CN103968574A - Heat supply method of efficient energy storage type solar heat pump operating around clock - Google Patents

Abstract

The invention discloses a high-efficiency energy-storage solar heat pump heat supply method for all-weather operation, which is used to provide domestic hot water or to a radiator for heating in winter. The phase change energy material in the solar collector transfers the instantaneous or previously stored solar energy to the composite heat exchanger through the oscillating heat pipe. During summer operation, the circulating water in the composite heat exchanger is directly heated to realize hot water supply; during winter operation, the heat is transferred to the evaporator in the composite heat exchanger to increase the evaporation temperature, and the heat pump is started to circulate and heat the hot water; One part directly heats the circulating water in the compound heat exchanger, and the other part is passed to the evaporator in the compound heat exchanger, and the heat pump system is started to heat the hot water to the required temperature. The method directly uses solar energy to supply hot water, or uses solar energy to increase the evaporation temperature of the heat pump system to supply hot water, thereby improving the heating efficiency of the heat pump system and optimizing the overall performance of the energy storage type solar heat pump hot water system.

Description

A kind of all-weather operation high-efficiency energy storage type solar heat pump heat supply method

technical field

The invention relates to a hot water supply method, in particular to a heat pump heat supply method combining heat collection by a solar heat collection tube, phase change heat storage of an energy storage material, and high-efficiency heat transfer of an oscillating heat pipe, belonging to the field of solar energy utilization.

Background technique

With the development of society, people's requirements for improving the quality of life are getting higher and higher, and the demand for heating and hot water supply is becoming stronger and stronger. The proportion of energy consumption in this area to the total energy consumption of buildings is increasing year by year. Utilizing renewable energy and taking the road of sustainable development is one of the effective ways to reduce building energy consumption. The white paper "China's Energy Policy (2012)" proposed to vigorously develop new energy and renewable energy, and pointed out that "increase the popularity of solar water heaters, encourage solar centralized hot water supply and solar heating". The State Council issued a notice on the "Twelfth Five-Year Plan" for energy development, and also pointed out that "accelerate the development of building-integrated solar energy applications and encourage solar heating". Solar energy is a renewable and clean energy. my country is rich in solar energy resources. In two-thirds of the regions, the total annual radiation is greater than 5020MJ/m2, and the annual sunshine hours are above 2200h. At present, solar water heaters have been developed rapidly, but due to the instability and intermittent nature of solar energy itself, it is not suitable to be used as the main heat source of the water supply system, and needs to be used together with auxiliary heating equipment. Therefore, the development of all-weather energy storage solar heat pump system has important practical significance for energy saving and consumption reduction.

Solar energy is a renewable and clean energy. Conventional low-temperature solar collectors have a heat collection temperature of 55-75°C, which has high heat collection efficiency and relatively low cost. Low-level solar collectors are also conducive to integration with buildings. Heat pumps have obvious energy-saving advantages. Therefore, when solar energy and heat pumps are operated together, solar energy can provide a heat source with a higher temperature than the ambient temperature. When used as a heat source on the evaporator side of a heat pump system, it can simultaneously improve solar heat collection efficiency and heat pump performance. However, the intensity of solar radiation is affected by various complex meteorological factors and changes at any time. It is unstable and intermittent, which leads to large fluctuations in the performance of the solar heat pump system. Once the solar radiation intensity is lower than 250W/m2, the collector temperature is lower than the ambient temperature, and the evaporator side of the heat pump cannot get enough heat, and the system cannot operate. Phase change energy storage technology can solve the mismatch between solar energy supply and demand in time and space, that is, it can store energy when there is a lot of energy, and release it when needed, thereby improving energy utilization. Moreover, the latent heat is used to store energy, so the energy storage density is large and the temperature change is small. The current energy-storage solar heat pump system is mostly arranged separately for heat collector, heat accumulator, and evaporator. There is a danger of pipes freezing and cracking in the water system at night in winter.

In Chinese patents CN200810020470.9 "Composite source heat collection/energy storage/evaporation integrated heat pump hot water system" and CN200710190062.3 "heat collection, energy storage and evaporation integrated solar heat pump system", the heat pump evaporator is in the form of a U-shaped tube Arranged in the solar vacuum heat collection tube, each evaporation tube and the vacuum heat collection tube are filled with phase change material to act as an energy storage container, reducing intermediate heat exchange links and saving manufacturing costs. However, these systems have a large amount of refrigerant charge, and the long evaporation pipeline leads to a large pressure drop in the pipeline, which reduces the volumetric efficiency of the compressor and affects the system performance. The internal heat transfer of the oscillating heat pipe integrates sensible heat transfer, phase change heat transfer, and bubble volume change, and does not require the liquid-absorbing core necessary for the heat pipe. It has simple structure, convenient operation, low cost, no power drive, and can It has the advantages of long-distance transmission, large equivalent thermal conductivity, fast thermal response, and can be bent according to the use requirements. Its heat transfer performance is more than ten times that of ordinary heat pipes. In view of this, the present invention proposes to use the oscillating heat pipe as a medium to transfer the heat stored in the phase change material in the heat collector to the circulating water in the three-stream composite heat exchanger or the evaporator of the heat pump system, shorten the pipeline of the heat pump system, and effectively improve overall system performance.

Contents of the invention

Aiming at the defects of the existing energy storage solar heat pump heating system, the present invention provides an all-weather, efficient and energy-saving solar heat pump heating method, the purpose of which is to rationally and effectively use the energy storage medium to realize the collection and peak shifting of solar energy Valley filling, and the use of oscillating heat pipes for efficient heat transfer, thereby improving the heating efficiency of the heat pump system and optimizing the overall performance of the energy storage solar heat pump hot water system.

The technical scheme that the present invention adopts is as follows:

A high-efficiency energy-storage solar heat pump heating method that operates around the clock is divided into heat pipe working medium circulation, heat pump refrigerant circulation and circulating water circulation. Thermal expansion valve, compressor, water-cooled condenser, water pump A, water pump B, water storage tank and stop valve, wherein, the energy storage type solar oscillating heat pipe collector includes solar vacuum heat collecting tube, phase change material and oscillating heat pipe, the heat supply The specific process of the method is as follows:

(1) During summer operation, the working medium of the heat pipe circulates: the solar radiation is sufficient, the instantaneous solar energy transferred by the phase change material in the energy storage type solar oscillating heat pipe collector or the heat released during the day and stored at night is sufficient, the evaporation section of the oscillating heat pipe After absorbing this part of solar energy, the heat is efficiently transferred to the condensation section of the oscillating heat pipe through the filling material in the oscillating heat pipe, and the oscillating heat pipe in the three-flow composite heat exchanger directly uses this part of the heat to heat the circulation in the composite heat exchanger Water, so as to realize hot water supply; the heat pump cycle stops working; the water cycle: the water whose temperature rises after receiving the heat transferred by the oscillating heat pipe in the three-stream composite heat exchanger enters the water storage tank through the water pump A, and passes through the shut-off valve After adjusting the flow rate, it enters the three-stream compound heat exchanger and continues to be heated to increase the temperature;

(2) During winter operation, the working medium circulation of the heat pipe: the solar radiation is insufficient, the heat transferred by the phase change material in the energy storage type solar oscillating heat pipe collector or stored during the day and released at night is relatively low, and the evaporation section of the oscillating heat pipe absorbs this part After solar energy, the heat is efficiently transferred to the condensing section of the oscillating heat pipe through the filling material in the oscillating heat pipe, and the condensing section of the oscillating heat pipe and the heat pump evaporator pipeline perform heat exchange in a three-stream composite heat exchanger; the heat pump cycle: The refrigerant in the heat pump evaporator pipeline is vaporized into refrigerant vapor after receiving the heat transferred by the heat pipe. After being pressurized by the compressor, it enters the refrigerant pipeline on the side of the water-cooled condenser, and releases heat to cool the condensed refrigerant liquid through heat. The expansion valve throttles, and then enters the heat pump evaporator pipeline to continue to absorb the heat transferred by the oscillating heat pipe, thus completing a cycle; the water cycle: the heat released by the refrigerant pipeline of the water condenser is used to heat the other side of the water-cooled condenser The circulating water on the side is sent to the water storage tank, and then through the water pump B, enters the water-cooled condenser and continues to be heated to the required temperature;

(3) When operating in transitional seasons, the heat pipe working fluid cycle: radiation is slightly insufficient, and the phase change material in the energy storage type solar oscillating heat pipe collector is transferred or the heat released during the day is stored and released at night through the oscillating heat pipe, which is not enough for heating When the hot water reaches the required temperature, the oscillating heat pipe uses part of the heat to heat the circulating water in the three-stream compound heat exchanger, and the other part is transferred to the heat pump evaporator pipeline in the three-stream compound heat exchanger; Heat pump cycle: The refrigerant in the heat pump evaporator pipeline is vaporized into refrigerant vapor after receiving the heat transferred by the heat pipe. After being pressurized by the compressor, it enters the refrigerant pipeline of the water-cooled condenser, and releases heat to cool the condensed refrigerant liquid. The thermal expansion valve throttles, and then enters the heat pump evaporator pipeline to continue to absorb the heat transferred by the oscillating heat pipe, thus completing a cycle; the water cycle is composed of two parallel pipelines, and a circulating water pipeline is combined in three streams for heat exchange After getting the heat transferred by the oscillating heat pipe in the water tank, the temperature rises, and enters the water storage tank through the water pump A, and then enters the three-stream composite heat exchanger to continue to be heated to increase the temperature after the flow is adjusted by the stop valve; the other water pipe is in the water condenser The heat released by the refrigerant pipeline is then sent to the water storage tank and then through the water pump B to enter the water-cooled condenser to continue heating to the required temperature.

In the energy storage type solar oscillating heat pipe heat collector, the evaporating section of the oscillating heat pipe is arranged in the solar vacuum heat collecting tube in the form of a U-shaped tube, the evaporating section is also provided with a brush, and the energy storage material is filled in the evaporating section of the oscillating heat pipe Between the solar vacuum collector tube.

The three-stream composite heat exchanger is a casing heat exchanger, which is composed of a heat exchanger shell, a heat pump evaporator pipeline, and a condensing section pipeline of an oscillating heat pipe. The inlet and outlet of the circulating water pipeline are arranged on the heat exchanger shell Above, the heat pump evaporator pipeline and the condensing section pipeline of the oscillating heat pipe are arranged in parallel in the heat exchanger shell, and the heat exchanger shell is filled with circulating water; the heat pipe working medium flows in the condensing section pipeline of the oscillating heat pipe, so The refrigerant flows in the pipeline of the heat pump evaporator.

The present invention is based on the oscillating heat pipe as the heat transfer medium, and transfers the instantaneous solar energy or the solar energy stored in the phase change material in the collector to the three-stream heat exchanger for direct heat supply or heating of hot water by using a heat pump to provide domestic hot water or Provided to the radiator for heating in winter, it has the following advantages:

(1) Reasonable and effective use of phase change energy storage to achieve solar heat collection and peak shifting to fill valleys can solve the mismatch between energy supply and demand in terms of time, that is, energy can be stored when there is a lot of energy and released when needed , thereby prolonging the energy utilization time and improving the energy utilization rate.

(2) Use solar energy in stages. When the solar radiation is strong, it is convenient to switch to the energy storage type solar collector tube heating water mode. When the solar radiation is weak, the heat pump system is used as auxiliary heating. At night or in continuous rainy days, switch to the energy storage type The solar heat pump cycle mode can exert higher thermal performance, thereby solving the mismatch contradiction between the energy supply and demand space of the solar heat pump system.

(3) The cycle uses oscillating heat pipes for efficient heat transfer, decouples the evaporation pipeline of the integrated energy storage solar heat pump system from the solar collector, and overcomes the long evaporation pipeline, large flow resistance, and poor performance of the compressor Shortcomings. The system is compact, the power consumption is small, and the structure is simple, which broadens the way for the application of solar energy as the low-temperature heat source of the heat pump system.

(4) This method provides a feasible method and solution for solar energy as a low-temperature heat source for heat pumps, which can be realized only by coupling and transforming the already mature heat pump system, oscillating heat pipes and energy storage solar vacuum tubes.

(5) A flat-plate heat collector can be selected and combined with the exterior wall of the building to realize building integration.

(6) It can realize energy saving, environmental protection, and efficient provision of hot water to families, large hotels, leisure places, business office buildings, etc. throughout the year, or provide heating and hot water to these places in winter.

Description of drawings

Fig. 1 is a schematic diagram of the device used to realize the method of the present invention, wherein: energy storage type solar oscillating heat pipe heat collector 1, three-stream composite heat exchanger 2, thermal expansion valve 3, compressor 4, water-cooled condenser 5, water pump A6 , water pump B7, water storage tank 8 and stop valve 9, circulating water pipeline 11, heat pump evaporator pipeline 12, refrigerant pipe 13 of water-cooled condenser, water pipe 14 of water-cooled condenser.

Fig. 2 is a schematic diagram of the summer operation mode of the method of the present invention.

Fig. 3 is a schematic diagram of the winter operation mode of the method of the present invention.

Fig. 4 is a schematic diagram of the transition season operation mode of the method of the present invention.

Fig. 5 is a schematic diagram of an energy storage type solar oscillating heat pipe collector. It includes a solar vacuum heat collecting tube 19, an oscillating heat pipe 10, a brush 21 and a phase change material 20.

Fig. 6 is a schematic diagram of a three-stream composite heat exchanger. Among them, the oscillating heat pipe 10 , the circulating water pipeline 11 , the heat pump evaporator pipeline 12 , and the heat exchanger shell 15 .

Fig. 7 is a cross-sectional view of a three-stream composite heat exchanger. Among them, the refrigerant 16 in the evaporator pipeline, the circulating water 17, and the working medium 18 of the heat pipe.

Detailed ways

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

The present invention provides a high-efficiency energy-storage solar heat pump heating method for all-weather operation. Its composition is shown in Figure 1. Heat collector 1, three-stream compound heat exchanger 2, thermal expansion valve 3, compressor 4, water-cooled condenser 5, water pump A6, water pump B7, water storage tank 8 and stop valve 9.

The energy storage type solar oscillating heat pipe heat collector 1 comprises a solar vacuum heat collecting pipe 19, an oscillating heat pipe 10, a brush 21 and a phase change material 20, and the evaporation section of the oscillating heat pipe 10 is arranged on the solar vacuum heat collecting pipe 19 in the form of a U-shaped tube. Inside.

The three-stream compound heat exchanger 2 is a casing heat exchanger, which is composed of a heat exchanger shell 15, a heat pump evaporator pipeline 12 and a condensation section of an oscillating heat pipe 10. There are two tube heat exchanger shells 15 Heat transfer tubes, one is the condensing section of the oscillating heat pipe 10, and the tube section 12 of the heat pump evaporator is parallel to it. The large casing outside the two parallel tubes is filled with circulating water 17 from the water tank. The outlet is arranged on the heat exchanger shell 15 , the heat pipe working fluid 18 flows in the condensing section of the oscillating heat pipe 10 , and the refrigerant 16 flows in the heat pump evaporator tube section 12 .

The heat pump refrigerant cycle is formed by serially connecting the heat pump evaporator pipeline 12 with the compressor 4, the refrigerant pipe 13 of the water-cooled condenser, the water-cooled condenser 5, and the thermal expansion valve 3 in series.

The water circulation is composed of two parallel pipelines: the water-cooled condenser 5, the water-cooled condenser water pipe 14, the water storage tank 8 and the water pump B7 are connected in series to form a water-cooled condenser water circulation loop; the water circulation pipeline 11 in the three-stream composite heat exchanger is sequentially It is connected in series with water pump A6, water storage tank 8 and stop valve 9 to form a closed water circulation loop.

The method of the present invention can operate in the following three modes:

(1) During summer operation, the working medium of the heat pipe circulates: the solar radiation is sufficient, the instantaneous solar energy transferred by the energy storage material 20 in the solar vacuum heat collecting tube 19 or the heat released during the day and stored at night is sufficient, and the evaporation section of the oscillating heat pipe 10 absorbs this After part of the solar energy, the heat is efficiently transferred to the condensation section of the oscillating heat pipe 10 through the working medium 18 in the oscillating heat pipe, and the oscillating heat pipe 10 in the three-stream composite heat exchanger 2 directly transfers this part of the heat to the circulation in the composite heat exchanger Water pipeline 11, so as to realize hot water supply. The heat pump cycle stops working; the water cycle: the water whose temperature rises after obtaining the heat transferred by the oscillating heat pipe 10 in the three-stream composite heat exchanger 2 enters the water storage tank 8 through the water pump A6, and enters after the flow is adjusted by the shut-off valve 9 Continue to be heated in the three-stream compound heat exchanger 2 to increase the temperature.

(2) During winter operation, the working medium of the heat pipe circulates: the solar radiation is insufficient, the energy storage material 20 in the solar vacuum heat collection tube 19 transfers or stores during the day and releases low heat at night, and the evaporation section of the oscillating heat pipe 10 absorbs this part of solar energy The heat is efficiently transferred to the condensation section of the oscillation heat pipe 10 through the working fluid 18 in the oscillation heat pipe 10 , and the heat exchange between the condensation section of the oscillation heat pipe 10 and the heat pump evaporator pipeline 12 is performed in the three-flow compound heat exchanger 2 . The heat pump cycle: the refrigerant 16 in the heat pump evaporator pipeline 12 is vaporized into refrigerant vapor after receiving the heat transferred by the heat pipe, pressurized by the compressor 4, enters the refrigerant pipeline 13 of the water-cooled condenser 5, and releases The refrigerant liquid cooled and condensed by heat is throttled by the thermal expansion valve 3, and then enters the heat pump evaporator pipeline 12, and continues to absorb the heat transferred by the oscillating heat pipe 10, thus completing a cycle. The water cycle: the heat released by the refrigerant pipeline 13 of the water condenser 5 is used to heat the circulating water 14 on the other side of the water-cooled condenser, and after being sent to the water storage tank 8, it enters the water-cooled condenser 5 through the water pump B7 to continue heating to the desired temperature;

(3) During operation in transitional seasons, the heat pipe working medium cycle: radiation is slightly insufficient, and the phase change material 20 in the solar vacuum heat collecting tube 19 is transferred or stored during the day and the heat released at night is transferred through the oscillating heat pipe 10, which is not enough to heat hot water When the required temperature is reached, the oscillating heat pipe 10 will partly heat the circulating water 17 in the three-stream compound heat exchanger 2 , and transfer the other part to the heat pump evaporator pipeline 12 in the three-stream compound heat exchanger 2 . The heat pump cycle: the refrigerant 16 in the heat pump evaporator pipeline 12 is vaporized into refrigerant vapor after receiving the heat transferred by the oscillating heat pipe 10, and enters the refrigerant pipeline 13 of the water-cooled condenser 5 after being pressurized by the compressor 4. The condensed refrigerant liquid is throttled by the thermal expansion valve 3 and then enters the heat pump evaporator pipeline 12 to continue absorbing the heat transferred by the oscillating heat pipe 10, thus completing a cycle. The water circulation is composed of two parallel pipelines. One circulating water pipeline gets the heat transferred by the oscillating heat pipe 10 in the three-stream composite heat exchanger 2 and then the temperature rises. It enters the water storage tank 8 through the water pump A6 and is regulated by the shut-off valve 9. After the flow rate, it enters the three-stream compound heat exchanger 2 again and continues to be heated to increase the temperature; the other water pipeline receives the heat released by the refrigerant pipeline 13 in the water condenser 5, and then is sent to the water storage tank 8 and then passes through the water pump B7 enters the water-cooled condenser 5 and continues to be heated to the required temperature.

Claims (3)

1. A high-efficiency energy storage solar heat pump heating method that operates around the clock, which is divided into heat pipe working medium circulation, heat pump refrigerant circulation and circulating water circulation. device, thermal expansion valve, compressor, water-cooled condenser, water pump A, water pump B, water storage tank and stop valve, wherein the energy storage type solar oscillating heat pipe collector includes solar vacuum heat collecting tube, phase change material and oscillating heat pipe, which It is characterized in that the specific process of the heat supply method is as follows: (1) During summer operation, the working medium of the heat pipe circulates: the solar radiation is sufficient, the instantaneous solar energy transferred by the phase change material in the energy storage type solar oscillating heat pipe collector or the heat released during the day and stored at night is sufficient, the evaporation section of the oscillating heat pipe After absorbing this part of solar energy, the heat is efficiently transferred to the condensation section of the oscillating heat pipe through the filling material in the oscillating heat pipe, and the oscillating heat pipe in the three-flow composite heat exchanger directly uses this part of the heat to heat the circulation in the composite heat exchanger Water, so as to realize hot water supply; the heat pump cycle stops working; the water cycle: the water whose temperature rises after receiving the heat transferred by the oscillating heat pipe in the three-stream composite heat exchanger enters the water storage tank through the water pump A, and passes through the shut-off valve After adjusting the flow rate, it enters the three-stream compound heat exchanger and continues to be heated to increase the temperature; (2) During winter operation, the working medium circulation of the heat pipe: the solar radiation is insufficient, the heat transferred by the phase change material in the energy storage type solar oscillating heat pipe collector or stored during the day and released at night is relatively low, and the evaporation section of the oscillating heat pipe absorbs this part After solar energy, the heat is efficiently transferred to the condensing section of the oscillating heat pipe through the filling material in the oscillating heat pipe, and the condensing section of the oscillating heat pipe and the heat pump evaporator pipeline perform heat exchange in a three-stream composite heat exchanger; the heat pump cycle: The refrigerant in the heat pump evaporator pipeline is vaporized into refrigerant vapor after receiving the heat transferred by the heat pipe. After being pressurized by the compressor, it enters the refrigerant pipeline on the side of the water-cooled condenser, and releases heat to cool the condensed refrigerant liquid through heat. The expansion valve throttles, and then enters the heat pump evaporator pipeline to continue to absorb the heat transferred by the oscillating heat pipe, thus completing a cycle; the water cycle: the heat released by the refrigerant pipeline of the water condenser is used to heat the other side of the water-cooled condenser The circulating water on the side is sent to the water storage tank, and then through the water pump B, enters the water-cooled condenser and continues to be heated to the required temperature; (3) When operating in transitional seasons, the heat pipe working fluid cycle: radiation is slightly insufficient, and the phase change material in the energy storage type solar oscillating heat pipe collector is transferred or the heat released during the day is stored and released at night through the oscillating heat pipe, which is not enough for heating When the hot water reaches the required temperature, the oscillating heat pipe uses part of the heat to heat the circulating water in the three-stream compound heat exchanger, and the other part is transferred to the heat pump evaporator pipeline in the three-stream compound heat exchanger; Heat pump cycle: The refrigerant in the heat pump evaporator pipeline is vaporized into refrigerant vapor after receiving the heat transferred by the heat pipe. After being pressurized by the compressor, it enters the refrigerant pipeline of the water-cooled condenser, and releases heat to cool the condensed refrigerant liquid. The thermal expansion valve throttles, and then enters the heat pump evaporator pipeline to continue to absorb the heat transferred by the oscillating heat pipe, thus completing a cycle; the water cycle is composed of two parallel pipelines, and a circulating water pipeline is combined in three streams for heat exchange After getting the heat transferred by the oscillating heat pipe in the water tank, the temperature rises, and enters the water storage tank through the water pump A, and then enters the three-stream composite heat exchanger to continue to be heated to increase the temperature after the flow is adjusted by the stop valve; the other water pipe is in the water condenser The heat released by the refrigerant pipeline is then sent to the water storage tank and then through the water pump B to enter the water-cooled condenser to continue heating to the required temperature. 2. A kind of high-efficiency energy-storage solar heat pump heat supply method for all-weather operation according to claim 1, characterized in that, in the energy-storage solar oscillating heat pipe collector, the evaporating section of the oscillating heat pipe is a U-shaped tube The form is arranged in the solar vacuum heat collection tube, the evaporation section is also provided with a brush, and the energy storage material is filled between the evaporation section of the oscillating heat pipe and the solar vacuum heat collection tube. 3. A kind of high-efficiency energy-storage solar heat pump heat supply method for all-weather operation according to claim 1 or 2, characterized in that, the three-stream compound heat exchanger is a casing heat exchanger, and the heat exchanger The shell, the heat pump evaporator pipeline and the condensing section pipeline of the oscillating heat pipe are composed. The inlet and outlet of the circulating water pipeline are arranged on the heat exchanger shell, and the heat pump evaporator pipeline and the condensing section pipeline of the oscillating heat pipe are arranged in parallel on the heat exchange Inside the shell of the heat exchanger, the shell of the heat exchanger is filled with circulating water; the working fluid of the heat pipe flows in the pipeline of the condensing section of the oscillating heat pipe, and the refrigerant flows in the pipeline of the heat pump evaporator.