WO2006034608A1

WO2006034608A1 - Soil low-grade energy extraction system

Info

Publication number: WO2006034608A1
Application number: PCT/CN2004/001184
Authority: WO
Inventors: Shengheng Xu
Original assignee: Shengheng Xu
Priority date: 2004-09-27
Filing date: 2004-10-19
Publication date: 2006-04-06
Also published as: CN1755295A; CN100374793C

Abstract

A soil low-grade energy extraction system, Includes: an energy collection device (2), an energy extractor (1) and a heating radiator (4). The energy collection device includes a heating collector (31), a low-level energy side heat-exchange coils (25) and a return liquid pump (24), which are connected in series to constitute a loop in turn. The heating collector (31) includes an energy accumulator (5) and a heat collection well (6). The energy accumulator (5) is comprised of an outer cylinder (9) and an inner cylinder (8) which assembles in the outer cylinder (9). Between the energy accumulator (5) 's outer cylinder (9) and heat collection well (6) fills with a mixture which is made of cement and bolar. The soil low-grade energy extraction system of the present invention solves the problem which troubles people long term, and the cement and bolar makes the energy accumulator tightly contact with the soil together. The soil's heat transfer efficiency can be increased. The energy collection device (2) 's loop fills with the antifreeze fluid, which be still able to work normally when the present system energy source temperature is zero belows.

Description

Technical field

The invention relates to a soil low-grade energy extraction system, in particular to a system for extracting low-grade energy in soil by single well pumping, which realizes low-grade heat energy into high-grade heat energy through an energy lifting device. Winter heating, summer cooling, daily supply of domestic hot water and cold source for the purpose of four. Background technique

The vertical geothermal energy storage air conditioning system of the Chinese invention patent number ZL01116085.3 previously filed by the applicant of the present invention provides a kind of collecting geothermal energy as energy, no pollution, small footprint, and can provide domestic heat. Vertical geothermal air conditioning system for water. The system must be used in areas where groundwater can be excavated, but in many places it is necessary to dig up the groundwater to dig the shaft deep, which is not only time-consuming and laborious, but also brings a lot of inconvenience to the installation and maintenance of the accumulator. Soil heat transfer, its heat transfer rate is slow, and the utilization rate is low. Summary of the invention

In order to improve the defects in the prior art and meet the needs of users in areas with insufficient groundwater resources, the object of the present invention is to provide a soil low-grade energy extraction system which can utilize the heat in the soil to achieve winter supply and summer cooling. the goal of.

The soil low-grade energy extraction system of the present invention comprises: an energy harvesting device, an energy lifting device and a heat sink which are sequentially connected in series, the energy collecting device comprising a heat collector, a low energy side heat exchange coil and a liquid return pump a circuit consisting in series, the collector comprising a heat collecting well and an accumulator disposed in the heat collecting well, wherein the circuit of the energy collecting device is filled with antifreeze, the accumulator including the outer tube and the set An inner cylinder in the outer cylinder, a gap is left between the outer cylinder and the inner cylinder, an upper cover is arranged on the top of the outer cylinder, and an inlet pipe of the heat collector is mounted on the upper cover, and the liquid collector is discharged The tube communicates with the annular gap between the outer tube and the inner tube, and a flow equaling plate is arranged between the upper cover and the inner tube, the inner tube is an open container, and the opening of the inner tube extends out of the upper cover of the outer tube to store energy A mixture of cement and clay is filled between the outer cylinder and the collecting well.

The soil low-grade energy extraction system of the present invention, wherein the ratio of cement to clay is between 1:3-1:5. The soil low-grade energy extraction system of the present invention, wherein the circuit of the energy harvesting device further comprises: a first valve, an eleventh valve, a fifth valve and a second valve, wherein: the first valve and the eleventh valve are connected in series Between the liquid discharge end of the collector and the liquid feed end of the low energy side heat exchange coil, the second valve and the fifth valve are sequentially connected in series at the liquid inlet end of the collector Between the liquid returning pump; a heat exchanger is arranged between the energy lifting device and the radiator, and the heat exchanger is composed of a high energy side heat exchange coil, an outlet pump, an eighth valve, an energy output coil and a The four valves are sequentially connected in series, the circuit is filled with antifreeze, the energy output coil is coupled with the energy input coil of the radiator; at the outlet end of the energy output coil and the outlet pump and the eighth valve a tenth valve and a seventh valve connected in series with each other in parallel between the connection points; a third valve is connected in parallel between the liquid output end of the energy output coil and the liquid inlet end of the low energy side heat exchange coil; a twelfth valve is connected between the liquid inlet end of the high energy side heat exchange coil and the connection point of the first valve and the eleventh valve; the pipe between the tenth valve and the seventh valve is connected with the second valve and the fifth The pipeline between the valves is connected to each other by a four-way pipe joint; the energy lifting device is composed of a first-stage heat pump and a second-stage heat pump, and the first-stage heat pump is a first evaporator, a thirteenth valve, and a first a compressor, a first condenser, a first expansion valve, and a fourteenth valve a circuit composed in series; the second stage heat pump is a circuit consisting of a second evaporator, a fifteenth valve, a second compressor, a second condenser, a second expansion valve, and a sixteenth valve in series; a seventeenth valve is connected between the output end of the evaporator and the connection point of the fifteenth valve and the second compressor; the input end of the first evaporator is connected in parallel with the connection point of the sixteenth valve and the second expansion valve An eighteen valve; the first evaporator is coupled to the low energy side heat exchange coil, and the second condenser is coupled to the high energy side heat exchange coil.

The soil low-grade energy extraction system of the present invention, wherein the second compressor and the second condenser are connected in series with a heating pipe of the water heater.

The soil low-grade energy extraction system of the present invention, wherein the heat exchange coil of the cold storage tank is connected in parallel between the liquid return pump and the fifth valve, and the liquid inlet end of the heat exchange coil of the cold storage is connected to the liquid outlet end of the liquid return pump, The liquid discharge end of the heat exchange coil of the cold storage is connected to the liquid inlet end of the energy output coil of the heat exchanger through the sixth valve, and the ninth valve is connected in parallel between the liquid inlet end and the liquid discharge end of the heat exchange coil of the cold storage, The pipe between the fifth valve and the ninth valve and the pipe between the liquid discharge end of the heat exchange coil of the cold store and the sixth valve are connected to each other by a four-way pipe joint.

The soil low grade energy extraction system of the present invention has the following advantages over prior art vertical geothermal energy storage air conditioning systems:

1. Solved the problem that has long plagued people, that is, in areas where water resources are scarce, vertical geothermal energy storage air conditioning systems in the prior art cannot be used. The use of soil heat transfer systems also solves this problem because of the low heat transfer efficiency of the soil, the large size of the equipment, and the low utilization rate. And the use of cement and clay tightly combines the accumulator and the soil, increasing the heat transfer efficiency of the soil.

2. The placement of the heat exchanger allows the antifreeze and water to be completely separated, whether it is cooling or heating, to ensure the normal operation of the entire system. 3. If you need to set up a cold storage or provide domestic hot water, the cold storage can obtain a stable cold source regardless of whether the system is in the state of cooling or heating. When the heat pump is working, the water heater placed at the rear of the compressor can always obtain stable high temperature. Heat, thus providing a stable domestic hot water. DRAWINGS

1 is a schematic view of a soil low-grade energy extraction system of the present invention in a state of heating in winter;

2 is a schematic view of the soil low-grade energy extraction system of the present invention in a state where the heat pump is not activated during the summer cooling; FIG. 3 is a schematic view of the soil low-grade energy extraction system of the present invention when the heat pump is started during summer cooling. Fig. 4 is an enlarged schematic view of the heat pump of Figs. 1 to 3, showing a state in which only the primary heat pump is started. BEST MODE FOR CARRYING OUT THE INVENTION

It can be seen from Fig. 1 and Fig. 3 that the connection relationship between the various components in the three figures is the same, except that in the above three states, the opening and closing states of the respective valves are different, for the sake of clarity, The three figures show that the unpainted valve indicates the "open" state and the blacked valve indicates the "closed" state.

Referring to Figures 1 to 3, the soil low-grade energy extraction system of the present invention comprises: an energy harvesting device 2, an energy boosting device 1 and a heat sink 4, and the energy harvesting device 2 is a low-grade energy harvesting device, which includes heat collecting a circuit composed of a first valve 11, a first valve 11, an eleventh valve 21, a low energy side heat exchange coil 25, a liquid return pump 24, a ninth valve 19 and a fifth valve 15, wherein the liquid flowing in the circuit is an antifreeze solution. A heat exchange coil 30 of a cold storage is connected between the liquid return pump 24 and the fifth valve 15 . The heat collector 31 comprises: an accumulator 5 and a heat collecting well 6 , and the accumulator 5 is placed in the heat collecting well 6 The accumulator 5 is composed of an outer cylinder 9 and an inner cylinder 8 fitted in the outer cylinder 9. The outer cylinder 9 and the inner cylinder 8 have a gap between the upper and lower sides and the inner cylinder 8, and the top of the outer cylinder 9 is provided with an upper cover 10, The liquid inlet pipe of the heat exchanger 31 is mounted on the upper cover 10, and the liquid discharge pipe of the heat collector 31 is installed in the lower portion of the annular space between the outer cylinder 9 and the inner cylinder 8, and the upper cover 10 and the inner cylinder 8 are disposed between The flow plate 7, the inner cylinder 8 is a well type container, and the opening of the inner cylinder 8 extends from the upper cover 10 of the outer cylinder 9, A mixture of cement and clay filled transducer 9 and the outer cylinder 5 between the collector well 6, according to the proportion of soil, cement and clay surrounding the collector well 6 in 1: 3 - 1: 5 between.

The radiator 4 is coupled to the energy boosting device 1 through a heat exchanger 3, which is composed of a high-potential side heat exchange coil 26, an outlet pump 23, an eighth valve 18, an energy output coil 32, and The fourth valve 14 is sequentially connected in series, the liquid flowing in the circuit is antifreeze, the high energy side heat exchange coil 26 is coupled with the energy lifting device 1, and the energy output coil 32 is coupled with the energy input coil of the radiator 4. Energy output coil 32 outlet end with discharge pump 23 and eighth The tenth valve 20 and the seventh valve 17 connected in series with each other are connected in parallel between the connection points of the wide door 18; the liquid output end of the energy output coil 32 and the liquid inlet end of the low energy side heat exchange coil 25 are connected in parallel. The valve 13, the liquid inlet end of the high energy side heat exchange coil 26 and the connecting line of the first valve 11 and the eleventh valve 21 are connected in parallel between the twelfth valve 22, the tenth valve 20 and the seventh valve 17 The pipe between the pipe and the second valve 12 and the fifth valve 15 are connected to each other through a four-way pipe joint, and the liquid inlet end of the heat exchange coil 30 of the cold store is connected to the liquid discharge end of the liquid return pump 24, and the cold storage is exchanged. The liquid discharge end of the heat coil 30 is connected to the liquid inlet end of the energy output coil 32 of the heat exchanger 3 through the sixth valve 16, the pipe between the fifth valve 15 and the ninth valve 19 and the heat exchange coil 30 of the cold store. The pipes between the liquid discharge end and the sixth valve 16 are connected to each other by a four-way pipe joint.

Referring to FIG. 4, the energy lifting device 1 is composed of a first stage heat pump 28 and a second stage heat pump 29 connected in series. The first stage heat pump 28 is composed of a first evaporator 116, a thirteenth valve 136, a first compressor 121, and a first condensation. The first expansion valve 123, the first expansion valve 123 and the fourteenth valve 134 are sequentially connected in series; the second stage heat pump 29 is composed of a second evaporator 125, a fifteenth valve 132, a second compressor 112, a heating pipe 113 of the water heater, The second condenser 117, the second expansion valve 114, and the sixteenth valve 135 are sequentially connected in series. The seventeenth valve 131 is connected in parallel between the output end of the first evaporator 116 and the junction of the fifteenth valve 132 and the second compressor 112, the input end of the first evaporator 116 and the sixteenth valve 135 and the second expansion The eighteenth valve 133 is connected in parallel between the connection points of the valve 114, the first evaporator 116 is coupled to the low energy side heat exchange coil 25, and the second condenser 117 is coupled to the high energy side heat exchange coil 26.

'The working process of the energy lifting device 1 is as follows:

In winter, when the energy used is higher than 5 °C, the seventeenth valve 131, the eighteenth valve 133 are opened, and the fifteenth valve 132, the fourteenth valve 134, the sixteenth valve 135 and the thirteenth valve 136 are closed. (As shown in Figure 4). At this time, the first evaporator 116, the seventeenth valve 131, the second compressor 112, the water heater heating pipe 113, the second condenser 117, the second expansion valve 114, and the eighteenth valve 133 of the energy lifting device 1 form a circuit. The working medium in the first evaporator 116 absorbs the low energy of the heat exchange coil 25 flowing through the low energy side to evaporate into a gas, and the gas enters the second compressor 112 through the seventeenth valve 131 to be heated and heated, and is heated by the water heater. The tube 113 heats the domestic hot water for people to wash. The second condenser 117 releases heat to the high energy side heat exchange coil 26 coupled to the condenser 117, and the energy output coil 32 of the heat exchanger 3 is coupled to the energy input coil of the radiator 4, and finally The heat energy is delivered to the user for heating purposes, and the condensed liquid working medium is depressurized by the second expansion valve 114, and again enters the first evaporator 116 through the eighteenth valve 133 to absorb heat.

When the energy source utilized is lower than 5 ° C, the first heat pump 28 does not work normally, that is, when the amount of heat raised is insufficient for heating, the first heat pump 28 and the second heat pump 29 work together, and the seventeenth is closed. Valve 131, tenth Eight valves 133 open the fifteenth valve 132, the fourteenth valve 134, the sixteenth valve 135, and the thirteenth valve 136 (shown in Figures 1 and 3). At the same time, the first and second compressors 121 and 112 are activated, at which time two circuits operate simultaneously, that is, when the liquid below 5 ° C flows through the heat exchange coil 25 on the lower energy side, the first evaporator 116 The low-grade energy of the working medium absorption heat exchange coil 25 is evaporated into a gas, and the gas is compressed and heated by the first compressor 121 (about 15 ° C) into the first condenser 124, and the first condenser 124 and the second evaporator 125 Coupling, the working medium is condensed in the first condenser 124 to release heat to the working medium in the second evaporator 125. The working medium absorbs heat and evaporates into a gas, and is heated by the second compressor 112 to enter the heating pipe 113 of the water heater. The domestic hot water is heated for washing, and then the second condenser 117 is condensed (about 50 ° C) to release heat, and the heat is released to the high-energy side heat exchanger 3 coupled to the second condenser 117. The working fluid of the heat coil 26 is then sent to the heat exchange coil of the heat sink 4 through the energy output coil 32 of the heat exchanger 3 to feed the user. The working fluid in the first condenser 124 releases heat in the condenser 124, is depressurized by the first expansion valve 123, enters the first evaporator 116 to absorb heat, and the working medium in the second condenser 117 is in the second condenser. After the heat is released in 117, the pressure is reduced by the second expansion valve 114, and then enters the second evaporator 125 to absorb heat and evaporate, and the cycle is repeated.

When cooling is required in summer, the energy output coil 32 of the heat exchanger 3 is connected to the heat exchange coil 25 on the low energy side, and after the operation of the primary or secondary heat pump, the cold after cooling is transferred to the low energy side. The hot coil 25 is then delivered to the user for refrigeration purposes.

As can be seen from the running process, the energy lifting device 1 is a heat pump that changes the operating conditions to adapt to changes in outside temperature. It can provide heating temperature of different temperature according to needs, maneuvering, flexible and wide application range. The compressors of its two circuits can be selected from the same compressor or different compressors, and the optimal configuration can be selected according to different needs.

The working principle of the soil low-grade energy extraction system is as follows:

(i) Winter heating

Figure 1 is a schematic view of the soil low-grade energy extraction system in the winter heating state, as shown in Figure 1, in this state, the valves 11, 12, 15, 21, 18, 14 are open, valves 20, 22, 19, 13, 16 and 17 are closed.

The liquid return pump 24 is activated, and the liquid return pump 24 extracts the antifreeze liquid of the low energy side heat exchange coil 25, and the antifreeze liquid flows into the accumulator 5 through the cold storage heat exchange coil 30, the fifth valve 15 and the second valve 12, The antifreeze liquid flows uniformly along the annular passage formed between the inner cylinder 8 and the outer cylinder 9 of the accumulator 5 through the equalizing plate 7 to the bottom of the accumulator 5, and the antifreeze is cooled from the annular passage after cooling in the process. The outer wall absorbs the heat transferred from the soil to the outer wall, absorbs the heat of the inner cylinder water from the inner wall of the annular passage, and the warmed antifreeze liquid again enters the low energy side heat exchange coil 25 through the first valve 11 and the eleventh valve 21 to release heat. Since the heat supplied to the antifreeze by the soil and the water is insufficient to balance the heat released by the low energy side heat exchange coil 25, the temperature of the antifreeze is continuously lowered. As the temperature difference between the soil and the antifreeze increases, the heat transfer rate of the soil continues Increasing, until the antifreeze reaches a certain temperature to reach equilibrium, that is, the heat released by the antifreeze on the low energy side heat exchange coil 25 is equal to the heat obtained by the accumulator 5. At this point, the antifreeze temperature is no longer lowered.

The working range of the energy lifting device 1 is between 15 ° C and 25 ° C, and the freezing point of the antifreeze is about 30 ° C. Therefore, the temperature of the equilibrium point is set to 25 ° C, and the size of the accumulator 5 is adjusted. Achievable.

After the evaporator 25 of the first stage heat pump 28 of the energy lifting device 1 obtains low-grade heat energy from the low-potential side heat exchange coil 25, the low-grade heat energy is boosted by the operation of the secondary heat pumps 28 and 29 of the energy boosting device 1. After the high-grade heat energy, the liquid of the high-potential side heat exchange plate 26 of the heat exchanger 3 absorbs the heat dissipated by the condenser of the second-stage heat pump 29 by heat exchange, and the anti-freezing liquid after the temperature rise is passed through the eighth pump by the discharge pump 23. The valve 18 is sent to the energy output coil 32 of the heat exchanger 3 to release heat, and the anti-freezing liquid after the P-trapping temperature again absorbs heat through the clamp heat exchange coil 26, so that the cycle is repeated, and the heat is continuously supplied to the energy output tray. The tube 32, and the energy input coil of the radiator 4 is coupled to the energy output coil 32, and the heat is continuously obtained from the energy output coil 32 of the heat exchanger 3, and is supplied to the user through the circulation pump 27 to thereby achieve heating. the goal of.

(ii) Summer cooling

Since a large amount of cold is stored underground in the winter heating, the minimum temperature can be around 25 Ό. Since the heat transfer rate of the soil is very slow, most of the cold is stored. Therefore, the summer cooling is divided into two working conditions, that is, starting the heat pump and not starting the heat pump.

(1) Refrigeration without starting the heat pump

m 2 is a schematic diagram of the soil low-grade energy extraction system that does not start the heat pump when it is cooled in summer; as shown in the figure, the valves 11, 12, 21, 20 and 16 are in the "open" state, and the valve 19, 15, 17, 18, 13, 14, 22 are in the "off" state.

The liquid return pump 24 extracts the antifreeze liquid of the low energy side heat exchange coil 25, releases the cold through the cold storage heat exchange coil 30, passes through the sixth valve 16 to the liquid inlet end of the heat output coil 32 of the heat exchanger 3, and enters the energy. After the output coil 32 continues to release the cold energy, the cold energy is transferred to the heat exchange coil of the energy input end of the radiator 4, and the warmed antifreeze passes through the tenth valve 20, the second valve 12 and the current equalizing plate 7, along The annular passage of the accumulator 5 releases heat, and the released heat is absorbed by the cold energy stored in the ground. The antifreeze liquid is cooled after the heat is released, and the antifreeze liquid after the temperature drop enters the low energy side heat exchange coil 25 through the first valve 11 and the eleventh valve 21 under the action of the liquid return pump 24, and enters the low energy side heat exchange coil. The antifreeze of 25 is once again sent to the cold storage heat exchange coil 30, and then sent to the liquid inlet end of the energy output coil 32 of the heat exchanger 3 through the sixth valve 16 to enter the energy output coil 32 and then continue to release cold. After the warmed antifreeze passes through the tenth valve 20 and the second valve 12, it enters the accumulator 5 to release heat. The cycle is repeated so that the energy output coil 32 of the heat exchanger 3 continuously obtains cold energy and dissipates heat. The water in the energy input coil of the device 4 is heat-exchanged with the output coil 32, and the temperature is lowered. The ring pump 27 delivers the obtained cold energy to the user for the purpose of cooling.

(2) Start the cooling of the heat pump

Fig. 3 is a schematic view showing the soil low-grade energy extraction system of the present invention in a state in which a heat pump is started during cooling in summer. As shown in the figure, in this state, valves 11, 12, 16, 22, 13, and 17 are in the "open" state, and valves 21, 14, 15, 18, 20, and 19 are in the "off" state.

The antifreeze liquid in the accumulator 5 is released by the first valve 11 and the twelfth valve 22 after the first valve 11 and the twelfth valve 22 enter the high energy side heat exchange coil 26 of the heat exchanger 3, and the antifreeze is heated after the temperature rises. The liquid is returned to the accumulator 5 through the outlet pump 23, the seventh valve 17, and the second valve 12, and the energy lifting device 1 is activated. Under the action of the energy lifting device 1, the heat in the low energy side heat exchange coil 25 is It is absorbed by the evaporator 116 (Fig. 4) of the first stage heat pump 28, and the temperature is lowered. The liquid return pump 24 sends the cooled antifreeze liquid in the low energy side heat exchange coil 25 to the cold storage heat exchange coil 30, through the first The six valve 16 enters the energy output coil 32 of the heat exchanger 3 to release the cold energy. After the warmed antifreeze liquid emerges from the energy output coil 32 of the heat exchanger 3, the third valve 13 enters the low energy side heat exchange coil. 25, and the heat exchange coil of the energy input end of the radiator 4 is coupled with the energy output coil 32 of the heat exchanger 3, and the heat output of the heat sink 4 from the heat output coil 32 of the heat exchanger 3 is continuously obtained. The circulation pump 27 is delivered to the user. This cycle is repeated to achieve the purpose of cooling.

'Industrial applicability

The soil low-grade energy extraction system of the invention can be used for residents, enterprises and institutions in areas with insufficient groundwater resources to heat in winter, cool in summer, supply daily hot water and provide a stable cold source for the cold storage.

Claims

Rights request

A soil low-grade energy extraction system, comprising: an energy harvesting device (2), an energy lifting device (1) and a heat sink (4) connected in series, the energy collecting device (2) comprising a set The heat exchanger (31), the low energy side heat exchange coil (25) and the liquid return pump (24) are sequentially connected in series, and the heat collector (31) includes a heat collecting well (6) and is placed in the heat collecting well An accumulator (5) in (6), characterized in that: the circuit of the energy harvesting device (2) is filled with antifreeze, the accumulator (5) comprising an outer cylinder (9) and a set in the outer cylinder ( 9) inner inner cylinder (8), a gap is left between the outer cylinder (9) and the inner cylinder (8), and an upper cover (10) is provided at the top of the outer cylinder (9), a heat collector (31) The inlet pipe is mounted on the upper cover (10), and the outlet pipe of the collector (31) communicates with the annular gap between the outer cylinder (9) and the inner cylinder (8), and the upper cover (10) Between the inner cylinder (8) and the inner cylinder (8), the inner cylinder (8) is an open container, and the opening of the inner cylinder (8) extends from the upper cover (10) of the outer cylinder (9). Outer tube (9) and collector (6) of the energy device (5) Fill a mixture of cement and clay.

2. The soil low grade energy extraction system according to claim 1, wherein the ratio of the cement to the clay is between 1:3 and 1:5.

3. The soil low-grade energy extraction system according to claim 1 or 2, wherein: the circuit of the energy harvesting device (2) further comprises: a first valve (11) and an eleventh valve (21) a fifth valve (15) and a second valve (12), wherein: the first valve (11) and the eleventh valve (21) are sequentially connected in series at the liquid outlet end and the low energy side of the heat collector (31) Between the liquid inlet ends of the hot coil (25), the second valve (12) and the fifth valve (15) are sequentially connected in series between the liquid inlet end of the heat collector (31) and the liquid return pump (24); A heat exchanger (3) is arranged between the energy lifting device (1) and the radiator (4), and the heat exchanger (3) is composed of a high-potential side heat exchange coil (26) and an outlet pump (23). Eighth valve

(18), the energy output coil (32) and the fourth valve (14) are sequentially connected in series, the circuit is filled with antifreeze, and the energy output coil (32) and the heat sink (4) of the energy input coil Phase coupling; between the outlet end of the energy output coil (32) and the connection point of the discharge pump (23) and the eighth valve (18), two tenth valves (20) connected in series are connected in parallel And a seventh valve (17); a third valve (13) is connected in parallel between the liquid output end of the energy output coil (32) and the low energy side heat exchange coil (25); The twelfth valve (22) is connected between the inlet end of the side heat exchange coil (26) and the connection point of the first valve (11) and the eleventh valve (21); the tenth valve (20) and the seventh valve (17) The pipe between the pipe and the second valve (12) and the fifth valve (15) is connected to each other by a four-way pipe joint; the energy lifting device (1) is composed of a first-stage heat pump (28) ) and the second stage heat pump (29) is connected in series, the first stage heat pump

(28) is a first evaporator (116), a thirteenth valve (136), a first compressor (121), a first condenser (124), The first expansion valve (123) and the fourteenth valve (134) are sequentially connected in series; the second stage heat pump (29) is composed of a second evaporator (125), a fifteenth valve (132), and a second compressor (112), a second condenser (117), a second expansion valve (114), and a sixteenth valve (135) are sequentially connected in series; the output end of the first evaporator (116) and the fifteenth valve ( 132) parallelizing the seventeenth valve (131) between the connection point of the second compressor (112); the input end of the first evaporator (116) and the sixteenth valve (135) and the second expansion valve (114) The eighteenth valve (133) is connected in parallel between the connection points; the first evaporator (116) is coupled to the low energy side heat exchange coil (25), and the second condenser (117) is The potential energy side heat exchange coil (26) is coupled.

4. The soil low-grade energy extraction system according to claim 3, wherein: the heating pipe (113) of the water heater is connected in series between the second compressor (112) and the second condenser (117). ).

5. The soil low-grade energy extraction system according to claim 4, wherein: the heat exchange coil (30) of the cold storage is connected in parallel between the liquid return pump (24) and the fifth valve (15), and the cold storage The liquid inlet end of the heat exchange coil (30) is connected to the liquid outlet end of the liquid return pump (24), and the liquid discharge end of the heat exchange coil (30) of the cold storage tank passes through the sixth valve (16) and the heat exchanger.

(3) The liquid inlet end of the energy output coil (32) is connected, and the ninth valve (19), the fifth valve (15) and the liquid inlet end and the liquid discharge end of the cold storage heat exchanger coil (30) are connected in parallel. The pipe between the ninth valve (19) and the pipe between the discharge end of the heat exchange coil (30) of the cold store and the sixth valve (16) are connected to each other by a four-way pipe joint.