JP2012177541A - Solar light cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve many difficulties of producing products based on a cogeneration system promising for obtaining hot heat simultaneously with power being hopeful, since while solar power generation is promising as a next generation energy supply source, the energy conversion efficiency of a power generation cell is currently around 15%, thereby necessitating a large light receiving area in any installation site and a practically disadvantageous point cannot be denied compared with energy devices using oil and gas in terms of installation space and energy unit price or the like.SOLUTION: Concerning a system for disposing a metal substrate for collecting hot heat on the back side of a power generation cell to achieve high energy conversion efficiency by cogeneration of power and hot heat, a technology and a method for commercializing the technology are provided to achieve basic tasks such as reduction of thermal distortion generated in the power generation cell, securement of heat resistance improvement of energy conversion efficiency, establishment of installation workability, and electrothermal load balance adjustment.

Description

At present, solar power generators and solar water heaters (solar heat collectors) are attracting attention not only in Japan but also overseas, reducing consumption of petroleum resources, preventing global warming, suppressing the rise in prices of petroleum resource-related components, Expansion is expected as a device system that meets other global environmental requirements and social needs. However, the scale of the market is less than 100,000 units sold every year for home use in Japan. On the other hand, there are 4 million units of gas / oil hot water supply units and 7 million units of home air conditioners. For this reason, the advantages such as energy saving without gas oil consumption, the effect of preventing global warming, and the reduction of heat island in the city center have not been sufficiently effective.
The technical field to which the technology of the present invention is applied is a field relating to energy supply system devices using sunlight used for consumer use, particularly home use, business use, and industrial use. The device uses a solar power generation device (hereinafter referred to as a solar cogeneration device) that generates power and supplies heat by receiving sunlight, and a back substrate that supports the solar power generation cell as a heat sink. It is a system that combines a method for transmitting heated solar heat to a cooling pipe. As a result, it is expected that the market fields of the current single-function solar power generation apparatus and solar water heater will be greatly expanded.

The reason why the market scale of single-function solar power generation devices and solar water heaters does not increase is that the output effect is insufficient for the investment price of the devices. That is, the period (PBT) for recovering the initial investment is 7 to 30 years, and it may take 30 years for the investment to be recovered in the solar cell for home use.
Furthermore, the photovoltaic power generation apparatus requires a large light receiving area, and this limits the place where it can be installed. For example, a 3KW solar power generation system for home use usually requires a light receiving area of 30 square meters, which not only imposes great restrictions on installation space, but also increases the price of actual installation work that is extremely difficult. It is a factor and also a factor that prevents the spread of the spread.
On the other hand, in the case of solar water heaters, the above issues are not definitive, but there is a problem of freezing water in cold regions and the use of its energy output is limited to hot water, and many other types of energy applications The fact that it is not possible to cover is also hindering widespread use.
In terms of energy efficiency, the conversion efficiency (ECR) for converting the solar energy irradiated to the solar power generation device into electric power is about 14% in a device in practical use, and the other 86% is not available. The situation is so high that the ECR of the power generation cell itself is expected to be improved, and many research institutions and companies are studying. There are great expectations for this technological advancement in the future expansion of products.

Therefore, research and development of a solar cogeneration apparatus that can obtain electric power and heat on the same light receiving surface have been studied for several decades. That is, a metal plate as a heat sink is installed on the back surface of the power generation cell, and the heat generated in the power generation cell is collected through water or a refrigerant in a pipe integrated with the metal plate. According to this method, the overall light receiving area can be reduced compared to the solar power generator and solar water heater installed separately, and the two basic effects of cost reduction and installation space reduction can be achieved. The installation work can be simplified. Furthermore, by forcibly cooling the power generation cell, the temperature of the power generation cell can be lowered, and the power generation effect of the power generation cell is improved. In addition, when used in a home or store, there is an advantage that electric power, hot water heating temperature, and heating temperature can be obtained simultaneously. However, even after several decades of technical research, this method has not been realized in the market in the form of concrete products.

The technology to be realized by the present invention relates to a structure, a material, and a system for realizing a solar cogeneration apparatus that generates both electric power and heat from sunlight simultaneously in a practical form. The technical aim of the solar cogeneration system is to convert the energy conversion efficiency (TCR: total conversion ratio) per unit light-receiving area into a single function of the electrical energy conversion efficiency (ECR) of the solar power generation system and the solar water heater. The purpose is to greatly improve the thermal energy conversion efficiency (HCR).

Recent research and development of solar power generation equipment is remarkable. Research is also progressing on the use of silicon crystal cells, such as polycrystallization, thinning of silicon crystals, improvement of power generation characteristics of crystal bodies and improvement of light reception characteristics of crystal surfaces. In the future, a silicon amorphous material formed on a glass surface or a plastic film surface or a material obtained by laminating it with a silicon crystal to improve the ECR is also expected. A material in which this amorphous is formed on a window glass for building materials and used as a window material for a building or the like so that the window generates electricity has been put into practical use. In addition, a material different from silicon, such as copper or indium, is used as a cell material to improve ECR, or a material that avoids material shortage as a substitute for silicon material is promising. The invention relating to the solar cogeneration apparatus of the present invention relates to a technical field for finishing the solar power generation apparatus itself or an improved product thereof and the technology as a solar cogeneration apparatus.

There are many reasons why solar cogeneration devices that are highly effective in practical use and energy efficiency have not been put into practical use. This is because the configuration of the solar power generation module and the cooling pipe as the heat collecting device is immature and the practical use including installation has not been developed. Furthermore, in order to meet the purpose of collecting heat, the module structure has an external structure and a heat insulation structure, so that the conversion efficiency is increased. It will be exposed to high temperature. One of the reasons is that the heat-resistant cell and its surrounding structure are not completed. Furthermore, the power generation cell such as silicon and the heat sink made of metal need to have a close contact structure with high heat conductivity, so one of the reasons is that the power generation cell is easily destroyed without being able to absorb the difference in coefficient of linear expansion. is there. In addition, commercialize and prepare solar cogeneration equipment suitable for the site site that is suitable for the power and heat usage ratio of households and stores where power generation and heat collection are actually installed and used. The reason for this is that it is difficult to use in practice and is a cause of cost increase.

Against this background, many researches and developments have been made on the technology of the solar cogeneration device for simultaneously obtaining heat from the solar power generation device. Among them, Patent Document 1 uses a solar cogeneration apparatus in which a solar cell is provided on the surface of a heat collecting panel, and operates a heat pump with the generated power.

In Patent Document 2, a heat exchanger having a solar battery mounted on its surface is cooled by a heat pump device to lower the temperature of the battery cell, thereby improving ECR, which is the energy conversion efficiency of the battery cell.
Patent Document 3 also improves the power generation efficiency by keeping the temperature of the solar cell at a low temperature by collecting heat in the solar heat collector at a low temperature and storing the collected heat in a low-temperature heat storage tank.

Patent Document 4 proposes a technique related to a structural method in which a heat collecting body is provided on the back surface of a photovoltaic power generation cell and a cooling heat collecting tube is attached to the heat collecting body. Patent document 5 is invention about the technique of transferring heat from the heat conductive board of the back surface of a photovoltaic power generation cell to piping of a heat pump. Non-patent document 1 shows a technical report on the simulation analysis of the thermal characteristics of such a method.

Patent Document 6 proposes another type of solar cogeneration method. A solar cogeneration system that installs a see-through solar cell on a glass such as a window and irradiates the sunlight that has passed through it onto a heat collecting plate with a heat-medium pipe installed behind it. is there.
Since the biggest aim of the solar cogeneration apparatus taken up in the present invention is a compact and cost-effective system, a power generation cell with high electrical energy conversion efficiency (ECR) is used. The top priority is to create a device with high power generation efficiency. For this reason, a see-through power generation cell with a low ECR cannot be adopted. The target method is a method of collecting power by installing a power generation cell on a heat sink substrate and transferring the heat generated in the power generation cell directly to the heat sink substrate, and the method of Patent Document 6 cannot be adopted.

Since the solar cogeneration apparatus collects heat without dissipating the generated heat unlike the photovoltaic power generation apparatus and uses the heat, a heat insulating structure is adopted around the apparatus. An upper surface glass is provided on the upper surface of the battery cell via an air space, and a heat insulating layer such as a heat insulating material or a vacuum panel is provided on the lower surface of the heat collecting heat sink substrate. Heat is collected by circulating a collection medium in the cooling pipe, and the power generation cell is cooled simultaneously with the heat collection. During the time period when the heat collecting medium is not circulated when the apparatus is stopped, the entire apparatus is irradiated with sunlight and the temperature rises. Patent Document 7 proposes a technique for providing a ventilation port so that air can be circulated through the above-described air space and cooling it in this case, and opening and closing it.
As can be seen in Patent Document 8, there is a fine processing technique for imparting light wavelength selective absorption characteristics to the cell surface or the heat radiating surface of a solar thermal power generation apparatus.

Although the technologies described above are presumed to have emerged from development activities for realizing a solar cogeneration device, the device itself has not appeared in the form of a product in the market. There are several reasons for this, but the biggest one is thought to be because a price-effective method or apparatus equivalent to the price of commercial power energy cannot be realized. This is due to the fact that a device having a method and configuration capable of practically installing the device has not been developed, and that the device configuration is complicated and the cost is not within a practical level. From the technical point of view, problems such as insufficient heat recovery effect, heat-resistant temperature, thermal strain absorption, etc. are considered to be unclear. The technology necessary for solving such problems in actual commercialization cannot be found in the background art described above.
JP-A-58-158455 Japanese Laid-Open Patent Publication No. 05-066605 Japanese Patent Application Laid-Open No. 07-234020 JP 2003-314903 A JP 2005-195187 A JP 2004-317117 A Japanese Laid-Open Patent Publication No. 2004-60972 Japanese Laid-Open Patent Publication No. 2003-332607 Matsushita Electric Works Technical Report (Mar. 2002) Thermal simulator for solar energy utilization design

The above contents can be summarized as follows. That is, there are the following technical problems that are necessary for putting the solar cogeneration apparatus into a commercial product with a high commercial value that is installed in a limited space such as a home or a store.
(1) The total effective in a solar cogeneration system of a type in which a solar power generation cell is arranged on a metal heat sink substrate, and the solar heat generated in the power generation cell is transferred to the heat sink substrate to collect it. Clarification of methods and configurations to ensure energy conversion efficiency (TCR).
(2) Same as above, clarification of devices and methods for further improving energy conversion efficiency and conversion amount.
(3) In order to improve the actual installation characteristics of the solar cogeneration system of the above method to a practical and easy level, the power generation module and the cooling medium circuit are divided and fixed so that heat can be transferred on site. And clarification of the structure and clarification of the fixing method and structure for realizing it.

(4) Clarification of the installation method that can simplify the overall installation work and ensure the quality of the work when installing a solar cogeneration system consisting of many modules on-site.
(5) The solar cell cogeneration system power generation cell, its surrounding materials, heat sink substrate, etc. adopt a heat insulating structure that suppresses heat dissipation throughout the device, so when the cooling medium does not operate, the maximum temperature around the power generation cell is To rise. It is conceivable that the solar power generation device reaches about 100 ° C. to 110 ° C. while it is about 80 ° C. In preparation for this, it is a challenge to clarify countermeasures against temperature rise, such as the use of heat-resistant materials or cooling systems.
(6) The power generation cell of the solar cogeneration apparatus is made of a material having a small thermal expansion coefficient such as silicon crystal or amorphous, while metal heat sink substrates generally have a large linear expansion coefficient. In particular, copper, aluminum, and alloys thereof, which are desirable metals with high thermal conductivity in terms of heat collection characteristics, have a large linear expansion coefficient. Therefore, it is necessary to optimize the structure or material that has a structure in which the power generation cell and the heat sink substrate are closely attached as much as possible so that heat can be transferred and that can absorb thermal strain caused by a wide range of temperature changes over summer and winter.
(7) Clarification of solar cogeneration system method that can set the output ratio of both according to the local consumption mode that consumes both generated power and heat.
(8) Realization of new functions and methods that use solar cogeneration equipment as a plus function in addition to using generated power and thermal output to further increase the investment effect of this system.
Etc.

The above is a specific technical problem to be solved by the present invention. By combining these, technical issues as a product system for installation in a limited space for home use and stores are summarized in the following three. That is, as a solar cogeneration device, it can cover the total amount of energy required by the user, and its light receiving area should be as small as possible so that it can be installed in home and consumer applications where the installation area is limited. In addition, improve the installation workability and prepare a foundation for promoting the use of solar energy. 2. The power conversion module light receiving area and the heat collection module light receiving area are integrated into the same area (cogeneration), and the energy conversion efficiency per light receiving area is more than doubled compared to the case of photovoltaic power generation alone, thereby improving cost performance. Improve the profitable effect on capital investment. 3. Realize a system that can ensure high quality and long-term reliability by simple and reliable configuration and operation under severe operating conditions, and promote the spread of solar energy utilization equipment in the consumer field. In order to achieve these three major product target issues, the above eight specific technical issues were clarified.

Eliminating all of the eight technical problems described above is a shortcut to achieving the three target problems of the product system. Therefore, the present specification will clarify the solving means for these eight items. A consumer-use solar power generation device or a solar cogeneration device is usually installed in a severe working environment such as on a roof. In addition, the current photovoltaic power generation apparatus requires a large light receiving area in order to obtain a practically effective energy amount. For example, in the home use, the total light receiving area of an average device is 25 square meters or more, the device is divided into about 10 to 20 modules, and the power generated by the power generation cells in each module is converted into modules from each cell. Then, the output is collectively output to the entire integrated power transmission circuit.

If the total sum of the total acquired energy is the same, the condensing area of the solar cogeneration system is almost equal to the amount of energy with an area scale of about one-third or less compared to the system with only solar power generation. Can be obtained. In solar power generation, the electrical energy conversion efficiency (ECR) is 13 to 5% of the total received energy, whereas in the solar cogeneration system, if the device incorporating the technology described in the present invention is realized, the generated power and heat This is because an energy output close to four times that of the output can be obtained, and as a result, the total energy acquisition efficiency (TCR) is expected to reach 50% or more.

Therefore, in the case of a household cogeneration apparatus, the total light receiving area can satisfy a practical effect even if it is downsized to about 10 to 15 square meters. It is divided into a large number of modules of about one. In order to collect the heat generated by these modules, it has been necessary to connect the cooling pipes provided in the modules in order after installing the modules with cooling pipes installed on the roof. there were. This is because water or coolant from a large number of connection points is likely to leak, and the connection work itself is a poor work such as on the roof. There was a drawback that it would be a big factor to raise.

Among the methods that are being considered as a configuration method for solar cogeneration, the method of optically concentrating the sunlight that has been studied recently is excellent in terms of energy acquisition, but large-scale concentrators are used in homes and stores. It is not suitable for and difficult in terms of cost. In addition, the method of separating the power generation part and the heat collection part with the power generation cell as the see-through is also a method suitable for cogeneration in terms of technology, but together with the increase in cost, the electrical energy conversion efficiency of the see-through power generation cell itself Since (ECR) is low and a light-receiving surface with a large area is required, it is suitable for use on the window glass surface of a building, but is not suitable for home use and store use.

The system of the device targeted by the present invention is to install a power generation cell in a state where it is mechanically or indirectly in close contact with a metal heat sink substrate, so that the heat generated in the power generation cell is not dissipated to the surroundings. It is premised on the method of collecting heat by transferring heat to the heat sink substrate, and the heat collecting pipe that collects the heat further aims to reduce the number of connection points as much as possible to improve reliability and simplify the installation work. .
Therefore, the eight items as described above are technical issues. The above is the outline of the overall configuration of the solar cogeneration apparatus targeted by the present invention.

The target power generation module is a hard glass plate as the top cover, a vacuum layer or air layer to prevent heat dissipation to the atmosphere, a sealing layer by EVA etc. to prevent condensation and cell deterioration on the power generation cell surface, power generation cell Layer, a thin film layer for joining and electrically insulating the power generation cell and the metal heat sink substrate and absorbing distortion due to the difference in linear expansion coefficient between them, a metal heat sink substrate for receiving the heat, and further preventing heat dissipation A flat plate (power generation module) laminated with a heat insulating material layer is surrounded by a module frame made of aluminum or the like. In order to improve the performance (TCR) of the problem 1 in this module configuration, it is important to increase the heat transfer property of the thin film layer in order to transmit the heat generated in the power generation cell to the heat sink substrate. Therefore, it is premised that the material should be as thin as possible by making it excellent in thermal conductivity.

In the solar cogeneration apparatus to which the present invention is directed, the power generation cell and the metal heat sink substrate are always electrically insulated, and power generation is performed by the relative difference in thermal strain caused by a wide range of temperature changes between the power generation cell and the heat sink substrate. Failures such as cell breakage and electrical circuit breakage are prevented, and the three elements of sufficient heat resistance are met even when the temperature rises when cooling is stopped when the amount of solar radiation is high. There is a need.
Here, the heat transfer resistance of the thin film layer is calculated as a performance verification. When the thin film layer is a resin and the average thickness is 1.0 mm, the average temperature difference between the two is calculated as follows. The generated temperature difference is the amount of heat divided by the thermal conductivity. That is, it is assumed that the thermal conductivity of the resin of the thin film layer is 0.3 Wm / ° C., the amount of heat generated per unit area is 40% of sunlight 1000 W / square meter, 400 W / square meter, and the resin thickness is 0.001 m. The temperature difference is 400 * 0.001 / 0.3, that is, about 1.3 ° C. This means that heat collection is performed in a state where the temperature of the power generation cell is 1.3 ° C. higher than the average temperature of the heat sink.

Furthermore, factors that increase the temperature difference include oxidation of the surface on the thin film layer side of the power generation cell and the heat sink substrate, contamination, and air bubbles, and the temperature difference of 1.3 ° C. is actually calculated to increase to about 3 ° C. . In addition to the heat transfer from the heat sink to the cooling pipe, the heat transfer from the cooling pipe to the heat storage tank, and further to the hot water supply pipe, the temperature difference of various heat exchanges or heat transfer losses exceeds 10 ° C. It is estimated. This is because when the temperature of hot water used by the user is 48 ° C, the temperature of the power generation cell needs to be heated by sunlight up to 58 ° C. In consideration of the utilization efficiency of sunlight and the heat dissipation loss from the equipment, it is practical. This temperature difference of 10 ° C. is regarded as the maximum allowable for the entire apparatus.

  Next, as mentioned above, the problem to be considered for the thin film layer is how to absorb the relative strain resulting from the difference between the heat resistance and the linear expansion coefficient mentioned in the technical problems (5) and (6). It is. In the case of photovoltaic power generation, the thin film layer can be made sufficiently thick and the maximum temperature can be kept low by natural heat dissipation. A material with a linear expansion coefficient close to the linear expansion coefficient of the power generation cell material is applied to the heat sink substrate. Such a problem was not important because the distortion could be reduced by the fact that it could be used. However, in the case of a solar cogeneration apparatus, as described above, it is desirable that the thin film layer is thinned to 1 mm or less from the viewpoint of performance, and a metal is also selected for the heat sink substrate for heat transfer performance reasons. In particular, the coefficient of linear expansion (lambda) is greater for metals with better heat transfer characteristics. The linear expansion coefficient near room temperature is a value of aluminum 24 microns m / m ° C, copper 16.5, iron 12.2, glass 10.0, hard glass 3.5, silicon 3.0, etc. Compared to silicon crystal, aluminum is about 7 times that of silicon crystal, indicating that the expansion and contraction due to temperature change is large and the relative strain is large.

  As mentioned above, the solar cogeneration system is equipped with devices to prevent problems such as the power generation cell being destroyed or the electric circuit being broken due to the relative thermal strain between the power generation cell and the heat sink substrate in response to a wide range of temperature changes. Need to be. There are many effective measures for this problem. For example, a thin film layer that selects materials having similar linear expansion coefficients of both materials, divides the area of each power generation cell on the heat sink substrate, and reduces the strain amount. It is effective to use a soft material to make the material easy to absorb the strain, or to make a structure that slides due to the relative strain between the two.

In the measure to make the material of the thin film layer a soft material, for example, a polyurethane resin or an ethylene vinyl acetate copolymer resin (EVA) or an ethylene methyl methacrylate copolymer resin (EMMA) such as a resin having flexibility even after being molded or solidified. Rubber materials such as materials, natural rubber, chloroprene rubber, and ethylene propylene rubber have a certain effect in absorbing the strain between them. Although it should be taken into consideration in combination with other strain absorption methods described above in the actual machine, it is intended to absorb electrical insulation and temperature strain using a soft resin on a metal heat sink substrate. Is extremely effective. In particular, if the value of the durometer hardness type D is 45 or less, it is based on a soft material buffer layer having a thickness of 1 mm for absorbing the temperature strain when the temperature range is changed from minus 20 ° C. to plus 90 ° C. The effect is known to be sufficient.

On the other hand, considering the heat resistance, the solar cogeneration apparatus that is the subject of the present invention collects heat without leaving excessive heat, so the heat insulation member of the air layer and the bottom part is minimized in order to minimize the heat dissipation loss from the power generation cell, heat sink substrate, etc. The structure and material of the layer are set so as to provide a sufficient heat insulating effect. In addition, the light receiving surface of the power generation cell is devised so as to minimize the amount of heat radiation loss from the surface by having a selective absorption characteristic in which the radiation characteristic changes depending on the wavelength of light. As a result, the apparatus can transfer most of the heat generated by the received sunlight to the cooling pipe through the heat sink substrate, and the heat acquisition efficiency indicated by the TCR is improved. Usually, the temperature of the power generation cell is controlled at 56 ° C., and the cooling pipe is controlled at about 53 ° C. as a guide. In this state, the system is operated at a temperature lower than the summer operating temperature of the power generation cell of a normal solar power generation device.

However, when the operation of the apparatus is stopped and the flow of the cooling medium in the cooling pipe is stopped, the temperature around the power generation cell is inevitably increased. Depending on the environmental temperature in the operation area and the degree of sunlight irradiation, 100 It is inevitable that the temperature will rise until it exceeds ℃. Patent Document 7 proposes a technique for controlling the temperature by opening and closing a ventilation port. In addition to this method, a method of forcibly circulating the cooling medium by detecting an increase in temperature of the power generation cell or the like is also an effective method.

EVA, which is currently used as a standard in photovoltaic power generation devices, is excellent in softness (the above-mentioned type D value is 45 or less), but the melting temperature is often around 80 ° C. The thin film layer of the invention cannot be used as it is because it rises in the vicinity of 100 ° C. Therefore, it can be adopted by reducing the component amount of acetic acid and setting the melting temperature to 100 ° C. or higher. Since this material does not need light transmission at all and may be colored instead of transparent resin like EVA, many candidate material resins in consideration of necessary moldability, electrical insulation, heat resistance, etc. Or the most suitable one can be selected from rubber. However, since the material for coating the upper surface of the power generation cell needs to be light transmissive, when the heat resistant EVA or EMMA is used, the upper and lower resins need to have mutual affinity. This is because a large number of power generation cells are mounted on the power generation module, so that the front and back resins come into contact with each other between the modules.

The factors that determine the thickness of the thin film layer are strain absorption, electrical insulation, heat resistance, and strength as described above, but in reality, a thin resin film is sandwiched between the power generation cell and the heat sink substrate. When considering the process of thermocompression bonding, it is also important to consider preventing the resin film from being damaged by the convex portion of the power generation cell or mixed dust. In other words, the minimum thickness of the resin film is practically determined in consideration of the above-described strain absorption effect, avoidance of the possibility of breakage, familiarity with the shape of the power generation cell, and the like. When crystalline silicon having an uneven shape is used in the power generation cell, the thickness is usually selected to be 0.8 to 1.0 mm to cover the uneven shape. When silicon amorphous formed on the film surface is used as a power generation cell and the above heat distortion countermeasures are fully incorporated, the film of the power generation cell is used for the thin film layer by taking advantage of its flatness. As the resin film, a thin film of 0.8 mm or less can be selected.

Here, the predetermined withstand voltage function means that the withstand voltage strength between the line of the power generation cell and the metal heat sink should be about 400 to 2000 volts from the viewpoint of preventing leakage in a normal use state. The limit allowable leakage current is a level of 1 milliampere or less, but the actual regulation value is set according to the specification requirement of the device. Actually, the upper surface of the power generation cell is covered with a protective seal as described above to protect the cell from moisture and dust. For this, light transmission is important, and EVA or EMMA is used. In this case, there is no need for electrical insulation and strain absorption, and the selection is made according to light transmission and reliability of adhesion to the power generation cell surface.

In the photovoltaic power generation apparatus, EVA is used as a material for a layer between the power generation cell and the back substrate, and EVA itself has a hot melt function, that is, an adhesive function, and the maximum temperature during operation and the processing temperature of the factory. Therefore, a melting temperature of about 80 ° C. is used. In order to use the same level of materials for solar cogeneration equipment, a temperature rise prevention mechanism has been added to prevent the temperature of the power generation cell or metal heat sink substrate from rising above 80 ° C. It is necessary to do. As its mechanism, when the temperature is detected and rises to a dangerous temperature, for example, as described above, a ventilation cooling port as shown in Patent Document 7 is opened and cooled, or a ventilation fan is forcibly operated. Alternatively, there are several methods such as additionally installing a radiator in the cooling medium circuit and forcibly circulating the cooling medium to cool the metal heat sink substrate.

However, since these additional functions increase costs, a method for improving the heat resistance of the material of the power generation cell and the material used for the thin film layer is practical. In this case, the melting temperature of the material of the thin film layer is selected to be 100 ° C. or higher. Possible heat-resistant materials having a melting temperature of 100 ° C. or higher or a temperature corresponding thereto include EVA having a reduced vinyl acetate component, EMMA having a reduced methyl methacrylate component, polyurethane, silicone rubber, ethylene propylene rubber, chloroprene rubber and the like. Either method is used as a hot melt or a processing method such as bonding a sheet-like material with a heat-resistant adhesive.

As another technology related to heat resistance, the temperature of the surroundings fluctuates greatly by adhering or bonding the power generation cell to a solid flat plate having a linear expansion coefficient close to that of the power generation cell. Even if strain occurs, the power generation cell is supported by the solid flat plate, so that the stress due to the difference in thermal strain generated in the power generation cell is small, and breakage and disconnection are unlikely to occur. For example, in the case of a power generation cell of silicon crystal (linear expansion coefficient: 2.7 μm / m ° C.), a flat plate (linear expansion coefficient: 7.7 μm / m ° C.) or glass plate (linear expansion coefficient) made of alumina solidified. The power generation cell is made of a heat sink substrate (if it is an aluminum plate) by joining a power generation cell on a thin flat plate made of a material having a small linear expansion coefficient such as 3.5 to 10 μm / m ° C. The coefficient of linear expansion is less affected by the difference in thermal strain with respect to 24 μm / m ° C.).

In the future, even if various power generation cells are put into practical use, a method of supporting a power generation cell using a solid flat plate having a coefficient of linear expansion is effective as a measure for absorbing thermal strain. An adhesive or hot-melt resin is used for the bonding between the two, but in any case, the combined surface and the combined thickness of the solid flat plates are required to be extremely thin in order to promote heat transfer. The heat sink substrate is made of aluminum or an iron plate with a heat pipe on the back, but since this linear expansion coefficient is large, the material that fills the space between the solid flat plates is thin and flexible enough to absorb thermal strain. Something is required.

Soft resin and rubber correspond to this material. For example, EVA, EMMA (ethylene methyl methacrylate copolymer resin), polyurethane resin, natural rubber (however sensitive to heat), silicon rubber, chloroprene rubber and the like are candidate materials. If these materials have a hot melt effect, they may be directly heat-bonded, otherwise they will be made into sheet materials and attached with an adhesive. The thickness of the resin or rubber layer is preferably 1 mm or less from the viewpoint of ensuring heat transfer characteristics.
Further, if the heat conduction of the above-described solid flat plate is poor, this thickness needs to be further reduced. In this respect, since the heat conduction is not so bad in the case of a glass plate or a flat plate made of alumina, it is considered that the thickness standard of 1 mm may be left as it is.

A method of using a sheet or film of resin or rubber as a material constituting the thin film layer is also effective. A part of the thin film layer is formed by adhering the sheet or film to the back surface of the power generation cell and the upper surface of the metal heat sink substrate. According to this method, the sheet material or film material is made heat resistant. It is possible to use a material having a melting temperature of 100 ° C. or higher and adhere it by hot melt at room temperature or about 80 ° C. This has the advantage that the sheet or film has heat resistance and does not require a high-temperature process for bonding. Further, since the sheet or film does not melt even in an environment close to 100 ° C., there is an advantage that the dimensions of the thin film layer can be easily maintained.

As described above, many types of power generation cells have been developed, and many types of materials are used. It has sufficient heat resistance at a temperature of about 100 ° C. like a silicon crystal or a glass substrate. However, in a structure in which a metal thin film of silicon amorphous or alloy is vapor-deposited on a resin film, the heat resistance of the film layer and the stretchability of the thin film may be insufficient. In addition, there is a possibility that problems such as breakage of the electrical leads connecting the silicon crystal power generation cells due to temperature changes may occur.

When selecting a power generation cell, we want to check its heat resistance first. Whether or not plastic parts are used, and if they are used, is their heat resistance and melting temperature sufficiently high? Whether or not it has sufficient heat resistance with respect to the maximum temperature required as a solar cogeneration apparatus becomes a problem. When not only the plastic member but also the entire power generation cell is used in at least a solar cogeneration system, it is usually important that the problem does not occur in a temperature environment of 100 ° C. or higher. If there is a problem, you must consider switching to another power generation cell or installing a cooling mechanism for solar cogeneration equipment.

Assuming that almost all materials of the device are heat-resistant, and as described above as a solar cogeneration device, does it have proper power generation characteristics after being exposed to a predetermined temperature of 100 ° C or higher for a predetermined time? It is necessary to confirm whether or not. This evaluation needs to be operated as a device, and the power generation cell alone cannot be sufficiently evaluated. In particular, it is necessary to check the evaluation in the actual installation state, and it is assumed that the evaluation is performed in the installation state that is the most severe evaluation. Normally, the installation surface has many inclined surfaces, but the vertical surface is also included in the evaluation range. The electrical energy conversion efficiency ECR is often a numerical value such as 13 to 16% in the case of polycrystalline silicon, for example, but here, it is required that an equivalent ECR is obtained in the evaluation after the high temperature holding.

This is a technique related to a mechanism for absorbing thermal strain generated between a power generation cell and a metal heat sink substrate. There is a significant difference between the coefficient of linear expansion when the power generation cell is made of silicon crystal or amorphous material and that of a metal with good thermal conductivity used for the metal heat sink substrate. In particular, there is a difference in coefficient nearly 10 times that of aluminum, which is most promising as a heat sink substrate, in terms of heat transfer characteristics and material cost.

In the combination of a power generation cell using a silicon crystal with a low linear expansion coefficient on a heat sink substrate using aluminum with a high linear expansion coefficient, a silicon cell or electrical lead is caused by a large temperature change in a method in which a thin hot-melt resin is bonded to a thin film layer. There is a risk of breakage, and a method of absorbing most of the strain by sliding the joint surface is extremely effective. It is necessary that the bonding surface be made of a plastic film, a sheet, and a metal flat surface such as aluminum that can be kept flat with little deformation. In order to assist the joining of the flat surfaces, it is also effective to apply heat-resistant grease on the joining surfaces. What is further required is a mechanism for keeping the joint surfaces in a joined state at all times. Therefore, a method of maintaining the thickness of the laminated body with a clasp that penetrates a plurality of power generation cells, thin film layers, and metal heat sink substrates, is employed. A structure in which a spring is added to the clasp to press-contact the power generation cell and the heat sink substrate is more effective for maintaining the joint surface.

A fixed band with a small loop may be used instead of the clasp. In order to exhibit the same effect, it is also effective to press the power generation cell against a metal heat sink substrate. Since the surface member of the power generation module uses hard glass, a plurality of support columns may be installed between the glass and the power generation cell using this glass, and the power generation cell may always be pressed against the heat sink substrate. Although there are restrictions on the shape of the column, it is considered that at least an elastic effect is effective in pressing down the power generation cell.

The solar cogeneration apparatus is provided with an air layer or a vacuum panel layer for heat insulation under a glass plate on the upper surface in order to reduce heat dissipation. The thickness is selected from about 5 mm to 20 mm. Therefore, the upper surface of the power generation cell of the laminated body is in contact with the air layer or the vacuum panel layer, and in order to prevent condensation on the surface of the power generation cell, the air layer or the vacuum panel layer and further the power generation cell. The surface in contact with the air needs to be sealed from the outside air. If the structure is not completely sealed, it is necessary to coat the surface of the power generation cell with a transparent hot melt resin such as EVA to form a coating layer. It is necessary to withstand a high temperature of about 100 ° C. using EVA having a melting temperature 15 ° C. to 30 ° C. higher than EVA used in solar power generation. A method of adding a hard glass or EVA sheet as the surface member of the coating layer to improve the accuracy of the flatness of the laminate and stabilizing the manufacturing process is also employed.

It is well known that heat sinks are made of aluminum or copper, which has high thermal conductivity in terms of heat transfer characteristics, that is, energy recovery efficiency, and if necessary, a heat pipe can be added to improve the heat transfer characteristics. It is. On the other hand, any of these metals having good thermal conductivity has a large coefficient of linear expansion due to heat. A method using an iron plate or stainless steel plate as a heat sink substrate has also been proposed, and its thermal expansion can be reduced because its linear expansion coefficient is small and it is close to that of silicon crystals of power generation cells. It is advantageous.

A so-called roll bond method in which a pipe line is formed by overlapping two aluminum plates is suitable for this heat sink, and heat conductivity can be increased by using the pipe line for a heat pipe. An aluminum extruded tube having a flat outer shape with holes arranged in a row can obtain substantially the same characteristics. However, in this case, the direction of the heat pipe is one direction. Another practical method is to install a heat pipe by brazing an aluminum tube to the back of an aluminum flat plate. In any case, it is important that the power generation cell side is flat and easy to form a laminate.
Since this material is aluminum having a large linear expansion coefficient, a combination with a method for reducing thermal strain is essential.

Solar-powered devices are usually installed in places that are difficult to install, such as on the roof. Therefore, its size and weight, ease of transportation, ease of installation work, etc. are important. A technology is required to realize a system in which the solar cogeneration device is transported and installed in a state where it is separated from the cooling pipe and the cooling pipe is attached after the installation. The conventional method of installing the cooling pipes after installing the cooling pipes on the equipment increases the weight of the equipment, and the construction of connecting the cooling pipes between many equipments after installation is difficult. Reliability often becomes a problem, and it is necessary to avoid leakage of water or refrigerant as a cooling medium in 20 or 30 years as much as possible. This is because the location of the leak and the repair thereof are extremely difficult. The best way is to do the work on the ground, not on the roof etc. This will be described in an implementation example.

For this reason, considering the method of using a single continuous cooling pipe, there are many problems in the method of attaching this pipe to the lower surface of the apparatus so that heat can be transferred after the apparatus is installed. First, in order to lay out and arrange a single pipe on the lower surface of many apparatuses, extremely flexible pipes are required. For example, a highly reliable ordinary copper pipe is difficult. In addition, fixing with the apparatus is a work of a narrow gap with the roof, and it is difficult to fix it firmly, which restricts the installation place and method of the apparatus. Therefore, a method of providing an end surface of the heat sink substrate or an end portion or a portion extended from the module portion where the power generation module is installed to the outside, and processing the shape into a shape structure that can easily fix the copper pipe in advance as a heat output portion. There is. After installing this apparatus, a method of molding a single copper pipe into a shape that can be fixed to each heat output portion, and then fixing it to the heat output portion is a highly probable method as an actual product.

Of course, the cooling pipe does not have to be a copper pipe, but it needs to be of a material and dimension that can perform sufficient heat transfer by bringing the outer periphery of the cooling pipe into contact with the heat output portion of the heat sink substrate and tightening it. Further, it is desirable that the heat output portion is provided over almost the entire length of one side of the square heat sink substrate. This is because the maximum contact area with the cooling pipe is ensured, the cooling pipes are easily arranged and formed, and the work of fixing them is easy. Fixing the folded cooling piping over two or three sides of the heat sink board is not workable, and fixing to a part of the heat sink board (for example, about half) may result in insufficient contact area. Because it is expensive. It can be said that it is a reasonable way to continuously install piping on the heat sink substrate of adjacent modules.

In the case where the heat transfer inside the heat sink substrate is improved by a heat pipe, the heat pipe is installed from the module portion, which is a heat generating portion, to the heat output portion to efficiently transfer heat. In this case, in order for the basic function of the heat pipe to operate effectively, it is an absolute condition that the heat generation part is located lower than the heat output part. Therefore, it is necessary to install the apparatus so that one side of the heat output portion of the heat sink substrate is the top. This is because water or the like is charged as a medium in the pipe of the heat pipe, receives heat at the lower part, evaporates the water, condenses at the upper part and dissipates heat. When the apparatus is installed flat or upside down, using an apparatus using a heat sink substrate with a heat pipe significantly impairs energy recovery efficiency.

A system is proposed in which a large number of solar cogeneration devices are sequentially communicated with one cooling pipe for cooling. This effect contributes to facilitating the installation work, improving the reliability of the piping work, and thus reducing the cost. In some cases, one system may be covered by one pipe, but in a large system, two or more pipes need to be connected together, but in any case several modules are connected to one pipe. It is reasonable to cover with. In addition, it is desirable that the branching points and connecting points of the pipes are located on the ground so that they can be confirmed and worked.

A large number of modules are actually installed on the roof, and a single copper pipe is formed in accordance with the heat output part that opens at the end face of each module frame, and the heat is formed so that it fits in advance. The work of fitting this copper pipe into the output part and tightening with a screw is practical and can contribute to the realization of high reliability and cost reduction.

Solar heat transmitted to the heat sink substrate flows toward the cooling pipe. A technique for minimizing the temperature difference in the substrate at this time and minimizing the amount of metal material used on the substrate will be described. When only heat transfer of a metal material is used without using a heat pipe, the amount of the metal use material is an important item that leads to cost and apparatus weight. When heat is collected by the cooling pipe, the heat transfer amount in the heat sink substrate increases as the distance to the cooling pipe increases, so that a metal plate having a certain thickness is inefficient. Therefore, it is desirable to gradually increase the thickness near the cooling pipe. For example, when an aluminum metal plate has an area of 1.2 meters square and a cooling pipe is attached to one end face, the wall thickness may be designed to be an inclined wall thickness of about 1.0 to 4.0 millimeters. Conceivable.

As the power generation cell receives sunlight and absorbs it to generate electricity, the temperature of the cell rises. The heat is dissipated from the cell by heat transfer and radiation, cooled, and the temperature is determined by the heat balance. If it is a single function device of photovoltaic power generation, the emissivity of the cell surface is flat regardless of the temperature wavelength, and a characteristic of 1.0 like a black body is desired. This is because the surface of the power generation cell whose temperature has risen to near 100 ° C. has an effect of radiating heat by radiation and suppressing further temperature rise. On the other hand, it can be said that the performance temperature characteristic of a normal power generation cell is effective for promoting power generation because the power generation efficiency decreases as the temperature increases. However, in the case of a solar cogeneration system, it is necessary to convert all of the irradiated sunlight into power generation and heat, so that the radiation rate (absorption rate) in the solar spectrum is as high as possible and is 90% or higher, 50 ° C. For the radiation spectrum of a black body at the above temperature, a cell surface characteristic of 50% or less with low emissivity is desired.

  In particular, in the present invention, the power generation cell is operated while being cooled to a temperature of about 56 ° C. or less by the heat sink substrate. Therefore, if a characteristic with a low emissivity can be imparted to the surface of the power generation cell in the radiation wavelength spectrum at this temperature, a power generation cell with little radiation heat dissipation can be obtained after sufficiently absorbing sunlight. As a result, it is easy to realize high total energy conversion efficiency (TCR) without dissipating the heat generated by sunlight. The radiation wavelength spectrum at a temperature of 56 ° C. is known from Planck's law, and the average wavelength is about 10 microns. This effect is increased if the surface of the power generation cell has a low radiation rate with a small radiation of about 10 microns. This can be realized if a power generation cell having a so-called selective absorption characteristic that makes this emissivity 50% or less of a black body (emissivity 1.0) can be used.

Although this 50% numerical value cannot be set strictly, it was set as follows. That is, the amount of heat that can be collected by receiving the solar radiation energy (1000 W / square meter) in the black body is about 40% (400 W / square meter) of the device average. The radiant energy from the surface of the object at a temperature of 55 ° C. is about 66 W in black body from Stefan Boltzmann's formula, that is, 17% of the solar heat amount of 400 W. If the radiation coefficient is 40% of black body, this value is That is about 7%, which is 26 W / square meter. Therefore, the heat loss ratio 7% due to this level of radiation is judged to be within the allowable range for the input heat quantity 400W. On the other hand, a radiation coefficient of 50% was set as a target value in consideration of the realization of actual selective absorption characteristics. On the other hand, since the characteristic of black nickel, which is said to be an ideal selective absorption film, is about 10%, it is judged that a radiation coefficient of 50% can be realized.

This selective absorption characteristic is determined by the characteristics of the surface material of the power generation cell. Black nickel, which has typical selective absorption characteristics, has an ideal selective absorption characteristic of 95% of the sunlight spectrum and about 10% of the spectrum from an object at 55 ° C. It is difficult to obtain the selective absorption characteristic of the material from the viewpoint of the material. Therefore, 100% black body radiation is obtained at a wavelength of 3 microns or less at a wavelength of 3 to 4 microns, which is a valley between both the sunlight spectrum and the radiation spectrum of a 55 ° C. black body, and a small radiation coefficient is obtained at 4 microns or more. I would like to show that it is effective to impart surface properties to the cell surface. The following reports indicate that it is effective to absorb or radiate light in the wavelength range by providing and forming a fine unevenness or continuous hole structure with a dimension in a certain wavelength range on the cell surface. Based on.

Patent Document 7 proposes a new technology for a selective absorption film used in a solar receiver of a thermophotovoltaic power generation system. In this case, the temperature of the heat receiver is as high as 1500 ° C., and the wavelength range of the radiation spectrum of the black body at that temperature is 1.2 to 3 μm. On the other hand, the spectrum of sunlight (5400 ° C.) to be absorbed is in a range smaller than 1.2 μm. Therefore, an extremely small cavity having a diameter of about 0.4 μm smaller than 1.2 μm is effective. On the other hand, in the present invention, the temperature of the power generation cell serving as the heat receiving plate is about 55 ° C., and the radiation spectrum of the black body at that temperature is in the range of 4 to 15 μm.

Accordingly, the size of the surface cavity that reduces the emissivity in the wavelength range of the light emitted from the 55 ° C. object is a size of 4 microns or less outside the range of 4-15. As a result, a periodic fine cavity structure composed of fine continuous irregularities, holes, grooves or the like having a fine dimension in the range of 0.3 to 4.0 microns as a unit dimension is effective. This fine structure also has an effect of bringing the absorption characteristic of sunlight closer to a black body. Therefore, there is a case where the same fine structure is given to the photovoltaic power generation cell. What is important here is that when a micro structure of 4 micrometer or less is used in a power generation cell of a solar cogeneration system, both the improvement of the light receiving efficiency of sunlight and the reduction of the loss of heat radiated from the surface are obtained. For this purpose, it is clarified that a fine structure having a unit size of fine structure of 4 μm or less and having a size that can be easily manufactured can be selected. This technology is effective in obtaining maximum total energy conversion efficiency (TCR) by the solar cogeneration system.

In order to increase the amount of light received on the upper surface of the power generation cell of the solar cogeneration apparatus according to the present invention, it is effective to attach a reflector for reflecting sunlight on the power generation cell outside the power generation module. When the heat output portion is provided at one end or outside of the module and the cooling pipe is fixed thereto, it is desirable that there is a working space. A method for improving the total energy conversion efficiency (TCR) by installing a solar reflector in this space is practical. If the reflector can be removed, the space can be used for construction, repair, and service spaces such as the power generation module, the output power lead, and the cooling pipe, and the effect is great when the performance is improved. It is necessary to devise the structure and position of the reflecting plate and the characteristics of the reflecting surface so that the reflected light is not concentrated only on some power generation cells. For example, the reflecting surface is preferably a scattering surface rather than a mirror surface.

It is important that the heat sink substrate made of metal is a material having high heat conductivity. However, when a heat pipe is attached to supplement heat transfer in the heat sink substrate, it is also effective to use an iron plate or a steel plate for the substrate. The iron plate has a linear expansion coefficient of 12X10 minus 6 / ° C, which is less than half that of aluminum. Therefore, distortion due to the difference in thermal expansion with the power generation cell is reduced, and there is a risk that the power generation cell will be destroyed by thermal strain. Because it will decrease. In particular, iron plates are cheap and easy to process, and it is also easy to weld and join copper pipe heat pipes, which may be advantageous both in terms of manufacturing and cost.

If the module of the solar cogeneration apparatus, and hence the heat sink substrate, is rectangular, the power generation module part is also rectangular. When fixing a cooling pipe that receives heat from a heat sink board to the heat sink board in a heat transfer relationship, as described above, fix the cooling pipe to the heat output part of the board as a part that extends over the entire width of one long side of the heat sink board. Things are recommended. Because heat flows in the short side direction in the heat sink board and flows into the cooling pipe, the heat transfer path is shorter and the temperature drop is less, while the cooling pipe uses the full length of one side to receive the heat. The temperature drop in that part can be reduced. As a result, energy efficiency can be improved.
On the other hand, since the cooling pipe is a straight pipe without meandering the heat transfer portion with each power generation module, it has superior formability and mountability.

On the other hand, in the case where heat transfer is improved by attaching a heat pipe mechanism to the heat sink substrate, the heat transfer in the heat sink substrate is good, and therefore it is not always necessary to set the heat pipe in the short direction. Rather, increasing the length of the heat pipe and reducing the number of the heat pipes is advantageous in terms of cost. In this case, a method is adopted in which the cooling pipe is fixed to the heat sink substrate in a heat transfer relationship by directing to the heat pipe at the heat output portion of the heat sink substrate which is the end of the heat pipe.

It is important to reduce heat loss from the back surface of the heat sink substrate. If 10 or more solar cogeneration modules are installed on a roof or the like as a system, the total area of the back surface of the heat sink substrate becomes large, and the heat loss has a great influence on the overall thermal efficiency. Furthermore, this part is required to have sufficient strength as a bottom part of the apparatus for ten years without deformation, rust, deterioration and the like. In addition, the material and shape of the device are extremely important in terms of reducing the weight of the device. The following shows a structure in which a honeycomb structure panel, which has recently been utilized in the heat insulation effect of a vacuum pack used for the wall surface of a refrigerator, and is extremely excellent in terms of weight to strength, is combined.

  Recently, the vacuum insulation block is used in the wall surface of a refrigerator or the like, and the heat insulation effect contributes to the improvement of the operation energy efficiency of the refrigerator and the improvement of the internal volume by making the refrigerator wall surface thinner. However, its wall formation and strength are inadequate, and it is attached to the inside of a casing composed of an outer wall of an iron plate. The object is achieved by placing a honeycomb panel underneath and combining it with an ideal honeycomb panel for supporting the heat insulation block. A honeycomb core is a honeycomb structure made by combining, for example, aluminum thin plates with a width of 1 centimeter by bonding, and the core is sandwiched between two aluminum thin plates and bonded together to form a flat plate-like structure. A honeycomb panel is constituted by the above. It is a structural material that is extremely excellent in terms of its flatness, strength, lightness, and heat insulation. If a large number of holes are made in advance in the aluminum thin plate of the honeycomb core, the overall weight can be reduced and the heat transfer between the two thin plates can be reduced.

It is desirable that the space inside the flat insulating block is mostly vacuum except for the filling material.
An inert gas may be filled. A plastic foam material having the same effect may be used instead of the honeycomb panel flat plate. The above laminated structure is a structure in which a heat insulating block is further laminated on a flat plate having heat insulating properties, and its heat insulating properties are extremely effective.

Workability when actually installing a system in which a large number of solar cogeneration devices described above are combined on a roof or the like is one of the most important items in the merchandise. In other words, the number of solar cogeneration devices to be installed is fixed and installed in the installation place, and electric wiring is performed. Up to this point, it is almost the same as the current photovoltaic power generation apparatus. After that, for example, the shape of the copper pipe is molded so that it can be fixed to the heat output portion of each apparatus over the whole or a fraction of the whole apparatus. If this molding work can be done on the ground, it will be done in that way, and if it is difficult in terms of space or other points, it will be done on the place where it is installed, for example on the roof. The heat output part is provided at the end of one side of the heat sink substrate or the part extended to the outside, and the inside is molded into a semi-annular shape so that a copper tube etc. can be fitted and attached easily, It can be tightened with screws.

Accordingly, the copper pipe can be easily attached to the attachment portion of each heat output portion of each heat sink substrate by applying thermal conductive grease or the like around it. After that, a cover is attached to the opening of the module frame body, the frame size is completed, and a rainwater ingress prevention seal is applied. Or the seal | sticker is completed by attaching the cover member attached outside the module frame which covers the said attachment part. Finally, if necessary, a solar reflector is installed in the upper part of the space between the power generation modules that are the pipe mounting portions. The effect is to increase the energy conversion efficiency by increasing the amount of supplemented sunlight.

Heating the solar cogeneration system by connecting hot water or a high temperature medium to the cooling pipe to melt the snow accumulated on the upper surface of the glass of the apparatus is extremely effective in practice and has already been studied. The heating function shows a method for order to have the sunlight cogeneration ray Deployment apparatus. When the snow on the glass surface is warmed and becomes semi-melted, the snow slides down the glass surface. At this time, if the lower side of the module frame protrudes above the glass surface, the half-melted snow cannot slide down. Therefore, it is important that the lowermost portion of the glass has a structure in which the module frame does not protrude from the upper surface.

The actual installation locations of the apparatus of the present invention are many at home, stores, etc., and the modes of power consumption and heat consumption are different. For example, in a bath shop or a barber shop that consumes a large amount of heat, a plurality of solar cogeneration devices and solar water heaters are installed to secure the necessary amount of heat and reduce the cost of the entire system. At convenience stores and other places where the consumption of heat is low, the number of solar power generation devices is increased to reduce the heat output and match the consumption to reduce the cost of the entire device system. At this time, it is desirable to standardize the dimensions and mounting methods of each type of device module, and thus the mounting base. This makes it easy to select the type of equipment in the system and to install it.

  Consider a circuit of a medium that collects solar heat by connecting cooling pipes across multiple solar cogeneration systems and dissipates it to the hot water in the hot water tank. For example, if water is used as the medium, the amount of heat exchange causes the temperature of the water to change. In the first device, the low temperature hot water is further heated in the next device, and finally reaches a high temperature and becomes a hot water tank. Return to. In order to reduce this temperature difference, the amount of circulating water must be increased, and thus the power of the circulating pump is increased. In addition, cold cooling water may cause condensation on the surface of the power generation cell, and warm cooling water raises the temperature of the power generation cell, reducing power generation efficiency and increasing heat dissipation loss from the device. is there.

  In order to solve these problems, a so-called refrigerant that can absorb warm heat by latent heat of vaporization is used. For example, propane gas, butane gas, carbon dioxide, etc. are strong candidates. Therefore, the refrigerant that exchanges heat by evaporation and condensation naturally has a two-phase flow. In order to flow the gas-liquid two-phase flow stably, it is desirable to eliminate a so-called parallel circuit using a plurality of refrigerant circuits as a plurality of devices and to make a single series circuit. Therefore, it is selected that a single refrigerant circuit is configured across a plurality of devices. In terms of the size of a power generation module used in a household solar cogeneration device, it is practical to share at least three or more devices with a single circuit.

Many studies have been made in the past to realize a device system that can sufficiently supply energy consumed in the household and consumer fields and is environmentally friendly. As one of them, a cogeneration system that integrates photovoltaic power generation and a solar water heater to greatly improve energy conversion efficiency has long been studied as an effective means. The effects of this wide range of technical inventions are considered to have provided a very high prospect for the realization of the cogeneration system. The contents can be summarized into the following three as described above.

In other words, it can cover the total amount of energy required by the user as a solar cogeneration system, and the light receiving area can be made as small as possible so that it can be installed in home and consumer applications where the area and workability are limited. To improve the installation workability. At the same time, the power conversion area of the power generation module and the heat collection module light reception area are integrated into the same area (cogeneration), and the energy conversion efficiency per light reception area is more than doubled compared to the case of solar power generation alone. Increase cost performance effect. In addition, a system that can ensure high quality and long-term reliability with a simple and reliable configuration and operation.

In order to realize these three goals, solutions are presented to the eight technical problems described above. These are innovative technologies for significantly increasing the efficiency of solar energy utilization and realizing solar energy devices with energy costs and convenience comparable to fossil fuels. This makes it possible to supply electric power and available heat as an energy device for home use, consumer use, and industrial use, and realize a solar energy system that can be used for hot water supply, air conditioning, etc., and make full use of natural energy. Pioneered the way to realize energy systems. In this way, we believe that we were able to provide a path for specific technical measures to shift from fossil fuels, which will be promoted in the future, to reusable energy supply systems using natural energy.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 shows a typical example of a solar cogeneration apparatus according to the present invention installed on a roof of a home with a schematic cross-sectional structure. FIG. 2 shows a layout when the entire system using a plurality of the devices of FIG. 1 is installed on the roof. FIG. 3 shows an enlarged cross-sectional structure of a part of the apparatus of FIG. FIG. 4 shows a cross-sectional structure of a sliding-type solar cogeneration apparatus that is different from FIG. 1 in absorbing thermal strain. FIG. 5 shows the structure of a separation-type solar cogeneration apparatus that is different from FIG. 1 in the arrangement of cooling pipes. FIG. 6 shows an example of a system product using electric power and heat obtained by the solar cogeneration apparatus according to the present invention.

The representative example shown in FIG. 1 shows a cross section of one cogeneration device of a solar cogeneration system in which six solar cogeneration devices are combined. One device is therefore called a module. The module is configured to be supported by the module frame 7 as a whole, and the module frame is attached to the roof by a vertical beam for installation and a horizontal beam. The sunlight 13 is received by the top glass cover 1 and the reflector 8 and irradiated to the power generation cell 3 to generate power and heat, but a part of the sunlight 13 is reflected and diffused to the outside. The generated power passes through a lead circuit (not shown) in the power generation cell 3 and is led to the outside of the module, is combined with leads from other power generation modules, and is adjusted to a power mode that can be combined with commercial power through a power converter. Reverse tide. This reverse power flow is purchased by the power company and the purchase price is paid to the owner of the solar cogeneration system.

On the other hand, several tens percent of the energy of sunlight irradiated to the power generation cell 3 is changed to heat, which is transmitted to the heat sink substrate 4 disposed on the back surface of the power generation cell, and further, heat is generated from the module portion 15 in the substrate. It flows to the output portion 14, is transmitted to the cooling pipe 6, is transmitted to the medium flowing through the inside thereof, and is heated. Here, propane gas is used as the cooling medium, and this heating evaporates the propane liquid to change it into gas. An air layer 2 having a thickness of about 1.5 centimeters is provided on the upper surface of the power generation cell 3, and a heat insulating member 5 having a thickness of 1.5 centimeters made of urethane foam is attached to the back surface of the heat sink substrate. ing. Thereby, conduction of heat from the laminated body of the power generation cell and the heat sink substrate 4 to the outside is minimized.

Propane gas flowing in the cooling pipe flows through one continuous copper pipe through the thermal output portion 14 of the heat sink substrate of all the solar cogeneration devices 9 as shown in FIG. 2 to cool all the heat sink substrates. . During this time, the propane gas flows in a gas-liquid mixed state, so the temperature is almost the same over the entire pipe length. Therefore, there is little risk that the temperature of the power generation cell is excessively lowered and dewed or excessively increased to unnecessarily deteriorate the power generation efficiency or to deteriorate the surrounding materials due to the high temperature. In addition, since there is no diversion in the middle of the cooling pipe, there is no problem that the diversion of the liquid refrigerant does not work well when the number of diversions is divided, or the liquid refrigerant stays in the middle. Further, in the case of a system with a large capacity, the flow resistance of the refrigerant in the cooling pipe becomes large, so that it is necessary to perform a refrigerant diversion using a plurality of cooling pipes.

In this case, it is necessary to devise a method such as using a high flow divider to make the flow division well, or adjusting the length of each cooling pipe. Therefore, it is important to reduce the diversion as much as possible. A heat exchanger (installed in the thermal tank, not shown) that disposes one cooling pipe across a plurality of modules, reduces the diversion as much as possible, and radiates heat to the hot water stored in the thermal tank 21. A simple refrigerant circulation circuit is constructed by incorporating it into the circulation circuit. Of course, in order to circulate the refrigerant, a liquid pump (not shown) for propane liquid is provided at the outlet of the heat exchanger. In this case, there is data that the power of this pump is less than about half that of a similar cooling circuit using water. This is because of the latent heat transfer, the circulation amount of the medium is small, and the flow resistance in the cooling pipe and the heat exchanger is reduced.

As can be seen from FIGS. 2 and 3, the cooling pipe 6 has a structure that can be separated from the module of the solar cogeneration apparatus 9. That is, since the module of the apparatus can be installed on the roof like the conventional solar power generator without the cooling pipe attached, the construction is easy and each module is a solar power generator, It becomes easy to select necessary components from the solar cogeneration device and the solar heat collecting device and to install them in an appropriate combination.
The overall length and diameter of the cooling pipe 6 have a great influence on the performance, workability, quality and reliability of the system. In that sense, as described above, in order to prevent refrigerant leakage and improve workability, it is possible to separate the heat output portion 14 of the heat sink substrate 4 by providing it at the end of the module together with the configuration of a pipe line with a continuous pipe with few joints This is shown in FIG.

After the module is installed, the cooling pipes are properly arranged as shown in FIG. Then, when the opening 17 of the module frame 7 is opened, the heat output portion of the heat sink substrate is located inside, and the cooling pipe is applied to the heat sink substrate. The heat conduction grease is applied, and the fixing bracket 18 is tightened. The heat sink substrate and the cooling pipe are fixed with good heat conduction.
The overall configuration of the module and the cooling pipe as described above is extremely important for installing the entire device and completing the construction on site. As in this case, a small system like a home or a large business system such as a hotel, a suburban restaurant, or a super public bath can be installed easily and highly reliable. This is because more things are required.

As is known from FIG. 2, the cooling pipe is fixed to one side of the longer side of the heat sink substrate. For example, when the light receiving module is a rectangle having a short side of 1 m and a long side of 2 m, the temperature difference in the heat sink substrate is quadrupled in the direction of heat flow when the support substrate thickness is the same. Therefore, in order to increase the overall energy conversion efficiency (TCR), it is important to flow heat in the short side direction and arrange the cooling pipe on one side in the longitudinal direction as shown in the figure. In the case of the figure, although not shown in the figure, the heat sink substrate is made of aluminum, and the thickness of the plate is inclined so that the vicinity of the pipe fixing portion is 4 mm and the opposite side is 0.5 mm. This facilitates the transfer of heat and reduces the overall amount of aluminum material used. The average wall thickness is 2.2 mm. If the short and long pieces are reversed, the average wall thickness is 8.8 mm, which is four times that of the same heat transfer characteristics, and a very large amount of aluminum must be used. Therefore, the weight is increased and the operation of lifting the power generation module to the roof is adversely affected.

  FIG. 4 shows a system in which the heat sink substrate 4 is an iron plate and a heat pipe 24 is welded to supplement the heat conductivity. In this case, the longer and shorter sides can be reversed. This is because the heat pipe itself has extremely excellent heat transfer characteristics, so even if it is attached in the long side direction, the temperature gradient is small, and conversely, if the number of installed heat pipes is reduced, that is, heat is applied in the long side direction. This is because it is possible to optimize the whole and reduce the cost by installing the pipe and installing the cooling pipe in the short side direction. The working refrigerant in the heat pipe is water or natural refrigerant.

  The details around the power generation cell will be described with reference to FIG. Here, the power generation cell 3 is a module in which a plurality of power generation cell elements having a small area based on silicon crystal are combined in a hybrid, and is the most commonly used solar power generation cell system. The surface of the cell is formed by etching about 3 microns, and the surface is easy to absorb sunlight, and the black body radiation spectrum at 56 ° C (long wavelength not including 3 microns) is Sunlight is easy to absorb because it has a characteristic that is difficult to radiate, and there is little radiation heat loss. The power generation cell is heated by sunlight irradiation, but is controlled to about 56 ° C. by adjusting the circulation amount of propane gas as a cooling medium.

  The laminate used here is EVA hot melt (the melting temperature is ensured by adjusting the vinyl acetate content and other adjustments) with the uppermost coating layer 20 having a thickness of 1.5 mm and a melting point temperature of 100 ° C. The power generation cell 3 is composed of an EVA hot melt having a melting point temperature of 100 ° C. in the thin film layer 19 below the power generation cell 3, and the aluminum heat sink substrate 4 having an average wall thickness of 2.2 mm below it. The coating layer also has an effect of preventing the condensation on the cell surface, the adhesion of dust, and the like, and reliably joining the power generation cell 3 to the thin film layer hot melt on the lower surface of the power generation cell.

Thin-film hot-melt EVA has electrical insulation and voltage resistance, and the thickness thereof is made as thin as possible (1 mm) in order to transfer solar heat to the heat sink substrate 4. In addition, it is a material that can withstand an environment of minus 20 to plus 95 ° C. as the temperature environment range of the part at the low temperature in winter and the high temperature in summer, and the relative thermal strain between the power generation cell 3 and the aluminum heat sink substrate 4 therebetween. It has a soft property that can absorb the stress caused by. In this case, the side length of the silicon substrate of the power generation cell is 20 cm or less and the electrical lead is structured to absorb strain. Therefore, even if aluminum having a large linear expansion coefficient is used as a heat sink substrate, it is used for buffering strain. Even if a thin EVA with a thickness of 1 mm is used, the relative thermal strain can be absorbed.

However, if a silicon substrate having a larger side length, a large area amorphous, or other power generation cell having a small linear expansion coefficient and weak against tensile strain is used, it is necessary to further devise strain absorption. For example, the strain buffering effect of the thin film layer 19 is increased, the power generation cell 3 is joined to a solid flat plate or glass plate such as alumina having a small linear expansion coefficient, or the heat sink substrate 4 itself has a linear expansion coefficient. It is effective to use a small iron plate. Or, when the temperature of the heat sink reaches about 60 to 80 ° C., it is necessary to take measures such as providing a mechanism for forcibly cooling.
A plastic support 16 is used for the purpose of supporting the space between the laminate and the upper glass 1, and a heat insulating member made of foamed resin is bonded to the lower surface of the heat sink substrate 4. The upper surface glass 1 and the aluminum heat sink substrate 4 are used as a structural substrate, and the outer periphery thereof is fixed by a module frame 7 to constitute a module device. With the above basic configuration, the module as a solar cogeneration device before mounting the cooling pipe 6 has the same structure, weight, and installation structure as a conventional solar power generation device. There is an effect that it is easy in terms of structure to have workability equivalent to that of a solar heat collecting device. Due to the equivalent workability, it is possible to easily provide an optimal combination system for customers and buildings by mixing with the solar power generation device and the solar heat collecting device as described above.

Of course, as described above, it is easy to attach the cooling pipe 6 after installing the module as described above. The solar reflector 8 is attached using the upper space of the part where the cooling pipe of this module is attached. The area of the reflecting plate is equivalent to 15% of the light receiving area of the module, and as a result, aims to improve the total energy conversion efficiency (TCR) per light receiving area, and is improved by 7 to 8%. Can be expected. The reflecting plate surface is a mirror surface processed in a smoke shape so that the reflected light is scattered and reflected. As a result, the reflected light softly covers the entire power generation cell of the module. Further, a space (not shown) is provided between the adjacent module on the reflection plate 8 side so that the reflection plate does not shade the light receiving surface of the module, and this also serves as a service space for the apparatus.

FIG. 4 shows a cross section of an example of a laminated body using another method as a heat sink substrate. As described above, in the case of a power generation cell that is vulnerable to thermal strain, first, a heat sink substrate using, for example, an iron plate having a small linear expansion coefficient must be used. In this case, the metal with a small coefficient of linear expansion generally has poor heat conduction and generates a large temperature difference inside. Therefore, a large temperature difference such as 10 ° C. is generated between the power generation cell and the cooling pipe, and as a cogeneration device. Deteriorates energy conversion efficiency (TCR). Therefore, in the example shown in FIG. 4, a steel plate having a thickness of 1 mm and heat pipes made of 8 mm diameter copper pipes welded at intervals of 20 cm are used. In this case, if the thin film layer (19 in FIG. 3) is used together with, for example, EMMA (ethylene methyl methacrylate copolymer resin) which is softer than EVA and excellent in strain absorption, the effect is enhanced.

The heat pipe medium 25 that is the working fluid of the heat pipe 24 is water. In this case, the power generation module must be installed with the side to which the cooling pipe 6 is attached at the top, and the heat pipe must be used with its axis aligned in a direction that assists heat conduction in the vertical direction in the heat sink substrate. It becomes a condition. FIG. 4 shows a measure for dealing with the case where the power generation cell is damaged due to thermal strain or its operation becomes poor even in this way. This is the third case. This is related to the thin film layer 19, and the power generation cell 3 is joined to a solid, flat, soft resin sheet 22 as shown in FIG. 4. In some cases, the resin sheet 22 is further supplemented by a metal plate (not shown) such as alumina having a linear expansion coefficient close to that of the power generation cell so as to keep a hard flat surface. The resin sheet 22 is bonded to the heat sink substrate 4 via a bonding surface 23. A heat-resistant heat-resistant grease is applied to the joint surface, and the resin sheet 22 and the heat sink substrate 4 can always slide relative to each other via the joint surface 23. The heat-resistant grease makes the sliding smooth. I am helping you to do it.

In order to maintain a state in which the bonding surface 23 is always bonded and heat transfer is possible, a binding band 26 for binding the laminated body in the thickness direction is provided. This is for the purpose of maintaining the joined surface 23 in a joined state by tightening the heat sink substrate 4 and the coating layer 20 on the power generation cell 3 through a through hole provided in the laminate. Bundling bands are provided at 1 to several tens of locations per power generation module. The binding band is a thin but strong resin, and the enlarged portions or nut-like portions provided at both ends prevent the laminate from bulging in the thickness direction and keep the joint surface in a joined state. If necessary, it is also effective to give the binding band 26 an expansion / contraction effect and always press the joining surface in the joining direction. Since the through hole for the binding band provided in the laminate is slightly larger than the binding band, sliding on the joint surface is not hindered. Of course, a number of binding bands used in one module may be a resin that is connected, integrated, and molded. In this case, forming the plastic support 16 and the binding band 26 shown in FIG. 3 with an integrated resin has a great practical effect. A method in which the binding band 26 is inserted into the laminated body and then fitted into the tip thereof, and a nut effect as a part to be fixed by screws or welding has a spring effect that acts to push the laminated body in the binding axial direction. Is practical.

Another proposal for the configuration of the cooling piping is presented in FIG. In this system, the power generation module 15 of the heat sink substrate 4 is housed inside the module frame 7 and the thermal output unit 14 is extended to the outside of the module frame. In this method, it is easier to fix the cooling pipe to the thermal output unit 14. However, since the heat sink substrate 4 extends outside through the module frame body 7, it is necessary to devise a way to rain the portion, and the thermal output portion is protected by another cover (not shown). Therefore, it is necessary to consider the strength during construction transportation. However, this configuration is effective when a large number of power generation module devices are combined and the cooling pipe is thickened to use a single pipe.

In order to adjust the power generation and thermal energy of the solar cogeneration system according to the user's request, it is necessary to adjust the type of module to be installed. In convenience stores in southern countries that use less heat energy, the number of solar power generation devices will be increased, and the system will have fewer solar cogeneration devices. However, it is better to increase the number of solar cogeneration devices in areas with a large heating load. On the other hand, it is appropriate to increase the number of solar cogeneration devices in a barber shop where the hot water supply load is large. In general households, it is desirable to use a solar cogeneration system as a standard, and in a household with a small heating load and a small amount of bathing, it is desirable to increase the proportion of the photovoltaic power generation apparatus. Such an adjustment is almost unnecessary, and a high-function system product that can be easily adapted to any demand mode is also possible, and the outline thereof is shown in FIG.

As described above, as a representative example of a product service that operates a solar cogeneration system utilizing the technology of the present invention as a system, the power output is reversely flowed (sold) into commercial power, and the heat is transferred to the heat tank 21. It is a system that stores heat and uses it as hot water for hot water supply or heating. However, FIG. 6 shows an example in which it is incorporated into a full system that fully supplies electric power, heating and cooling, and hot water as a higher level utilization system. This is adjusted by adjusting the thermal output of the solar cogeneration device (in the figure, the device is represented by a single module, but actually a system with multiple devices) so that it can be obtained in the optimum state by the heat pump device 28. The heat storage tanks 30 and 31 store heat, and the heat is used for air conditioning and hot water supply through the hot water supply line 38 and the hot and cold water line 39. This is a solar cogeneration system with a heat pump device added thereto. As described, the following effects can be expected.

1. Optimal control of power generation cell temperature (including TCR maximization). 2. Optimal control of heat storage temperature for thermal storage. 3. Cold heat storage by atmospheric heat source heat pump operation is possible. 4. Thermal storage of exhaust heat from cold operation. 5. Adjustment of electric power, heat, and cold supply according to the energy demand mode. 6. Ensuring efficient heat with an atmospheric heat source heat pump even on days when sunlight is insufficient. 7. Reducing energy costs by using midnight power. In other words, it is possible to achieve a very rational operation at the highest level by combining the use of the solar power system, the atmospheric heat source heat pump system and the commercial power supply. According to this system, it is not necessary to install a large-scale solar cogeneration system that can cover up to rainy days, and 70-80% of the annual energy demand is covered by sunlight. It is thought that the most compact system can be realized by optimizing the whole system by using a power supply system on the day.

Expectations for a reliable solar cogeneration system have two aspects: a stable energy supply and absorption of initial investment costs due to long-term use. Therefore, the reliability of long-term use is extremely important. Therefore, in the present invention, a technique for solving the problems focusing on the technical aspects of thermal strain stress, high temperature environment, and insulation characteristics generated in the power generation cell is presented. In addition, a scheme, structure and structure that make installation work easier were presented. This is because it is recognized that an apparatus system having a problem in workability does not become a highly reliable system in the installed state. Some techniques for improving energy conversion efficiency were also presented. This is because it is both wheels of the car in terms of product completion and cannot be separated.

Schematic cross-sectional structure of solar cogeneration equipment installed on the roof Solar cogeneration system system roof layout layout Cross-sectional structure diagram of a typical solar cogeneration system Cross-sectional view of solar cogeneration system sliding system Solar cogeneration system cooling pipe separation system structure diagram System output power and heat utilization system product examples

DESCRIPTION OF SYMBOLS 1 Upper surface glass cover 2 Air layer 3 Power generation cell 4 Heat sink board 5 Heat insulation member 6 Cooling piping 7 Module frame 8 Reflector 9 Solar cogeneration apparatus 10 Vertical beam 11 for installation Horizontal beam 12 for installation Roof 13 Sunlight 14 Heat sink board Thermal output unit 15 Heat sink substrate power generation module unit 16 Plastic support column 17 Module frame body opening 18 Cooling pipe fixing bracket 19 Thin film layer 20 Film layer 21 Thermal tank 22 Resin plate 23 Joining surface 24 Heat pipe 25 Heat pipe medium 26 Binding band 27 Cooling Piping fixing screw 28 Heat pump device 29 Blower fan 30 Cold heat storage tank 31 Thermal heat storage tank 32 Power controller 33 Transmission line 34 Heat pump power supply 35 Cooling refrigerant line 36 Heating refrigerant line 37 Tap water 38 Hot water supply line 39 Hot and cold water line 40 Fan coil unit 41 for air conditioning Floor heating wall heating panel

Claims (2)

In a solar cogeneration device that collects both power from a power generation cell and heat from a heat sink substrate by sunlight projected on the upper surface of the power generation cell, the optimal control of the power generation cell temperature and the power in combination with a heat pump device Solar cogeneration system characterized by optimal control of thermal temperature In a system in which a plurality of solar power generation devices and the above-mentioned solar cogeneration devices are installed, the shape and dimensions of the modules of these devices are substantially the same, and the mounting method to the roof and other installation locations is the same, The solar cogeneration system according to claim 1, wherein a system that responds to customer's energy needs can be configured by selecting and installing those devices on an occasional basis.