CN1731027A - Solar Seasonal Heat Storage System Using Phase Change Materials - Google Patents

Abstract

The present invention is one seasonal solar heat accumulating system with phase changing material, relates to solar energy accumulating system, and aims at providing city with heat energy in reduced power consumption and environmental pollution. The seasonal solar heat accumulating system consists of solar heat collector, circulating pump, T-valve, valves, plate heat exchanger, heat pump set, heat accumulator with phase changing material and fluid passage. The present invention has the features of best utilization of solar energy, small size of phase changing heat accumulator, high heat accumulating efficiency, high running efficiency of the heat pump set and less ecological pollution.

Description

Solar Seasonal Heat Storage System Using Phase Change Materials

Technical field:

The present invention relates to solar heat storage systems.

Background technique:

At present, the traditional heating system in my country's "Three North" region is composed of heat sources (such as coal-fired boilers, gas (oil) boilers, thermal power plants, etc.), heating networks and indoor heating systems. As we all know, most of China's heating systems are centralized heating systems introduced by the former Soviet Union in the early 1950s. During long-term operation, the following problems were found: (1) China's heating energy consumption is too high, and its indicators are similar Under the climatic conditions, it is 2 to 3 times that of developed countries; the energy consumption of heating and air conditioning of buildings in China accounts for 30 to 40% of the total energy consumption; (2) The heat source of traditional heating emits a large amount of CO ₂ , SO ₂ and dust and other harmful objects, leading to the destruction of the ecological environment (such as global warming, acid rain, etc.). Coal accounts for more than 70% of my country's energy production and consumption. Under the condition of coal-based energy structure, building heating energy is one of the main factors causing urban air pollution. my country is located in the eastern part of Eurasia in the northern hemisphere, with a vast territory and abundant solar energy resources. According to the long-term measured and accumulated data of 700 meteorological stations across the country, the total amount of solar radiation in various parts of my country is about 3300-8400MJ/m2·a, and the average value is about 5900MJ/m2·a.

Invention content:

In order to solve the problems of high energy consumption for heating in existing cities and serious environmental pollution, the present invention further provides a solar seasonal heat storage system using phase change materials. The technical solution to solve this problem is as follows:

The present invention comprises a solar heat collector 1, a circulation pump 7, a three-way valve 8, and a valve 9, and the output ends of the solar heat collector 1 are respectively connected to the first valve 9-1 and the first three-way valve 8-1-1. , the other end of the first valve 9-1 is connected to one end of the second valve 9-2, the other end of the second valve 9-2 is connected to the input end of the circulation pump 7, and the output end of the circulation pump 7 is connected to the second tee One end of the valve 8-2-1 is connected, one end of the second three-way valve 8-2-2 is connected with one end of the first three-way valve 8-1-3, and one end of the second three-way valve 8-2-3 is connected with The input end of the solar heat collector 1 is connected, and a heat accumulator 2 is arranged between the connection points of the first three-way valve 8-1-2 and the first valve 9-1 and the second valve 9-2 to store heat The device 2 is built with a phase change material 13, and a fluid channel 14 is arranged on the phase change material 13.

The solar seasonal heat storage system using phase change materials of the present invention has the advantages of fully utilizing renewable energy solar energy, small volume of the phase change heat storage device, high heat storage efficiency of the heat accumulator 2, high operating efficiency of the heat pump unit 12, and ecological environment. The characteristics of little pollution.

Description of drawings:

Fig. 1 is a schematic diagram of the overall structure of the system, Fig. 2 is a schematic diagram of the exterior structure of the heat accumulator 2, and Fig. 3 is a sectional view along line A-A of Fig. 2 .

Detailed ways:

Specific embodiment one: this embodiment is made up of solar heat collector 1, circulation pump 7, three-way valve 8, valve 9, the output end of solar heat collector 1 is connected with the first valve 9-1 and the first three-way valve 8 -1-1 connection, the other end of the first valve 9-1 is connected to one end of the second valve 9-2, the other end of the second valve 9-2 is connected to the input end of the circulation pump 7, and the output end of the circulation pump 7 One end of the second three-way valve 8-2-1 is connected, one end of the second three-way valve 8-2-2 is connected with one end of the first three-way valve 8-1-3, and the second three-way valve 8-2- One end of 3 is connected to the input end of the solar heat collector 1, and a heat accumulator is arranged between the connection points of the first three-way valve 8-1-2 and the first valve 9-1 and the second valve 9-2 2. The heat accumulator 2 is built with a phase change material 13, and a fluid channel 14 is provided on the phase change material 13.

Since the phase change latent heat of the phase change material is much greater than its sensible heat, the volume of the heat accumulator 2 can be greatly reduced, and the feasibility is greatly improved. The phase change material 13 used in the regenerator 2 is CaCl ₂ ·6H ₂ O, the melting point of the phase change material is 29°C, the latent heat of phase change is 187.49kJ/kg, and the solid specific heat is 1.46kJ/kg·K. The specific heat of liquid is 2.13kJ/kg·K, the thermal conductivity of solid phase is 1.088W/m·K, the thermal conductivity of liquid phase is 0.54W/m·K, and the average density is 1710kg/m ³ . The heat storage capacity per m ³ of the phase change material is about 3.46×10 ⁸ J to 3.82×10 ⁸ J.

A building with a usable area of 239.21m2 is a two-story north-south villa building. Heat collection time: about 11 months; solar radiation intensity: the daily average solar radiation intensity is about: 200-500W/m ² .

Taking Harbin as an example, the area of solar collector 1 is Ac=70~100m ² , the volume of heat accumulator 2 is 565~850m ³ , and the collected heat is Q=1.54×10 ¹¹ ～2.61×10 ¹¹ J. It is 1.31×10 ¹¹ J～2.12×10 ¹¹ J, the building heat load Qa=2.01×10 ¹¹ J, and the heat supply accounts for about 65～100% of the heat load.

Taking the Beijing area as an example, the area of solar collector 1 is Ac=30~40m ² , the volume of heat accumulator 2 is 282m ³ , the collected heat is Q=8.21×10 ¹⁰ J~10.2×10 ¹⁰ J, and the stored heat is 7.13×10 ¹⁰ J～8.55×10 ¹⁰ J, building heat load Qa=9.54×10 ¹⁰ J, heat supply accounts for about 75～89.6% of the heat load. The area of the solar collector 1 and the volume of the heat accumulator 2 in the system can be designed according to the heat load of the region and the building to achieve the best match.

Specific embodiment two: In this embodiment, the system is in heat storage mode, the solar heat collector 1 in the system operates together with the heat accumulator 2 and the circulation pump 7, the first valve 9-1 is closed, and the heat exchange fluid collects heat from the solar energy The flow out of device 1 is input to the end of the first three-way valve 8-1-1, and output to the heat accumulator from the end of the first three-way valve 8-1-2 (one end of the first three-way valve 8-1-3 is closed) 2 and flows through the fluid channel 14 on the phase change material 13 in the heat accumulator 2, the phase change material 13 (PCM) in the heat accumulator 2 absorbs heat from the heat exchange fluid flowing out of the solar collector 1 And stored in the phase change material 13 in the heat accumulator 2, after the heat exchange fluid flows out from the output end of the heat accumulator 2, it is delivered to the input end of the circulating pump 7 through the second valve 9-2, and the output of the circulating pump 7 The heat exchange fluid is sent to the input end of the second three-way valve 8-2-1, and the output of the second three-way valve 8-2-3 is returned to the input end of the solar collector 1 (the second three-way valve 8 -2-2 ends closed), this cycle process can make the phase change material 13 (PCM) in the heat accumulator 2 absorb heat from the heat exchange fluid flowing out of the solar collector 1 and store it, and complete the heat storage process ( This process is achieved by high solar radiation intensity in summer).

Embodiment 3: In this embodiment, the system is in the heat release mode. In this embodiment, a heat pump unit 12 is added. The two input ends of the evaporator 3 of the heat pump unit 12 are connected to the connection points at both ends of the second valve 9-2. Heat pump unit 12 (SHSR-250 heat pump unit can be used in Harbin area, the heating capacity of standard working condition is 30KW; SHSR-150 heat pump unit can be used in Beijing area, the heating capacity of standard working condition is 18KW) composed of evaporator 3, throttling mechanism 4, Condenser 5, compressor 6, one end of throttling mechanism 4 is connected to one end of evaporator 3, the other end of throttling mechanism 4 is connected to one end of condenser 5, the other end of condenser 5 is connected to one end of compressor 6 Connect, the other end of compressor 6 is connected with the other end of evaporator 3. Heat accumulator 2, circulation pump 7 and heat pump unit 12 operate together, close the first valve 9-1 and the second valve 9-2, the heat exchange fluid enters from the first three-way valve 8-1-3, and enters from the first The three-way valve 8-1-2 end (one end of the first three-way valve 8-1-1 is closed) is output to the input end of the heat accumulator 2 and from the fluid channel 14 on the phase change material 13 in the heat accumulator 2 (The heat accumulator 2 has stored enough heat energy through the process of the specific embodiment 1), so that the heat exchange fluid flows into the heat pump unit 12 after absorbing heat energy from the phase change material 13 (PCM) in the heat accumulator 2 The evaporator 3 is used as the low-level heat source of the heat pump, and the heat pump unit 12 supplies heat to the building 11. After releasing heat, the heat exchange fluid is transported from the other end of the evaporator 3 of the heat pump unit 12 to the input end of the circulation pump 7, and passes through the circulation pump 7. The output heat exchange fluid enters the input end of the second three-way valve 8-2-1, and then is output to the first three-way valve 8-2-2 (the second three-way valve 8-2-3 is closed). Pass valve 8-1-3 end to circulate. This heat release process is suitable for winter, night or cloudy days. This embodiment also adds a plate heat exchanger 10 and a third valve 9-3. The plate heat exchanger 10 can be heated by electricity or water, and the two output ends of the plate heat exchanger 10 are connected in parallel to the third valve 9-3. 3, the two ends of the third valve 9-3 are connected in series between the input end of the circulation pump 7 and the connection point between the second valve 9-2 and the evaporator 3. When the solar radiation is weak or the heat storage is insufficient, the plate heat exchanger 10 can be activated to supplement heat for the heat exchange fluid. When the plate heat exchanger 10 does not need to be activated, the third valve 9-3 is opened to short-circuit the plate heat exchanger 10, and when the plate heat exchanger 10 is activated, the third valve 9-3 is closed.

Specific Embodiment Four: In this embodiment, the system is in the dual mode of heat storage and heat release. The solar heat collector 1, the heat accumulator 2, the circulation pump 7 and the heat pump unit 12 operate together, and the first valve 9-1 and the second valve 9-1 are closed. Valve 9-2, the heat exchange fluid is input to the end of the first three-way valve 8-1-1 after absorbing heat through the solar collector 1, and from the end of the first three-way valve 8-1-2 (the first three-way valve 8- One end of 1-3 is closed) output to the input end of the heat accumulator 2 and flow through the fluid channel 14 on the phase change material 13 in the heat accumulator 2, the phase change material 13 (PCM) in the heat accumulator 2 flows from The heat exchange fluid flowing out of the solar heat collector 1 absorbs heat and is stored in the phase change material 13 in the heat accumulator 2. After the heat exchange fluid flows out from the output end of the heat accumulator 2, it enters the evaporator 3 of the heat pump unit 12, as The low-level heat source of the heat pump unit 12 supplies heat to the building 11, and the heat exchange fluid is delivered from the other end of the evaporator 3 of the heat pump unit 12 to one end of the third valve 9-3 after releasing heat. The other end of the pump is output to the input end of the circulation pump 7, and the heat exchange fluid output by the circulation pump 7 enters the input end of the second three-way valve 8-2-1, and then the second three-way valve 8-2-3 (the second three-way valve 8-2-3) Two and three way valves 8-2-2 are closed) output to the input end of the solar heat collector 1 to continue to absorb heat. The above-mentioned cyclic process not only stores heat but also releases heat. This process is suitable for strong solar radiation during the day in winter and when the area of the heat collector is large, the heat collected by the solar heat collector 1 is more than the heat load of the building 11. Therefore, excess solar energy can be stored for future use.

Claims (4)

1, utilize the seasonal solar energy heat storage system of phase-change material, it comprises solar thermal collector (1), circulating pump (7), triple valve (8), valve (9), the output of solar thermal collector (1) is connected with first triple valve (8-1-1) end with first valve (9-1) respectively, the other end of first valve (9-1) is connected with an end of second valve (9-2), the other end of second valve (9-2) is connected with the input of circulating pump (7), the output of circulating pump (7) is connected with an end of second triple valve (8-2-1), one end of second triple valve (8-2-2) is connected with an end of first triple valve (8-1-3), one end of second triple valve (8-2-3) is connected with the input of solar thermal collector (1), it is characterized in that at first triple valve (8-1-2) and first valve (9-1), be provided with storage heater (2) between the tie point place of second valve (9-2), storage heater (2) is built-in with phase-change material (13), and phase-change material (13) is provided with fluid passage (14).

2, the seasonal solar energy heat storage system that utilizes phase-change material according to claim 1 is characterized in that phase-change material (13) adopts CaCl ₂6H ₂O.

3, the seasonal solar energy heat storage system that utilizes phase-change material according to claim 1, it is characterized in that it also includes source pump (12), two inputs of source pump (12) are connected on the tie point at second valve (9-2) two ends, source pump (12) is by evaporimeter (3), throttle mechanism (4), condenser (5), compressor (6) is formed, one end of throttle mechanism (4) is connected with an end of evaporimeter (3), the other end of throttle mechanism (4) is connected with an end of condenser (5), the other end of condenser (5) is connected with an end of compressor (6), and the other end of compressor (6) is connected with the other end of evaporimeter (3).

4, the seasonal solar energy heat storage system that utilizes phase-change material according to claim 1, it is characterized in that it also contains plate type heat exchanger (10) and the 3rd valve (9-3), two outputs of plate type heat exchanger (10) are connected in parallel on the two ends of the 3rd valve (9-3), and the two ends of the 3rd valve (9-3) are connected between the tie point of evaporimeter (3) of the input of circulating pump (7) and second valve (9-2) and source pump (12).

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