an underground space multi-layer film type heat exchanger and a working method, the multi-layer film type heat exchanger is arranged in the ground or the wall surface of the underground space, is provided with a main pipe orifice I and a main pipe orifice II, and is used for transferring heat or cold of underground soil into a heat exchange medium in the multi-layer film type heat exchanger; the heat pump unit transfers heat or cold carried by a heat exchange medium in the multi-layer film type heat exchanger to the radiation tail end through a compressor, a throttling valve, an evaporator and a condenser. The radiation tail end is used for providing heat or cold for the overground building; two connectors of the evaporator are connected with a first main pipe opening and a second main pipe opening of the multi-layer film type heat exchanger through pipelines respectively, and the evaporator is used for transferring heat in underground soil into refrigerants of the heat pump unit through the evaporator. Two connectors of the condenser are connected with a first main pipe opening and a second main pipe opening of the multi-layer film type heat exchanger through pipelines respectively, and the condenser is used for transferring cold energy in underground soil into refrigerants of the heat pump unit through the condenser.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a heat pump system of an underground space multilayer film heat exchanger and a working method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Underground space (such as underground garage) is a common facility in urban space. In summer, the temperature of the walls and ground in the underground space is usually lower than the air temperature in the underground space due to the influence of the soil. The relative humidity in the underground space is affected by the high humidity of the outdoor air in summer, and its relative humidity is also relatively high, resulting in an increase in its dew point temperature. When the temperature of the wall and the ground is lower than the dew point temperature of the air in the underground space, condensation will occur on the wall and the ground, which will seriously affect the safety of personnel, equipment or vehicle operation in the underground space.

[0004] To address the high humidity problem in underground spaces, most current methods use mechanical ventilation or natural ventilation systems. Mechanical ventilation alleviates the condensation problem by installing exhaust systems and fresh air systems to enhance air circulation, increase wall temperature, and reduce the temperature difference between the wall and the air. However, since underground spaces (such as underground garages) generally occupy a large area, the operation of mechanical ventilation systems consumes a lot of electricity, especially in high temperature or high humidity seasons, the cost is high. Natural ventilation depends on external climatic conditions, and changes in wind speed and temperature may affect the ventilation effect, and the effect is limited in environments with insufficient wind. In addition, under extreme weather conditions (such as high humidity or high temperature), ventilation may not be able to achieve uniform coverage, and the efficiency of the ventilation system may be limited, resulting in some areas still being humid or stuffy, and unable to completely and effectively reduce the humidity or temperature in the garage.

[0005] At the same time, because underground space is in contact with the underground soil, its air temperature is generally low, but this part of the cold energy has not been effectively utilized. Although some heat pump systems can utilize the cold energy of the soil, they are limited by high humidity and lack efficient and energy-saving utilization solutions. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a heat pump system and working method of a multilayer film heat exchanger in an underground space. The multilayer film heat exchanger is used as the main heat exchange equipment, which can effectively solve the condensation problem in the underground space, has the advantages of environmental protection, economical and practical, and long service life, and can make full use of the cold and heat of the underground space and soil to provide heating in the heating season and cooling in the air-conditioning season for the above-ground buildings. The system and method can freely switch its operating mode according to the condensation situation of the underground space and the user's heating and cooling needs, giving full play to the advantages of the composite heat pump system.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A first aspect of the present invention provides a heat pump system of an underground space multilayer membrane heat exchanger, comprising:

[0009] The multilayer film heat exchanger is arranged on the ground or wall of the underground space, and has a main inlet 1 and a main inlet 2, which are used to transfer heat or cold of the underground soil to the heat exchange medium inside the multilayer film heat exchanger;

[0010] The heat pump unit transfers the heat or cold carried by the heat exchange medium from the multi-layer film heat exchanger to the radiation end through the compressor, throttle valve, evaporator and condenser;

[0011] Radiant terminals, used to provide heat or cooling to above-ground buildings;

[0012] Among them, the two interfaces of the evaporator are respectively connected to the main port 1 and the main port 2 of the multilayer film heat exchanger through pipes, so as to transfer the heat in the underground soil to the refrigerant of the heat pump unit through the evaporator; the two interfaces of the condenser are respectively connected to the main port 1 and the main port 2 of the multilayer film heat exchanger through pipes, so as to transfer the cold in the underground soil to the refrigerant of the heat pump unit through the condenser.

[0013] Furthermore, the multilayer thin film heat exchanger includes multiple groups of thin film heat exchangers arranged in parallel, and all thin layer heat exchangers have an inlet main pipe, a return main pipe, a capillary grid connected between the inlet main pipe and the return main pipe, and valves arranged on the inlet main pipe and the return main pipe.

[0014] Furthermore, the capillary grid is laid vertically along the wall of the underground space or horizontally along the ground, and the capillary grid includes a plurality of capillary heat conducting pipes evenly distributed between the water inlet pipe and the water return pipe and penetrating the water inlet pipe and the water return pipe.

[0015] Furthermore, the first interface a and the third interface c of the evaporator are connected for the flow of heat exchange medium, and the second interface b and the fourth interface d are connected for the flow of refrigerant; the first interface e and the third interface g of the condenser are connected for the flow of refrigerant, and the second interface f and the fourth interface h are connected for the flow of heat exchange medium.

[0016] Furthermore, the outlet of the compressor is connected to the first interface e of the condenser, the third interface g of the condenser is connected to the throttle valve, the other end of the throttle valve is connected to the fourth interface d of the evaporator, and the second interface b of the evaporator is connected to the inlet of the compressor, forming a circulation loop of the ground source heat pump unit.

[0017] Furthermore, the first interface of the evaporator is connected to the main port 1 of the multilayer film heat exchanger through a pipeline via a first circulating water pump; the third interface of the evaporator is connected to the main port 2 of the multilayer film heat exchanger through a pipeline, forming a circulation loop between the soil source side heat exchanger and the heat pump unit in winter; specifically:

[0018] The first interface a of the evaporator is connected to the main port r of the multilayer film heat exchanger through a pipeline through the second tee j, the valve 1D, the first tee i, and the first circulating water pump A in sequence; the third interface c of the evaporator is connected to the main port 2 t of the multilayer film heat exchanger through a pipeline through the seventh tee p, the valve 8K and the sixth tee o in sequence, forming a circulation loop between the soil source side heat exchanger and the heat pump unit in winter.

[0019] Furthermore, the first interface of the evaporator is connected to the return water end of the radiation end through a pipeline, and the third interface of the evaporator is connected to the water inlet end of the radiation end through a pipeline via a second circulating water pump, forming a circulation loop between the radiation end on the summer load side and the heat pump unit. Specifically:

[0020] The first interface a of the evaporator is connected to the return water end of the radiation end through valve three F, the second tee j and the fourth tee m, and the third interface c of the evaporator is connected to the water inlet end of the radiation end through valve seven J, the seventh tee p, the fifth tee n and the second circulating water pump B, forming a circulation loop between the radiation end and the heat pump unit on the summer load side.

[0021] Furthermore, the second interface of the condenser is connected to the water inlet of the radiation terminal through a pipeline; the fourth interface of the condenser is connected to the return water end of the radiation terminal through a pipeline via the third circulating water pump, forming a circulation loop between the radiation terminal on the winter load side and the heat pump unit. Specifically:

[0022] The second interface f of the condenser is connected to the water inlet end of the radiation terminal through a pipeline through the third tee k, valve four G, and fourth tee m in sequence; the fourth interface h of the condenser is connected to the return water end of the radiation terminal through a pipeline through the eighth tee q, valve five H, the third circulating water pump C and the fifth tee n in sequence, forming a circulation loop between the radiation terminal on the winter load side and the heat pump unit.

[0023] Furthermore, the second interface of the condenser is connected to the second pipe port of the multilayer film heat exchanger through a pipeline; the fourth interface of the condenser is connected to the first main pipe port of the multilayer film heat exchanger through a pipeline via the first circulating water pump, forming a circulation loop between the soil cold source side and the heat pump unit in summer, specifically:

[0024] The second interface f of the condenser is connected to the pipe port 2 t of the multilayer film heat exchanger through a pipeline sequentially through the third tee k, the valve 2 E and the sixth tee o; the fourth interface h of the condenser is connected to the main pipe port 1 r of the multilayer film heat exchanger through a pipeline sequentially through the eighth tee q, the valve 6 I, the first tee i and the first circulating water pump A, forming a circulation loop between the soil cold source side and the heat pump unit in summer.

[0025] A second aspect of the present invention provides a method for operating a heat pump system of an underground space multilayer membrane heat exchanger, comprising the following steps:

[0026] The low-temperature and low-pressure refrigerant gas is compressed by the compressor, condensed into a normal-temperature and high-pressure liquid after passing through the condenser, and then converted into a low-temperature and low-pressure liquid after passing through the throttle valve. The evaporator absorbs heat and converts it into a low-temperature and low-pressure refrigerant gas, and then flows back into the compressor;

[0027] During heating, the heat exchange medium in the multi-layer film heat exchanger absorbs heat from the underground soil and exchanges heat with the refrigerant in the evaporator. After the heat exchange, the heat exchange medium returns to the multi-layer film heat exchanger to heat the soil again. At the same time, the heat exchange medium at the radiation end exchanges heat with the refrigerant in the condenser, and the heated heat exchange medium is used to heat the above-ground buildings. After releasing heat, the heat exchange medium returns to the condenser to continue absorbing heat, thus realizing cyclic heating.

[0028] During cooling, the heat exchange medium produced by the multi-layer film heat exchanger absorbs the cold from the underground soil and exchanges heat with the refrigerant in the condenser. The heat exchange medium after the heat exchange returns to the multi-layer film heat exchanger to heat the underground soil. At the same time, after the refrigerant is cooled in the condenser, it is transported to the evaporator through the throttle valve and exchanges heat with the heat exchange medium in the evaporator. The cooled heat exchange medium is used to cool the ground buildings through the radiation terminal. The heat exchange medium after absorbing heat and heating up returns to the evaporator to continue cooling, thereby realizing circulating cooling.

[0029] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0030] 1. Using multi-layered thin-film heat exchangers to absorb cold or heat in the underground soil and transfer the cold or heat in the underground space to the above-ground buildings can efficiently take heat from or release heat to the soil, provide heating or cooling for the buildings, form a sustainable and environmentally friendly heating and cooling solution, reduce dependence on traditional cooling and heating equipment, and provide stable temperature control effects in different seasons. It is environmentally friendly, economical, practical, has high heat exchange efficiency and long service life.

[0031] 2. The coldness of the underground space can be fully utilized. The cold and heat of the underground space and the soil can be fully utilized to provide heating for the above-ground buildings in the heating season and cooling for the air-conditioning season. While providing cooling in summer, the absorbed indoor heat is released to the soil through the circulation loop between the summer soil cold source side and the heat pump unit. The released heat can increase the ground and wall temperature of the underground space, reduce the temperature difference between the wall and the air, and effectively solve the condensation phenomenon caused by high humidity in the underground space in summer, and can also give full play to the advantages of the composite heat pump system.

[0032] 3. The switching between the cooling and heating states of the system does not affect the refrigerant circulation direction in the heat pump unit. It can be switched through a combination of different valves and water pumps. Regardless of whether it is in the cooling or heating state, the heat pump unit itself does not need to perform a reversing operation, which makes the refrigerant circulation loop very small. The refrigerant plays an efficient heat transfer role during the circulation, so that the compressor only needs relatively small energy to support the operation of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 It is a schematic diagram of the structure of a heat pump system of an underground space multilayer thin film heat exchanger provided by one or more embodiments of the present invention;

[0035] Figure 2 is a schematic structural diagram of a multilayer thin film heat exchanger provided by one or more embodiments of the present invention;

[0036] Figure 3 It is a schematic diagram of a capillary grid structure provided by one or more embodiments of the present invention.

[0037] In the figure, 1-compressor, 2-throttle valve, 3-evaporator, 4-condenser, 5-radiation end, 6-water inlet main pipe, 7-water return main pipe, 8-capillary heat conduction pipe, 9-reserved hole, 10-B2 floor slab, 11-membrane heat exchanger, 12-multi-layer membrane heat exchanger, 13-concrete layer, 14-moisture-proof layer, 15-B2 layer membrane heat exchanger a, 16-cement mortar, 17-concrete foundation, 18-B2 layer membrane heat exchanger b, 19-plain soil layer, 20-B1 layer membrane heat exchanger. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] The following embodiment provides a heat pump system and working method of a multilayer film heat exchanger in an underground space. The multilayer film heat exchanger is used as the main heat exchange equipment, which can effectively solve the condensation problem in the underground space, has the advantages of environmental protection, economical and practical, and long service life, and can make full use of the cold and heat of the underground space and soil to provide heating in the heating season and cooling in the air conditioning season for the above-ground buildings. The system and method can freely switch its operating mode according to the condensation situation of the underground space and the user's heating and cooling needs, giving full play to the advantages of the composite heat pump system.

[0041] Embodiment 1:

[0042] A heat pump system of an underground space multilayer film heat exchanger, comprising:

[0043] A multi-layer thin film heat exchanger, comprising a plurality of groups of thin film heat exchangers arranged in parallel, the thin film heat exchangers are arranged on the ground or wall of an underground space, cement mortar is filled between adjacent multi-layer thin film heat exchanger bodies, a moisture-proof layer and a concrete layer are arranged between the topmost thin-layer heat exchanger and the ground or wall, a heat exchange medium is arranged inside the thin film heat exchanger, and heat or cold of underground soil is transferred to the heat exchange medium through the thin film heat exchanger;

[0044] The heat pump unit transfers the heat or cold carried by the heat exchange medium from the multi-layer film heat exchanger to the radiation end through the compressor, throttle valve, evaporator and condenser;

[0045] Radiant terminals are used to provide heating or cooling to above-ground buildings.

[0046] In this embodiment, Figure 1 As shown, the radiation terminal 5 is inside an above-ground building.

[0047] In this embodiment, Figure 1-Figure 2 The codes of the pumps, tees and valves involved are as follows:

[0048] Water pump code: A is the first circulating water pump, B is the second circulating water pump, C is the third circulating water pump.

[0049] Valve code: D valve one, E valve two, F valve three, G valve four, H valve five, I valve six, J valve seven, K valve eight, L valve nine, M valve ten, N valve eleven, O valve twelve, P valve thirteen, Q valve fourteen.

[0050] Tee codes: first tee i, second tee j, third tee k, fourth tee m, fifth tee n, sixth tee o, seventh tee p, eighth tee q.

[0051] In this embodiment, Figure 1 As shown, the ground source heat pump system includes a compressor 1, a throttle valve 2, an evaporator 3 with a first interface a, a second interface b, a third interface c, and a fourth interface d, and a condenser 4 with a first interface e, a second interface f, a third interface g, and a fourth interface h.

[0052] In this embodiment, Figure 1 As shown, the first interface a and the third interface c of the evaporator 3 are connected for the heat exchange medium to flow through, and the second interface b and the fourth interface d are connected for the refrigerant to flow through.

[0053] In this embodiment, Figure 1 As shown, the first interface e and the third interface g of the condenser 4 are connected for the refrigerant to flow through, and the second interface f and the fourth interface h are connected for the heat exchange medium to flow through.

[0054] In this embodiment, the heat exchange medium is water.

[0055] The system is connected to the valve through pipelines. The specific connection method is: the outlet of the compressor 1 is connected to the first interface e of the condenser 4, the third interface g of the condenser 4 is connected to the throttle valve 2, the other end of the throttle valve 2 is connected to the fourth interface d of the evaporator 3, and the second interface b of the evaporator 3 is connected to the inlet of the compressor 1, forming a circulation loop of the ground source heat pump unit.

[0056] The first interface a of the evaporator 3 is connected to the main port r of the multilayer film heat exchanger through a pipeline through the second tee j, the valve 1D, the first tee i, and the first circulating water pump A in sequence; the third interface c of the evaporator 3 is connected to the main port 2 t of the multilayer film heat exchanger through a pipeline through the seventh tee p, the valve 8K and the sixth tee o in sequence, forming a circulation loop between the soil source side heat exchanger and the heat pump unit in winter.

[0057] The first interface a of the evaporator 3 is connected to the return water end of the radiation terminal 5 through valve three F, the second tee j and the fourth tee m, and the third interface c of the evaporator 3 is connected to the water inlet end of the radiation terminal 5 through valve seven J, the seventh tee p, the fifth tee n and the second circulating water pump B, forming a circulation loop between the radiation terminal on the summer load side and the heat pump unit.

[0058] The second interface f of the condenser 4 is connected to the water inlet end of the radiation terminal 5 through a pipeline through the third tee k, the fourth valve G, and the fourth tee m in sequence; the fourth interface h of the condenser 4 is connected to the return water end of the radiation terminal 5 through a pipeline through the eighth tee q, the fifth valve H, the third circulating water pump C and the fifth tee n in sequence, forming a circulation loop between the radiation terminal on the winter load side and the heat pump unit.

[0059] The second interface f of the condenser 4 is connected to the pipe port 2 t of the multilayer film heat exchanger through a pipeline through the third tee k, the valve 2 E and the sixth tee o in sequence; the fourth interface h of the condenser 4 is connected to the pipe port 1 r of the multilayer film heat exchanger through a pipeline through the eighth tee q, the valve 6 I, the first tee i and the first circulating water pump A in sequence, forming a circulation loop between the soil cold source side and the heat pump unit in summer.

[0060] like Figure 1 and 2 As shown, the multilayer film heat exchanger 12 has heat exchange medium inlet and outlet interfaces r and t. Taking the arrangement in the two underground layers (B1, B2) as an example, the multilayer film heat exchanger 12 includes multiple groups of film heat exchangers 11 arranged in parallel, and the underground soil is arranged from bottom to top with a soil layer 19, a concrete foundation 17, a multilayer film heat exchanger 12 and a concrete layer 13, and cement mortar 16 is filled between adjacent multilayer film heat exchangers 12. A moisture-proof layer 14 and a concrete layer 13 are arranged between the top film heat exchanger and the ground, and heat is exchanged with the underground soil through the multilayer film heat exchanger 12.

[0061] The number of layers of the membrane heat exchanger depends on the geological conditions and construction conditions of the underground space. In this embodiment, the membrane heat exchanger 20 of the B1 layer is the topmost membrane heat exchanger, and the membrane heat exchanger of the B2 layer has two groups, namely, the membrane heat exchanger a15 of the B2 layer and the membrane heat exchanger b18 of the B2 layer, with cement mortar 16 between them.

[0062] like Figure 3As shown, each layer of membrane heat exchanger has an inlet main pipe 6, a return main pipe 7, a capillary grid connected between the inlet main pipe and the return main pipe, and valves arranged on the inlet main pipe and the return main pipe. The capillary grid is laid along the vertical direction of the garage wall or the horizontal direction of the ground; the capillary grid includes a plurality of capillary heat conducting pipes 8 evenly distributed between the inlet main pipe and the return main pipe and penetrating the inlet main pipe and the return main pipe. The inlet main pipe and the return main pipe are arranged in a reserved hole 9 on the same side of the wall of the underground space.

[0063] Since the thermal conductivity of soil is small, the heat exchange capacity of a single underground pipe is limited. Therefore, when the heat supply is certain, the required length of the underground pipe is longer, resulting in more holes for the underground pipe and a larger heat exchange site. In addition, underground drilling is involved in the installation of underground pipes, which is difficult to construct and has high drilling costs. When the underground pipe fails, it is also difficult to repair and replace it. The heat conduction pipe of the multilayer thin film heat exchanger provided in this embodiment is a PPR pipe with an outer diameter of 20mm and a wall thickness of 2mm for the header, a diameter of 4.3mm for the capillary heat conduction pipe and a wall thickness of 0.85mm. The spacing between adjacent capillary heat conduction pipes is determined according to actual conditions.

[0064] The color of the capillary grid should be uniform, and the inner and outer surfaces of the pipes and fittings should be smooth, flat and clean, without dents, bubbles, obvious scratches and other surface defects that affect performance.

[0065] The PPR pipe should be formed in one step, and no joint welding in the middle is allowed. The end face of the pipe should be cut flat and should be perpendicular to the axis. The PPR pipe grid requires factory water pressure testing, and the end requires seamless sealing and pressure testing, and the factory test pressure must not be lower than 0.3Mpa and maintained for 5-10 minutes.

[0066] In the design, in order to avoid compression or deformation between layers, some supporting materials are filled, such as plastic grids or metal brackets. These materials can ensure that the capillaries maintain a fixed distance and avoid deformation under pressure. When fixing, make sure that the capillaries are close to the ground or wall, without any hanging parts, to ensure the smoothness of the pipeline.

[0067] When arranging the multi-layer thin film heat exchanger, only one layer is arranged at the non-bottom layer. The multi-layer thin film heat exchanger exchanges heat with the soil, increases the ground and wall temperature of the underground garage, reduces the temperature difference between the wall and the air to alleviate the condensation problem, and is used to prevent condensation in the underground garage.

[0068] The above-mentioned multi-layer film heat exchanger body is laid vertically along the wall of the underground garage. The multi-layer film heat exchanger body is arranged in the space where the wall is in direct contact with the soil. The specific construction and laying method is the same as the above-mentioned horizontal construction and laying method. The materials of the water inlet pipe, water return pipe, and its connectors, system pipes and pipe fittings are made of plastic, stainless steel or copper. The specific requirements should be determined after comprehensive comparison based on the working temperature, working pressure, design life, on-site waterproofing, water quality requirements, and construction requirements.

[0069] In winter, the multi-layer thin film heat exchanger transports high-temperature liquid to the evaporator through the circulation loop between the winter soil source side heat exchanger and the heat pump unit. The evaporator transports the high-temperature liquid to the condenser through the compressor. The low-temperature return water at the radiation end is transported to the condenser through the circulation loop between the winter load side radiation end and the heat pump unit. After heat exchange in the condenser, the temperature is increased to become high-temperature water. The high-temperature water flows from the condenser into the radiation end to heat the ground buildings.

[0070] In summer, the cooling water produced by the multi-layer film heat exchanger exchanges heat with the high-temperature and high-pressure refrigerant gas in the condenser, and then returns to the multi-layer film heat exchanger for cooling; the low-temperature and high-pressure refrigerant at the outlet of the condenser is transported to the evaporator through a throttle valve, and the low-temperature and low-pressure refrigerant liquid in the evaporator exchanges heat with the chilled water. After the chilled water is cooled, it is transported to the radiation end through a circulation loop between the radiation end on the summer load side and the heat pump unit to provide cooling for the ground buildings.

[0071] To arrange multi-layer membrane heat exchangers according to the construction conditions of underground space, the following steps can be adopted:

[0072] Determine the location of the capillary grid, check whether the ground or wall is flat, and open grooves at the corresponding locations;

[0073] Conduct leak test on capillary grid;

[0074] After the test is passed, the soil is compacted to make it smooth and free of debris on the surface;

[0075] After the soil is compacted, it should be partially trimmed to meet the design elevation requirements. Then pour concrete to build the foundation. The surface should be flat, pressed and free of hollows.

[0076] Lay the multi-layer thin film heat exchanger to the designated area and ensure that the capillary spacing meets the design requirements; ensure that the pipeline is laid evenly without twisting or kinking;

[0077] Carry out water pressure test on the capillary grid in sections, and then fill the capillary grid and header with cement mortar;

[0078] Further proceed with the laying of the upper layer of thin film heat exchanger;

[0079] After the top layer of thin film heat exchanger is laid, a moisture-proof layer is laid to prevent water vapor from causing damage to the multi-layer thin film heat exchanger and affecting its service life;

[0080] Finally, pour the concrete layer to level the ground.

[0081] Arranging multiple layers of thin-film heat exchangers according to the construction conditions of the underground space can transfer the cold or heat in the underground space to the above-ground buildings. It can efficiently take heat from or release heat to the soil, provide heating or cooling for the buildings, and is a sustainable and environmentally friendly heating and cooling solution. At the same time, it can reduce the dependence on traditional refrigeration and heating equipment, and can provide stable temperature control effects in different seasons. It is environmentally friendly, economical, practical, has high heat exchange efficiency and long service life.

[0082] The cold capacity of the underground space can be fully utilized, and the cold and heat of the underground space and soil can be fully utilized to provide heating in the heating season and cooling in the air-conditioning season for the above-ground buildings. While providing cooling in summer, the absorbed indoor heat is dissipated to the soil through the circulation loop between the summer soil cold source side and the heat pump unit. The dissipated heat can increase the ground and wall temperature of the underground garage, reduce the temperature difference between the wall and the air, effectively solve the condensation problem in the underground space, and give full play to the advantages of the composite heat pump system.

[0083] The system's cooling and heating states are switched through a combination of different valves and water pumps. Regardless of whether it is in the cooling or heating state, the refrigerant circulation direction in the heat pump unit remains unchanged, and the heat pump unit itself does not need to perform a reversing operation, making the refrigerant circulation loop very small. The refrigerant plays the role of transporting heat or cold during the cycle, so that the compressor only needs relatively small energy to help the entire system run.

[0084] Embodiment 2:

[0085] A working method of a heat pump system of an underground space multilayer film heat exchanger comprises the following steps:

[0086] The high-temperature and high-pressure refrigerant gas discharged from the compressor enters the condenser and condenses into a normal-temperature and high-pressure liquid. The normal-temperature and high-pressure refrigerant liquid passes through the throttle valve and becomes a low-temperature and low-pressure refrigerant liquid. It then flows into the evaporator, absorbs heat in the evaporator, becomes a low-temperature and low-pressure refrigerant gas, and flows back into the compressor.

[0087] During winter heating, valves 1, 4, 5, 8, 9, 10, 11, 12, 13 and 14 are opened, valves 2, 3, 6 and 7 are closed, the first circulating water pump and the third circulating water pump are opened, and the second circulating water pump is closed; the high-temperature liquid in the multilayer film heat exchanger is pumped into the evaporator through the pipe port 1 by the first circulating water pump, and heat is exchanged with the low-temperature and low-pressure refrigerant liquid in the evaporator, and the low-temperature liquid flows back from the third interface of the evaporator to the multilayer film heat exchanger to heat the soil again; at the same time, the low-temperature liquid at the radiation end is pumped into the condenser through the second circulating water pump, and heat is exchanged with the high-temperature and high-pressure refrigerant gas in the condenser before being heated to become high-temperature water, and the high-temperature water flows out from the second interface of the condenser and enters the radiation end to heat the ground building, and the low-temperature water is pumped into the condenser through the second circulating water pump, and circulates in sequence to supply heat;

[0088] During cooling in summer, valve two, valve three, valve six, valve seven, valve nine, valve eleven, valve thirteen, valve fourteen, the first circulating water pump and the second circulating water pump are opened, and valve one, valve four, valve five, valve eight, valve ten, valve twelve and the third circulating water pump are closed; the cooling water produced by the multi-layer film heat exchanger exchanges heat with the high-temperature and high-pressure refrigerant gas in the condenser, and then returns to the multi-layer film heat exchanger through the second interface of the condenser for cooling; the low-temperature and high-pressure refrigerant in the condenser is transported to the evaporator through the throttle valve, and the low-temperature and low-pressure refrigerant liquid exchanges heat with the chilled water in the evaporator. After the chilled water is cooled, it is pressed into the radiation end through the second circulating water from the third interface of the evaporator to cool the ground buildings. The chilled water temperature rises and flows back to the evaporator, and circulates in sequence for cooling.

[0089] In winter, a multi-layer film heat exchanger is used to extract heat from the soil. In winter, the underground soil temperature is usually higher than the surface air temperature. The cold fluid in the heat exchanger (such as antifreeze) absorbs heat in the soil. The heat absorbed by the cold fluid is transferred to the building through the heat pump and supplied to the users in the above-ground building. Since the underground space is in contact with the underground soil, its air temperature is generally low, but this part of the cold energy has not been effectively used. In order to maintain heat balance, the cold energy of the underground space is selected as the cold source for cooling in summer. At the same time, the heat emitted by the film radiator to the soil can increase the wall temperature of the underground garage and reduce the temperature difference between the wall and the air to alleviate the problem of condensation.

[0090] like Figure 1As shown, in winter heating, valves D, K, G, H, L, M, N, O, P, Q are opened, valves E, F, I, J are closed, circulating water pumps A and C are opened, and circulating water pump B is closed. The high-temperature liquid generated by the multilayer film heat exchanger due to the absorption of soil heat is pumped into the evaporator 3 by the circulating water pump A through the r interface, and heat is exchanged with the low-temperature and low-pressure refrigerant liquid in the evaporator 3. After the heat exchange, the liquid on the source side flows back to the multilayer film heat exchanger from the c interface of the evaporator 3 to extract heat again; at the same time, the low-temperature liquid in the hot water supply cycle on the load side is pumped into the condenser 4 through the circulating water pump C, and heat is exchanged with the high-temperature and high-pressure refrigerant gas in the condenser 4. The liquid used for heating is heated to become high-temperature water and flows out from the f interface of the condenser 4, and then enters the terminal radiation system 5 to heat the ground building. The return water for heating flows back to the circulating water pump C and returns to the condenser 4 through the interface h to complete the cycle.

[0091] like Figure 1 As shown, in summer cooling, valves E, I, F, J, L, N, P, Q are opened, valves D, G, H, K, M, O are closed, circulating water pump A and circulating water pump B are opened, and circulating water pump C is closed. For the circulation between the soil cold source side and the heat pump unit in summer, the liquid in the multilayer film heat exchanger is pumped into the condenser 4 through the h interface by the circulating water pump A and heat exchanged with the high-temperature and high-pressure refrigerant gas. After the temperature of the circulating liquid increases, it flows out from the f interface of the condenser 4 and is sent back to the multilayer film heat exchanger for cooling. After cooling, it is sent back to the condenser to complete the cycle; at the same time, the circulation between the radiation terminal on the load side and the heat pump unit in summer is a chilled water circulation for this embodiment. The low-temperature and low-pressure refrigerant liquid in the evaporator 3 exchanges heat with the chilled water. After the chilled water is cooled, it is pressed into the radiation terminal 5 from the c interface of the evaporator 3 by the second circulating water pump. After providing cooling to the user in the ground building, the chilled water temperature increases and flows back to the evaporator 3 through the a interface to complete the cycle.

[0092] The cold capacity of the underground space can be fully utilized, and the cold and heat of the underground space and soil can be fully utilized to provide heating in the heating season and cooling in the air-conditioning season for the above-ground buildings. While providing cooling in summer, the absorbed indoor heat is dissipated to the soil through the circulation loop between the summer soil cold source side and the heat pump unit. The dissipated heat can increase the ground and wall temperature of the underground garage, reduce the temperature difference between the wall and the air, effectively solve the condensation problem in the underground space, and give full play to the advantages of the composite heat pump system.

[0093] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat pump system of underground space multilayer film heat exchanger, characterized in that: include: The multilayer film heat exchanger is arranged on the ground or wall of the underground space, and has a main inlet 1 and a main inlet 2, which are used to transfer heat or cold of the underground soil to the heat exchange medium inside the multilayer film heat exchanger; The heat pump unit transfers the heat or cold carried by the heat exchange medium from the multi-layer film heat exchanger to the radiation end through the compressor, throttle valve, evaporator and condenser; Radiant terminals, used to provide heat or cooling to above-ground buildings; Among them, the two interfaces of the evaporator are respectively connected to the main port 1 and the main port 2 of the multilayer film heat exchanger through pipes, so as to transfer the heat in the underground soil to the refrigerant of the heat pump unit through the evaporator; the two interfaces of the condenser are respectively connected to the main port 1 and the main port 2 of the multilayer film heat exchanger through pipes, so as to transfer the cold in the underground soil to the refrigerant of the heat pump unit through the condenser.

2. A heat pump system of an underground space multilayer film heat exchanger as claimed in claim 1, characterized in that: The multilayer film heat exchanger comprises a plurality of groups of film heat exchangers arranged in parallel, all of which have an inlet main pipe, a return main pipe, a capillary grid connected between the inlet main pipe and the return main pipe, and valves arranged on the inlet main pipe and the return main pipe.

3. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 2, characterized in that: The capillary grid is laid vertically along the wall of the underground space or horizontally along the ground. The capillary grid includes a plurality of capillary heat-conducting water pipes uniformly distributed between the water inlet pipe and the water return pipe and penetrating the water inlet pipe and the water return pipe.

4. A heat pump system of an underground space multilayer film heat exchanger as claimed in claim 1, characterized in that: The first interface and the third interface of the evaporator are connected for the flow of heat exchange medium, and the second interface and the fourth interface are connected for the flow of refrigerant; the first interface and the third interface of the condenser are connected for the flow of refrigerant, and the second interface and the fourth interface are connected for the flow of heat exchange medium.

5. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 1, characterized in that: The outlet of the compressor is connected to the first interface of the condenser, the third interface of the condenser is connected to the throttle valve, the other end of the throttle valve is connected to the fourth interface of the evaporator, and the second interface of the evaporator is connected to the inlet of the compressor, forming a circulation loop of the soil source heat pump unit.

6. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 1, characterized in that: The first interface of the evaporator is connected to the main port 1 of the multilayer film heat exchanger through a pipeline via a first circulating water pump; the third interface of the evaporator is connected to the main port 2 of the multilayer film heat exchanger through a pipeline, forming a circulation loop between the soil source side heat exchanger and the heat pump unit in winter.

7. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 1, characterized in that: The first interface of the evaporator is connected to the return water end of the radiation end through a pipeline, and the third interface of the evaporator is connected to the water inlet end of the radiation end through a pipeline via a second circulating water pump, forming a circulation loop between the radiation end on the summer load side and the heat pump unit.

8. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 1, characterized in that: The second interface of the condenser is connected to the water inlet end of the radiation end through a pipeline; the fourth interface of the condenser is connected to the return water end of the radiation end through a pipeline via the third circulating water pump, forming a circulation loop between the radiation end on the winter load side and the heat pump unit.

9. A heat pump system of an underground space multilayer membrane heat exchanger as claimed in claim 1, characterized in that: The second interface of the condenser is connected to the second pipe port of the multilayer film heat exchanger through a pipeline; the fourth interface of the condenser is connected to the first main pipe port of the multilayer film heat exchanger through a pipeline via the first circulating water pump, forming a circulation loop between the soil cold source side and the heat pump unit in summer.

10. A working method of a heat pump system based on the underground space multilayer membrane heat exchanger according to any one of claims 1 to 9, characterized in that: The following steps are involved: The low-temperature and low-pressure refrigerant gas is compressed by the compressor, condensed into a normal-temperature and high-pressure liquid after passing through the condenser, and then converted into a low-temperature and low-pressure liquid after passing through the throttle valve. The evaporator absorbs heat and converts it into a low-temperature and low-pressure refrigerant gas, and then flows back into the compressor; During heating, the heat exchange medium in the multi-layer film heat exchanger absorbs heat from the underground soil and exchanges heat with the refrigerant in the evaporator. After the heat exchange, the heat exchange medium returns to the multi-layer film heat exchanger to heat the soil again. At the same time, the heat exchange medium at the radiation end exchanges heat with the refrigerant in the condenser, and the heated heat exchange medium is used to heat the above-ground buildings. After releasing heat, the heat exchange medium returns to the condenser to continue absorbing heat, thus realizing cyclic heating. During cooling, the heat exchange medium produced by the multi-layer film heat exchanger absorbs the cold from the underground soil and exchanges heat with the refrigerant in the condenser. The heat exchange medium after the heat exchange returns to the multi-layer film heat exchanger to heat the underground soil. At the same time, after the refrigerant is cooled in the condenser, it is transported to the evaporator through the throttle valve and exchanges heat with the heat exchange medium in the evaporator. The cooled heat exchange medium is used to cool the ground buildings through the radiation terminal. The heat exchange medium after absorbing heat and heating up returns to the evaporator to continue cooling, thereby realizing circulating cooling.

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