A Trombe wall device based on phase change slurry

Abstract

The present invention relates to a Trombe wall device based on phase change slurry, belonging to the technical fields of building energy conservation and solar energy application. It includes a Trombe wall system and a phase change slurry circulation system: The Trombe wall system includes four air vents, two phase change slurry flow channels, an air duct and a heat storage wall; The phase change slurry circulation system includes two circulation water pumps, two phase change slurry storage tanks, an outer flow channel, an inner flow channel, eight three-way valves and eight electronic valves. The Trombe wall device of the present invention can achieve eight working modes, among which the heat preservation mode and the heat insulation mode solve the problem of increased energy consumption of the indoor air temperature regulation system under low-irradiance and severe cold conditions and high-irradiance and hot conditions in the Trombe wall system; By flexibly switching the eight modes by adjusting the valves, the hourly energy consumption of the air conditioning system is effectively reduced, and the utilization rate of solar energy by the building under different meteorological conditions is improved.

Description

Technical Field

[0001] The present invention belongs to the technical fields of building energy conservation and solar energy application, and particularly relates to the application of phase change slurry in a Trombe system and a thermal management system under all-weather conditions. Background Art

[0002] The construction industry currently accounts for approximately 40% of the global energy consumption, and it is necessary to reduce the energy consumption of buildings by applying various renewable technologies and integrating them with systems. Making full use of local solar energy can partially meet the energy needs of buildings. However, buildings in different seasons and regions are subject to different solar irradiations, and the required cooling and heating capacities are also different. Therefore, it is particularly important to design an energy-saving component that can adapt to different meteorological conditions. Only by popularizing this device on a large scale can the carbon emissions of the construction industry be significantly reduced.

[0003] The solar Trombe wall system is a passive energy-saving component commonly used in today's ecological buildings because of its simple design, mature technology, low operating cost, and remarkable energy-saving effect. However, this system also has two obvious disadvantages. On the one hand, in order to absorb more heat, the surface of the heat storage wall is covered with a coating with a high absorption rate, which will cause overheating indoors in summer or when the solar irradiation intensity is large. On the other hand, compared with the high infrared band emissivity of ordinary walls, it will increase the radiative heat transfer between the heat storage wall and the outdoor environment, and will significantly increase the heat load of the building in continuous rainy weather.

[0004] Although phase change materials have the characteristic of constant temperature during the melting process and can partially improve the inherent defects of the Trombe wall, in the actual application process, problems such as their service life, whether they will pollute the environment, and whether the material parameters match need to be considered. The service life of a building is more than ten years, and it is inevitable that the phase change material will react with the air, and the phase change temperature and latent heat will change. The external environment has different meteorological parameters in winter and summer, which will lead to the problem of mismatch of the properties of the phase change material. How to replace the phase change material has become an urgent problem to be solved.

[0005] The above two points illustrate that it is necessary to design a new type of Trombe system with phase change materials that can adapt to changes in the external environment and is relatively easy to maintain. Summary of the Invention

[0006] In order to cope with changing outdoor environmental parameters and solve the problems in the actual application of phase change materials, optimize the solar energy utilization efficiency of the Trombe wall system, and at the same time reduce the building heating and cooling energy consumption, the present invention provides a new type of Trombe wall device based on phase change slurry.

[0007] A Trombe wall device based on phase change slurry includes a Trombe wall mechanism, and the Trombe wall mechanism includes adjacent heat storage walls 8 and air ducts 7. The upper ends of the air ducts 7 are respectively provided with an outer upper air inlet 1 and an inner upper air inlet 4, and the lower ends of the air ducts 7 are respectively provided with an outer lower air inlet 2 and an inner lower air inlet 3;

[0008] It further includes a phase change slurry circulation system; the phase change slurry circulation system includes an outer flow channel 5, an inner flow channel 6, a first liquid storage tank 15, a second liquid storage tank 16, a first water pump 13, a second water pump 14, a first valve mechanism and a second valve mechanism;

[0009] The outer flow channel 5 is arranged on the outer side wall of the air duct 7. The upper port of the outer flow channel 5 is an outer outlet 10, and the lower port of the outer flow channel 5 is an outer inlet 9; the inner flow channel 6 is arranged on the inner side wall of the heat storage wall 8 adjacent to the air duct 7. The upper port of the inner flow channel 6 is an inner outlet 12, and the lower port of the inner flow channel 6 is an inner inlet 11;

[0010] The first liquid storage tank 15, the second liquid storage tank 16, the first water pump 13 and the second water pump 14 are respectively located outside the Trombe wall mechanism; the first liquid storage tank 15 is connected to the inner inlet 11 of the inner flow channel 6 through the first valve mechanism, and is connected to the inner outlet 12 of the inner flow channel 6 through the second valve mechanism and the first water pump 13. The second liquid storage tank 16 is connected to the outer outlet 10 of the outer flow channel 5 through the first valve mechanism, and is connected to the outer inlet 9 of the outer flow channel 5 through the second valve mechanism and the second water pump 14;

[0011] The first liquid storage tank 15 is filled with high-absorbance phase change slurry, and the high-absorbance phase change slurry is prepared from materials such as titanium dioxide (TiO 2 ), copper sulfide (CuS) and graphene oxide and paraffin wax, and the absorbance is between 1 and 3; the second liquid storage tank 16 is filled with low-absorbance phase change slurry, and the low-absorbance phase change slurry is prepared from a polymer and magnetic iron oxide (Fe 3 O 4 ), and the absorbance is between 0.1 and 0.3;

[0012] The first valve mechanism includes four three-way valves and four valves; the second valve mechanism includes another four three-way valves and another four valves;

[0013] In winter, the phase change slurry runs in the inner flow channel 6, converts sunlight into heat, a part of the heat directly enters the room, and another part is used to offset the night heat load; the outer flow channel 5 is filled with air or evacuated to prevent additional heat load;

[0014] In summer, the phase change slurry runs in the outer flow channel 5. At this time, the inner flow channel 6 is equivalent to a sunshade, preventing irradiation from directly acting on the wall. The inner flow channel is filled with air or evacuated to prevent excessive heat from entering the room and avoid an increase in the cooling load.

[0015] The further technical solutions are as follows:

[0016] The four three-way valves of the first valve mechanism are respectively the fifth three-way valve 25, the sixth three-way valve 27, the seventh three-way valve 29, and the eighth three-way valve 32. The four valves of the first valve mechanism are respectively the fifth valve 26, the sixth valve 28, the seventh valve 30, and the eighth valve 31.

[0017] The first port of the fifth three-way valve 25 is connected to the outer inlet 10 of the outer flow channel 5. The first port of the sixth three-way valve 27 is connected to the second liquid storage tank 16. The first port of the seventh three-way valve 29 is connected to the inner outlet 12 of the inner flow channel 6. The first port of the eighth three-way valve 32 is connected to the first liquid storage tank 15.

[0018] The fifth valve 26 is connected in series between the second port of the fifth three-way valve 25 and the third port of the sixth three-way valve 27. The sixth valve 28 is connected in series between the third port of the fifth three-way valve 25 and the third port of the eighth three-way valve 32. The seventh valve 30 is connected in series between the third port of the seventh three-way valve 29 and the second port of the eighth three-way valve 32. The eighth valve 31 is connected in series between the second port of the seventh three-way valve 29 and the second port of the sixth three-way valve 27.

[0019] The other four three-way valves of the second valve mechanism are respectively the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, and the fourth three-way valve 20. The other four valves of the second valve mechanism are respectively the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24.

[0020] The first port of the first three-way valve 17 is connected to the inner inlet 11 of the inner flow channel 6 through the first water pump 13 connected in series. The first port of the second three-way valve 18 is connected to the outer outlet 9 of the outer flow channel 5 through the second water pump 14 connected in series. The first port of the third three-way valve 19 is connected to the first liquid storage tank 15. The first port of the fourth three-way valve 20 is connected to the second liquid storage tank 16.

[0021] The first valve 21 is connected in series between the second port of the first three-way valve 17 and the third port of the third three-way valve 19. The second valve 22 is connected in series between the second port of the first three-way valve 17 and the second port of the fourth three-way valve 20. The fourth valve 24 is connected in series between the third port of the second three-way valve 18 and the second port of the fourth three-way valve 20. The third valve 23 is connected in series between the second port of the third three-way valve 19 and the second port of the second three-way valve 18.

[0022] The phase change slurry with high absorption rate is prepared by uniformly mixing paraffin phase change microcapsules, nanoparticles, carbon nanotubes and deionized water; the shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n - heneicosane with a phase change temperature of 39 - 43 °C. The mass concentration of the paraffin phase change microcapsules in the phase change slurry is 100 mg / ml; the nanoparticles are titanium dioxide (TiO2) particles or copper sulfide (CuS) particles or silicon dioxide (SiO2) particles, the diameter of the nanoparticles is 10 - 50 nm, and the mass concentration of the nanoparticles in the phase change slurry is 1.25 - 20 mg / ml; the length of the carbon nanotubes is 10 - 20 nm, and the mass concentration of the carbon nanotubes in the phase change slurry is 0.06 - 4 mg / ml.

[0023] The phase change slurry with low absorption rate is prepared by uniformly mixing paraffin phase change microcapsules and deionized water, and the concentration is 50 mg / ml. The shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n - eicosane with a phase change temperature of 36 °C.

[0024] Both the first water pump 13 and the second water pump 14 are peristaltic pumps.

[0025] The width of the cross - section of the air duct 7 is 0.15 m, and the length is 1.00 m.

[0026] Both the outer flow channel 5 and the inner flow channel 6 are tempered glass circular tubes with a diameter of 0.02 m. The low emissivity of the tempered glass circular tubes is 0.08 - 0.12, and the high transmittance is 0.85 - 0.95.

[0027] The beneficial technical effects of the present invention are reflected in the following aspects:

[0028] 1. The phase change slurry flows in a circulation system composed of a flow channel and a liquid storage tank, which not only avoids contact with the external environment, but also increases the usage amount of the phase change material and is easy to maintain. Due to the volume change during the melting process of the phase change material, there is a problem of leakage; in addition, the phase change material will react with substances in the environment and thus lose its heat storage capacity; finally, the PCM material itself may be toxic. The present invention solves the above three problems. First, the liquid storage tank can well solve the problem of volume expansion and avoid leakage due to excessive pressure. Compared with directly attaching the phase change material to the wall surface, making the phase change material into a slurry and storing it in the pipeline can well isolate the air and prevent the volatilization of harmful substances in the phase change material. If there are problems such as aging of the phase change material and it needs to be replaced, the phase change slurry in the liquid storage tank can be directly replaced, which has no impact on the building body. According to research, after the phase change material circulates 1000 times, its heat storage performance will approximately decrease by 20%. In addition, the requirements for the phase change temperature are generally different in different seasons. Using the same material will lead to problems such as energy conservation in summer and non - energy conservation in winter, extending the payback period of the investment. Therefore, being able to quickly replace the phase change material is crucial.

[0029] 2. The present invention solves the problems that the traditional system will increase the cooling load in summer and the heating load in winter. The present invention is provided with two phase change slurry flow channels, and by changing the position of the phase change slurry, the system can well adapt to the changes in the outdoor environment. When the outdoor temperature is relatively low in winter, the phase change slurry is in the inner flow channel close to the heat storage wall. After converting sunlight into heat, a part of the heat directly enters the room, and the other part is used to offset the night heat load. The outer flow channel is filled with air or evacuated to improve the heat insulation performance of the cover plate and prevent additional heat load. For Beijing in winter, using the device of the present invention can bring an energy - saving effect of up to 75%, and compared with the traditional Trombe wall system, the heat load can be reduced by 49%. When the solar irradiation is relatively strong and the outdoor environmental temperature is also relatively high in summer, the phase change slurry flows in the outer flow channel. At this time, the outer flow channel is equivalent to a sunshade, preventing the irradiation from directly acting on the wall. The inner flow channel is filled with air or evacuated, which can effectively increase the heat resistance of the wall, prevent too much heat from entering the room, and avoid the increase of the cooling load. For the Guangzhou area, using the present invention can reduce the maximum load of the refrigeration equipment by 10%, and the refrigeration energy consumption is reduced by 34% compared with the ordinary brick wall.

[0030] 3. The present invention stores solar energy through the phase change slurry in the liquid storage tank, so the requirement for the thickness of the heat storage wall is lower and it can be applied to thinner walls, such as a 240 - mm wall. Compared with the traditional system, it greatly saves space, and the floor area can be reduced by 38%, improving the effective usable area of the building. Description of the Drawings

[0031] Figure 1Structural diagram of the device of the present invention.

[0032] Figure 2 Circulation mechanism diagram of the phase change slurry of the present invention.

[0033] Figure 3 Device operation diagram under the winter heat preservation and high heat supply operation modes of the present invention.

[0034] Figure 4 Device operation diagram under the low heat supply, ventilation and heat collection operation modes of the present invention.

[0035] Figure 5 Device operation diagram under the summer heat insulation and hot water operation modes of the present invention.

[0036] Figure 6 Device operation diagram under the sunshade operation mode of the present invention.

[0037] Figure 7 Operation schematic diagram under the heat preservation mode of the present invention.

[0038] Figure 8 Operation schematic diagram under the high heat supply mode of the present invention.

[0039] Figure 9 Operation schematic diagram under the low heat supply mode of the present invention.

[0040] Figure 10 Operation schematic diagram under the ventilation mode of the present invention.

[0041] Figure 11 Operation schematic diagram under the heat collection mode of the present invention.

[0042] Figure 12 Operation schematic diagram under the sunshade mode of the present invention.

[0043] Figure 13 Operation schematic diagram under the heat insulation mode of the present invention.

[0044] Figure 14 Operation schematic diagram under the hot water mode of the present invention.

[0045] The serial numbers in the above figure: upper outer air inlet 1, lower outer air inlet 2, lower inner air inlet 3, upper inner air inlet 4, outer flow channel 5, inner flow channel 6, air duct 7, heat storage wall 8, outer inlet 9, outer outlet 10, inner inlet 11, inner outlet 12, first water pump 13, second water pump 14, first liquid storage tank 15, second liquid storage tank 16, first three-way valve 17, second three-way valve 18, third three-way valve 19, fourth three-way valve 20, first valve 21, second valve 22, third valve 23, fourth valve 24, fifth three-way valve 25, fifth valve 26, sixth three-way valve 27, sixth valve 28, seventh three-way valve 29, seventh valve 30, eighth valve 31, eighth three-way valve 32. Detailed implementation mode

[0046] The present invention will be further described below in conjunction with the accompanying drawings through embodiments.

[0047] Embodiment 1

[0048] See Figure 1 , the Trombe wall mechanism of a Trombe wall device based on phase change slurry includes an adjacent heat storage wall 8 and an air duct 7. An upper outer air inlet 1 and an upper inner air inlet 4 are respectively opened at the upper end of the air duct 7, and a lower outer air inlet 2 and a lower inner air inlet 3 are respectively opened at the lower end of the air duct 7.

[0049] It further includes a phase change slurry circulation system, which includes an outer flow channel 5, an inner flow channel 6, a first liquid storage tank 15, a second liquid storage tank 16, a first water pump 13, a second water pump 14, a first valve mechanism and a second valve mechanism.

[0050] The outer flow channel 5 is fixedly installed on the outer side wall of the air duct 7. The upper port of the outer flow channel 5 is the outer outlet 10, and the lower port of the outer flow channel 5 is the outer inlet 9. The inner flow channel 6 is fixedly installed on the inner side wall of the heat storage wall 8 adjacent to the air duct 7. The upper port of the inner flow channel 6 is the inner outlet 12, and the lower port of the inner flow channel 6 is the inner inlet 11.

[0051] The first liquid storage tank 15, the second liquid storage tank 16, the first water pump 13 and the second water pump 14 are respectively located outside the Trombe wall mechanism.

[0052] The first liquid storage tank 15 is connected to the inner inlet 11 of the inner flow channel 6 through the first valve mechanism, and is connected to the inner outlet 12 of the inner flow channel 6 through the second valve mechanism and the first water pump 13. The second liquid storage tank 16 is connected to the outer outlet 10 of the outer flow channel 5 through the first valve mechanism, and is connected to the outer inlet 9 of the outer flow channel 5 through the second valve mechanism and the second water pump 14.

[0053] See Figure 2, the first valve mechanism includes four three-way valves and four valves, and the second valve mechanism includes another four three-way valves and another four valves; and the four three-way valves, the four valves, the other four three-way valves, and the other four valves are all electronic valves.

[0054] The four three-way valves of the first valve mechanism are the fifth three-way valve 25, the sixth three-way valve 27, the seventh three-way valve 29, and the eighth three-way valve 32 respectively, and the four valves of the first valve mechanism are the fifth valve 26, the sixth valve 28, the seventh valve 30, and the eighth valve 31 respectively;

[0055] The first port of the fifth three-way valve 25 is connected to the outer inlet 10 of the outer flow channel 5, the first port of the sixth three-way valve 27 is connected to the second liquid storage tank 16, the first port of the seventh three-way valve 29 is connected to the inner outlet 12 of the inner flow channel 6, and the first port of the eighth three-way valve 32 is connected to the first liquid storage tank 15;

[0056] The fifth valve 26 is connected in series between the second port of the fifth three-way valve 25 and the third port of the sixth three-way valve 27, the sixth valve 28 is connected in series between the third port of the fifth three-way valve 25 and the third port of the eighth three-way valve 32, the seventh valve 30 is connected in series between the third port of the seventh three-way valve 29 and the second port of the eighth three-way valve 32, and the eighth valve 31 is connected in series between the second port of the seventh three-way valve 29 and the second port of the sixth three-way valve 27.

[0057] The other four three-way valves of the second valve mechanism are the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, and the fourth three-way valve 20 respectively, and the other four valves of the second valve mechanism are the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 respectively;

[0058] The first port of the first three-way valve 17 is connected to the inner inlet 11 of the inner flow channel 6 through the series-connected first water pump 13, the first port of the second three-way valve 18 is connected to the outer outlet 9 of the outer flow channel 5 through the series-connected second water pump 14, the first port of the third three-way valve 19 is connected to the first liquid storage tank 15, and the first port of the fourth three-way valve 20 is connected to the second liquid storage tank 16;

[0059] Both the first water pump 13 and the second water pump 14 are peristaltic pumps.

[0060] The first valve 21 is connected in series between the second port of the first three-way valve 17 and the third port of the third three-way valve 19; the second valve 22 is connected in series between the second port of the first three-way valve 17 and the second port of the fourth three-way valve 20; the fourth valve 24 is connected in series between the third port of the second three-way valve 18 and the second port of the fourth three-way valve 20; the third valve 23 is connected in series between the second port of the third three-way valve 19 and the second port of the second three-way valve 18.

[0061] The first liquid storage tank 15 is filled with a high-absorbency phase change slurry, and the absorbance of the high-absorbency phase change slurry is 2.

[0062] The high-absorbency phase change slurry is prepared by uniformly mixing paraffin phase change microcapsules, nanoparticles, carbon nanotubes and deionized water; the shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n-heneicosane with a phase change temperature of 41 °C. The mass concentration of paraffin phase change microcapsules in the phase change slurry is 100 mg / ml; the nanoparticles are silicon dioxide (SiO2) particles, the diameter of the nanoparticles is 10–50 nm, and the mass concentration of the nanoparticles in the phase change slurry is 15 mg / ml; the length of the carbon nanotubes is 10 - 20nm, and the mass concentration of the carbon nanotubes in the phase change slurry is 2 mg / ml.

[0063] The second liquid storage tank (16) is filled with a low-absorbency phase change slurry, and the absorbance of the low-absorbency phase change slurry is 0.2. The low-absorbency phase change slurry is prepared by uniformly mixing paraffin phase change microcapsules and deionized water, and the concentration is 50 mg / ml. The shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n-eicosane with a phase change temperature of 36 °C.

[0064] When the Trombe wall device works, when the solar irradiation intensity is relatively high, the phase change slurry in the phase change slurry circulation system enters the outer flow channel 5 or the inner flow channel 6 from the state of lower temperature, either from the first liquid storage tank 15 or the second liquid storage tank 16, to achieve the absorption of solar irradiation and the control of the average temperature in the air duct 7. The phase change slurry at a higher temperature returns to the liquid storage tank from the flow channel, storing the heat in the liquid storage tank. When the solar irradiation intensity is relatively low, the phase change slurry in the phase change slurry circulation system enters the slurry flow channel from the state of higher temperature, heating the air in the air duct 7 and releasing the heat stored in the slurry in the liquid storage tank.

[0065] The Trombe wall device of the present invention realizes eight working modes: heat preservation mode, high heat supply mode, low heat supply mode, ventilation mode, heat collection mode, sunshade mode, heat insulation mode and hot water mode. The specific working conditions are described as follows:

[0066] Heat preservation mode

[0067] See Figure 7 , in the case of relatively low outdoor temperature in winter, when the average temperature of the air in the air duct 7 is lower than the indoor temperature and the system cannot effectively supply heat to the indoor, the states of each air outlet and the flow direction of the pipeline.

[0068] At this time, the outer upper air inlet 1, the outer lower air inlet 2, the inner upper air inlet 4, and the inner lower air inlet 3 are all closed, and the air in the interlayer does not exchange with the indoor air or the outdoor air. The first water pump 13 is in the working state, while the second water pump 14 is closed. The phase change slurry only flows in the inner flow channel 6, and there is no phase change slurry in the outer flow channel 5. Only a part of the air plays a role in heat preservation and insulation.

[0069] See Figure 3 , in the phase change slurry circulation system, the second valve 22, the third valve 23, and the fourth valve 24 at the inner inlet 11 section of the inner flow channel 6 are all closed, and the first valve 21 is opened; the fifth valve 26, the sixth valve 28, and the eighth valve 31 at the inner outlet 12 section of the inner flow channel 6 are all closed, and the seventh valve 30 is opened. The high-absorbance phase change slurry stored in the first liquid storage tank 15 enters the inner flow channel 6 under the action of the first water pump 13 and returns to the first liquid storage tank 15 after absorbing solar irradiation.

[0070] After the phase change slurry absorbs solar irradiation, its temperature rises, which will heat the air in the air duct 7. When the average temperature of the air in the air duct 7 is higher than the indoor average temperature, the working mode will be converted to the high heat supply mode.

[0071] High heat supply mode

[0072] See Figure 8 , different from the heat preservation mode, at this time, the air in the air duct 7 has accumulated a certain amount of heat, and the average temperature of the air in the air duct 7 is higher than the indoor average temperature, so it can provide heat to the indoor, thus offsetting a part of the heat load. On the basis of the heat preservation mode, the opening degrees of all the valves in the phase change slurry circulation system remain unchanged. The outer upper air inlet 1 and the outer lower air inlet 2 still remain closed, and the inner upper air inlet 4 and the inner lower air inlet 3 are opened. The relatively cold air on the indoor side will enter the air duct 7 from the inner lower air inlet 3 and be heated by the higher-temperature low-absorbance phase change slurry in the inner flow channel 6. Under the action of the density difference, the hot air will flow upward and enter the indoor from the inner upper air inlet 4, realizing the circulation of the indoor air and the air in the air duct 7, and achieving the goal of heating the indoor environment of the building by using the energy of solar irradiation.

[0073] See Figure 3 , since the outer flow channel 5 is evacuated or filled with air, its structure is similar to that of double-layer glass at this time and has good heat preservation performance. The low-absorbance phase change slurry converts solar irradiation into heat and continuously provides heat to the indoor through the circulation of the interlayer and the indoor air. The indoor temperature is a continuously rising process. When the indoor temperature is too high, people will also feel uncomfortable. In order to improve the indoor thermal comfort, when the indoor average temperature reaches 24 °C, the working mode automatically switches to the low heat supply mode.

[0074] Low heat supply mode

[0075] See Figure 9 Figure 9 , when the indoor temperature is higher than 24 °C, a higher temperature will instead increase thermal discomfort. At this time, it is only necessary to meet the indoor heat load to maintain the indoor temperature at about 24 °C. When the outdoor ambient temperature is relatively high or the solar irradiance intensity is relatively high, indoor overheating is likely to occur. On the basis of the high heat supply mode, open the third valve 23 and the fifth valve 26, and turn on the second water pump 14. The low-absorptivity phase change slurry stored in the second liquid storage tank 16 first passes through the fourth three-way valve 20, the third valve 23, and the second three-way valve 18, and then enters the outer flow channel 5 under the action of the second water pump 14. After absorbing part of the solar irradiance, the low-absorptivity phase change slurry returns to the second liquid storage tank 16 after passing through the fifth three-way valve 25, the fifth valve 26, and the sixth three-way valve 27 in sequence.

[0076] Although the low heat supply mode reduces the utilization efficiency of solar energy, the low-absorptivity phase change slurry in the outer flow channel 5 absorbs part of the solar irradiance, increasing its own temperature and also increasing the heat exchange amount with the external environment, resulting in a significant increase in heat loss. However, this mode is applicable to the situation of relatively high ambient temperature, and its goal is to effectively control the indoor temperature and improve the indoor environmental ground thermal comfort, as shown in Figure 4 shown.

[0077] Ventilation mode

[0078] See Figure 10 Figure 10 , when in the transitional season and the difference between the ambient temperature and the indoor temperature is not large, it is particularly important to use outdoor air to provide fresh air for the indoor or offset part of the cooling load at this time. On the basis of the low heat supply mode, close the inner lower air outlet 3, open the outer lower air outlet 2, and keep the valve opening degree in the phase change slurry circulation system pipeline unchanged. The air with a relatively low outdoor temperature enters the air duct from the outer lower air outlet 2. After the outdoor fresh air is heated, it enters the indoor from the inner upper air outlet 4, providing fresh air and part of the heat for the indoor at the same time. By adjusting the flow rates of the first water pump 13 and the second water pump 14, control the flow rate and temperature of the fresh air entering the indoor.

[0079] Heat collection mode

[0080] See Figure 11 Figure 11 , when the outdoor temperature is relatively high, sending the heated fresh air into the indoor will instead increase the indoor cooling load. At this time, the excess heat can be collected for heating hot water or heating the indoor at night. On the basis of the ventilation mode, close the outer lower air outlet 2 and the inner upper air outlet 4, and by adjusting the first water pump 13, control the flow rate of the high-absorptivity phase change slurry entering the inner flow channel 6 from the first liquid storage tank 15; by adjusting the second water pump 14, control the flow rate of the low-absorptivity phase change slurry entering the outer flow channel 5 from the second liquid storage tank 16.

[0081] Sunshade mode

[0082] See Figure 12 , when the demand for hot water is low and it is necessary to reduce the impact of solar irradiation on the indoor cooling load, at this time, the heat entering the room through the envelope structure should be reduced as much as possible. Therefore, the high-absorptivity phase change slurry enters the outer flow channel, and the low-absorptivity phase change slurry enters the inner flow channel to enhance the heat insulation ability of the wall. On the basis of the heat collection mode, open the upper outer air inlet 1 and the lower outer air inlet 2, so that outdoor air enters the air duct 7 from the lower outer air inlet 2 and leaves the air duct 7 from the upper outer air inlet 1 after being heated, thereby cooling the air duct 7.

[0083] Close the first valve 21, the third valve 23, the fifth valve 26 and the seventh valve 30. Open the fourth valve 24 so that the high-absorptivity phase change slurry stored in the first liquid storage tank 15 can enter the outer flow channel 5 under the action of the second water pump 14; at the same time, open the sixth valve 28 so that the high-absorptivity phase change slurry in the outer flow channel 5 can return to the first liquid storage tank 15. Open the second valve 22 so that the low-absorptivity phase change slurry stored in the second liquid storage tank 16 enters the inner flow channel 6 under the action of the first water pump 13; at the same time, open the eighth valve 31 so that the low-absorptivity phase change slurry in the inner flow channel 6 can return to the second liquid storage tank 16, see Figure 6 as shown.

[0084] Heat insulation mode

[0085] See Figure 13 , in hot summer weather, especially in some southern regions, the cooling load accounts for a large part of the annual energy consumption of the building. At this time, it is necessary to give priority to reducing the required cooling capacity in the room and using the phase change slurry to store solar irradiation energy. On the basis of the sunshade mode, close the second valve 22 and the eighth valve 31, drain the low-absorptivity phase change slurry in the inner flow channel 6, and replace it with air in the flow channel to increase the thermal resistance of the system and reduce the heat entering the room through the wall, see Figure 5 as shown. The high-absorptivity phase change slurry flowing in the outer flow channel 5 can absorb most of the solar irradiation, and outdoor air can also enter the air duct 7 through the air inlet, playing a certain cooling role in the air duct 7 and reducing the surface temperature of the inner flow channel 6.

[0086] Hot water mode

[0087] See Figure 14, when the outdoor temperature is too high to effectively cool the air in the air duct 7, or the building needs solar energy to provide hot water, then the phase change slurry needs to collect enough heat. On the basis of the heat insulation mode, the outer upper air inlet 1 and the outer lower air inlet 2 are closed. By adjusting the second water pump 14, the flow rate of the high-absorption phase change slurry entering the outer flow channel 5 is controlled to minimize the average temperature of the air duct 7 while improving the heat collection efficiency of the high-absorption phase change slurry, ensuring that most of the solar irradiation is stored in the high-absorption phase change slurry.

[0088] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Trombe wall device based on phase change slurry, comprising a Trombe wall mechanism, the Trombe wall mechanism including adjacent heat storage walls (8) and air ducts (7), the upper ends of the air ducts (7) being respectively provided with an outer upper air inlet (1) and an inner upper air inlet (4), and the lower ends of the air ducts (7) being respectively provided with an outer lower air inlet (2) and an inner lower air inlet (3); Characterized in that: It further includes a phase change slurry circulation system; the phase change slurry circulation system includes an outer flow channel (5), an inner flow channel (6), a first liquid storage tank (15), a second liquid storage tank (16), a first water pump (13), a second water pump (14), a first valve mechanism and a second valve mechanism; The outer flow channel (5) is arranged on the outer side wall of the air duct (7), the upper port of the outer flow channel (5) being an outer outlet (10), and the lower port of the outer flow channel (5) being an outer inlet (9); the inner flow channel (6) is arranged on the inner side wall of the heat storage wall (8) adjacent to the air duct (7), the upper port of the inner flow channel (6) being an inner outlet (12), and the lower port of the inner flow channel (6) being an inner inlet (11); The first liquid storage tank (15), the second liquid storage tank (16), the first water pump (13) and the second water pump (14) are respectively located outside the Trombe wall mechanism; the first liquid storage tank (15) is connected to the inner inlet (11) of the inner flow channel (6) through the first valve mechanism, and is connected to the inner outlet (12) of the inner flow channel (6) through the second valve mechanism and the first water pump (13), and the second liquid storage tank (16) is connected to the outer outlet (10) of the outer flow channel (5) through the first valve mechanism, and is connected to the outer inlet (9) of the outer flow channel (5) through the second valve mechanism and the second water pump (14); The first liquid storage tank (15) is filled with a high-absorbance phase change slurry, which is prepared from titanium dioxide (TiO 2 ), copper sulfide (CuS), graphene oxide and paraffin, and has an absorbance between 1 and 3; the second liquid storage tank (16) is filled with a low-absorbance phase change slurry, which is prepared from a polymer and magnetic iron oxide (Fe 3 O 4 ), and has an absorbance between 0.1 and 0.3; The first valve mechanism includes four three-way valves and four valves; the second valve mechanism includes another four three-way valves and another four valves; In winter, the phase change slurry operates in the inner flow channel (6), converting solar energy into heat, a part of the heat directly entering the room, and another part being used to offset the night-time heat load; the outer flow channel (5) is filled with air or evacuated to prevent additional heat load; In summer, the phase change slurry operates in the outer flow channel (5), at this time the inner flow channel (6) is equivalent to a sunshade, preventing irradiation from directly acting on the wall; the inner flow channel is filled with air or evacuated to prevent excessive heat from entering the room and avoid an increase in the cooling load.

2. The Trombe wall device based on phase change slurry according to claim 1, Characterized in that: The four three-way valves of the first valve mechanism are respectively a fifth three-way valve (25), a sixth three-way valve (27), a seventh three-way valve (29) and an eighth three-way valve (32), and the four valves of the first valve mechanism are respectively a fifth valve (26), a sixth valve (28), a seventh valve (30) and an eighth valve (31); The first port of the fifth three-way valve (25) is connected to the outer outlet (10) of the outer flow channel (5), the first port of the sixth three-way valve (27) is connected to the second liquid storage tank (16), the first port of the seventh three-way valve (29) is connected to the inner outlet (12) of the inner flow channel (6), and the first port of the eighth three-way valve (32) is connected to the first liquid storage tank (15); A fifth valve (26) is connected in series between the second port of the fifth three-way valve (25) and the third port of the sixth three-way valve (27), a sixth valve (28) is connected in series between the third port of the fifth three-way valve (25) and the third port of the eighth three-way valve (32), a seventh valve (30) is connected in series between the third port of the seventh three-way valve (29) and the second port of the eighth three-way valve (32), and an eighth valve (31) is connected in series between the second port of the seventh three-way valve (29) and the second port of the sixth three-way valve (27).

3. A Trombe wall device based on phase change slurry according to claim 1, characterized in that: The other four three-way valves of the second valve mechanism are respectively a first three-way valve (17), a second three-way valve (18), a third three-way valve (19), and a fourth three-way valve (20), and the other four valves of the second valve mechanism are respectively a first valve (21), a second valve (22), a third valve (23), and a fourth valve (24); The first port of the first three-way valve (17) is connected to the inner inlet (11) of the inner flow channel (6) through a series-connected first water pump (13), the first port of the second three-way valve (18) is connected to the outer inlet (9) of the outer flow channel (5) through a series-connected second water pump (14), the first port of the third three-way valve (19) is connected to the first liquid storage tank (15), and the first port of the fourth three-way valve (20) is connected to the second liquid storage tank (16); A first valve (21) is connected in series between the second port of the first three-way valve (17) and the third port of the third three-way valve (19); a second valve (22) is connected in series between the second port of the first three-way valve (17) and the second port of the fourth three-way valve (20); a fourth valve (24) is connected in series between the third port of the second three-way valve (18) and the second port of the fourth three-way valve (20); a third valve (23) is connected in series between the second port of the third three-way valve (19) and the second port of the second three-way valve (18).

4. A Trombe wall device based on phase change slurry according to claim 1, characterized in that: The phase change slurry with high absorption rate is prepared by uniformly mixing paraffin phase change microcapsules, nanoparticles, carbon nanotubes and deionized water; the shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n - heneicosane with a phase change temperature of 39 - 43 °C. The mass concentration of the paraffin phase change microcapsules in the phase change slurry is 100 mg / ml; the nanoparticles are titanium dioxide (TiO2) particles or copper sulfide (CuS) particles or silicon dioxide (SiO2) particles, the diameter of the nanoparticles is 10–50 nm, and the mass concentration of the nanoparticles in the phase change slurry is 1.25 - 20 mg / ml; the length of the carbon nanotubes is 10 - 20 nm, and the mass concentration of the carbon nanotubes in the phase change slurry is 0.06 - 4 mg / ml.

5. A Trombe wall device based on a phase change slurry according to claim 1, characterized in that: The low - absorption - rate phase change slurry is prepared by uniformly mixing paraffin phase change microcapsules and deionized water, and the concentration is 50 mg / ml; the shell of the paraffin phase change microcapsules is polymethyl methacrylate (PMMA), and the core is n - eicosane with a phase change temperature of 35 - 37 °C.

6. A Trombe wall device based on a phase change slurry according to claim 1, characterized in that: Both the first water pump (13) and the second water pump (14) are peristaltic pumps.

7. A Trombe wall device based on a phase change slurry according to claim 1, characterized in that: The width of the cross - section of the air duct (7) is 0.15 m and the length is 1.00 m.

8. A Trombe wall device based on a phase change slurry according to claim 1, characterized in that: Both the outer flow channel (5) and the inner flow channel (6) are tempered - glass circular tubes with a diameter of 0.02 m. The low emissivity of the tempered - glass circular tubes is 0.08 - 0.12 and the high transmittance is 0.85 - 0.95.

Images