CN103604248B - A kind of three use type earth source absorption type heat pump and operation method - Google Patents

Abstract

A three-purpose ground source absorption heat pump system and its operation method, the system includes an absorption heat pump, an underground pipe, a domestic hot water tank, a plate heat exchanger, a switching pump and a plurality of valves. This method is based on the combination of fuel combustion heating system and ground source absorption heat pump, and adds a heat recovery loop and switching device to provide heating in winter, air conditioning in summer and domestic hot water throughout the year. According to the load characteristics of different seasons and different needs, a variety of different operating modes can be realized by switching. While cooling in summer, the exhaust heat of the absorber and/or the condenser is recovered to make domestic hot water. Compared with electric heat pumps, absorption heat pumps take less heat from the soil when heating, and dissipate more heat to the soil when cooling, while the demand for domestic hot water throughout the year can further increase the heat taken, and heat recovery in summer can further reduce emissions. Therefore, it can effectively reduce the annual thermal imbalance rate, improve the primary energy efficiency of traditional systems, and maintain stable and reliable heating and air conditioning performance for many years.

Description

A three-purpose ground source absorption heat pump system and its operating method

technical field

The invention relates to a three-purpose ground source absorption heat pump system and an operation method, belonging to the field of heating and air conditioning. This technology can not only improve the primary energy efficiency of the traditional system, but also maintain stable and reliable heating and air conditioning performance for many years. It is especially suitable for heating in winter, air conditioning in summer, domestic hot water supply throughout the year, and areas with sufficient fuel supply.

Background technique

Northern cities and towns mainly adopt the centralized heating method based on fossil fuel combustion, which results in large energy consumption due to low overall energy efficiency, and is accompanied by a large amount of polluting gas and inhalable particulate matter emissions. Ground source heat pump system has been more and more widely used as a clean and efficient way of heating and air conditioning. However, when used in cold regions dominated by heat loads, the heat gain in winter may be greater than the heat output in summer, and long-term operation will cause the soil temperature to drop year by year, resulting in a significant decline in the heating performance of the unit, or even failure to operate normally. For systems with year-round domestic hot water demand, the soil thermal imbalance will be even more severe. This problem can be alleviated by increasing the spacing of buried pipes or the number of buried pipes, but it requires a large land area and investment in buried pipes, and the thermal imbalance cannot be fundamentally reduced. The composite ground source heat pump system with the boiler as the auxiliary heat source is a feasible solution, but the use of the boiler reduces the advantages of the ground source heat pump to a certain extent; Boiler + small ground source heat pump system. However, the composite ground source heat pump system combined with solar energy has poor reliability and requires a large installation space and initial investment.

How to effectively solve the problem of low energy efficiency and high pollution in the heating mode based on fuel combustion in the north, as well as the thermal imbalance of traditional ground source heat pumps in the cold regions of the north, is of great significance to energy conservation and emission reduction in the construction field.

Contents of the invention

Based on the above problems, the present invention proposes a three-purpose ground source absorption heat pump system and its operation method. The system combines a heating system based on fuel combustion with a ground source absorption heat pump to provide winter heating, summer air conditioning and year-round Hot water; and can realize a variety of different operating modes according to the load characteristics of each part. In summer, the exhaust heat of the absorber and/or the condenser can be recovered while cooling to make domestic hot water. When traditional electric heat pumps are used in northern cold regions, the soil temperature will drop year by year due to more heat intake and less heat discharge, and the performance of heat pumps will gradually decline. Compared with electric heat pumps, absorption heat pumps take less heat from the soil when heating, and dissipate more heat to the soil when cooling, while the demand for domestic hot water throughout the year can further increase the heat taken, and heat recovery in summer can further reduce emissions. Therefore, it can effectively reduce the annual thermal imbalance rate. The three-purpose ground source absorption heat pump can not only improve the primary energy efficiency of the traditional system, but also maintain stable and reliable heating and air conditioning performance for many years.

The following technical scheme of the present invention is as follows:

A three-purpose ground source absorption heat pump system, including an absorption heat pump, buried pipes, heating and air conditioning users, and a domestic hot water tank; the absorption heat pump includes a generator, an absorber, a condenser, an evaporator, and a solution heat pump exchanger, solution pump, first throttling valve and second throttling valve; the solution outlet of the generator is connected with the hot end of the solution heat exchanger, the first throttling valve and the solution inlet of the absorber in turn; the absorber The solution outlet of the generator is connected with the solution pump, the cold end of the solution heat exchanger and the solution inlet of the generator in sequence; the steam outlet of the generator is connected with the steam inlet of the condenser, the second throttle valve, the evaporator and the absorber in sequence The outlet of the buried pipe is divided into a ground source side refrigeration circuit and a ground source side heating circuit after passing through the ground pipe pump, and the ground source side refrigeration circuit is connected to the sixth valve, the condenser, the ninth valve and the fifth valve circuit in turn. to the buried pipe, the heating circuit on the ground source side is connected to the third valve, the evaporator and the second valve to return to the buried pipe in turn; the user outlet of the heating and air conditioner is divided into the user-side refrigeration circuit and the user-side heating circuit after passing through the user pump The cooling circuit on the user side is connected to the fourth valve, the evaporator and the first valve in sequence and returns to the heating and air conditioning user, and the heating circuit on the user side is connected to the eighth valve, the condenser, the ninth valve and the seventh valve in sequence and returns to the heating Air conditioner users; the outlet of the domestic hot water tank is connected to the fourteenth valve, the domestic hot water pump, the absorber and the fifteenth valve in turn, and then returns to the domestic hot water tank to form a domestic hot water circuit; it is characterized in that: the three-purpose The type ground source absorption heat pump system also includes a plate heat exchanger, a switching pump, a tenth valve, an eleventh valve, a twelfth valve, and a thirteenth valve; the condenser side outlet of the plate heat exchanger passes through the switching pump Then it is divided into heating series branch and domestic hot water series branch. The domestic hot water series branch is connected to the tenth valve, condenser and the condenser side inlet of the plate heat exchanger in turn. The heating series branch passes through the eleventh valve and the The outlet of the ninth valve is connected; the absorber side outlet of the plate heat exchanger is connected with the domestic hot water pump inlet; the absorber side inlet of the plate heat exchanger is connected with the absorber outlet through the thirteenth valve, forming a total heating The branch road is connected with the outlet of the domestic hot water tank through the twelfth valve to form a whole domestic hot water branch road.

The three-purpose ground-source absorption heat pump system of the present invention is characterized in that: the cycle form of the absorption heat pump includes multi-stage cycle, single-effect cycle, multi-effect cycle, GAX cycle and improved versions of these cycles.

The three-purpose ground source absorption heat pump system of the present invention is characterized in that: the driving heat source of the absorption heat pump includes one of solar energy, geothermal energy, waste heat, steam, high temperature hot water, fossil fuel and biomass energy one or a combination of several.

The operating method of the three-purpose ground source absorption heat pump system according to the present invention is characterized in that: the operating method includes six independent operating modes: simultaneous heating and domestic hot water supply mode, simple heating mode, and simple domestic hot water supply mode. Hot water mode, simultaneous cooling, domestic hot water supply and absorption heat recovery mode, simultaneous cooling, domestic hot water supply, absorption heat recovery and condensation heat mode, and pure cooling mode.

The simultaneous heating and domestic hot water supply mode: close the first valve, the fourth valve, the fifth valve, the sixth valve, the tenth valve, the eleventh valve, the twelfth valve, the thirteenth valve and switch the pump , the water from the buried pipe enters the evaporator through the buried pipe pump and the third valve to provide a low-level heat source for the absorption heat pump; the heating return water enters the condenser through the user pump and the eighth valve to be heated to the required temperature, and then passes through the ninth valve And the seventh valve returns to the heating and air conditioning users; the water from the domestic hot water tank enters the absorber through the fourteenth valve and the domestic hot water pump to be heated, and then returns to the domestic hot water tank through the fifteenth valve to mix with tap water;

The simple heating mode: close the first valve, the fourth valve, the fifth valve, the sixth valve, the ninth valve, the tenth valve, the twelfth valve, the fourteenth valve and the fifteenth valve, the buried pipe The outlet water enters the evaporator through the buried pipe pump and the third valve to provide a low-level heat source for the absorption heat pump; the heating return water enters the condenser through the user pump and the eighth valve to be heated, and then enters the plate heat exchanger for further heating. After switching the pump, The eleventh valve and the seventh valve return to the heating and air-conditioning users; the water from the absorber enters the plate heat exchanger through the thirteenth valve to release heat, and then returns to the absorber from the domestic hot water pump to take away the absorbed heat; in this mode, the condenser and The absorber realizes the indirect series connection through the plate heat exchanger, the heating return water is directly heated by the condensation heat first, and then indirectly heated by the absorption heat;

Said mode of simply supplying domestic hot water: closing the first valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, the ninth valve, the eleventh valve, the thirteenth valve, the fourteenth valve and The user pump, the water from the buried pipe enters the evaporator through the buried pipe pump and the third valve to provide a low-level heat source for the absorption heat pump; the water from the domestic hot water tank enters the plate heat exchanger through the 12th valve for preheating and then from The hot water pump enters the absorber for further heating, and then returns to the domestic hot water tank through the fifteenth valve; the effluent water from the condenser enters the plate heat exchanger to release heat, and then returns to the condenser by switching the pump to take away the condensation heat; in this mode, The condenser and the absorber are indirectly connected in series through the plate heat exchanger. The domestic hot water is firstly preheated indirectly by the condensation heat, and then directly heated by the absorption heat;

The simultaneous cooling supply, domestic hot water supply and absorption heat recovery mode: close the second valve, the third valve, the seventh valve, the tenth valve, the eleventh valve, the twelfth valve and the thirteenth valve, ground The water from the buried pipe enters the condenser through the buried pipe pump and the sixth valve to absorb the condensation heat, and then returns to the buried pipe to discharge heat through the ninth valve and the fifth valve; the return water of the air conditioner enters the evaporator through the user pump and the fourth valve to be cooled to the required chilled water temperature, and then return to the heating and air conditioning users from the first valve; the domestic hot water tank goes through the fourteenth valve and the domestic hot water pump into the absorber to recover the absorption heat, and then returns to the domestic heat through the fifteenth valve The water tank is mixed with the mains water supply;

The simultaneous cooling, domestic hot water supply, absorption heat recovery and condensation heat mode: close the second valve, the third valve, the fifth valve, the sixth valve, the seventh valve, the ninth valve, the eleventh valve, The thirteenth valve, the fourteenth valve and the buried pipe pump, the heat exchange part of the buried pipe stop running; the return water of the air conditioner enters the evaporator through the user pump and the fourth valve to be cooled to the required chilled water temperature, and then from the first One valve returns to heating and air-conditioning users; the outlet water from the domestic hot water tank first enters the plate heat exchanger through the twelfth valve for preheating, then enters the absorber from the domestic hot water pump for further heating, and then returns to the domestic hot water tank; this mode In this case, the condenser and the absorber are indirectly connected in series through the plate heat exchanger, and the domestic hot water first indirectly recovers the condensation heat, and then directly recovers the absorption heat;

The simple cooling mode: close the second valve, the third valve, the seventh valve, the eighth valve, the ninth valve, the tenth valve, the twelfth valve, the fourteenth valve and the fifteenth valve, buried After passing through the buried pipe pump and the sixth valve, the outlet water first enters the condenser to absorb the condensation heat, then enters the plate heat exchanger to take away the absorption heat, and then returns to the buried pipe drain through the switching pump, the eleventh valve and the fifth valve. heat; the air-conditioning return water enters the evaporator through the user pump and the fourth valve to be cooled to the required chilled water temperature, and then returns to the heating and air-conditioning user from the first valve; in this mode, the condenser and the absorber pass through the plate heat exchanger The indirect series connection is realized, and the water outlet of the buried pipe first directly takes away the heat of condensation, and then takes away the heat of absorption indirectly.

Compared with the existing heating and air conditioning system, the present invention has the following advantages:

①Using the existing centralized heating system or fuel direct combustion to drive the absorption heat pump to extract low-grade heat energy from the soil, which significantly improves the primary energy efficiency of heating and reduces pollutant emissions; realizes thermal energy or fuel refrigeration, large area It will not increase the pressure on the power grid after application; it uses natural refrigerants and will not damage the ozone layer;

② One machine with three functions can efficiently realize heating in winter, cooling in summer and domestic hot water throughout the year; while cooling in summer, domestic hot water can be produced by recovering absorption heat and (or) condensation heat, and the effect is remarkable;

③Compared with traditional electric heat pumps, absorption heat pumps take less heat from the soil when heating, and dissipate more heat to the soil when cooling, while the demand for domestic hot water throughout the year can further increase the heat taken, and heat recovery in summer can further increase Reduce heat dissipation, so it can effectively reduce the annual heat imbalance rate, reduce soil temperature drop and heating performance attenuation.

In general, the present invention can improve the primary energy efficiency of traditional heating and air-conditioning systems, while supplying cooling in summer while producing domestic hot water through heat recovery, and can effectively reduce the annual soil heat imbalance rate of traditional ground source heat pump systems , Maintain stable and reliable heating and air conditioning performance for many years.

Description of drawings

Fig. 1 is a structural principle diagram of a three-purpose ground source absorption heat pump provided by the present invention.

Fig. 2 is a schematic diagram of a three-purpose ground source absorption heat pump provided by the present invention in a mode of simultaneous heating and domestic hot water supply.

Fig. 3 is a schematic diagram of the simple heating mode of the three-purpose ground source absorption heat pump provided by the present invention.

Fig. 4 is a schematic diagram of a three-purpose ground source absorption heat pump provided by the present invention in a mode of only supplying domestic hot water.

Fig. 5 is a schematic diagram of a three-purpose ground source absorption heat pump provided by the present invention in a mode of simultaneously supplying cooling and domestic hot water, and recovering absorption heat.

Fig. 6 is a schematic diagram of the three-purpose ground source absorption heat pump provided by the present invention in the mode of simultaneously supplying cooling and domestic hot water, recovering absorption heat and condensation heat.

Fig. 7 is a schematic diagram of a three-purpose ground source absorption heat pump provided by the present invention in a cooling-only mode.

Among them: 1-ground source absorption heat pump; 2-drive heat source outlet; 3-drive heat source inlet; 4-generator; 5-solution heat exchanger; 6-solution pump; 7-first throttle valve; 8-absorption 9-condenser; 10-second throttle valve; 11-evaporator; 12-buried pipe; 13-buried pipe pump; 14-heating and air conditioning users; 15-user pump; 16-first valve; 17-second valve; 18-third valve; 19-fourth valve; 20-fifth valve; 21-sixth valve; 22-seventh valve; 23-eighth valve; 24-ninth valve; 25- 10th valve; 26-11th valve; 27-plate heat exchanger; 28-switching pump; 29-12th valve; 30-13th valve; 31-domestic hot water pump; 32-14th valve; 33-tap water inlet; 34-domestic hot water tank; 35-the fifteenth valve.

detailed description

The structure and operation mode of the present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the schematic diagram of the structure of the three-purpose ground source absorption heat pump provided by the present invention, including the absorption heat pump 1, the buried pipe 12, the heating and air conditioning user 14 and the domestic hot water tank 34; 4, absorber 8, condenser 9, evaporator 11, solution heat exchanger 5, solution pump 6, first throttle valve 7 and second throttle valve 10; The hot end of the heat exchanger 5, the first throttling valve 7 and the solution inlet of the absorber 8 are connected; the solution outlet of the absorber 8 is sequentially connected with the solution pump 6, the cold end of the solution heat exchanger 5 and the solution inlet of the generator 4 connected; the steam outlet of the generator 4 is connected with the steam inlet of the condenser 9, the second throttle valve 10, the evaporator 11 and the absorber 8 in sequence; It is the ground-source side refrigeration circuit and the ground-source side heating circuit. The ground-source side refrigeration circuit connects the sixth valve 21, the condenser 9, the ninth valve 24 and the fifth valve 20 back to the buried pipe 12 in sequence, and the ground-source side controls The heat circuit is sequentially connected to the third valve 18, the evaporator 11 and the second valve 17 to return to the buried pipe 12; the outlet of the heating and air conditioning user 14 passes through the user pump 15 and is divided into a user-side refrigeration circuit and a user-side heating circuit. The cooling circuit on the side is connected to the fourth valve 19, the evaporator 11 and the first valve 16 in sequence and returns to the heating and air conditioning user 14, and the heating circuit on the user side is connected to the eighth valve 23, the condenser 9, the ninth valve 24 and the seventh valve in sequence After 22, return to the heating and air-conditioning user 14; the outlet of the domestic hot water tank 34 is connected to the fourteenth valve 32, the domestic hot water pump 31, the absorber 8 and the fifteenth valve 35 and then returns to the domestic hot water tank 34, forming a domestic Hot water circuit; the three-purpose ground source absorption heat pump system also includes a plate heat exchanger 27, a switching pump 28, a tenth valve 25, an eleventh valve 26, a twelfth valve 29 and a thirteenth valve 30; The condenser side outlet of the plate heat exchanger 27 is divided into a heating series branch and a domestic hot water series branch through a switching pump 28, and the domestic hot water series branch is connected to the tenth valve 25, the condenser 9 and the plate heat exchanger in sequence. The condenser side inlet of the heat exchanger 27, the heating series branch is connected with the outlet of the ninth valve 24 through the eleventh valve 26; the absorber side outlet of the plate heat exchanger 27 is connected with the inlet of the domestic hot water pump 31; The side inlet of the absorber of the plate heat exchanger 27 is connected to the outlet of the absorber 8 through the thirteenth valve 30 to form a full heating branch, and is connected to the outlet of the domestic hot water tank 34 through the twelfth valve 29 to form a full domestic hot water branch road.

In the three-purpose ground source absorption heat pump system of the present invention, the cycle form of the absorption heat pump 1 includes multi-stage cycle, single-effect cycle, multi-effect cycle, GAX (generator absorber heat exchange) cycle and improved types of these cycles; The driving heat source of the absorption heat pump 1 includes one or a combination of solar energy, geothermal energy, waste heat, steam, high temperature hot water, fossil fuel and biomass energy.

Fig. 2 is a schematic diagram of the three-purpose ground source absorption heat pump provided by the present invention for heating and domestic hot water supply at the same time. Type heat pump 1 provides a low-level heat source; the heating return water on the user side enters the condenser 9 through the user pump 15 and the eighth valve 23 to be heated to the required hot water temperature, and then passes through the ninth valve 24 and the seventh valve 22 to the heating and air conditioning User 14 provides heating and hot water. The outlet water of the domestic hot water tank 34 enters the absorber 8 through the fourteenth valve 32 and the domestic hot water pump 31 to be heated, and then returns to the domestic hot water tank 34 through the fifteenth valve 35 to be mixed with tap water, and is continuously circulated and heated to the temperature and hot water required.

Fig. 3 is a schematic diagram of the simple heating mode of the three-purpose ground source absorption heat pump provided by the present invention, which is different from the operation mode shown in Fig. After heating, it enters the plate heat exchanger 27 for further heating, and then provides heating and hot water to heating and air-conditioning users 14 through the switching pump 28 , the eleventh valve 26 and the seventh valve 22 . The outlet water of the absorber 8 enters the plate heat exchanger 27 through the thirteenth valve 30 to release heat, and then returns to the absorber 8 from the domestic hot water pump 31 to take away the heat of absorption. Since domestic hot water and heating hot water have different water quality requirements, the plate heat exchanger 27 is used to isolate the two. The plate heat exchanger can exchange heat with a small temperature difference, so the reduction in heating performance will not be too large . In this mode, the condenser 9 and the absorber 8 are indirectly connected in series through the plate heat exchanger 27, and the heating return water is first directly heated by the condensation heat, and then indirectly heated by the absorption heat. When the domestic hot water is not needed or the domestic hot water tank 34 is full, it can be switched from the operating mode shown in FIG. 2 to this mode.

Fig. 4 is a schematic diagram of the mode of the three-purpose ground source absorption heat pump provided by the present invention for simply supplying domestic hot water. When the operating mode is different from that shown in Fig. 2, this mode does not produce heating hot water, and the domestic hot water tank 34 The outlet water first enters the plate heat exchanger 27 through the twelfth valve 29 for preheating, then enters the absorber 8 from the domestic hot water pump 31 for further heating, and then returns to the domestic hot water tank 34 through the fifteenth valve 35 . The outlet water of the condenser 9 enters the plate heat exchanger 27 to release heat and returns to the condenser 9 through the switching pump 28 to take away the heat of condensation. In this mode, the condenser 9 and the absorber 8 are indirectly connected in series through the plate heat exchanger 27, and the domestic hot water is first indirectly preheated by condensation heat and then directly heated by absorption heat. Since the heat of condensation first heats the domestic hot water, the condensation temperature can be appropriately lowered. This mode generally operates in the transition season, the beginning and end of the heating season, and the beginning and end of the cooling season.

Fig. 5 is a schematic diagram of the three-purpose ground source absorption heat pump provided by the present invention in the mode of simultaneously supplying cooling and domestic hot water, and recovering absorption heat. In the device 9, after absorbing the condensation heat, return to the buried pipe 12 through the ninth valve 24 and the fifth valve 20 to discharge heat. The air-conditioning return water enters the evaporator 11 through the user pump 15 and the fourth valve 19 to be cooled to the required chilled water temperature, and then returns to the heating and air-conditioning user 14 from the first valve 16 for cooling. The outlet water of the domestic hot water tank 34 enters the absorber 8 through the fourteenth valve 32 and the domestic hot water pump 31 to recover the absorption heat, and then returns to the domestic hot water tank 34 through the fifteenth valve 35 to mix with tap water supply, and is continuously circulated and heated to required temperature and volume of hot water.

Fig. 6 is a schematic diagram of the three-purpose ground source absorption heat pump provided by the present invention in the mode of simultaneously supplying cooling and domestic hot water, recovering absorption heat and condensation heat. Unlike the mode shown in Fig. 5, no operation is required in this mode Buried pipe heat exchange part. The outlet water of the domestic hot water tank 34 first enters the plate heat exchanger 27 for preheating through the twelfth valve 29 and then enters the absorber 8 from the domestic hot water pump 31 for further heating, and then returns to the domestic hot water tank 34 . In this mode, the condenser 9 and the absorber 8 are indirectly connected in series through the plate heat exchanger 27, and the domestic hot water first indirectly recovers the heat of condensation, and then directly recovers the heat of absorption. Compared with the mode of only recovering absorption heat, without using the water from the buried pipe as cooling water, the condensation temperature will be slightly higher, and the COP of the heat pump will be reduced. However, due to the simultaneous recovery of absorption heat and condensation heat, the heating capacity of domestic hot water is relatively large , suitable for occasions with a large demand for domestic hot water.

Fig. 7 is a schematic diagram of the simple cooling mode of the three-purpose ground source absorption heat pump provided by the present invention. The outlet water of the buried pipe 12 first enters the condenser 9 to absorb the condensation heat after passing through the buried pipe pump 13 and the sixth valve 21, and then Enter the plate heat exchanger 27 to take away the absorbed heat, and then return to the buried pipe 12 through the switching pump 28, the eleventh valve 26 and the fifth valve 20 to discharge the heat. In this mode, the condenser 9 and the absorber 8 are indirectly connected in series through the plate heat exchanger 27, and the water outlet from the buried pipe first directly takes away the heat of condensation, and then takes away the heat of absorption indirectly. This mode can be switched to this mode from the operating mode shown in Fig. 5 and Fig. 6 when the domestic hot water is not needed and only cooling is required, or when the domestic hot water tank 34 is full.

Claims (10)

1. A three-purpose ground source absorption heat pump system, comprising an absorption heat pump (1), buried pipes (12), heating and air conditioning users (14) and a domestic hot water tank (34); the absorption heat pump ( 1) Contains generator (4), absorber (8), condenser (9), evaporator (11), solution heat exchanger (5), solution pump (6), first throttle valve (7) and The second throttle valve (10); the solution outlet of the generator (4) is successively connected with the hot end of the solution heat exchanger (5), the first throttle valve (7) and the solution inlet of the absorber (8); The solution outlet of the absorber (8) is connected with the solution inlet of the solution pump (6), the solution heat exchanger (5) and the solution inlet of the generator (4) successively; the steam outlet of the generator (4) is connected with the solution successively. The steam inlet of the condenser (9), the second throttle valve (10), the evaporator (11) and the absorber (8) are connected; the outlet of the underground pipe (12) is divided into It is the ground-source side refrigeration circuit and the ground-source side heating circuit, and the ground-source side refrigeration circuit is connected to the sixth valve (21), the condenser (9), the ninth valve (24) and the fifth valve (20) in order to return to the ground. The buried pipe (12), the heating circuit on the ground source side is connected to the third valve (18), the evaporator (11) and the second valve (17) in turn to return to the buried pipe (12); the heating and air conditioning user (14) After passing through the user pump (15), the outlet is divided into a user-side refrigeration circuit and a user-side heating circuit. The user-side refrigeration circuit is connected to the fourth valve (19), the evaporator (11) and the first valve (16) in turn, and returns to the heating circuit. For the air conditioner user (14), the heating circuit on the user side is connected to the eighth valve (23), the condenser (9), the ninth valve (24) and the seventh valve (22) in sequence, and then returns to the heating and air conditioning user (14); The outlet of the domestic hot water tank (34) is connected to the fourteenth valve (32), the domestic hot water pump (31), the absorber (8) and the fifteenth valve (35) in sequence and returns to the domestic hot water tank (34), Constitute a domestic hot water circuit; it is characterized in that: the three-purpose ground source absorption heat pump system also includes a plate heat exchanger (27), a switching pump (28), a tenth valve (25), an eleventh valve (26 ), the twelfth valve (29) and the thirteenth valve (30); the condenser side outlet of the plate heat exchanger (27) is divided into a heating series branch and a domestic hot water series series branch after the switching pump (28) branch, the series branch of domestic hot water connects the tenth valve (25), the condenser (9) and the condenser side inlet of the plate heat exchanger (27) in turn, and the heating series branch passes through the eleventh valve (26) and The outlet of the ninth valve (24) is connected; the absorber side outlet of the plate heat exchanger (27) is connected with the inlet of the domestic hot water pump (31); the absorber side inlet of the plate heat exchanger (27) passes through the first The thirteenth valve (30) is connected with the outlet of the absorber (8) to form a full heating branch, and is connected to the outlet of the domestic hot water tank (34) through the twelfth valve (29) to form a full domestic hot water branch. 2. The three-purpose ground source absorption heat pump system according to claim 1, characterized in that: the circulation form of the absorption heat pump (1) includes multi-stage circulation, single-effect circulation, multi-effect circulation, GAX circulation and Improved versions of these loops. 3. The three-purpose ground source absorption heat pump system according to claim 1, characterized in that: the driving heat source of the absorption heat pump (1) includes solar energy, geothermal energy, waste heat, steam, high-temperature hot water, fossil fuels and one or a combination of biomass energy. 4. A three-purpose ground source absorption heat pump operating method using the system as claimed in claim 1, characterized in that: the operating method includes six independent operating modes: simultaneous heating and domestic hot water supply mode, simple Heating mode, pure domestic hot water supply mode, simultaneous cooling, domestic hot water supply and absorption heat recovery mode, simultaneous cooling, domestic hot water supply, domestic hot water supply, absorption heat recovery and condensation heat mode, and pure cooling mode. 5. A three-purpose ground source absorption heat pump operation method as claimed in claim 4, characterized in that: the simultaneous heating and domestic hot water supply mode is: closing the first valve (16), the fourth valve ( 19), the fifth valve (20), the sixth valve (21), the tenth valve (25), the eleventh valve (26), the twelfth valve (29), the thirteenth valve (30) and switching pump (28), the water outlet of the buried pipe (12) enters the evaporator (11) through the buried pipe pump (13) and the third valve (18) to provide a low-level heat source for the absorption heat pump (1); the heating return water passes through the user pump ( 15) and the eighth valve (23) enter the condenser (9) to be heated to the required temperature, and then return to the heating and air conditioning user (14) through the ninth valve (24) and the seventh valve (22); (34) The outlet water enters the absorber (8) through the fourteenth valve (32) and the domestic hot water pump (31) to be heated, and then returns to the domestic hot water tank (34) through the fifteenth valve (35) to mix with tap water . 6. A three-purpose ground source absorption heat pump operation method according to claim 4, characterized in that: the simple heating mode is: closing the first valve (16), the fourth valve (19), the fifth Valve (20), sixth valve (21), ninth valve (24), tenth valve (25), twelfth valve (29), fourteenth valve (32) and fifteenth valve (35), The water from the buried pipe (12) enters the evaporator (11) through the buried pipe pump (13) and the third valve (18) to provide a low-level heat source for the absorption heat pump (1); the heating return water passes through the user pump (15) and the third valve The eight valves (23) enter the condenser (9) to be heated, then enter the plate heat exchanger (27) for further heating, and then return to heating through the switching pump (28), the eleventh valve (26) and the seventh valve (22). Air-conditioning user (14); water from the absorber (8) enters the plate heat exchanger (27) through the thirteenth valve (30) to release heat, and then returns to the absorber (8) from the domestic hot water pump (31) to take away the absorption heat; In this mode, the condenser (9) and the absorber (8) are indirectly connected in series through the plate heat exchanger (27), and the heating return water is first directly heated by condensation heat and then indirectly heated by absorption heat. 7. A three-purpose ground source absorption heat pump operation method as claimed in claim 4, characterized in that: the simple domestic hot water supply mode is: closing the first valve (16), the fourth valve (19) , the fifth valve (20), the sixth valve (21), the seventh valve (22), the ninth valve (24), the eleventh valve (26), the thirteenth valve (30), the fourteenth valve ( 32) and the user pump (15), the water outlet from the buried pipe (12) enters the evaporator (11) through the buried pipe pump (13) and the third valve (18) to provide a low-level heat source for the absorption heat pump (1); The outlet water of the water tank (34) first enters the plate heat exchanger (27) through the twelfth valve (29) for preheating, then enters the absorber (8) from the domestic hot water pump (31) for further heating, and then enters the absorber (8) for further heating through the fifteenth valve (29). The valve (35) returns to the domestic hot water tank (34); the water from the condenser (9) enters the plate heat exchanger (27) to release heat and then returns to the condenser (9) by switching the pump (28) to take away the heat of condensation; In this mode, the condenser (9) and the absorber (8) are indirectly connected in series through the plate heat exchanger (27), and the domestic hot water is first indirectly preheated by condensation heat and then directly heated by absorption heat. 8. A three-purpose ground source absorption heat pump operation method as claimed in claim 4, characterized in that: said simultaneous cooling, domestic hot water supply and absorption heat recovery mode: closing the second valve (17), The third valve (18), the seventh valve (22), the tenth valve (25), the eleventh valve (26), the twelfth valve (29) and the thirteenth valve (30), buried pipe (12 ) through the buried pipe pump (13) and the sixth valve (21) into the condenser (9) to absorb the heat of condensation and then return to the buried pipe (12) through the ninth valve (24) and the fifth valve (20) for discharge Heat; air-conditioning return water enters the evaporator (11) through the user pump (15) and the fourth valve (19) to be cooled to the required chilled water temperature, and then returns to the heating and air-conditioning user (14) from the first valve (16) The domestic hot water tank (34) outlet water enters the absorber (8) through the fourteenth valve (32) and the domestic hot water pump (31) to reclaim the absorption heat, and then returns to the domestic hot water tank through the fifteenth valve (35) ( 34) Mix with tap water supply. 9. A three-purpose ground source absorption heat pump operation method as claimed in claim 4, characterized in that: the simultaneous cooling, domestic hot water supply, absorption heat recovery and condensation heat modes are: closing the second valve (17), the third valve (18), the fifth valve (20), the sixth valve (21), the seventh valve (22), the ninth valve (24), the eleventh valve (26), the thirteenth valve The valve (30), the fourteenth valve (32) and the buried pipe pump (13), the heat exchange part of the buried pipe stops running; the return water of the air conditioner enters the evaporator through the user pump (15) and the fourth valve (19) ( 11) is cooled to the required chilled water temperature, and then returns to the heating and air-conditioning user (14) from the first valve (16); the outlet water from the domestic hot water tank (34) first enters the plate exchange through the twelfth valve (29) Heater (27) enters the absorber (8) from the domestic hot water pump (31) to further heat after preheating, and then returns to the domestic hot water tank (34); under this mode, the condenser (9) and the absorber ( 8) Through the plate heat exchanger (27), the indirect series connection is realized, and the domestic hot water first indirectly recovers the condensation heat, and then directly recovers the absorption heat. 10. A three-purpose ground source absorption heat pump operation method according to claim 4, characterized in that: the simple cooling mode is: closing the second valve (17), the third valve (18), the first Seventh valve (22), eighth valve (23), ninth valve (24), tenth valve (25), twelfth valve (29), fourteenth valve (32) and fifteenth valve (35) , the water from the buried pipe (12) passes through the buried pipe pump (13) and the sixth valve (21) and then enters the condenser (9) to absorb the heat of condensation, then enters the plate heat exchanger (27) to take away the heat of absorption, and then After the switch pump (28), the eleventh valve (26) and the fifth valve (20) return to the buried pipe (12) to discharge heat; the return water of the air conditioner enters the evaporation through the user pump (15) and the fourth valve (19) The condenser (11) is cooled to the required chilled water temperature, and then returns to the heating and air conditioning user (14) from the first valve (16); The device (27) realizes the indirect series connection, and the water outlet of the buried pipe first directly takes away the heat of condensation, and then takes away the heat of absorption indirectly.