rexresearch.com
rexresearch.com
Isik TARAKCIOGLU, et al.
Cooling / Heating Textile
via KeelyNet.com ( 7/06/07 ) --
http://www.turkishdailynews.com.tr/article.php?enewsid=77279
Turkish scientists develop cooling textiles
Products developed by the Aegean University (EÜ) Turkish Textile Association Joint Research Center, inspired hope with its cooling effect during hot summer days.
Using salt hydrates obtained from Acigöl, in hats, scientists managed to make temperatures of 50 degrees Celsius feel like 35 degrees Celsius, reported Dogan news agency.
This is not a new invention. This system was first used in clothing for astronauts. We just simplified it. Moreover we used the salt hydrates obtained from Acigöl [ volcano -- sodium sulfate ? http://goldschmidt.info/2013/abstracts/finalPDFs/2382.pdf ] as phase converters. Thus we could reduce the cost. The cost of 100 grams hydrate, which is used for one hat, is YTL 0.10. To use it for curtains, the cost per square meter will not exceed YTL two.
Tarakçioglu pointed out that they developed their first projects with car seats in mind since they get excessively warm during hot days. "After succeeding at that, we tried it on hats, blankets and curtains."
Emphasizing that the phase changing system can save energy by 25-30 percent in curtain and roof systems of houses, Tarakçioglu stressed: "It is possible to use them as a heater in winter months in houses facing southward. During the summer, it can also prevent excessive heating thus reducing the energy consumed by air conditioners."
TEXTILE BASED FLEXIBLE WATER HEATING SOLAR ENERGY COLLECTOR
WO2014189474
The low cost textile based flexible water heating solar energy collector which is considerably simple, consists of a black fabric or felt (2), the back surface of which is coated with a water-tight layer (3), and a polyethylene, polyester or similar transparent sheet (1) resistant to UV lights is located thereon without leaving any space between thereof. If desired, a flexible insulation layer (4) can be placed under the water-tight layer, in other words, at the rear surface of the collector. Water inlet to the collector is performed via a separate perforated or cleft pipe (5) positioned in such a manner that the holes or cleft thereof face to the black fabric, and having a hose inlet, and the hot water outlet (6) is provided at the lower center of the collector. The collectors that can be lifted by being rolled and transported, can be mounted in desired areas in a few minutes thanks to the separate carrier (7) having a holder (11) for the perforated or cleft pipe, legs (10) which can be folded and a clothes peg framework (8) which can be collapsed.
Description
The present invention is a water heating solar energy collector that does not comprise a collector box and pipes, and is made of textile surfaces (fabric or felt) and is flexible.
State of the Art
The use of alternative energy sources instead of fossil based fuels is the leading measure to be taken in order to slow down the global warming arising from the excessive use of fossil based fuels. While the wind energy becomes prominent among the alternative energy sources for obtaining electric energy, solar energy is widely used for heating water.
Although there are differences between the water heating solar energy collectors with pipe which are common in the market, depending on their construction and the material used, the majority of the costs thereof belong to the pipes through which water flows. The bigger the total surface area of the pipes through which water is flowing while passing through the collector is, in other words, the smaller the diameter of the pipes is and the longer the pipes are, the more the efficiency of the collector increases. However, the production costs of the collector increase accordingly.
In order to eliminate the above mentioned disadvantages, titled "Water Heating Solar Collectors without Pipe" (TR 2007 01274 B) which is developed by us, is based on flowing the water through the inside of a black textile surface (fabric, felt) instead of a long and corrugated pipe located inside the collector box.
The textile surfaces such as fabric and felt can be obtained by weaving and knitting the yarns consisting of fibers or obtained directly from the fibers (via nonwoven technology or felting). Tens of thousands even hundreds of thousands capillaries exist between the fibers of the textile surfaces. When a fluid is poured onto the front surface of a textile surface.which is water-tight back-coated and which is in inclined position, through the upper side thereof via a perforated cleft pipe through the width of the collector in a regularly distributed manner, said fluid penetrates into the textile surface thanks to capillary absorption of the textile surface and then.flows downwards through the capillary voids inside the textile surface because of gravity.
Depending on the structure of the textile surface (woven, knitted, nonwoven surface), construction thereof (tightness, density, thickness, texture, whether it comprises pile thread or not, and whether it is raised or not), the construction (number and twist etc.)of the yarn if it is not a nonwoven textile surface, the properties of the fiber used ( hydrophob, hydrophile or mixture; the titer and length thereof, etc.), and with regards to the flow rate and viscosity of the fluid, the flow time of a fluid flowing from the upper edge of a 3-meter textile surface positioned in a 45°-inclined manner to the lower edge thereof, carfblTreg^^
In the standard collectors with pipes, majority of the sun rays received by the collector box is absorbed by a special black plate and the heat energy on said hot plate is transferred to the pipes located under this absorber plate, and then to the water or to the fluid flowing in the pipe. However, in the textile based solar collectors without pipe, solar energy is absorbed by the black textile surface and transferred to the water and fluid flowing through the said textile surface (through the capillaries between the fibers). Therefore, heat transfer is performed with higher efficiency. On the other hand, the production costs of textile based solar collectors are relatively lower when compared to collectors with pipe, because in these collectors instead of expensive copper pipes and special black plates only a cheap textile surface (fabric, felt) is used.
Thus, when water flows through the back-coated black textile surfaces, the temperature of water can increase up to the boiling temperature (100 °C) especially in summer periods, depending on the mass flow rate of the water, but problems such as evaporation, condensation on the glass, over-heating of the glass and extreme heat loss through the surface of the glass, decrease the efficiency of the collector. In winter periods, however, the water can freeze at nights as in all direct water heating collectors. In addition, at the morning operation, the steaming up (fogging) of the front glass pane increases by the increase of the water temperature, so the solar radiation is restricted and therefore the efficiency of the collectors decreases to a great extent.
As in our patent application titled "Textile Based Solar Energy Collector (TR 2009/011 14)", a proper heat transfer liquid with a boiling temperature of above 200 °C such as mineral and synthetic oils, glycerin, ethylene glycol etc. flows instead of water through a black textile surface placed in a solar collector box. Heating of the heat transfer fluid up to temperatures above 100 °C can be obtained without any problems such as evaporation, steaming up (fogging) of the front glass pane, condensation, calcification on the textile surface, etc.
Thus, the system can not be operated for direct heating of the water, in other words, the hot water used isn't heated directly while passing through the collector; it can be operated by passing the hot transfer liquid through a liquid/liquid heat exchanger or a serpentine while the usage water at the outside thereof will be indirectly heated. In spite of the above mentioned advantages, in indirect heating, production and operating costs slightly increase and the efficiency slightly decreases.
Object of the Invention
The object of said invention is to disclose a solar energy collector that can provide water at approximately 50 °C in summer and can be transported and stored easily by being rolled when it is not in use and it is constructed without collector box, transparent plate like glass, polycarbonate and GRP (Glass fiber Reinforced Polyester) located at the front surface of the boxes facing the sun, and insulation material, which constitute 95% of the costs of the textile based solar collectors which are operating without expensive and heavy pipes. Description of the Figures
Figure 1 is the lateral sectional view of the collector.
Figure 2 is the front top view of the collapsible cloths peg carrier in open manner position
Figure 3 is the front view of the collapsible cloths peg carrier in closed position
Reference Numerals
1. Transparent sheet
2. Black textile surface (fabric, felt)
3. Water-tight layer
4. Insulation layer (optional)
5. Perforated or cleft pipe (separate)
6. Warm water outlet
7. Collapsible clothes peg carrier (separate)
8. Clothes peg framework (body)
9. Collapsible mechanism of clothes peg framework
10. Foldable legs ;
1 1. Holder for perforated or cleft pipe Detailed Description of the Invention
When water flows directly through the textile based solar collector comprising a black textile surface (2) (fabric or felt), the back surface of which is coated with a water-tight layer (3), the temperature of water can increase up to 100°C especially in the summer depending on to the flow rate of water and the angle of the collector with the horizon; however, the problems such as evaporation, condensation on the glass, over-heating of the glass and excessive heat loss through the glass, decrease the efficiency of the collector considerably. As the said situation becomes clearer when the temperature of the water increases, it does not create any disturbance in the areas where the outer temperature is above 30°C and the temperature of water is below 30 °C, and it barely disturbs when the temperature of the water is approximately 35 to 40 °C. If a transparent sheet (1 ) is located on the upper surface of the black fabric (2), the back surface of which is coated with water-tight layer (3), so as to contact the upper surface of the said fabrie-or elt-(-possibly-without-leaving-any-spaGe-between^ evaporation and condensation on the transparent layer (1 ) do not create disturbing situations even when the temperature of the heated water is above 40 °C. Therefore, hot water having temperature of approximately 50°C with adequate efficiency can be obtained in summer thanks to the said construction.
As it does not provide an important advantage to locate an insulation layer (4) under the layer (3) of the back-coated black fabric, in the areas where the temperature is 30-35 °C in the shade and 45-50 °C under the sun, this option may be abandoned optionally. Thus, the collector consists of a black fabric or felt (2), the back surface of which is coated with a water-tight layer (3), and polyethylene, polyester or a similar transparent sheet (1 ) resistant to UV lights is located thereon without leaving any space between thereof. A separate perforated or cleft pipe (5) having a hose inlet at the top, and a separate carrier (7) having a holder (1 1 ) for the said perforated or cleft pipe (5) and legs which can be folded and a clothes peg framework which can be collapsed. The way of using and applying the present invention
The water heating solar energy collectors according to the present invention, which is flexible and thus, can be rolled and transported easily, can be used in all residences and work places, especially in summer houses, camping and picnic areas, and caravans, where hot water at 50 °C is adequate in the summer (June-September) period . The collectors can be used by being directly laid on the roof layer (3) in the buildings having roofs that face to the south. The collectors according to the present invention can be applied in order to warm up the water of swimming pools and the cold artesian water.
TEXTILE BASED SOLAR COLLECTOR
WO2010093339
By the flowing process of a proper heat transfer fluid with a boiling temperature of above 120 DEG C through a back coated (3) or specially constructed black textile surface (4) placed in a solar collector box, the heating of the heat transfer fluid up to temperatures above 100 DEG C can be provided without any problems such as evaporation, steaming up of the front glass pane, condensation, calcification of the textile surface (fabric), etc. In order to heat water or air, the hot heat transfer fluid from the collector outlet (7) passes through a liquid/liquid (10) or a liquid/gas (10) heat exchanger, respectively. The warm heat transfer fluid from the heat exchanger outlet (12) is pumped by a proper pump (9) to the inlet of the perforated or cleft pipe (6) to complete the recirculation route.
The present invention relates to flowing of heat transfer fluids with a boiling point of above 120 <0>C through in the solar collector box placed black or dark colored textile surfaces which preferably are back coated for indirect air or water heating purposes.
Background of the invention:
Fossil-based fuels are not renewable resources and therefore they will run out after a certain period of time. On the other hand, the global warming occurring by the greenhouse effect due to carbon dioxide emissions generated by the combustion of fossil-fuels has increased the importance of the alternative energy resources.
Solar energy has the easiest and most common available use in the renewable and clean energy sources such as hydroelectric, solar, wind, tide, geothermal, etc.
Unlike the conversion of solar energy to electric energy via using photovoltaic cells, water heating with solar energy already has a common use. Even the use of different materials and constructions, the common technique of the water heating solar collectors is the heating of water or any heat transfer fluid while it is passing through the pipes placed in the collector. These collectors may also be operated for indirect heating of the running water by passing the obtained hot water through a heat exchanger, as well as for direct heating of the running water, that is, the direct use of the hot water heated in the collector. In the indirect heating, production and operating costs increase to some extent; on the other hand the collector can be used at winter periods by adding antifreeze to the circulating water or instead of using water, heat transfer fluids with much lower freezing points can be used as circulating liquid.
Unlike the water heating solar collectors, the solar air heating collectors are not widespread. These collectors are based on black-colored metallic, plastic, ceramic or composite plates which are placed inside the rectangular boxes made of metallic, plastic or composite materials. The back and side surfaces of boxes are insulated and the face (sun face) sides are covered with normal or special glasses, polycarbonates or other transparent layers.
The black plates heated by the absorption of high-IR radiation of sun rays, heats the air in the boxes to a limited extent, in which a green house effect occurs. On the other hand, especially in case of moving air, just like in the air heater collectors; the actual heat transfer takes place by convection.
The purpose of the invention:
The cost of the pipes through which the water or heat transfer fluid flows causes a significant portion of the total production cost of water heating collectors, even it varies depending on the collector construction and material. The higher the total surface area of the pipes through which water or heat transfer fluid flows; that is, the lower the diameter of the pipes and the longer the length of the pipeline; the higher the efficiency of the collectors. But in parallel to this, the production and maintenance costs of the collector increase.
As mentioned in the patent application No: 2007/01274 "Water heating solar collectors without pipes", when water flows down through the capillary pores of a black textile surface instead of flowing through the pipes, it warms up more efficiently.
In the U.S. patent dated 27 April 1982 and No. 4326504 entitled "Textile Solar Collector", it was indicated that the water warms up while it is passes through a special construction of a black textile surface whose top layer is looser (lower density) and the sub-layer is denser (higher density) and at least one layer is formed by non-woven material.
However, due to the direct passing of water through the back-coated or specially constructed black textile materials, the temperature of the water can reach the boiling point (100 <0>C) in summer periods depending on the mass flow rate of the water and reduces the efficiency of the collector due to the problems such as evaporation, condensation on the transparent layer, overheating of the transparent layer, extreme heat loss through the surface of the transparent layer, etc. In the winter periods, as in all direct heating water collectors, the water can freeze at nights. In addition, at the morning operation, the steaming up of the front glass pane increases by the increase of the water temperature, so the solar radiation is restricted and therefore the efficiency decreases to a great extent.
In the solar collectors in which the water is heated by passing through black textile surfaces, the evaporation rate increases by the increase of the temperature. Especially when the water temperature is higher than 45-50 <0>C, evaporation rate becomes more problematic. So, in the course of time the calcification starts, thus the fabric (textile surface) needs to be changed frequently due to the efficiency losses. This is why the two of the three examples of U. S Patent No. 4326504 are related to the heating of water from 20 <0>C to 25 <0>C, and the third is related to the heating of 40 liters of water from 25 <0>C to 40 <0>C in 2 hours by the recirculation of water.
The technical problem that this invention intends to solve is the elimination of aforementioned problems in direct water heating with textile based solar collectors in which the water passes through a back coated or specially constructed black textile surface and therefore heating water up to 85-90 <0>C in textile based solar collectors without problems, and also providing air heating if requested.
Description of the invention:
A textile based solar collector system to reach the objective of the invention has been schematized in the attached figure, and this figure presents the following:
Figure 1-The schematic of the textile based solar collector and heat transfer fluid recirculation
The units in the figures have been numbered and shown below:
1) Insulation
2) Metallic, plastic or composite collector box
3) Back coating
4) Textile surface 5) Transparent layer
6) Cleft or perforated pipe (cold or warm heat transfer fluid inlet)
7) Hot heat transfer fluid outlet
8) Insulated tank
9) Pump
10) Liquid/liquid or liquid/gas heat exchanger
11) Hot heat transfer fluid inlet
12) Warm heat transfer fluid outlet
13) Cold water or air inlet
14) Hot water or air outlet
In this invention, heat transfer fluids with boiling points of above 120 <0>C warms up to the temperatures above 50 <0>C in solar collectors without pipes while they pass through black or dark colored, back coated (3) or not textile surfaces (4) and these hot heat transfer fluids heat water or air indirectly.
When a liquid is poured by the help of a perforated or cleft pipe (6) from the upper face side of the black textile surface (4) which is in vertical or inclined position, the liquid penetrates into the textile surface due to the capillary absorption, and it flows down through the capillary pores, and in the mean time the liquid warms up more or less.
In this manner, by passing of a proper heat transfer fluid with a boiling temperature of above 120 <0>C such as mineral or synthetic oils, glycerin, ethylene glycol, etc. instead of water through a black textile surface (4) placed in a solar collector box (2), the heating of the heat transfer fluid up to temperatures above 100 <0>C can be obtained without any problems such as evaporation, steaming up of the front transparent layer (glass pane) (5) , condensation, calcification on the textile surface, etc.
In order to heat water or air, the hot heat transfer fluid from the collector outlet (7) passes through a liquid/liquid or a liquid/gas heat exchanger (10), respectively. The cooled heat transfer fluid from the heat exchanger outlet (12) is pumped by a proper pump (9) to the inlet of the perforated or cleft pipe (6) to complete the recirculation route. As optional, photocell or thermostat valves can be used to start up or stop the pump automatically. After the pump stop, the heat transfer fluid which flows through the fabric is stored in an insulated tank (8) which is installed between the heat transfer fluid outlet (7) and the pump (9). After the pump start up, the stored heat transfer fluid is pumped to the upper inlet of the collector (6).
Utilization and applicability of the invention:
The flow time of the heat transfer fluid from the upper edge to the bottom edge of a 2 meters long textile surface with a 45 ° slope can be adjusted to be from a few seconds to above 30 minutes, depending on the mass flow rate of the heat transfer fluid, the type of the textile surface (woven, knitted, nonwoven), the construction of the textile surface (tightness, density, thickness, texture, piled or not, raised or not, etc.), if textile surface is not a nonwoven the construction of the yarns and the type of the fibre (hydrophobic, hydrophilic, blended or not, fineness, length) and the viscosity of the heat transfer fluid.
The surface area of the capillary voids (tubes) of the textile surface through which a liquid passes is larger than the surface area of the pipes of a conventional solar collector due to the fibrous character<'> of the textile structures. Therefore, the absorption of the solar radiation by the black or dark colored textile surfaces and the transfer of this energy to the heat transfer fluid in the hundreds of thousands pores (capillaries) between the fibers can occur with a higher efficiency.
The combination of this type of solar collector with a liquid/liquid heat exchanger can be used to obtain running hot water or to heat the furnace water; and if it is combined with a liquid/gas heat exchanger it can be used for space heating, for drying purposes and for heating the inlet air of the fuel burners.
TEXTILE BASED AIR HEATER SOLAR COLLECTOR
US2011297144
In the active type textile based air heater solar collector, as solar energy absorber plate a black single layered homogenous non woven textile surface (fabric) has been used instead of black metallic, ceramic, plastic or composite plates, nets, mats, woven or knitted fabrics and passing of the air to be heated through this textile surface has been achieved. The movement of the air in the collector and the transportation to the space to be heated or drying medium is provided by a fan which is connected to output or input side of the collector. It is also possible to connect two fans both input and output sides of the collector.
BACKGROUND OF THE INVENTION
[0005] 1. Field of the Invention
[0006] This invention relates to textile based solar collector that ensures hot air production for heating or drying operations.
[0007] 2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
[0008] Fossil-based fuels are not renewable resources and therefore they will run out after a certain period of time. On the other hand, the global warming occurring by the greenhouse effect due to carbon dioxide emissions generated by the combustion of fossil-fuels has increased the importance of the alternative energy resources.
[0009] Solar energy has the easiest and most common available use in the renewable and clean energy sources such as hydroelectric, solar, wind, geothermal, etc.
[0010] Even the solar collectors that enable water heating already have a common use, the solar air heating for space heating and drying purposes are not widespread because of the lower efficiency of these types of solar collectors.
[0011] The conventional air heater solar energy collectors are based on a black-colored metallic, plastic, ceramic or composite absorber plate; placed inside a box in the form of a rectangular prism made of metallic, plastic or composite material. The back and side surfaces of the rectangular box are insulated and the upper surface (sun seeing surface) is covered with a normal or special glass, polycarbonate or other transparent layer.
[0012] The black absorber plate heated by the absorption of high-IR radiation of sun rays, heats the air to a limited extent in the box, in which a green house effect occurs. On the other hand, especially in case of moving air, this is the case in the air heater collectors; the actual heat transfer takes place by convection.
[0013] In the heating through convection, the amount of heat transfer rate is proportional to the surface area of heat transfer. Thus, the majority of the development works and granted patents regarding air heater solar collectors are intended to increase the contact surface area between the air and hot black absorber plate. The heat transfer efficiency is aimed to be increased by several constructions by providing the contact of the air with the both sides of the black plate, using finned absorber plates of one or both sides, perforated absorber plates or special black absorber plates with rough surface structures, creating a meander type passing route for the air to extend the contact path with the hot plate, placing of metallic networks between the transparent layer and the black plate, etc.
BRIEF SUMMARY OF THE INVENTION
[0014] The purpose of the invention is to increase the heat transfer rate from the black absorber plate to the air to be heated.
[0015] The convection heat transfer equation is:
[0000] [mathematical formula][mathematical formula]
[0000] where,
[0016] Q is the heat transfer rate,
[0017] A the surface area participating to the heat transfer (m<2>),
[0018] a the heat transfer coefficient (W/m<2>K),
[0019] Tp the temperature of the black absorber plate (K),
[0020] Tathe temperature of the air to be heated (K),
[0021] ? the thermal conductivity at the boundary layer (W/mK) and
[0022] h the thickness of the boundary layer.
[0023] The surface area of the heat transfer is equal to the surface area of the absorber plate, in case of an air flow parallel to one face of the hot plate. On the other hand, when the air flows by contacting both faces of the plate the heat transfer area doubles.
[0024] In case of laminar flow parallel to the surface of the black plate, none of the air flow elements are perpendicular to the surface of the plate, and therefore, the air boundary layer (h) to be overcome by convection reaches the maximum thickness and the heat transfer coefficient (a) is less than 50 W/m<2>K. Hence, as aforementioned in the “background of the invention” section, a number of constructions were developed and patented to increase the heat transfer surface area (A) and to reduce the thickness of boundary layer (h), but none of them could provide the optimum heat transfer rate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] To reach the objective of the invention, textile based air heater solar collector have been schematized in the attached figures, and these figures present the following:
[0026] FIG. 1—The front view of the textile based air heater solar collector
[0027] FIG. 2—The side view of the textile based air heater solar collector
[0028] The units in the figures have been numbered and shown below:
[0029] 1) Collector outer body
[0030] 2) Surface of the collector insulation
[0031] 3) Transparent surface
[0032] 4) Cold air inlet
[0033] 5) Hot air outlet
[0034] 6) Non-woven fabric
[0035] 7) Fabric support
[0036] 8) Collector insulation
DETAILED DESCRIPTION OF THE INVENTION
[0037] In this invention, as solar energy absorber plate a black single layered homogenous non woven textile surface (fabric, felt) (6) has been used on an active type air heater solar collector instead of black metallic, ceramic, plastic or composite plates, and passing of the air to be heated through this non-woven textile surface has been maintained. The movement of the air in the collector and the transportation to the space to be heated or drying medium is provided by a fan which is connected to output or input side of the collector. It is also possible to connect two fans both input and output of the collector.
[0038] In case of passing of the air through the black non-woven textile fabric, the air passes through the capillary pores between the fibers, thus the surface area participating to the heat transfer is equal to the total area of the fiber surfaces, namely, much higher compared to the plates with no air permeability or non fibrous air permeable plates. As the air passes through the capillary pores between the fibers instead of a parallel flow to the fabric surface, the thickness of the air boundary layer (h) on the fibers decreases to a minimum, and the heat transfer coefficient (a) exceeds the value of 400 W/m<2>K.
[0039] Warm-up time of the fabrics is a good proof of the increase in the heat transfer rate due to the air flow through the non-woven fabrics. The time required to heat a dry non-woven fabric up to 200° C. by a hot air of 200° C. is longer than 60 s for air flow parallel to the surface of the fabric, and 1 s to 3 s for the airflow through the fabric. During the hot air flow through the non-woven fabric, the heat transfer rate (Q) depends on the temperature and velocity of the air flow and the structure and the temperature of the non-woven fabric.
[0040] Black or dark colored, woven, knitted or non-woven fabrics made by natural, regenerated or synthetic fibers and their blends can be used as absorber plates. The heat transfer rate is lower in loose woven and knitted fabrics, because air tends to flow through the pores between the yarns, instead of the capillary pores between the fibers within the yarns. On the other hand the fabrics with very tight structures require higher fan power for air flow through the textile structures. In order to extend the flow path of the air through the fabric, increasing of fabric thickness is useful. However, airflow through a tight and thick woven fabric without piles requires very high fan power. Thus, the optimum results can be provided with single layered, not tight, homogenous, bulky non-woven structures.
[0041] The fabric is placed diagonally into the rectangular prism-shaped box (1). At the entry side of the collector fabric is placed to the base (2) and is diagonally ascended through the output side, where the fabric contacts with the transparent surface (3) in order to enhance the airflow through the hot fabric (6) in the collector box.
[0042] The collectors are mounted on the roofs facing to the south or placed on the south-facing walls. The cold air inlet (4) to the collector is above the non-woven fabric (6), and the hot air outlet (5) stays under the fabric (6). The air enters at the bottom side of the collector, where the distance (volume) between the fabric (6) and the transparent surface (3) is at maximum. By the blowing (if the fan is located to the air inlet) or suction (if the fan is placed to the air outlet) effect of the fan, the air tends to flow to the exit, and due to the decrease of the distance between the fabric (6) and the transparent surface (3) during the movement of the air, the pressure and therefore the flow rate of the air through the fabric increases according to the law of Boyle-Marriott. On this account, by the diagonal placement of the fabric, the air heated by the greenhouse effect between the transparent surface (3) and the non-woven fabric (6) passes through the hot fabric and enters the exit section between the base (2) and fabric (6). This permeation is higher at the upper side of the collector (close to the air outlet), where the air and the fabric have maximum temperature.
[0043] Utilization and applicability of the invention:
[0044] Textile based air heater solar collectors can be used anywhere and in the same way for space heating and drying operations, in which the currently available active type solar collectors are used.
COMBINATION OF PHOTOVOLTAIC (PV) CELLS AND TEXTILE - BASED AIR HEATER SOLAR COLLECTOR (PV-T)
WO2012026901
In this PV-T collector/panel which is a combination of photovoltaic (PV) cells and Textile - Based Air Heater Solar Collectors (our patent application with no TR 2009 00196), at the inlet side of the collectors at the area close to the floor photovoltaic cells (9) are placed instead of some part of the textile surface (fabric, felt) (6). At the inlet part of the upper compartment of the collector, the compartment between the transparent upper layer (3) / the textile surface (6), the temperature of the air increases due to cooling of the photovoltaic cells and due to the greenhouse effect in the collector box. As this warm air passes through the hot textile surface (fabric) to the textile surface (6) / floor (2) lower compartment, due to diagonally placement of the photovoltaic cells and of the textile surface (fabric), its temperature increases even more.; Because in the hybrid (PV-T) collectors according to the invention, both the cooling of the photovoltaic cells and therefore increasing the efficiency of theirs as high as 10-20%, and hot air at higher temperatures (= 50 DEG C) with high flow rate can be obtained, the total (electrical + heat) energy efficiency of these hybrid (PV-T) panels / collectors exceeds 80%.
DESCRIPTION
Technical Field
This invention relates to the special hybrid (PV-T) solar energy panels/collectors that provide generation of both electrical energy and hot air with high efficiency thanks to the combination of textile-based air heater solar collectors with photovoltaic (PV) cells.
The Prior Art in the Field of Hybrid (PV-T) Solar Energy Panels
The photovoltaic solar panels on the market convert as much as 10-20% of the solar energy falling on them into electrical energy, while the vast majority of the remaining is lost as transformed into heat. Therefore, it is beneficial to cool the photovoltaic (PV) panels. Thanks to the cooling, electrical energy yield of crystalline silicon cells increase as much as 0,5% / °C, while the yield of amorphous cells on the other hand increase as much as 0,15-0,20% / °C . Given the fact that the temperature of PV cells easily reaches 50 - 70°C even on a sunny day in Spring, it is possible to generate 15-25% more electrical energy in case temperature can be kept at 25°C by cooling.
The cooling process is usually performed with water or air or when worked in combination with a heat pump with the pump's cooling gas (liquid). There are patents and commercial products about hybrid (PV-T) solar panels wherein the cooling water or air is used as warm-hot water or warm-hot air.
The Technical Problems the Invention Aims To Solve
In cooling that is performed by using air, flow rate of the cooling air must be kept high to cool PV cells sufficiently, because as the air moves touching the upper or lower or both surfaces of the PV cells, the heat transfer yield from PV cells to the air is low. On the other hand when the cooling is executed with high air flow rates the temperature of air leaving the panel remains generally below 50°C. Purpose of this invention is to heat the air to higher temperatures (= 50°C), while its flow rate is high enough to cool PV cells sufficiently and therefore to increase the total (electrical + heat) energy output of the hybrid panel / collector. Description of the Invention
Within the framework of this invention, a 'Textile-Based Air Heater Solar Collector' which is explained in our patent application titled with no TR 2009/00196, is combined with photovoltaic cells. "Textile-Based Air Heater Solar Collectors' contain an absorber plate; a black or dark coloured textile surface (fabric, felt) which is placed into a rectangular prism box. The back and the lateral surfaces of the collector's boxes which are made of metallic, plastic or composite materials are insulated, and the upper surface facing the sun is coated with an ordinary or special glass or a polycarbonate or similar transparent layers. The air to be heated is passed through the textile surface (fabric) and the movement of the air both inside the collector and its transfer to the place to be warmed up or to a drying chamber is provided by a fan of which the suction side is connected to the outlet of the collector or the blowing side is connected to the inlet of the collector. It is possible to connect two fans to the outlet and to the inlet of the collector.
To support the passage of the warm air which is heated due to the greenhouse effect in the upper compartment of the collector box through the hot textile surface (fabric) (6), the textile surface (fabric, felt) is placed diagonally into the rectangular prism shaped collector box (1 ), raising from the floor (2) at the inlet side towards the transparent ceiling (3) at the outlet side, and the opening of the cold air inlet (4) is placed in the upper compartment over the textile surface, while the opening of the hot air outlet (5) on the other hand is placed in the lower compartment below the textile surface. In the 'Combination Of Photovoltaic (PV) Cells And Textile - Based Air Heater Solar Collector' patent application of which has been made, photovoltaic cells (9) are placed instead of some part of the textile surface (fabric), remaining in the area close to the floor on the inlet side, used in the textile - based air heater solar collectors. The "Combination of Photovoltaic (PV) Cells and Textile - Based Air Heater Solar Collector PV-T' has been realised to reach the purpose of the invention is depicted in the figures attached. Of these figures: Figure-1 is a front view of the hybrid (PV-T) panel / collector which is a combination of photovoltaic (PV) cells and textile - based air heater solar collector.
Figure-2 is an AB-Cross-sectional view of the hybrid (PV-T) panel / collector which is a combination of photovoltaic (PV) cells and textile - based air heater solar collector. The components in the figures are described below:
1 ) Collector (box) outer casing
2) Insulating layer surface
3) Transparent upper surface
4) Cold air inlet
5) Hot air outlet
6) Textile surface (fabric, felt)
7) Textile surface supporter
8) Collector insulation
9) Photovoltaic (PV) cells
The openings of the cold air inlets (4) in the lower part of the collectors mounted as inclined towards the south are placed above the photovoltaic cells (9) and the openings of the hot air outlets (5) in the upper part of the collectors are placed below the textile surfaces (6). The air enters the collector in the lower part of the collector at the point (4) where the distance (volume) between the photovoltaic cells (9) in the lower part and the transparent upper surface (3) is maximum and begins to move within the collector towards the outlet (upward) due to the blowing effect of the fan if it is placed at the inlet, or due to the suction effect if it is placed at the outlet. As the air moves towards the outlet (upward) by contacting with the upper and/or lower surfaces of the photovoltaic cells (9) the pressure and therefore the passage through the textile surface (6) increases according to the Boyle-Mariotte gas law because the distance (volume) between the transparent upper surface (3) and first the photovoltaic cells (9), and subsequently the textile surface (6) decreases. At the inlet part of the upper compartment of the collector which is the compartment between the transparent upper layer (3) / the textile surface (6) the cold air cools the surfaces of the PV cells and warms up itself. Through this effect and the greenhouse effect warmed up air passes through the hot textile surface (fabric) (6) due to diagonally placement of the photovoltaic cells and especially of the textile surface (fabric) (6), mostly at the upper part of the collector, exactly at the area where the air and the textile surface are the hottest.
In conclusion, in the PV-T collectors according to the invention, with the same amount of the fan power used in the "textile - based air heater solar collector", both the cooling of the photovoltaic cells and therefore increasing the efficiency of theirs as high as 10-20%, and air at higher temperatures (> 50°C) with high flow rate can be obtained. Thus, total (electrical + heat) energy efficiencies of these hybrid (PV-T) panels/collectors are more than 80%. Utilisation and Applicability Opportunities of the Invention
Hybrid (PV-T) panels / collectors in form of a combination of photovoltaic (PV) cells and textile - based air heater solar collectors can be used anywhere that electrical energy and hot air are needed. As is known, hot air can be used for heating buildings, heating water, cooling buildings (in particular, in cooling according to desiccative - evaporative method) and in drying of both industrial products (textile, food, leather, ceramics, etc.) and of agricultural and forest products such as apricots, figs, grapes, red peppers, onions, tomatoes, apples, pistachio, tobacco, spices, herbal teas. One of the most important applicability areas of the hybrid panels / collectors according to the invention on the other hand is drying of the agricultural products in the fields where electricity is not supplied. The fans can be run by the electrical energy generated from the panels. Because the production and consumption (running of the fans) of the electrical energy are concurrent, if electrical energy is not also going to be used for some other purpose, the system can be run in that case without requiring electrical energy storage units (batteries).
