Solar heat supply is a method of heating a residential building, which is becoming more and more popular every day in many, mainly developed, countries of the world. The greatest successes in the field of solar thermal energy today can boast in the countries of Western and Central Europe. On the territory of the European Union for last decade there is an annual growth of the renewable energy industry by 10-12%. This level of development is a very significant indicator.
solar collector
One of the most obvious applications for solar energy is its use for heating water and air (as heat carriers). In climatic regions where cold weather prevails, for a comfortable stay of people, the calculation and organization of heating systems for each residential building is mandatory. They must have hot water supply for various needs, besides, the houses must be heated. Of course, the best option here would be to use a circuit where they work automated systems heat supply.
Large volumes of daily hot water supply during the production process require industrial enterprises... As an example, we can cite Australia, where almost 20 percent of all consumed energy is spent on heating a liquid heat carrier to a temperature not exceeding 100 o C. For this reason, in some of the developed countries of the West, and to a greater extent in Israel, North America, Japan and, of course, in Australia, the production of solar heating systems is expanding very quickly.
In the near future, the development of energy will undoubtedly be directed towards the use of solar radiation. Density solar radiation on the earth's surface is an average of 250 watts per square meter. And this despite the fact that to meet the economic needs of a person in the least industrialized regions, two watts per square meter are enough.
The advantageous difference between solar energy and other energy industries that use fossil fuel combustion is the environmental friendliness of the energy received. The operation of solar equipment does not entail the release of harmful emissions into the atmosphere.
Selection of equipment application scheme, passive and active systems
There are two schemes for using solar radiation as a heating system for a home. These are active and passive systems. Passive solar heating systems are those in which the element that directly absorbs solar radiation and generates heat from it is the structure of the house itself or its individual parts. These elements can serve as a fence, roof, individual parts of the building, built on the basis of a certain scheme. Passive systems do not use mechanical moving parts.
Active systems work on the basis of the opposite scheme of heating a house, they actively use mechanical devices (pumps, motors, when they are used, they also calculate the required power).
Passive systems are the simplest in design and less costly in financial terms when installing the circuit. Such heating schemes do not need to be installed additional devices for the absorption and subsequent distribution of solar radiation in the heating system of the house. The operation of such systems is based on the principle of direct heating of the living space directly through the light-transmitting walls located on the south side. An additional heating function is performed by the outer surfaces of the house fencing elements, which are equipped with a layer of transparent screens.
To start the process of converting solar radiation into thermal energy they use a system of structures based on the use of solar collectors with a transparent surface, where the main function is played by the "greenhouse effect", the ability of glass to retain thermal radiation is used, thereby increasing the temperature inside the room.
It should be noted that the use of only one of the types of systems may not be entirely justified. Often a careful calculation shows that it is possible to achieve significant reductions in heat loss and a building's energy requirements through integrated systems. General work both active and passive systems by combining positive qualities will give the maximum effect.
Typically, efficiency calculations show that the passive use of solar radiation will cover your home's heating needs by about 14-16 percent. Such a system will be an important part of the heat production process.
However, in spite of certain positive qualities of passive systems, the main possibilities for fully meeting the building's heat needs still require the use of active heating equipment... Systems whose function is directly absorption, accumulation and distribution of solar radiation.
Planning and calculation
Calculate the possibility of installing active heating systems using solar energy (crystalline solar cells, solar collectors), preferably at the stage of building design. But nevertheless, this moment is not obligatory, the installation of such a system is also possible on an already existing task, regardless of the year of its construction (the basis for success is the correct calculation of the entire scheme).
Installation of equipment is carried out on the south side of the house. This arrangement creates conditions for maximum absorption of incoming solar radiation in winter. Photocells that convert the energy of the sun and installed on a fixed structure are most effective when they are installed relative to the earth's surface at an angle equal to the geographical location of the heated building. The angle of inclination of the roof, the degree of turn of the house to the south - these are significant points that must be taken into account when calculating the entire heating scheme.
Solar cells and solar collectors should be installed as close as possible to the place of energy consumption. Remember that the closer you build the bathroom and kitchen, the less heat loss will be (in this option, you can do with one solar collector, which will heat both rooms). The main criterion for assessing the selection of the equipment you need is its efficiency.
Active solar heating systems are divided into the following groups according to the following criteria:
General economic data will serve as the main factor in choosing one of the types of equipment. A competent thermal calculation of the entire system will help you to determine correctly. The calculation must be performed, taking into account the indicators of each specific room, where the organization of solar heating and (or) hot water supply is planned. It is worth considering the location of the building, climatic natural conditions, the size of the cost of the displaced energy resource. Correct calculation and good choice heat supply organization schemes - pledge economic feasibility application of solar energy equipment.
Solar heating system
The most common heating scheme used is the installation of solar collectors, which provide for the function of accumulating absorbed energy in a special container - a battery.
To date, the most widespread are two-circuit heating schemes for residential premises, in which a forced circulation system of the coolant in the collector is installed. The principle of its operation is as follows. Hot water is supplied from the top point of the storage tank, the process occurs automatically according to the laws of physics. Cold running water is pumped into the lower part of the tank by pressure, this water displaces the heated water that collects in the upper part of the tank, which then enters the hot water supply system of the house to meet its household needs and heating needs.
For a single-family home, a storage tank with a capacity of 400 to 800 liters is usually installed. For heating the heat carrier of such volumes, depending on natural conditions it is required to correctly calculate the surface area of the solar collector. It is also necessary to justify the use of the equipment economically.
Standard set of equipment for mounting heating system on solar radiation the following:
System based on heat absorbing panels. Such panels are usually used during the new construction phase. For their installation, it is necessary to build a special structure called a hot roof. This means that the panels must be installed directly into the roof structure, while using the roofing elements as building blocks of the equipment body. Such an installation will reduce your costs for creating a heating system, however, it will require high-quality waterproofing of the joints of the devices and the roof. This method of installing equipment will require you to carefully design and plan all stages of work. It is necessary to solve many problems on piping, placing the storage tank, installing the pump, adjusting the slopes. Quite a lot of installation problems will have to be solved if the building is not turned to the south in the most successful way.
The whole project solar systems heating will be different from others in varying degrees. Only basic principles systems. Therefore, it is impossible to give an exact list of the necessary parts for the complete installation of the entire system, since during the installation process it may be necessary to use additional elements and materials.
In systems operating on the basis of a liquid heat carrier, they use plain water... Energy absorption takes place in flat solar collectors. Energy is accumulated in the storage tank and consumed as the need arises.
To transfer energy from the storage device to the building, a water-to-water or water-to-air heat exchanger is used. The hot water system is equipped with an additional tank called a preheating tank. Water is heated in it by solar radiation and then enters a conventional water heater. 
Such a system uses air as a heat carrier. Heating of the coolant is carried out in a flat solar collector, and then the heated air enters the heated room or into a special storage device, where the absorbed energy is accumulated in a special nozzle, which is heated by the incoming hot air. Thanks to this feature, the system continues to supply the home with warmth even at night when solar radiation is not available.
The basis of the operation of systems with natural circulation is the independent movement of the coolant. Under the influence of the rising temperature, it loses its density and therefore tends to the top of the device. The resulting pressure difference makes the equipment function.
Heating systems are divided as follows: into passive (see Ch. 5); active, which mostly use liquid solar collectors and storage tanks; combined.
Abroad wide use received air heating systems, where the structure of the building or a special stone filling under it are used as accumulators. In our country, the Physicotechnical Institute of the Academy of Sciences of the Uzbek SSR and TbilZNIIEP are working in this direction, however, the results of the work are clearly insufficient and debugged solutions have not been created, although air systems theoretically more efficient than liquid ones, in which the heating system itself is made of a low-temperature radiant panel or a high-temperature one with conventional heating devices. In our country, buildings with liquid systems have been developed by IVTAN, FTI AN UzSSR, TashZNIIEP, TbilZNIIEP, KievZNIIEP and dr. and in some cases they were erected.
A large amount of information on active solar heating systems is given in a book published in 1980. The following describes the developed KievZNIIEP, built and tested two individual residential buildings With autonomous systems solar heat supply: with a low-temperature radiant panel heating system (residential building in the village of Kolesnoye, Odessa region) and with a heat pump (residential building in the village of Bucuria, Moldavian SSR).
When developing a system solar heating residential building in the village. Wheeled, a number of changes were made to the architectural and construction part of the house (project UkrNIIPgrazhdanselskstroy) aimed at adapting it to the requirements of solar heat supply: efficient masonry with insulation for the outer walls and triple glazing of window openings were used; heating system coils are combined with interfloor ceilings; a basement is provided for placing equipment; additional insulation of the attic and heat recovery from the exhaust air were carried out.
In terms of architecture and layout, the house is made on two levels. On the first floor there is a front room, a common room, a bedroom, a kitchen, a bathroom and storage rooms, and on the second floor there are two bedrooms and a bathroom, an electric stove for cooking is provided. Solar heating equipment (excluding collectors) is located in the basement; Electric water heaters serve as a backup for the system, which allows for a single energy input into the building and improves the comfortable quality of housing.
Residential building solar heating system (fig. 4.1) consists From three circuits: heat-receiving circulation and heating and hot water supply circuits. The first of them includes solar water heaters, a coil-heat exchanger of a storage tank, a circulation pump and a pipe-in-pipe heat exchanger for the system to operate in the summer in natural circulation mode. The equipment is united by a system of pipelines with fittings, instrumentation and automation devices. A two-section coil heat exchanger with a surface area of 4.6 m2 for the coolant of the circulation circuit and a single-section heat exchanger with a surface area of 1.2 m2 for a hot water supply system are mounted in a storage tank with a capacity of 16 m3. The heat capacity of the tank with a water temperature of +45 ° C provides a three-day heat demand for a residential building. A pipe-in-pipe heat exchanger with a surface of 1.25 m2 is located under the ridge of the roof of the house.
The heating circuit consists of two sections connected in series: a radiant panel with flow heating panels, which ensure the operation of the system in the basic mode with a water temperature difference of 45 ... 35 ° С, and a vertical one-pipe section with "Comfort" type convectors, providing peak system loads heating with a water temperature difference of 75 ... 70 ° C. The pipe coils of the heating panels are embedded in the plaster-finishing layer of the hollow-core ceiling panels. Convectors are installed under windows. The circulation in the heating system is incentive. Peak water heating is carried out by a flowing electric water heater EPV-2 with a capacity of 10 kW; it also serves as a backup for the heating system.
The hot water supply circuit includes a heat exchanger built into the storage tank and a second instantaneous electric water heater as a closer and backup of the system.
During the heating period, the heat from the collectors is transferred by the heat carrier (45% aqueous solution of ethylene glycol) to the water in the storage tank, which is pumped into the heating panel coils, and then returns back to the storage tank.
The required air temperature in the house is maintained by the automatic regulator RRT-2 by turning on and off the electric water heater on the convector section of the heating system.
In summer, the system provides for the needs of hot water supply from a pipe-in-pipe heat exchanger with natural circulation of the coolant in the heat-receiving circuit. The transition to forced circulation is carried out using the electronic differential regulator RRT-2.
Solar heating system for a four-room residential building in the village. Bucuria of the Moldavian SSR was designed by the Moldgiprograzhdanselstroy Institute under the scientific supervision of KievZNIIEP.
Residential building - attic type. On the first floor there are a common room, a kitchen, a laundry room, a utility room, and on the second there are three bedrooms. A garage is located in the basement floor, as well as a storage room for a solar heating system. An outbuilding is blocked with the house, which includes a summer kitchen, shower, shed, inventory and workshop.
Autonomous solar heating system (Fig. 4.2) is a combined solar-heat pump unit designed to meet the needs of heating (estimated heat - house losses 11 kW) and hot water supply throughout the year. The lack of solar heat and heat from the compressor of the heat pump unit is covered by electric heating. The system consists of four circuits: heat-receiving circulation, circuits of a heat pump installation, heating and hot water supply.
The equipment of the heat-receiving circuit includes solar collectors, a pipe-in-pipe heat exchanger and a storage tank with a capacity of 16 m3 with a heat exchanger built into it with a surface area of 6 m2. Solar collectors designed by KievZNIIEP with double-layer glazing with a total area of 70 m2 are placed in a frame on the southern slope of the roof of the house at an angle of 55 ° to the horizon. 45 % water solution ethylene glycol. The heat exchanger is located under the ridge of the roof, and the rest of the equipment is located in basement Houses.
A compressor-condensing unit serves as a heat pump unit. refrigeration unit AK1-9 with a heating capacity of 11.5 kW and a power consumption of 4.5 kW. The working agent of the heat pump unit is Freon-12. Compressor - piston sealless, condenser and evaporator - shell-and-tube with water cooling.
The heating circuit equipment includes a circulation pump, heating devices of the "Comfort" type, an EPV-2 flow-through electric water heater as a closer and a backup. The hot water supply circuit equipment includes a capacitive (0.4 m3) STD-type water heater with a heat exchanger surface of 0.47 m2 and an end electric heater BAS-10 / M 4-04 with a capacity of 1 kW. Circulating pumps of all circuits - type TsVTs, sealless, vertical, low-noise, foundationless.
The system works as follows. The heat carrier transfers heat from the collectors to the water in the storage tank and freon in the heat pump evaporator. The vaporous freon, after being compressed in the compressor, condenses in the condenser, while heating the water in the heating system and tap water in the hot water supply system.
In the absence of solar radiation and the use of heat stored in the storage tank, the heat pump unit is turned off and the house is supplied with heat completely from electric water heaters (electric boilers). In winter, the heat pump unit is in operation only at a certain level negative temperatures outside air (not lower than - 7 ° С) in order to exclude freezing of water in the storage tank. In summer, the hot water supply system is provided with heat mainly with the natural circulation of the coolant through a pipe-in-pipe heat exchanger. As a result of the implementation of various operating modes, the combined solar-heat pump installation allows you to save heat about 40 GJ / year (the results of the operation of these installations are given in Chapter 8).
The combination of solar energy and heat pumps is reflected in the engineering equipment developed by TsNIIEP
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Rice. 4.3. Schematic diagram heat supply systems in Gelendzhik 1 - solar collector; 2 - reheating heat exchanger with coolant from the heat pump condenser loop; 3 - reheating heat exchanger with heat carrier from the heating network; 4 - condenser circuit pump; 5 - Heat pump; 6 - Evaporator circuit pump; 7 - heat exchanger for heating (cooling) water in the evaporator (condenser) circuit; 8 - Heat exchanger for heating the source (raw) water; 9 - hot water pump; 10 - Battery tanks; 11 - solar circuit heat exchanger; 12 - solar circuit pump |
Heat supply project for the hotel complex "Privetlivy Bereg" in Gelendzhik (fig. 4.3).
The basis of the solar heat pump installation is made up of flat solar collectors with a total area of 690 m2 and three serially produced refrigeration machines MKT 220-2-0 in heat pump mode. The estimated annual heat production is about 21,000 GJ, including the solar plant - 1,470 GJ.
The low-grade heat source for heat pumps is seawater. To ensure a corrosion-free and scale-free operation of the heating surfaces of collectors, pipelines and condensers, they are filled with softened and deaerated water from the heating network. In comparison with the traditional scheme of heat supply from a boiler house, the attraction of non-traditional heat sources is
Sun and sea water, saves about 500 tons conv. fuel / year.
Another typical example of the use of new energy sources is a project for heating a manor house with the help of
Solar heat pump installation. The project provides for a year-round full satisfaction of the heating and hot water supply needs of a mansard-type mansard house with a living area of 55 m2. The low-potential source of heat for the heat pump is the soil. Presumptive economic effect from the introduction of the system - at least 300 rubles. per apartment compared to the traditional option of heating from a solid fuel apparatus.
Building solar heating for a private house with your own hands is not such a difficult task as it seems to an uninformed layman. This will require the skills of a welder and materials available at any hardware store.
Full autonomy is the dream of every owner starting a private construction. But is solar energy really capable of heating a residential building, especially if the device for its accumulation is assembled in a garage?
Depending on the region, the solar flux can produce from 50 W / m2 on a cloudy day to 1400 W / m2 with a clear summer sky. With such indicators, even a primitive collector with low efficiency (45-50%) and an area of 15 sq. M. can produce about 7000-10000 kWh per year. And this is the saved 3 tons of firewood for a solid fuel boiler!
As it becomes clear, effective heating system solely using solar energy is quite problematic to implement. Indeed, in a gloomy winter season, solar radiation is extremely small, and place a collector with an area of 120 sq.m. on the site. will not always work.
So are solar collectors non-functional? Don't discount them in advance. So, with the help of such a storage device, you can do without a boiler in the summer - there will be enough power to provide a family with hot water. In winter, it will be possible to reduce energy costs by supplying already heated water from the solar collector to an electric boiler.
In addition, the solar collector will be an excellent companion to the heat pump in the house with low temperature heating(warm floors).
So, in winter, the heated coolant will be used in warm floors, and in summer the surplus heat can be sent to the geothermal circuit. This will reduce the power of the heat pump.
After all, geothermal heat is not renewed, so over time, an ever-increasing "cold bag" forms in the soil. For example, in a conventional geothermal circuit, at the beginning of the heating season, the temperature is +5 degrees, and at the end of -2C. When heated, the initial temperature rises to +15 C, and by the end of the heating season does not fall below + 2C.
For a self-confident master, it will not be difficult to assemble a heat collector. You can start with small device to provide hot water in the country, and in case of a successful experiment, proceed to the creation of a full-fledged solar station.
The simplest collector is flat. For his device you will need:
Assembling the solar collector is pretty simple:
For the full functioning of the collector, you will need a storage tank. It can be made from plastic barrel, insulated from the outside, in which a heat exchanger connected to a solar collector is laid in a spiral. The heated water inlet should be at the top and the cold water outlet at the bottom.
It is important to correctly position the tank and manifold. To ensure the natural circulation of water, the tank must be above the collector, and the pipes must have a constant slope.
If it was not possible to make friends with the welding machine, you can make a simple solar heater from what is at hand. For example, from cans. For this, holes are made in the bottom, the cans themselves are fastened to each other with a sealant, and they sit on it at the junctions with PVC pipes. They are painted black and fit into the frame under the glass in the same way as ordinary pipes.
Why not decorate your home with something useful instead of regular siding? For example, by making a solar heater on the south side of the entire wall.
This solution will allow to optimize heating costs in two directions at once - to reduce energy costs and significantly reduce heat loss due to additional insulation of the facade.
The device is simply outrageous and does not require special tools:
If this method also seems complicated, the video shows an option made of tin, polypropylene pipes and films. Much easier!
With the rise in energy prices, the use of alternative energy sources is becoming increasingly important. And since heating is the main item of expenses for many, then we are talking about heating in the first place: you have to pay practically all year round and considerable sums. If you want to save money, the first thing that comes to mind is solar heat: a powerful and completely free source of energy. And it's quite possible to use it. Moreover, the equipment is expensive, but several times cheaper than heat pumps... Let's talk in more detail about how the sun's energy can be used to heat a house.
If we talk about using solar energy for heating, then you need to keep in mind that there are two different devices for converting solar energy:
Both options have their own characteristics. Although you must immediately say which of them you choose, do not rush to give up the heating system that you have. The sun rises, of course, every morning, but not always enough light will fall on your solar cells. The smartest solution is to make a combined system. When there is enough energy from the sun, the second heat source will not work. With this you will protect yourself, and you will live in comfortable conditions, and save money.
If there is no desire or opportunity to install two systems, your solar heating should have at least a double power reserve. Then you can definitely say that you will have warmth in any case.
Benefits of using solar energy for heating:
Flaws:
Now let's take a closer look at each of the types of solar heating elements.
It is solar collectors that are used for solar heating. These installations use the heat of the sun to heat a heating fluid, which can then be used in a hot water heating system. The specificity is that a solar water heater for heating a house produces only a temperature of 45-60 ° C, and shows the highest efficiency at 35 ° C at the outlet. Therefore, such systems are recommended for use in tandem with warm water floors. If you do not want to give up radiators, either increase the number of sections (approximately two times) or warm up the coolant.
Solar collectors (flat and tubular) can be used to provide the house with warm water and for hot water heating.
Now about the types of solar collectors. Structurally, there are two modifications:
In each of the groups there are variations in both materials and design, but they have the same principle of operation: a coolant runs through the tubes, which heats up from the sun. But the designs are completely different.
These solar heating systems have simple design and therefore it is them that can, if desired, be made with your own hands. A solid bottom is fixed to the metal frame. A layer of thermal insulation is laid on top. Insulated to reduce losses and housing walls. Then comes the layer of adsorber - a material that absorbs solar radiation well, converting it into heat. This layer is usually black. Pipes are fixed on the adsorber through which the coolant flows. From above, this whole structure is closed with a transparent lid. The material for the cover can be tempered glass or one of the plastics (most often polycarbonate). In some models, the light-transmitting material of the cover can undergo a special treatment: to reduce the reflectivity, it is made not smooth, but slightly matte.
The pipes in a flat solar collector are usually arranged in a snake, there are two holes - an inlet and an outlet. One-pipe and two-pipe connection can be realized. This is as you like. But a pump is needed for normal heat exchange. A gravity system is also possible, but it will be very ineffective due to the low speed of movement of the coolant. It is this type of solar collector that is used for heating, although it can be used to efficiently heat water for hot water supply.
There is a variant of a gravity collector, but it is used mainly for heating water. This design is also called a plastic solar collector. These are two transparent plastic plates sealed to the body. Inside there is a labyrinth for the movement of water. Sometimes the bottom panel it can be painted black. There are two openings - inlet and outlet. The water is supplied inside, as it moves through the labyrinth, it is warmed by the sun, and comes out already warm. This scheme works well with a water tank and easily heats the hot water supply. It is a modern replacement for the conventional barrel mounted on summer soul... Moreover, it is a more effective replacement.
How efficient are solar collectors? Among all household solar installations today they show the best results: their efficiency is 72-75%. But not everything is so good:
Nevertheless, heating of a private house from the sun is often done with the help of these solar installations. Such installations are popular in southern countries with active radiation and positive temperatures in winter period... They are not suitable for our winters, but they show good results in the summer season.
This setting can be used to air heating Houses. Structurally, it is very similar to the plastic collector described above, but air circulates and heats up in it. Such devices are hung on the walls. They can work in two ways: if the solar air heater is hermetically sealed, air is taken from the room, heats up and returns to the same room.
There is another option. It combines heating with ventilation. There are holes in the outer casing of the air manifold. Through them, cold air enters the structure. Passing through the labyrinth, it heats up from the sun's rays, and then warmed up enters the room.
Such heating of the house will be more or less effective if the installation occupies the entire southern wall, and there will be no shadow on this wall.
Here, too, the coolant circulates through the pipes, but each of these heat exchange pipes is inserted into a glass flask. They all come together in a manifold, which is essentially a comb.
Scheme of a tubular collector (click to enlarge the picture)
Tubular collectors have two types of tubes: coaxial and feather. Coaxial - pipe in pipe - are nested one into the other and their edges are sealed. A rarefied airless environment is created between the two walls. Therefore, such tubes are also called vacuum tubes. Feather tubes are a regular tube that is sealed on one side. And they are called feathers because to increase heat transfer, an adsorber plate is inserted into them, which has curved edges and is somewhat reminiscent of a feather.
In addition, heat exchangers can be inserted into different housings. different types... The first are Heat-pipe thermal channels. This is a whole system for converting sunlight into thermal energy. Heat-pipe is hollow copper tube small diameter, soldered at one end. The second has a massive tip. The tube is filled with a substance with a low boiling point. When heated, the substance begins to boil, part of it turns into a gaseous state and rises up the tube. On the way from the heated tube walls, it heats up more and more. It gets to the top, where it stays for a while. During this time, the gas transfers part of the heat to the massive tip, gradually cools, condenses and settles down, where the process is repeated again.
The second way - U-type - is a traditional tube filled with a coolant. No news or surprises here. Everything is as usual: from one side the coolant enters, passing through the tube, heats up from the sunlight. Despite its simplicity, this type of heat exchanger is more efficient. But it is used less often. This is because solar water heaters of this type form a single whole. If one tube is damaged, the entire section has to be replaced.
Tubular collectors with the Heat-pipe system are more expensive, show less efficiency, but are used more often. And all because a damaged tube can be changed in a couple of minutes. Moreover, if a coaxial flask is used, then the tube can also be repaired. It is simply disassembled (the top cap is removed) and the damaged element (the heat channel or the bulb itself) is replaced with a serviceable one. Then the tube is inserted into place.
For southern regions with mild winters and a lot of sunny days a year the best way- flat collector. In this climate, it shows the highest productivity.
For regions with more severe climates, tubular collectors are suitable. Moreover, systems with Heat-pipe are more suitable for harsh winters: they heat even at night and even in cloudy weather, collecting most spectrum of solar radiation. They are not afraid of low temperatures, but the exact temperature range needs to be clarified: it depends on the substance in the heat channel.
These systems, if properly calculated, can be basic, but more often they simply save heating costs from another, paid source of energy.
Another auxiliary heating can be an air manifold. It can be made in the entire wall, and it is easy to do it yourself. It is perfect for heating a garage or summer cottage. Moreover, problems with insufficient heating may arise not in winter, as you expect, but in autumn. In frost and snow, the sun's energy is many times greater than in cloudy rainy weather.
Hearing the word "solar energy" we primarily think about batteries, which convert light into electricity. And this is done by special photoelectric converters. They are commercially available from a variety of semiconductors. Most often, we use silicon solar cells for domestic use. They have the lowest price and show a fairly decent performance: 20-25%.
Solar panels for a private house are common in some countries
It is possible to use solar panels directly for heating only if the boiler or other heater on electricity, you connect to this current source. Also, solar panels in conjunction with electric batteries can be integrated into the home's electricity supply system and thus reduce monthly bills for used electricity. In principle, it is quite realistic to fully meet the needs of the family from these attitudes. It just takes a lot of funds and space. On average, 120-150W can be obtained from a square meter of the panel. So count how many squares of the roof or adjoining territory should be occupied by such panels.
The feasibility of installing a solar heating system is questionable for many. The main reason is it's expensive and will never pay for itself. With the fact that it is expensive, we have to agree: the prices for the equipment are rather big. But no one is stopping you from starting small. For example, to assess the effectiveness and practicality of an idea, make a similar installation yourself. Costs are minimal, and you will have a first-hand idea. Then you will decide whether to deal with all this or not. Here's just the thing: all the negative messages from theorists. Not a single one was encountered from practitioners. There is an active search for ways to improve, rework, but no one said that the idea was useless. It says something.
Now that installing a solar heating system will never pay off. As long as the payback period
bridges in our country are large. It is comparable to the lifespan of solar collectors or batteries. But if we look at the dynamics of the growth of prices for all energy resources, we can assume that soon it will be reduced to quite acceptable terms.
Now, actually about how to make a system. First of all, you need to determine the need of your house and seven for heat and hot water. The general method for calculating a solar heating system is as follows:
In addition to determining the number of components of the solar system, it will be necessary to determine the volume of the tank in which it will accumulate hot water for DHW. This can be done easily by knowing your family's actual expense. If you have a DHW meter installed and you have data for several years, you can display the average daily consumption rate (average monthly consumption divided by the number of days). This is approximately the volume of the tank you need. But the tank needs to be taken with a margin of 20% or so. Just in case.
If there is no hot water supply or a meter, you can use the consumption rates. One person consumes on average 100-150 liters of water per day. Knowing how many people permanently live in the house, you will calculate the required volume of the tank: the rate is multiplied by the number of residents.
It must be said right away that the rational (in terms of payback) for central Russia is a solar heating system, which covers about 30% of the heat demand and fully supplies hot water. This is an average result: in some months heating will be provided by 70-80% by the solar system, and in some months (December-January) by only 10%. Again, a lot depends on the type solar panels and from the region of residence.
And it’s not just “north” or “south”. It's about the number of sunny days. For example, in very cold Chukotka, solar heating will be very effective: the sun is almost always shining there. In the much milder climate of England, with eternal fogs, its effectiveness is extremely low.
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Despite many critics who talk about the inefficiency of solar energy and too long a payback period, more and more people are switching to alternative sources at least partially. In addition to savings, many are attracted by independence from the state and its pricing policy. In order not to regret the money invested in vain, you can first conduct an experiment: make one of the solar installations with your own hands and decide for yourself how much it attracts you (or not).
