The main criterion of comfort in a private cottage or apartment is warm. In a cold house, even the most elegant atmosphere will not help create comfortable conditions. But that the temperature is optimal for living supported in the room not only in the summer, but in winter it will be necessary to install the heating system.

This can be done today easily, acquiring a gas, diesel or electric boiler as a heat source. But the problem is that the fuel for such equipment is expensive and not available in all settlements. What then to choose? Better decision There are alternative heat sources and in particular solar heating.

Device and principle of operation

What is such a system? First of all, it should be said that there are two options for solar heating. They assume the use of various both in a constructive plan and on the purpose of the elements:

• Collector;
• Photoelectric panel.

And if the equipment of the first type is intended for a purely to maintain a comfortable temperature, the solar panels for home heating can be used to produce electricity and heat. Their principle of operation is based on the transformation of the energy of the Sun and accumulating it in the batteries to then use for various needs.

We watch the video, all about this collector:

The use of the collector allows you to organize only the solar system heating for a private house, while the heat energy is used. Such a device acts as follows. The sun rays are heated by water, which is the coolant and enters the pipeline. The same system can be used as a hot water supply. The composition includes special photocells.

Collector device

But besides them, the solar heating is included:

• Special tank;
• Avankamers;
• The radiator made of tubes and enclosed in the box, in which the front wall is made of glass.

Solar panels for home heating are placed on the roof. In it, the water heats up moves into the avank meter where it is replaced by a hot heat carrier. This allows you to maintain constant dynamic pressure in the system.

Types of heating using alternative sources

The easiest way to transform energy shone to heat is use solar batteries For heating at home. They are increasingly used as additional sources of energy. But what are these devices and are they really effective?

We watch video, types and their features of the work:

The task set on the roof of the solar heating system for home to absorb as much as possible solar radiationBy converting it then to the so-called energy. But it should be borne in mind that it can be turned into both thermal and electrical energy. To obtain heat and water heating, solar heating systems are used. Electrical current use special batteries. They accumulate energy during the daytime day and give it at night. However, today there are combined systems. In them, the solar panels produce warm and electricity at the same time.

As for solar water heaters for home heating, they are represented in the market with a wide range. And models can have various appointment, design, principle of operation, dimensions.

Various options

For example, in appearance And the design of a private house heating system is divided into:

1. Flat;
2. Tubular vacuum.

By destination, they are classified on those used for:

• Heating systems and DHW;
• To heat water in the pool.

There are differences and principle of work. Sunny heating using collectors is the perfect choice for dacha DomikovSince you do not require connection to the power grid. Models S. forced circulation Connect to K. general System Heating, in them circulation of the coolant is carried out using the pump.

We look at the video, compare the flat and tubular collector:

Not all collectors are suitable for solar heating country house. According to this criterion, they are divided into:

• Seasonal;
• Year-round.

The first are used for the heating of country buildings, the second in private households.

Compare with the usual heating system

If you compare this equipment with a gas or electric, then it has much more advantages. First of all it is fuel economy. Summer solar heating is able to fully provide people living in the house hot water. In autumn and spring, when there are few clear days, the equipment can be used to reduce the load on the standard boiler. As for the winter pore, usually at this time the efficiency of the reservoirs is very small.

We watch the video, the efficiency of collectors in winter:

But besides saving fuel, the use of solar battery equipment reduces the dependence on gas and electricity. To install solar heating, it is not necessary to obtain permission and install it will be able to anyone who has elementary knowledge in the plumbing.

We watch video, equipment selection criteria:

Another plus is a big duration of the collector. The guaranteed service life is at least 15 years, it means that for this period your utility payments will be minimal.

However, as with any device at the collector, there are some drawbacks:

• On the solar water heaters For a private house, the price is high enough;
• The impossibility of using as a single heat source;
• Installing a tank-drive is required.

There is another nuance. The efficiency of solar heating depends on the region. In the southern regions where the activity of the Sun is high, the equipment will have the largest efficiency. Therefore, it is most profitable to use such equipment in the south and less efficient it will be in the north.

Selection of a solar collector and its installation

Before entering the installation of equipment included in the heating system, it is necessary to study its capabilities. In order to find out how much heat will need to be heated at home, it is necessary to calculate its area. It is important to choose the right place to install the solar collector. It should be as high as possible throughout the day. Therefore, the equipment usually is installed on the southern part of the roof.

Performance mounting work It is better to entrust to those skilled in the art, because even a small error in the installation of the solar heating system will lead to a significant reduction in system efficiency. Only as proper installation He will last a sun collector until 25 years, and completely occupying himself for the first 3 years.

The main types of collectors and their characteristics

If the building for any reason is not suitable for installing the equipment, then you can place the panels on the adjacent structure, and the drive is put in the basement.

Benefits of solar heating

The nuances for which it is worth paying attention to when choosing this system was considered above. And if you did everything right, then your heating system on solar collectors will deliver you only to pleasant moments. Among her advantages should be noted:

• The possibility of year-round maintenance of the house with heat, with the possibility of adjusting the temperature;
• Complete autonomy from centralized utility networks and reduced financial expenses;
• Using solar energy to various needs;
• Long operational service life and rare emergencies.

The only thing that stops consumers from buying a solar system for the heating of a private house is the dependence of their work from the geography of residence. If your area has clear days a rarity, then the efficiency of the equipment will be minimal.

What is thermal solar collectors? Where you can use them - scope of application, application options, pros and cons of collectors, specificationsEfficiency. Is it possible to make yourself and how justified it. Application schemes and perspectives.

Purpose

Collector and solar battery two different devices. The battery uses the conversion of solar energy into electric, accumulating in batteries and used for household needs. Solar collectors, like a heat pump, are designed to collect and accumulate the environmentally friendly energy of the Sun, the transformation of which is used to heat water or heating. In an industrial scale began to be widely used solar heat power plantstransforming heat into electricity.

Device

Collectors consist of three main parts:

• panels;
• avankamers;
• cumulative tank.

The panels are presented in the form of a tubular radiator placed in a box with an outer wall of glass. They must be placed on any well-lit place. The panel radiator enters the liquid, which is then heated and moves to the avasterna, where cold water is replaced by hot, which creates a constant dynamic pressure in the system. In this case, the cold liquid enters the radiator, and the hot tank is hot.

Standard panels are easy to adapt to any conditions. With the help of special mounting profiles, they can be installed in parallel to each other in a row in an unlimited quantity. In aluminum mounting profiles, holes are drilled and attached to the panels from the bottom to bolts or rivets. After the operation of the solar absorber panel is completed, together with the mounting profiles, are a single rigid design.

System solar heat supply It is divided into two groups: with air and with liquid coolant. Collectors catch and absorb radiation, and, by making it transformation into thermal energyTransmitted to the accumulative element from which heat is distributed over the room. Any of systems can be complemented with auxiliary equipment ( circulation pump, pressure sensors, safety valves).

Principle of operation

In the daytime, thermal radiation is transmitted to the coolant (water or antifreeze) circulating through the collector. The heated coolant transmits energy to the water heater tank, located above it and collecting water for hot water supply. In a simple version, water circulation is carried out naturally due to the difference in density hot and cold water In the contour, and in order for the circulation to be stopped, a special pump is used. The circulation pump is designed for active water fluid pumping.


In the complicated version, the collector is included in a separate outline filled with water or antifreeze. The pump helps them begin to circulate, while transmitting stored solar energy into a heat-insulated tank battery, which allows you to store heat and take it if necessary. If the energy is not enough, the electrical or gas heater provided in the tank design, automatically turns on and maintains the required temperature.

Views

Those who want to be a solar heat supply system in his house, to begin with, decide on the most suitable type of collector.

Flat type collector

It is represented in the form of a box closed with tempered glass, and having a special layer absorbing solar heat. This layer is connected to the tubes for which the circulation of the coolant is conducted. The more energy it will receive, the higher its effectiveness. Reducing heat losses in the panel itself and ensuring the greatest heat absorption on the plates of the absorber allows maximum energy collection. In the absence of stagnation, flat collectors are able to heat water to 200 ° C. They are designed to heal water in pools, household needs and home heating.

Vacuum type collector

It is glass batteries (row of hollow tubes). The outer battery has a transparent surface, and the inner battery is covered with a special layer, which catches radiation. The vacuum layer between the internal and external batteries helps to preserve about 90% of the absorbed energy. Heat conductor are special tubes. When the panel is heated, the fluid is converted at the bottom of the battery to the pairs, which rises, betrays heat into the collector. This type of system has a larger efficiency compared to collectors. flat typeSince it can be used at low temperatures and in poor illumination conditions. The vacuum solar battery allows you to heat the temperature of the coolant to 300 ° C, when using a multilayer glass coating and creating in vacuum collectors.

Heat pump

Solar heat supply systems are most effectively working with such a device as a heat pump. Designed to collect energy from the environment, regardless of weather conditions and can be installed inside the house. Water, air or soil can act as an energy source here. The heat pump can work using only solar collectors if enough solar electricity. When using the combined system, the "heat pump and a solar collector" does not matter the type of collector, however suitable option There will be a solar vacuum battery.

What's better

The solar heat supply system can be installed on the roofs of any kind. Flat collectors are considered more durable and reliable, unlike vacuum, the design of which is more fragile. However, if the flat collector is damaged, you will have to replace the entire absorbent system, while only a damaged battery is subject to vacuum replacement.


The efficiency of the vacuum collector is much higher than flat. They can be used in winter time And they produce more energy in cloudy weather. The heat pump received quite large enough, despite its high cost. An indicator of energy generation in vacuum collectors depends on the values \u200b\u200bof the tubes. Normally, the size of the tubes should be in diameter 58 mm at a length of 1.2-2.1 meters. It is enough difficult to install the collector with your own hands. However, the possession of certain knowledge, as well as following detailed instructions On the installation and selection of the site, specified when buying equipment will significantly simplify the task and will help bring solar heat into the house.

Description:

Of particular importance in the design of the Olympic facilities in Sochi is the use of environmentally friendly renewable energy sources and primarily solar radiation energy. In this regard, the experience of developing and implementing passive solar heat supply systems in residential and public buildings in Liaoning Province (China), since the geographical location and climatic conditions This part of China is comparable with similar characteristics of Sochi.

The experience of the People's Republic of China

Zhao Jinlin, Cand. tehn Sciences, Dalian Polytechnic University (PRC), Intern of the Department of Industrial Heat and Power Systems,

A. Ya. Shelginsky, Doctor Tehn. Sciences, prof., Scientific Head, MEI (TU), Moscow

Of particular importance in the design of the Olympic facilities in Sochi is the use of environmentally friendly renewable energy sources and primarily solar radiation energy. In this regard, the experience of developing and implementing passive solar heat systems in residential and public buildings in Liaoning (China) province is interesting, since the geographical location and climatic conditions of this part of China are comparable with similar characteristics of Sochi.

The use of renewable energy sources (RES) for heat supply systems is relevant and very promising at present, subject to a competent approach to this issue, since traditional energy sources (oil, gas, etc.) are not limitless. In this regard, many countries, including the PRC, are transferred to the use of environmentally friendly renewable energy sources, one of which is the heat of solar radiation.

The possibility of efficient use of heat of solar radiation in the People's Republic of China depends on the region, since climatic conditions in different parts Countries are very different: from moderate continental (West and North) with hot summer and harsh winter, subtropical in the central regions of the country to the tropical monsoon on the southern coast and the islands, is caused by the geographic location of the territory on which the object is located (table).

In the province of Liaoning, the intensity of solar radiation ranges from 5,000 to 5,850 MJ / m 2 per year (in Sochi - about 5,000 MJ / m 2 per year), which allows you to actively apply the systems of heating and cooling buildings based on the use of solar radiation energy. Such systems that convert heat of solar radiation and outer air can be divided into active and passive.

In passive systems of solar heat supply (PST) used natural circulation Heated air (Fig. 1), i.e. gravitational forces.

In active systems of solar heat supply (Fig. 2), additional sources of energy are involved to ensure its operation (for example, electricity). The heat of the solar radiation enters the solar collectors, where it is partially accumulated and is transmitted to the intermediate coolant, which is transported by pumps and is distributed over the premises.

Systems with zero consumption of heat and cold are possible, where the corresponding air parameters in the premises are provided without additional energy consumption due to:

• necessary thermal insulation;
• choice structural materials buildings with appropriate heat transfer and accumulating properties;
• use in the system of additional heat transfer accumulators with the corresponding characteristics.

In fig. 3 presents an improved scheme of the passive heat supply system of the building with elements (curtains, valves), allowing more accurate to adjust the air temperature indoors. On the south side of the building, the so-called Tromba wall is installed, which consists of a massive wall (concrete, brick or stone) and a glass partition installed at a short distance from the wall with outside. The outer surface of the massive wall is painted in dark color. Through the glass partition heats up a massive wall and air located between a glass partition and a massive wall. The heated massive wall due to radiation and convective heat exchange transmits the accumulated heat into the room. Thus, in this design, the function of the collector and the heat battery are combined.

The air located in the layer between the glass partition and the wall, in the cold period of time and on a sunny day is used as a heat carrier for supplying heat into the room. To prevent heathotesters in environment In the cold period of time, at night and excess heat flow on sunny days, curtains are used, which significantly reduce heat exchange between the massive wall and an external environment.

Curtains are performed from nonwoven materials with silver coating. To ensure the necessary air circulation, air valves are used, which are located in the upper and lower parts of the massive wall. Automatic control The operation of air valves allows you to maintain the necessary heat transfer or heat pumps in the serviced room.

The system of passive solar heat supply works as follows:

1. In the cold period of time (heating):

• sunny day - curtains raised, valves are open (Fig. 3a). This leads to heat of a massive wall through a glass partition and heating the air in a layer between glass partition and wall. The heat enters the room from the heated wall and heated in the layer of air circulating through the layer and the room under the influence gravitational forcescaused by the difference in air densities at different temperatures (natural circulation);
• night, evening or cloudy day - curtains omitted, valves are closed (Fig. 3b). The heat pumps into the external environment are significantly reduced. The room temperature is maintained due to the receipt of heat from the massive wall that has accumulated this heat from solar radiation;

2. In the warm period of time (cooling):

• sunny day - curtains omitted, bottom valves are open, the tops are closed (Fig. 3B). Curtain protects the heating of a massive wall from solar radiation. The outer air enters the room from the shaded side of the house and goes through the layer between the glass partition and the wall into the environment;
• night, evening or cloudy day - curtains raised, the lower valves are open, the tops are closed (Fig. 3g). The outer air enters the room from the opposite side of the house and goes into the environment through the layer between the glass partition and the massive wall. The wall is cooled as a result of a convective heat exchange with air passing through the layer, and due to the outflow of heat by radiation to the environment. Chilled wall in the daytime supports the necessary temperature mode in room.

To calculate the systems of passive solar heating of buildings, mathematical models of non-stationary heat transfer were developed with natural convection to ensure the premises with the necessary temperature conditions depending on the thermophysical properties of the enclosure structures, the daily change of solar radiation and the outdoor temperature.

To determine the authenticity and clarification of the results obtained in the Dalian Polytechnic University, the experimental model of a residential building, located in Dalian, with passive solar heating systems was manufactured and investigated. The tombra wall is placed only on the southern facade, with automatic air valves and curtains (Fig. 3, photo).

When conducting an experiment, used:

• small meteorological station;
• devices for measuring the intensity of solar radiation;
• rHAT-301 anemograph to determine the air velocity;
• tR72-S thermometerography and thermocouples for measuring temperatures indoors.

Experimental studies were carried out in the warm, transitional and cold periods of the year under various meteorological conditions.

The algorithm for solving the task is shown in Fig. four.

The results of the experiment confirmed the accuracy of the calculated ratios and allowed to adjust certain dependencies taking into account specific boundary conditions.

Currently, in the province of Liaoning there are many houses and schools that use passive solar heating systems.

An analysis of passive solar heat supply systems shows that they are quite promising in individual climatic regions compared to other systems for the following reasons:

• cheapness;
• simplicity;
• reliability.

The disadvantages of passive solar heating systems include the fact that the parameters of the air indoor may differ from the required (calculated) when the outdoor air temperature changes beyond the limits taken in the calculations.

To achieve a good energy-saving effect in the heat supply systems of buildings with more accurate maintenance of temperature conditions in the given limits, the combined use of passive and active solar heat supply systems is advisable.

In this regard, further theoretical studies and experimental work on physical models are required, taking into account the previously obtained results.

Literature

1. Zhao Jinling, Chen Bin, Liu Jingjun, Wang Yongxun Dynamic Thermal Performance Simulation of An Improved Passive Solar House with Trombe Wall Ises Solar Word Congress, 2007, Beijing China, Vols 1-V: 2234-2237.

2. Zhao Jinling, Chen Bin, Chen Cuiying, Sun Yuanyuan Study On Dynamic Thermal Response of the Passive Solar Heating Systems. Journal of Harbin Institute of Technology (New Series). 2007. Vol. 14: 352-355.

The main share of the cost of content own house Associate on heating costs. Why not use the free energy of natural sources, for example, the sun, for the heating of the structure? After all, modern technologies allow it to implement it!

For energy accumulation sun ray Special solar panels installed on the roof of the house are used. After receiving, this energy is transformed into electrical energy, which is then divided by the power supply and is used, as in our case, in heating devices.

Compared to other sources of energy - standard, autonomous and alternative - the benefits of solar batteries is obvious:

• practically free use;
• independence from power companies;
• the amount of energy obtained is easily regulated by changing the number of solar panels in the system;
• long service life (about 25 years) solar cells;
• lack of systematic maintenance.

Of course, this technology has its own minuses:

• dependence on weather conditions;
• the presence of additional equipment, including bulky batteries;
• fairly high cost, which increases payback period;
• synchronization of the voltage of batteries with a voltage of the local substation requires the installation of special equipment.

Applying solar panels

Batteries converting solar energy are mounted directly on the surface of the roof of the house by connecting them to each other into the system of the required power. If the roof configuration or other structure features do not allow them to fasten them directly, then on the roof or even on the walls are installed frame blocks. Alternatively, installation of a system on separate racks in the house is possible.

Solar panels are generator electrical Energywhich is allocated in the process of photovoltaic reactions. The low efficiency of the chain elements with a total area of \u200b\u200b15-18 square meters. m However, it allows to damn the premises whose area exceeds 100 square meters. M! It is worth noting that modern technology Such equipment allows the use of sun energy even during periods of medium cloud.

In addition to installing solar panels, the implementation of the heating system requires the installation of additional elements:

• device for selecting electric batteries;
• primary converter;
• controllers for solar cells;
• batteries with their own controller, which offline will switch the system to the substation network in the event of a critical charge lack;
• device for converting a constant electrical current to variable.

The most optimal version of the heating system when used alternative source Energy - electrical system. This will warm up large rooms By installing conductive floors. Moreover, the electrical system allows you to flexibly change the temperature regime in the residential premises, and also eliminates the need to install threshold radiators and pipes under the windows.

IN perfect version Heating electrical system that uses solar energy must be additionally equipped with a thermostat and automatic temperature controls in all rooms.

Applying solar collectors

Solar collector-based heating systems allow you to heat not only residential buildings and cottages, but also whole hotel complexes and industrial facilities.

Such collectors, the principle of operation of which is based on the "greenhouse effect", accumulates solar energy to further use almost lossless. This allows you to carry out a number of possibilities:

• provide residential premises with full heating;
• establish the autonomous hot water supply mode;
• implement water heating in pools and saunas.

The operation of the solar collector is to convert the energy of solar radiation that falls into a closed space into thermal energy that is accumulated and is saved for a long time. The design of the collectors does not allow the saved energy to go out through the transparent installation. Central hydraulic system Heating uses the thermosphonic effect, due to which the heated liquid displaces the colder, forcing the latter to move to the heating site.

There are two implementations of the described technology:

• flat collector;
• vacuum collector.

The most common is a flat solar collector. Due to its simple design, it is successfully used for heating the premises of residential buildings and in domestic water supply systems. The device consists of a plate of an energy collector, mounted in a glazed panel.

The second type is a vacuum collector with a direct heat transfer - is a tank with water with the tubes installed at the angle to it, along which the heated water rises up, freeing the place for the cold liquid. Such natural convection causes uninterrupted circulation of the working fluid in a closed collector circuit and heat distribution through the heating system.

Another vacuum collector configuration is a design of closed copper tubes With a special fluid of low boiling point. Heating, this liquid evaporates, absorbing heat from metal tubes. The pairs raised upward are condensed with heat transfer transmission to the heat carrier - water in the heating system or the main element of the contour.

When implementing the home heating, through the use of solar energy, it is necessary to take into account the possible restructuring of the roof or walls of the building to obtain maximum effect. The project should take into account all factors: from the location and dimming of the structure to geographical weather indicators.

Doctor of Technical Sciences B.I. Kazanzhan
Moscow Energy Institute
(Technical University), Russia
Magazine Energy, №12, 2005.

1. Introduction.

The main reasons that prompted humanity to engage in large-scale industrial development of renewable energy sources are:
-climatic changes due to an increase in CO2 content in the atmosphere;
- the dependence of many developed countries, especially European, from the import of fuel;
- Restriction of organic fuel reserves on Earth.
The recent signing of the Kyoto Protocol by the majority of developed countries of the world has raised the agenda of the accelerated development of technologies to reduce CO2 emissions into the environment. The incentive for the development of these technologies is not only awareness of the threat of climate change and related economic losses, but also the fact that the quotas for greenhouse gas emissions have become a product that has quite real cost. One of the technologies to reduce organic fuel consumption and reduce CO2 emissions, is the production of low-precious heat for hot water, heating, air conditioning, technological and other needs due to solar energy. Currently, more than 40% of the primary energy spent by humanity falls on covering these needs, and it is in this sector that the technology of using solar energy is the most mature and economically acceptable for extensive practical use. For many countries, the use of solar heat supply systems is also a way to reduce the dependence of the economy from importing fossil fuels. This task is particularly relevant for the countries of the European Union, the economy of which is already 50% in terms of imports of fossil energy resources, and until 2020, this dependence may increase to 70%, which is the threat of economic independence of this region.

2. Scientific use of solar heat supply systems

The following statistics indicate the scale of the modern use of solar energy for the needs of heat supply.
The total area of \u200b\u200bsolar collectors installed in the EU countries by the end of 2004 reached 13960000 m2, and in the world exceeded 150000000 m2. The annual increase in the area of \u200b\u200bsolar collectors in Europe is 12%, and in individual countries it reaches a level of 20-30% or more. By the number of manifolds per thousand residents of the population, the world leader is Cyprus, where 90% of houses are equipped with solar installations (for a thousand inhabitants there are 615.7 m2 of solar collectors), Israel, Greece and Austria followed. The absolute leader in the area of \u200b\u200binstalled collectors in Europe is Germany - 47%, followed by Greece - 14%, Austria - 12%, Spain - 6%, Italy - 4%, France - 3%. European countries are indisputable leaders in the development of new technologies of solar heat systems, but China is strongly inferior in the volume of commissioning of new solar installations. Statistical data on the increase in the number of solar collectors in the world in 2004 give the following distribution: China - 78%, Europe - 9%, Turkey and Israel - 8%, the rest of the countries - 5%.
According to the expert assessment of ESTIF (European Solar Plant Industry Federation), technical and economic potential for the use of solar collectors in heat supply systems Only in EU countries is more than 1.4 billion m2 capable of producing more than 680,000 GWTH thermal energy per year. Plans for the near future provide installation in this region 100,0000 m2 collectors by 2010.

3. Solar collector - the key element of the solar heat supply system

Solar collector is the main component of any solar heat supply system. It is in it that there is a conversion of solar energy to heat. The efficiency of the entire system of solar heat supply and its economic indicators depends on its technical excellence and cost.
In heat supply systems, two types of solar collectors are used mainly: flat and vacuum.

A flat solar collector consists of a case, transparent fencing, absorber and thermal insulation (figure 1).

FIG. 1 Typical Flat Solar Collector Design

The housing is the main supporting structure,. Transmitted fencing passes sunny radiation Inside the manifold, protects the absorber from the exposure to the external environment and reduces heat losses With the front of the collector. The absorber absorbs solar radiation and on the tubes connected with its thermal surface transfers heat to heat carrier. Heat insulation Reduces thermal losses from the back and side surfaces of the collector.
The thermal surface of the absorber has a selective coating having a high absorption coefficient in the visible and neighboring infrared region sun spectrum and low radiation coefficient in the range of the appropriate collector operating temperatures. At the best modern reservoirs, the absorption coefficient is within 94-95%, the radiation coefficient is 3-8%, and the efficiency in the field of operating temperatures typical for heat supply systems exceeds 50% non-selective black coverage of the absorber in modern reservoirs is rarely used due to high emission losses . Figure 2 shows examples of modern flat collectors.

In vacuum collectors (Fig. 3), each element of the absorber is placed in a separate glass pipe, inside of which a vacuum is created, due to which the heat loss due to convection and thermal conductivity of air are supplied almost completely. Selective coating on the surface of the absorber allows you to minimize emission losses. As a result, the KPD of the vacuum collector is significantly higher than that of a flat collector, on and the cost of it is more comprehensive above.

but b.

Figure 2 Flat Solar Collectors

a) Firm Wagner, b) Firm Feron

but B.

Figure 3 Vacuum collector Visman
but) general formb) mounting scheme

3. Thermal schemes of solar heat supply systems

In world practice, small solar heat supply systems are most widely distributed. As a rule, such systems include solar collectors with a total area of \u200b\u200b2-8m2, the battery tank, the container which is determined by the area of \u200b\u200bused collectors, circulation pump or pumps (depending on the type of thermal circuit) and the other auxiliary equipment. IN small systems, the circulation of the coolant between the collector and the battery can be carried out without a pump, due to the natural convection (thermosifle principle). In this case, the battery should be located above the collector. The simplest type of such installations is a collector, a paired with a tank battery located on the top of the collector (Fig. 4). Systems of this type are usually used for the needs of hot water supply in small single-sided cottage houses.

Fig.4 Thermosi-and-diagonal solar heat supply system.

In fig. 5 shows an example of an active system bigger sizein which the battery tank is located below collectors and coolant circulation is carried out using a pump. Such systems are used for the needs and hot water supply and heating. As a rule, in active systems involved in the coverage of the heating load, it is envisaged to a duplicate heat source using electricity or gas .

Figure 5. Heat scheme Active Solar Hot Water Supply and Heating System

Relatively new phenomenon in the practice of using solar heat supply there are large systems that are able to provide the needs of hot water supply and heating of apartment buildings or entire residential neighborhoods. In such systems, either daily or seasonal heat accumulation is used.
Daily accumulation involves the ability to operate the system using accumulated heat for several days, seasonal - for several months.
For seasonal heat accumulation, large underground tanks, filled with water, in which all excess heat obtained from collectors during the summer are reset. Another seasonal accumulation option is to warm the soil using wells with pipes for which circulates hot watercoming from collectors.

Table 1. The main parameters of large solar systems with daily and seasonal heat accumulation in comparison with a small solar system for a single-family house are presented.