CN111238080A - Ammonia water absorption-compression type composite heat pump driven by solar energy and fuel gas double heat sources - Google Patents

Abstract

The invention discloses an ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources. It belongs to the field of solar thermal utilization and heat pump air conditioning. The invention includes a generator high temperature section, a generator medium temperature section, a generator low temperature section, a rectifier, a condenser, a subcooler, a throttle valve A, an evaporator, a three-way valve A, a compressor, a solution cooling absorber, Water cooling absorber, throttle valve B, solution circulation pump, gas furnace, three-way valve B, solar collector, collector working fluid circulation pump, collector working fluid circulation pipeline, heating water return port, heating Water outlet, compressor bypass pipe and collector working medium bypass pipe. The invention is applied to heating in northern winter, improves the heating structure in winter mainly by burning coal, and uses clean energy to improve the environment.

Description

An ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources

technical field

The invention relates to the fields of solar thermal utilization and heat pump air conditioning, in particular to an ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources.

Background technique

With the aggravation of the energy crisis and the improvement of environmental protection requirements, energy saving and emission reduction technology has become a worldwide research topic. China is a big country in energy consumption and CO ₂ emissions, and is facing increasingly severe pressure on energy conservation and emission reduction. At the same time, the smog problem, which is closely related to the coal-based energy consumption model, has attracted increasing attention.

In the cold regions of northern my country, the energy consumption of building heating accounts for more than 50% of the total energy consumption of buildings. At the same time, the heating demand in areas with hot summer and cold winter, such as the middle and lower reaches of the Yangtze River, is increasing. In addition, with the successive introduction of a series of policies such as "limiting coal" and "reforming coal to electricity" in winter heating in northern my country, solar energy is used for efficient and stable heating in winter. , has become an urgent problem to be solved.

At present, vapor compression heat pump heating consumes a lot of electricity, and refrigerants such as Freon used in household air conditioning heating will cause ozone layer damage and greenhouse effect. Compared with vapor compression heat pumps, absorption heat pumps use environmentally friendly working fluids, such as ammonia water (NH ₃ -H ₂ O), etc., and can be driven by renewable energy, waste heat, etc., which can effectively reduce the consumption of fossil fuels. However, compared with vapor compression heat pumps, absorption heat pumps have lower heating efficiency, require more installation area under the same heat load, and are difficult to work efficiently at ambient temperatures below -20°C.

Referring to the traditional vapor compression heat pump, an ammonia gas compressor is introduced at the evaporator outlet of the traditional GAX-based ammonia water absorption heat pump, and the suction process of the compressor is used to make the evaporator reach a certain negative pressure and reduce the evaporation pressure. Reduce the evaporating temperature, enhance the adaptability of heat pump units to cold environments, and expand the range of areas where heat pump heating is suitable for use in winter in my country.

Therefore, those skilled in the art are devoted to developing a new device that utilizes solar energy and reduces energy consumption.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is the comprehensive utilization of multiple energy sources, and the problem solved is that the ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources is applied to heating in northern winter.

In order to achieve the above purpose, the present invention provides an ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources, which includes a generator high temperature section, a generator medium temperature section, a generator low temperature section, a rectifier, a condenser, and a filter. Cooler, throttle valve A, evaporator, three-way valve A, compressor, solution cooling absorber, water cooling absorber, throttle valve B, solution circulating pump, gas furnace, three-way valve B, solar collector , Collector working fluid circulation pump, collector working fluid circulation pipeline, heating water return port, heating water outlet, compressor bypass pipe and collector working fluid bypass pipe.

Further, it is characterized in that the heating water is preheated in the water cooling absorber, and a large amount of heat is absorbed in the condenser to increase temperature.

Further, the heat collector working fluid absorbs heat in the solar heat collector, and releases heat in the middle temperature section of the generator to heat the ammonia solution.

Further, the gas furnace heats the ammonia solution in the high temperature section of the generator.

Further, the saturated aqueous ammonia solution from the high temperature section of the generator flows through the low temperature section of the generator and the throttle valve B in sequence and enters the solution cooling absorber.

Further, the ammonia gas generated in the high temperature section of the generator, the middle temperature section of the generator and the low temperature section of the generator sequentially flows into the rectifier for purification.

Further, the ammonia gas purified from the rectifier enters the condenser for heat exchange with the heating water.

Further, the gas-liquid two-phase ammonia enters the evaporator, absorbs the heat of the surrounding air to form gas-phase ammonia, that is, ammonia gas, and comes out from the outlet of the evaporator.

Further, the solar thermal collector is a small trough solar thermal collector.

Further, the compressor is an oil-free scroll compressor.

Further, the outlet solution of the high temperature section of the generator is a saturated solution under the corresponding temperature and pressure conditions.

Further, the ammonia at the inlet of the evaporator is a gas-liquid two-phase, and its dryness depends on the opening degree of the throttle valve A and the requirements on the evaporation temperature.

Compared with the prior art, the advantages of the ammonia water absorption-compression composite heat pump driven by solar energy and gas dual heat sources of the present invention are:

(1) Using ammonia-water working medium, the established cycle is more suitable for heat pump heating in the cold winter environment in northern China, and improves the winter heating structure dominated by coal combustion;

(2) Part or all of the solar thermal drive can be used, which can reduce the consumption of fossil fuels and help alleviate the heating haze problem in the north;

(3) The three-way valve A can be used to adjust whether the compressor is connected to the heat pump circuit, so as to more efficiently adapt to the working needs of different ambient temperatures;

(4) Through the three-way valve B, adjust whether the heat collecting circuit of the trough collector is connected to the heat pump circuit. When the solar radiation condition is good, use as much solar heat as possible to drive the heat pump of the present invention, and when the solar radiation condition is insufficient, use Gas combustion ensures the normal operation of the heat pump.

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present invention.

Description of drawings

Fig. 1 is the flow chart of the ammonia water absorption-compression compound heat pump system driven by solar energy and gas dual heat source according to the first embodiment of the present invention;

Fig. 2 is the system flow chart of the second embodiment of the present invention;

Fig. 3 is the system flow chart of the third embodiment of the present invention;

Fig. 4 is the system flow chart of the fourth embodiment of the present invention;

Among them, 1- generator high temperature section, 2- generator medium temperature section, 3- generator low temperature section, 4- rectifier, 5- condenser, 6- subcooler, 7- throttle valve A, 8- evaporation device, 9-three-way valve A, 10-compressor, 11-solution cooling absorber, 12-water cooling absorber, 13-throttle valve B, 14-solution circulating pump, 15-gas furnace, 16-three-way Valve B, 17- Small trough solar collector, 18- Collector working fluid circulating pump, 19- Collector working fluid circulating pipeline, 20- Heating water return port, 21- Heating water outlet, 22- Compressor bypass pipe, 23-collector working fluid bypass pipe.

Detailed ways

The following describes several preferred embodiments of the present invention with reference to the accompanying drawings, so as to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned herein.

In the drawings, structurally identical components are denoted by the same numerals, and structurally or functionally similar components are denoted by like numerals throughout. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thicknesses of components are appropriately exaggerated in some places in the drawings.

As shown in FIG. 1 , the ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources of the first embodiment includes a generator high temperature section 1, a generator medium temperature section 2, a generator low temperature section 3, a rectifier 4, Condenser 5, subcooler 6, throttle valve A7, evaporator 8, three-way valve A9, compressor 10, solution cooling absorber 11, water cooling absorber 12, throttle valve B13, solution circulating pump 14, gas Furnace 15, three-way valve B16, solar collector 17, collector working fluid circulation pump 18, collector working fluid circulation pipeline 19, heating water return port 20, heating water outlet 21, compressor bypass pipe 22 and the collector working fluid bypass pipe 23.

Solar heating circuit, the solar heating circuit pipe 19 is a heat collecting working medium, which is sent to the heat collecting pipe of the solar collector 17 by the heat collecting working medium circulating pump 18, where the heat collecting working medium absorbs the solar energy collector. The heat of the heater 17 enters the middle temperature section 2 of the generator through the three-way valve B16, and conducts heat exchange with the ammonia solution of the heat pump working medium there. The heat collection working medium circulation pump 18 is sent to the solar heat collector 17, and so on continuously. There is also a bypass pipe 23 in the solar heating circuit, which is controlled by a three-way valve B16, which cuts off or communicates the heat-collecting working medium entering the middle temperature section 2 of the generator as appropriate. The solar thermal collector 17 is a small trough solar thermal collector.

In the heating water circuit, the heating water flowing back from the indoor heating enters the circuit through the heating water return port 20, and enters the water cooling absorber 12, where the ammonia solution absorbs ammonia gas, releases the absorption heat, and the heating water passes through the heat exchange pipe and the ammonia solution. Heat exchange, the heating water must absorb heat to heat up; it enters the condenser 5, where the ammonia gas condenses to release the condensation heat, the heating water in the pipeline exchanges heat with the ammonia working medium, and the heating water obtains a large amount of heat to continue to heat up, and then heating Water enters the indoor heating system for use. The warm water flows back to the warm water return port 20 and then enters the circuit, and so on.

In the heat pump working fluid circuit, the ammonia solution in the high temperature section 1 of the generator is heated by the gas furnace 14, the generated ammonia solution enters the middle temperature section 2 of the generator, receives solar heat and continues the process, and the generated ammonia solution flows into the generator low temperature section 3, receives The process of regenerating sensible heat continues, and the finally produced dilute aqueous ammonia solution flows through the throttle valve B13 and enters the solution cooling absorber 11 . All ammonia vapors generated by the three generating processes in the generator high temperature section 1, the generator medium temperature section 2 and the generator low temperature section 3 enter the rectifier 4 for purification, and the purified ammonia gas enters the condenser 5, where it is combined with the condenser 5. The heating water in the indoor heating circuit conducts heat exchange, releases a large amount of heat, and becomes liquid-phase ammonia after being fully condensed; some heat is released through the subcooler 6, and becomes gas-liquid two-phase low-temperature ammonia through the throttle valve A7, and then flows into the evaporation. The evaporator 8 absorbs the heat of the surrounding air at the evaporator 8 and evaporates it into gas-phase ammonia; the ammonia flow from the evaporator 8 passes through the cooler 6 and receives the sensible heat of the ammonia subcooled from the condenser 5 to achieve superheating. , and then enter the compressor 10 through the three-way valve A9 to be compressed and enter the solution cooling absorber 11 . A small amount of ammonia solution refluxed from the rectifier 4 enters the low temperature section 3 of the generator. The ammonia solution entering the solution cooling absorber 11 absorbs part of the high-temperature ammonia vapor from the compressor 10, and releases the absorption heat for preheating the internal solution. Then, the water-cooled absorber 12 absorbs the remaining high-temperature ammonia vapor from the compressor 10, generates absorption heat, and exchanges heat with the indoor heating water flowing there. The solution at the outlet of the water cooling absorber 12 flows through the solution circulation pump 14, the rectifier 4, and the solution cooling absorber 11 through the pipeline, and then mixes with a small amount of ammonia solution refluxed from the rectifier 4, and enters the low temperature section 3 of the generator.

The ammonia at the outlet of the water-cooled absorber 12 is a concentrated ammonia solution.

The solution at the inlet of the generator low temperature section 3 exchanges heat with the hot ammonia solution, the solar collector working medium, and the gas furnace 15 in the generator low temperature section 3, the generator medium temperature section 2, and the generator high temperature section 1 respectively. When it becomes saturated, high temperature and high pressure ammonia vapor is generated. The whole process is not isothermal, and there is temperature slip. The outlet solution of the high temperature section 1 of the generator is a saturated solution under the corresponding temperature and pressure conditions.

The ammonia working medium at the inlet of the evaporator 8 is gas-liquid two-phase, and its dryness depends on the opening degree of the throttle valve 7 and the requirements on the evaporation temperature. In the evaporator 8, the low-temperature pure ammonia absorbs the heat of the low-temperature ambient air, the temperature rises, and evaporates into low-temperature and low-pressure ammonia vapor. The entire phase transition process is isothermal, and there is no temperature slip.

The high temperature driving heat source in the present invention is the high temperature solar heat (>170°C) generated by the small trough solar collector 17, and the low temperature driving heat source is the low temperature ambient heat (>-35°C), waste heat and low temperature solar heat (10～ 35°C) etc.

The solar thermal collector 17 is a small trough solar thermal collector, and an appropriate heat collecting area is determined according to factors such as heating load and installation site.

The compressor 10 is preferably a small oil-free scroll compressor, the suction pressure is at least 0.07-0.08MPa, and the pressure ratio is in the range of 4.0-8.0.

In the present invention, for a fixed and reasonable working high pressure, low pressure and water supply temperature, the solution circulation rate of the generator and the distribution ratio of the flow of each part in the circulation can be determined.

The ammonia absorption-compression composite heat pump driven by the dual heat sources of solar energy and gas in the present invention has a water supply temperature of 40-60°C, which is suitable for the temperature requirements of floor heating, fan coil heating, etc.; the ambient temperature cannot be too low (>-35°C). °C). When the ambient temperature is too low, limited by the suction pressure and pressure ratio of the compressor 10, the evaporation process cannot continue, and the heat pump cannot work.

This embodiment is suitable for indoor heating in a cold environment (-35--15°C) in winter and when the solar irradiation conditions are sufficient.

As shown in FIG. 2 , in the ammonia water absorption-compression composite heat pump driven by solar energy and gas dual heat sources in the second embodiment, the gas furnace 15 and the compressor 10 are connected to the system, and the solar collector 17 is not connected to the system. The collector working fluid circulating pump 18 and adjusting the three-way valve B16 can realize that the solar collector 17 is not connected to the system. On the basis of the heat pump flow chart shown in FIG. 1 , the three-way valve B16 is adjusted, and the heat pump is driven by a single external heat source gas furnace 15 , and the same content refers to the first embodiment. This embodiment is suitable for indoor heating in winter when the ambient temperature is very low (-35 to -15° C.) and the solar irradiation condition is insufficient.

As shown in Figure 3, in the third embodiment of the ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources, the solar collector 17 and the gas furnace 15 are connected to the system, and the compressor bypass is connected through the three-way valve A9. Line pipe 22, so that the compressor 10 is not connected to the system. The same contents refer to the first embodiment. This embodiment is suitable for indoor heating in winter when the ambient temperature is low (>-15°C) and the solar irradiation condition is sufficient.

As shown in FIG. 4 , in the fourth embodiment of the ammonia absorption-compression composite heat pump driven by solar energy and gas dual heat sources, the gas furnace 15 is connected to the system, and the working medium circulating pump 18 of the collector is turned off and the three-way valve B16 is adjusted. , so that the solar collector 17 is not connected to the system, and at the same time, the compressor bypass pipe 22 is connected through the three-way valve A9, so that the compressor 10 is not connected to the system. On the basis of FIG. 3 , the heat pump is driven by a single external heat source gas furnace 15 . The same contents refer to the first embodiment. This embodiment is suitable for indoor heating in winter when the ambient temperature is low (>-15°C) and the solar radiation condition is insufficient.

Due to the weak solar radiation in winter, it is difficult to drive the heat pump heating in the present invention by using solar heat alone for a long time, but all non-enumerated embodiments of using a single solar heat to drive the heat pump heating in the present invention should be determined in the claims within the scope of protection.

The preferred embodiments of the present invention have been described in detail above. It should be understood that many modifications and changes can be made according to the concept of the present invention by those skilled in the art without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (10)

1. The ammonia water absorption-compression type composite heat pump driven by solar energy and fuel gas double heat sources is characterized by comprising a generator high-temperature section, a generator medium-temperature section, a generator low-temperature section, a rectifier, a condenser, a subcooler, a throttle valve A, an evaporator, a three-way valve A, a compressor, a solution cooling absorber, a water cooling absorber, a throttle valve B, a solution circulating pump, a gas furnace, a three-way valve B, a solar heat collector, a heat collector working medium circulating pump, a heat collector working medium circulating pipeline, a heating water return port, a heating water outlet, a compressor bypass pipe and a heat collector working medium bypass pipe.

2. The ammonia absorption-compression type compound heat pump driven by the solar energy and the gas dual heat source as claimed in claim 1, wherein the heating water is preheated in the water cooling absorber, and absorbs a large amount of heat in the condenser to raise the temperature.

3. The ammonia water absorption-compression type compound heat pump driven by the solar energy and the fuel gas dual heat source as claimed in claim 1, wherein a heat collector working medium absorbs heat in the solar heat collector, and releases heat to heat the ammonia water solution in the middle temperature section of the generator.

4. The ammonia absorption-compression type compound heat pump driven by the solar energy and the gas dual heat source as claimed in claim 1, wherein the gas furnace heats the ammonia solution at the high temperature section of the generator.

5. The ammonia water absorption-compression type compound heat pump driven by the solar energy and the gas dual heat source as claimed in claim 1, wherein the saturated ammonia water solution from the high-temperature section of the generator flows through the low-temperature section of the generator in sequence for heat recovery, then enters the solution cooling absorber after throttling and pressure reduction through the throttle valve B.

6. The ammonia water absorption-compression type compound heat pump driven by the solar energy and the fuel gas dual heat source as claimed in claim 1, wherein ammonia gas generated in the high-temperature section of the generator, the medium-temperature section of the generator and the low-temperature section of the generator sequentially flows into the rectifier for purification.

7. The ammonia water absorption-compression type compound heat pump driven by the solar energy and the gas dual heat source as claimed in claim 1, wherein the ammonia gas purified from the rectifier enters the condenser to exchange heat with heating water.

8. The ammonia water absorption-compression type compound heat pump driven by the solar energy and the fuel gas dual heat source as claimed in claim 1, wherein gas-liquid two-phase ammonia enters the evaporator, absorbs ambient air heat to form gas-phase ammonia, and the gas-phase ammonia is discharged from an outlet of the evaporator.

9. The ammonia absorption-compression type compound heat pump driven by the solar energy and the gas dual heat source as claimed in claim 1, wherein the solar heat collector is a small-sized trough type solar heat collector.

10. The ammonia absorption-compression hybrid heat pump driven by a solar and gas dual heat source as set forth in claim 1, wherein said compressor is an oil-free scroll compressor.

Images