Solar collectors for home heating as an eco-energy source
Solar collectors for home heating as an alternative energy source
A large amount of solar radiation enters the earth’s surface every day, which is mostly not used. However, it is a free source of heat that can be converted into energy suitable for human needs. Solar collectors for home heating perfectly cope with this task. What is the principle of their operation, what are the differences between them and how effective they are, you can learn from this article.
Solar collectors are a profitable source of energy for home heating
What is a solar collector and the principle of its operation
A solar thermal collector is a technical device that is capable of converting solar energy into thermal energy. It is used to obtain hot water, which can later be used for various needs. The main difference between solar collectors and other variants of similar technology is the principle of changing the density of water during heating. Cold masses displace the heated water flow upward, so there is no need to use additional pumping equipment.
Diagram of the principle of operation of a solar thermal collector
The principle of operation of the device is as follows. Solar energy is absorbed in a receiving device, which can be used as copper or glass surfaces of dark or black color. Such materials are characterized by a good ability to absorb energy.
Solar water heaters are conveniently located on the roof, where there is a lot of space and where the maximum amount of sunlight falls. Here, such devices do not take up useful space and do not interfere with anyone. Next, the heat from the storage is transferred to the coolant tank. It can be water, antifreeze or other liquid that is used in the heating system.
In most cases, a mixture consisting of 40% glycol and 60% distilled water is used. The coolant, which is heated to a certain temperature, is supplied to the radiators through a pipeline system.
The direction of water movement in the system can change thanks to the mixer. Cooled and warm water constantly replace each other. This natural circulation occurs due to the expansion of warm water, which rises, displacing cold water into the heating tank.
A solar collector is a device for converting solar energy into thermal energy
This heating system must be equipped with a thermal insulation layer with a thickness of at least 25-30 cm, which will ensure its efficient and stable operation. As a storage tank for the coolant, it is better to use a rectangular tank. A duplicate heating element may be located here. It will automatically turn on when weather conditions are created that do not contribute to heating the coolant to the required temperature.
Advantages and disadvantages of solar collectors for water heating
In summer, solar collectors are able to fully provide the house with hot water. In the off-season, such an alternative heating system is able to reduce the load on the gas boiler, which will reduce gas consumption, while reducing financial costs.
Important! In winter, solar collectors work inefficiently, which is due to a small amount of solar radiation.
The collector acts as an additional source of free heat, which makes it possible to reduce dependence on gas. In the summer, no financial costs will be needed to get hot water.
A solar collector in the summer can provide the house with warm water
The installation of a solar collector does not require a permit. When choosing equipment, you should study in detail all the available information and consult with a knowledgeable seller. The installation of the system must be entrusted to a specialist or performed independently if there are certain skills and abilities in the field of plumbing. The average period of operation of the system is about 15 years. During this time, you can use free solar heat for your own needs.
The disadvantages of such a system include large financial costs that will need to be incurred when buying solar collectors. The average cost of one item is $500-1000. A system consisting of two collectors and assembled on a turnkey basis will cost between $ 2300-3000.
The intensity of solar energy differs in different periods of the year, so solar collectors cannot be used as the only source of heat. For the system to work, you will need a storage capacity, the purchase of which will entail an increase in the cost of equipping the water heating system from the sun.
Solar collectors for home heating: types of installations
According to the design, solar collectors can be flat or vacuum. The latter option is a more common type, which is characterized by ease of installation, high efficiency, and the ability to provide the necessary amount of heat to the entire house. A vacuum solar collector for home heating, the price of which exceeds the cost of a flat product, is represented by a complex design that can be used for full-fledged room heating and water heating in any season of the year.
According to the type of construction, solar collectors are vacuum and flat
There is a special type of installation called a collector-hub. It is a system of parabolic reflectors that are located on one curved surface, where sunlight is concentrated at certain points. To get the maximum effect, it is necessary to change the position of the device, which can be in two planes, following the movement of the sun.
Depending on the coolant, liquid and air structures are distinguished. In the first case, distilled water or antifreeze is used, and in the second – heated air.
According to the application of the coolant, passive and active systems are distinguished. In the first variant, the solar collector is used in conjunction with the storage tank. Such a system is acceptable for hot water supply and is not equipped with additional engineering elements. The active option involves the installation of a solar collector and other technical devices, such as a pump, storage tank, safety valves, additional devices for heating the coolant. Such a system can be used both for hot water supply and for home heating.
According to the type of use, collectors can be passive and active
The method of heat transfer can be indirect or direct. The first option assumes the presence of a storage tank in which the heat energy received by the outer circuit from solar radiation is transferred to the inner circuit circulating in heating and hot water systems. In direct-flow systems that are used for hot water supply, water circulation in the collector circuit occurs under the influence of temperature differences and due to the presence of additional elements in the form of valves and taps.
Classification of solar collectors for heating by the heating temperature of the coolant
Air or water solar collectors for home heating can be classified according to the degree of heating of its working organs and coolant. Depending on this criterion, low-, medium- and high-temperature installations are distinguished. Low-temperature variants are able to provide heating of the coolant up to 50 ° C. Such thermal collectors are used to heat water in showers in summer, in irrigation tanks, to create comfortable conditions in cool spring and autumn evenings.
Medium-temperature systems provide heating of the coolant up to 80 ° C. Such installations are used for heating rooms, for swimming pools. Solar collectors of this category are most advisable to install when arranging a private house. High-temperature systems are capable of heating the coolant to a temperature of 250-300 ° C. It is recommended to use such devices on an industrial scale. They are used for heating commercial buildings, production workshops and other technological premises.
High-temperature systems involve a complex process of conversion and transfer of thermal energy. The structures have impressive dimensions, requiring a lot of free space for their installation. The process of manufacturing the system is very time-consuming and costly, which is associated with the use of specialized equipment. You will not be able to perform this option yourself.
According to the heating temperature, collectors are classified into low-, medium- and high-temperature
Design features of a flat solar collector
The most popular option is, according to numerous reviews, a flat-type solar collector that can be made with your own hands. Such a system is effective for organizing hot water supply in the warm season. In winter, the efficiency of the device is very low.
The collector housing has a flat square or rectangular shape. It is made of metal or other material with a high coefficient of thermal conductivity. The product is covered with dark paint to improve the absorbent qualities.Inside the case there is a plate in which there is a coil made of a copper tube of small cross-section. The coolant is circulated through the tubes. To minimize heat loss, thermal insulation material is laid inside the housing.
To prevent debris from entering the device body, it is closed from above with a glass or polycarbonate lid, which can increase heating. For efficient operation of the collector, it must be periodically wiped from dirt and dust.
It is recommended to install a flat solar collector in the southern regions, where this option is characterized by the best price and efficiency indicators. Such a device is characterized by the ability to self-clean, high efficiency in the summer and low cost.
Flat solar collectors are the most popular
However, flat collectors are characterized by significant heat losses that arise due to the design features of the device. Such a system has a low efficiency in the spring and autumn period. The structure is characterized by high windage, which causes a risk of damage during operation of its elements.
Characteristics of a vacuum solar collector for home heating in winter
A vacuum solar collector is a rather complex device. The main working element is represented by an expensive light-absorbing bulb with a transparent surface in which the tube is located. The work is based on the principle of a thermos. The vacuum flask lets sunlight into the inner tube, where there is no air, which allows you to save up to 95% of the heat.
Useful advice! It is impractical to make a vacuum solar collector with your own hands, which is due to the specifics of the production technology.
The lower part of the inner vacuum tube for the solar collector is occupied by antifreeze, which turns into a gaseous state when heated. In its upper part, heat is transferred to a collector with a coolant. At the same time, the antifreeze cools and condenses, returning to its original state.
A vacuum solar collector is a complex device, so it costs quite a lot
The vacuum solar collector is characterized by a high efficiency value in poor light conditions and temperatures below -37 ° C. It was specially designed for northern latitudes and can function in the absence of direct solar radiation. For effective operation, the structure needs constant care, which consists in cleaning its surface from contamination.
Important! The collector must be mounted at a certain angle, as indicated in the installation instructions of the device.
The main disadvantage is the high cost of construction. If at least one tube fails, repair will be problematic, since all products are mounted sequentially.
Solar air collector for heating: product features
In air solar collectors, air is used as a heat carrier for heating. The device can be made in two versions: in the form of a flat corrugated or perforated panel or a system of metal pipes.
The principle of operation of a solar air collector for home heating
The simplest option is a flat absorber consisting of a panel and a tube with an inlet and outlet pipe. All elements are located in a box, the back and side walls of which are covered with thermal insulation. The panel is made of copper or aluminum and painted black. It is covered with a transparent protective surface made of glass, plastic or polycarbonate.
The air entering the panel is heated by contact with metal. The ribs on the surface of the product contribute to an increase in heat transfer. For maximum efficiency, the structure should be installed on the south side of the house, having performed high-quality insulation. The system can be organized with natural or forced circulation of the coolant. The latter option involves the installation of a fan.
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The principle of operation and distinctive features. Varieties of the device. How to make it yourself. Manufacturers and popular models.
The system with natural circulation is used extremely rarely, which is associated with the slow movement of air masses, resulting in significant heat loss. Solar Fox air solar collectors can function already at a temperature of 25 ° C, while the optimal value for a water solar system is 45 ° C. Such constructions can only be used for air heating of the house. Collectors are not able to heat water. The devices are characterized by low efficiency, have very impressive dimensions, but have a simple design, are easy to install and affordable.
Useful advice! To increase the efficiency of air solar systems, collectors can be built into the walls of the southern orientation at the construction stage of the house.
Solar air collectors can be flat or in the form of a system of pipes
The thermal conductivity of the air is significantly lower than these water indicators, which affects the efficient operation of the system. In order to avoid heat loss, all butt joints must be carefully insulated. Despite the existing disadvantages, the air solar collector copes well with the task of heating the air in the room with a temperature difference inside and outside of 15-17 ° C.
Requirements for materials for the manufacture of a homemade solar collector
For the manufacture of a solar collector frame for heating with their own hands, plywood, wooden beams, OSB plates or other similar options are used. As an alternative, you can use an aluminum or steel profile with inserts of similar materials, which will give the structure strength and reliability. However, such a case will have a high cost.
The materials must meet the requirements for structures that are located outdoors. Since the average period of operation of a solar collector is 20-30 years, it is necessary that the materials are characterized by high performance characteristics that will remain unchanged throughout the entire service life of the installation.
The wood for the housing must be treated with water-polymer compounds and coated with paint and varnish emulsions. The steel profile must be reliably protected from corrosion.
Plywood, OSB plates or timber are used for the manufacture of the collector frame
To make a heliostat absorber with their own hands, they use available improvised materials. The coil can be made of rigid PVC pipe with fittings, flexible HDPE pipe, bent copper or metal tube. The heat exchanger of an old refrigerator is suitable for the absorber. The element can also be made of aluminum cans or plastic bottles. The main selection criterion is the thermal conductivity of the material.
To prevent heat loss, the housing should be insulated from all sides. Mineral wool or foam is mainly used for these purposes. The foil version of the insulation has proven itself well, which will provide not only thermal insulation, but also reflection of the sun’s rays from the surface.
Important! In the foam insulation layer, it is necessary to make grooves for laying the coil.
The heat exchanger is closed with a protective surface, which can be used as tempered glass or monolithic polycarbonate. The material should have a grooved, not a smooth surface.
To prevent heat loss, the collector housing is insulated with mineral wool or foam
Making a flat solar collector with your own hands
At the first stage, the calculation of the solar collector for heating is performed, based on the area of the room. Its dimensions are also determined by the level of solar activity in a given region, the location of the house, and the characteristics of the terrain.
The collector housing is made of wood or glass. You can use old windows with glazing. Aluminum or copper tubes, rolled rubber hose, flat steel batteries are suitable for creating an absorber. You can create a collector from polypropylene pipes of black color.
Thermal insulation material in the form of foam or mineral wool is placed on the bottom of the housing. Next, the entire area is covered with a metal sheet made of thin steel or aluminum to enhance the effect of heat transfer.
The coil pipes are mounted on top, which are attached to the metal sheet with staples. Its ends are brought out. The surface of the structure is covered with impact-resistant tempered glass or transparent polycarbonate, leaving a gap of 10-15 cm for good heat exchange. The storage tank is protected by a heat-insulating material or painted black. A heating element is connected to it, from which the wiring of the pipes of the heating system of the house is carried out.
A flat-type solar collector can be made with your own hands
Important! All butt joints must be securely sealed.
Options for creating an air solar collector with your own hands
The production of a traditional air solar collector for heating a house with your own hands begins with the creation of a frame made of wooden boards. The back and end walls should be insulated with mineral wool. The case is fixed to the wall. All gaps must be insulated with mounting foam. On the sides, holes are made for pipes for the entry and exit of air masses. The outer elements are securely wrapped with thermal insulation material.
Perforated aluminum sheet metal is used as an absorber, which is characterized by high thermal conductivity and low cost. To increase the selective qualities, it is covered with black paint. A sheet of glass or polycarbonate is placed on top.
Important! The degree of heating is determined by the dimensions of the solar panel.
Water pipes can be used as an absorber for the air collector
The absorber can be made of rectangular water pipes, which are installed on an aluminum sheet and fixed to it with a mounting tape and screws. The back wall of the wooden case is insulated with mineral wool, and the sides are insulated with expanded polystyrene. The pipes are painted black and covered with a sheet of tempered glass or polycarbonate.
An even simpler design is made of profiled flooring. The frame is made of wooden bars. An exit hole is made in the bottom. Profiled flooring is laid on the beam with many holes throughout the entire area of the product, which will provide air flow.
A good solution is to build an air collector on the window. This is a fairly effective option that allows you to heat the room well. The frame is made of aluminum frames and is attached to the window in the form of a mosquito net. The back wall is made of aluminum sheet, in which holes are made in the lower (for cold air intake) and in the upper (for warm air removal) parts. The role of the absorber can also be performed by black foil, which is covered with a protective PVC film.
Solar collector for home heating: reviews and recommendations for choosing a device
When choosing a solar collector, some nuances should be taken into account. Flat models are more durable than other varieties. However, such structures are unsuitable for repair. A minor breakdown can disable the entire absorption system, which leads to the cost of purchasing a new one. You can save money by making a flat solar water heater with your own hands, heating the coolant at 30-40 ° C above the ambient temperature.
When choosing a collector, it should be taken into account that flat models are more durable, but not repairable.
Vacuum solar heating systems are very sensitive to external influences, more susceptible to damage, which is due to the fragility of hollow pipes. However, if one of the flasks fails, it can be replaced with a new one. This collector is much more efficient in winter than the flat version, since it provides heating in a wider range and is able to maintain the temperature for a long time.
The performance of the vacuum collector depends on the size of the tubes. The shorter they are, the less heat energy is generated. The best option is a system with several flasks 2 m long and 6 cm wide. To ensure effective thermogenesis, a straight or U-shaped insert should be located in the inner part of the bulb.
The air variants have a simple design, rarely need repair, and are able to withstand very low temperatures. Their service life exceeds the period of operation of other systems. However, they heat the room weakly.
Useful advice! Before purchasing the system, it is necessary to perform the calculation of the solar collector with the participation of a qualified specialist in this field of activity.
Vacuum collectors provide heating in a wider range than flat ones
It is important to choose the right place to install the system. The solar water heater with your own hands must be placed on the south side or with a deviation of 30 ° from it. Measures should be provided for the removal of precipitation in winter. The device can be positioned vertically, which will eliminate the problems associated with cleaning the collector from snow. However, this situation will negatively affect the efficiency of the heater.
The sequence of installation of solar system for heating from the sun
After buying or making a solar collector for home heating with your own hands, you can start installing it.
Installation begins with the installation of a storage tank with a capacity of 20-40 liters. You can also use several small tanks that are connected in a sequential chain using pipes. The tank should be insulated to avoid rapid loss of thermal energy. The storage capacity is located at the highest point. At the same time, it should be borne in mind that when filling the system with liquid, the structure will have a significant weight, which will require strengthening the overlap at its location.
Next, the installation of a solar collector for heating water is carried out with your own hands, which is located on the south side of the building at an angle relative to the horizon line of 35-45 °. Then the system is tied with pipes, which is necessary to obtain a closed hydraulic circuit. For this purpose, inch or half-inch elements are used. Smaller diameter parts are used to organize the pressure part of the system. Pipes should be insulated, which will reduce the likelihood of heat loss.
In order for the collector to work efficiently, it is necessary to assemble and install the structure correctly
Important! The effective operation of the heating collector depends on the tightness of all connection nodes.
Upon completion of the installation, the system is tested. Its filling takes place through a branch pipe in the lower part of the collector, which will eliminate the possibility of air jams. The coolant enters the storage tank until the optimum level is reached, which is regulated by a float valve. The heated liquid will rise in the ante-chamber and enter the heating system. Natural circulation occurs until the temperature of the liquid entering the radiator and that coming out of the collector is equalized.
When arranging the hydraulic system, the installation of shut-off valves is provided, which prevents the reverse circulation of the coolant into the storage tank from the collector. This phenomenon occurs when the ambient temperature decreases, which is typical for the evening or night time of the day.
Domestic manufacturers of solar collectors for home
A popular manufacturer of solar collectors is the company Novy Polyus, which offers a wide range of models at affordable prices. A special place is occupied by flat devices made of aluminum. The coolant circulates through copper tubes equipped with double insulation protection, which ensures efficient operation of the system at low temperatures.
The domestic company Novy Polyus offers a wide range of collectors
Home heating equipment can be purchased complete with a storage tank, a temperature controller and a circulation pump. The average price of a solar collector will be 20-22 thousand rubles.
Another successful manufacturer of solar energy to thermal converters is the company Altenergy, which produces flat and vacuum collectors. The first version of the products can be supplied together with a boiler with a volume of 200-500 liters, which operates on the principle of indirect heating. Vacuum collectors are equipped with storage tanks for 100-1000 liters and circulation pumps.
Important! Products from the company Altenergy are certified in Germany.
A flat device will cost about 13 thousand rubles. The price of a vacuum solar collector will be 35-50 thousand rubles.
A flat solar collector from Altenergy will cost about 13 thousand rubles
The domestic manufacturer ANDI Group specializes in the manufacture of vacuum type collectors. The main feature of the product is their ability to adapt to difficult weather conditions. Collectors are able to convert energy even on cloudy days. Each bulb has a three-layer coating, which ensures maximum absorption of solar radiation. You can buy a solar collector for an average of 25-35 thousand rubles.
The NPO Mashinostroeniya company produces a number of solar collectors that differ in simple modification, functionality and affordable cost. The latest technologies are used in the manufacture of products. A distinctive feature of collectors is the presence of a multilayer absorber, which is applied to the absorber by magnetic spraying. This layer contributes to the maximum capture and retention of solar energy, so that the efficiency of the devices is 85-90%. You can buy a solar system for 15-20 thousand rubles.
Overview of popular models of solar collectors for heating
A popular model of a flat-type solar collector is the Sokol-Effect A product of domestic production. This installation can be used all year round. The panel size is 2.06 m2. The absorber is made of aluminum. Absorbs up to 95% of solar energy. Heat loss is 5%. The average capacity of the installation is 125 liters. The liquid can be heated up to 50 ° C. The price of a solar heating collector is 17 thousand rubles.
Another effective flat model is the FPC-2200 collector. The adsorber is represented by an aluminum panel, which is capable of absorbing up to 94% of solar radiation. The maximum installation pressure is 1 MPa. The active area of the panel is 2.1 m2. A solar collector is considered a high-temperature installation that heats the coolant to a temperature of 135 ° C. The cost of the device is 28 thousand rubles.
The Sokol-Effect A flat solar collector can absorb up to 95% of solar energy
The best vacuum solar collector is the HH-SCH-12 model. The device consists of 12 flasks with a length of 1.8 m and a diameter of 5.8 cm. The collector efficiency is 92%. The working area of the installation is 1.5 m2. Such a solar collector is considered an ideal solution for split systems. To increase productivity, several such devices can be combined sequentially. This model costs 27 thousand rubles.
The Solarventi SV3 model is popular among aerial solar collectors. Such a device can work offline. The collector is used for heating residential, warehouse and technical premises with an area of up to 25 m2. The complete air exchange cycle takes place within 2 hours. The efficiency of the system is 57%. The collector heats the coolant to 15 °C. Due to its light weight, which is 6 kg, the device can be fixed vertically to the wall. The cost of such a collector is 40 thousand rubles.
The solar collector is one of the most popular and affordable alternative heat sources for centralized hot water supply and home heating. Such a technical device can be purchased ready-made or made independently from improvised materials, which will save finances. You should choose a certain type of product after studying all the advantages and disadvantages of the design that need to be taken into account for a specific situation.
