Solar heating systems: analysis of technologies for arranging heating based on solar systems

Positive qualities and disadvantages

The main differences between closed heat supply networks and outdated open systems with natural circulation are the lack of contact with the atmosphere and the use of transfer pumps. This gives rise to a number of advantages:

• the required pipe diameters are reduced by 2-3 times;
• the slopes of the highways are made minimal, since they serve to drain water for the purpose of flushing or repair;
• the coolant is not lost by evaporation from an open tank, respectively, you can safely fill pipelines and batteries with antifreeze;
• ZSO is more economical in terms of heating efficiency and cost of materials;
• closed heating lends itself better to regulation and automation, can act in conjunction with solar collectors;
• forced flow of the coolant allows you to organize floor heating with pipes embedded inside the screed or in the furrows of the walls.

The gravitational (gravity-flowing) open system outperforms the ZSO in terms of energy independence - the latter is unable to operate normally without a circulation pump. Moment two: a closed network contains much less water and in case of overheating, for example, a TT boiler, there is a high probability of boiling and the formation of a vapor lock.

Boiler designs

When choosing a heating device, one should start first of all from the type of energy carrier

When considering this issue, you should pay attention to its cost and the possibility of its delivery.
The second most important factor influencing the choice of a boiler is the power of the equipment. It is generally accepted that for heating 10 sq.m. room area required 1 kW

room area required 1 kW

the area of ​​the room requires 1 kW.

When designing a country heating system, it is necessary to take into account the installation location of the boiler equipment. It is recommended to take it outside the house and place it in the annex. In any case, the specific installation conditions determine how the boiler is to be placed.

Consider options for heating equipment for a summer residence.

Oil boilers

Such units run on diesel fuel or waste oil. The latter option is more preferable, since the cost of fuel is significantly reduced. Liquid-fuel equipment is attracted not so much by its efficiency, but by the possibility of full automation of its operation.
The use of diesel fuel does not provide an opportunity to obtain cost savings. Fuel at low temperatures becomes more viscous, which prevents a stable combustion process. For such a boiler, the construction of a separate room is required, since its operation is accompanied by strong noise.

Oil boiler

Solid fuel boilers

Despite the fact that it is necessary to constantly replenish firewood, the cost of solid fuel is not comparable with liquid fuel, and even more so with electricity and gas. You can get savings by collecting deadwood in the nearest forest belt.

The disadvantage of this type of fuel is a quick burn-out, one bookmark is enough to operate the boiler for no more than six hours. The installation of pyrolysis boilers increases the duration of the equipment on one tab, but it is not advisable to use them for giving a small area.

The combustion temperature in solid fuel boilers cannot be regulated. There is only one way to influence the combustion process: to change the air supply with a damper. In addition, in order to store a supply of fuel, it is required to organize a room in a certain way.

Gas boilers

If there is a main gas pipeline nearby, gas equipment will be the optimal heating boiler. These units are characterized by reliability and efficiency, because the efficiency usually does not fall below 87%. Expensive condensing models have an efficiency of 97%. Gas heaters are compact, safe and have a good level of automation. Maintenance of this type of equipment is carried out once a year: all that is usually required is to check or change the settings.Budget gas boilers will cost an order of magnitude cheaper than solid fuel ones. The presence of a chimney in this case is also required.

Heating greenhouses with a solar air collector

Such a collector is the main element of this heating system. Depending on the location of this collector, heating can be carried out either by natural air circulation in the system or by fans.

In the first case, the outlet of the collector must be located below the socket of the inlet in the greenhouse. Then the air heated in the collector, according to the laws of convection, will rise through the duct and enter the greenhouse. The displaced cooled air through the return duct enters the collector, heats up and returns to the greenhouse. This cycle is continuous, lasting the entire daylight hours.

In the second case, the location of the solar collector does not matter, since the air circulation is maintained by fans installed in the greenhouse at the warm air inlet.

With this method, a uniform distribution of warm air masses throughout the heated volume is ensured, and, which is very important, uniform heating of the soil.

Naturally, air ducts (especially hot ones) must be covered with thermal insulation so that the air cannot cool down quickly. In the dark, the air in the greenhouse without hot make-up can cool quite quickly. Therefore, to maintain the thermal regime, it is necessary to provide a backup heating circuit. It can be fan heaters, heaters.

The air solar collector itself is an extremely simple design. You can assemble it yourself from improvised materials in less than an hour. This is a sealed wooden box with a height of 10 - 15 cm.The bottom is made from fiberboard. For strength, the side walls are connected with wooden blocks with a section of 5x5 centimeters.

A heat insulator is laid on the bottom - polystyrene foam or mineral wool. An absorber is placed on top of the heat-insulating layer, for example, galvanized iron sheet. To increase the heating area, additional ribs can be attached to this sheet.

All seams of the inner part of the box are carefully treated with Sealant, after which the box is covered from the inside with black heat-resistant paint. Depending on where and how the collector will be installed, pipes for air inlet and outlet are built into its sidewalls. After all the preparatory work, the box is closed with tempered glass, the joints of the glass with the body are sealed with "Sealant".

It remains to put the collector in place and connect it with air ducts to the greenhouse. In this case, the outlet pipe of the collector must be located above the inlet pipe. The dimensions of the collector are determined only by the dimensions of the metal sheet and glass. Depending on the size of the greenhouse, there may be several such collectors.

The air in such a collector warms up to a temperature of 45°C - 50°C. Heated air not only maintains a comfortable temperature for plants in the greenhouse, but, giving off its heat, also heats the soil, which creates the most favorable conditions for the development of the plant root system.

Solid fuel boilers

Solid fuel heat generators are presented in three varieties - direct combustion, pyrolysis and pellet.The popularity of this type of equipment is explained by the low cost of operation, since firewood and coal are an order of magnitude cheaper than other types of energy carriers. Natural gas in Russia stands apart here: however, if you calculate all the costs of connecting it, then the amount of money necessary for this is sometimes enough to purchase and install a heating boiler in a private house. That is why coal and wood boilers are so popular.

There is also a reverse side of the coin - such equipment functions like traditional stoves. It will take a lot of effort to harvest and load firewood. To ensure the durability and safety in the operation of a solid fuel boiler, its high-quality piping will be required. It's all about inertia, when even after closing the damper, water heating continues for some time. To achieve a good effect in the use of the received energy, it is necessary to install a heat accumulator.

For solid fuel boilers, high efficiency is rare: the average efficiency here is usually at the level of 75%. Pyrolysis and pellet models are slightly more efficient - 80-83%. The most comfortable equipment is considered to be on pellets, which is characterized by good automation and the almost complete absence of inertia. It does not require a heat accumulator and frequent fuel loads. The only drawback is the high cost of pellet boilers.

Two-pipe system

In a two-pipe heating scheme, the coolant is supplied to and removed from the battery through different pipes.This is more costly in terms of materials, but this small drawback is more than compensated by the uniform distribution of heat throughout the rooms and the wide possibilities of temperature regulation in individual rooms using thermostats and control devices.

In private homes, such a scheme is most often used with a lower wiring. For the most part, this is due to aesthetic reasons - the pipes can be partially hidden from view, and if prudently brought out into the floor even at the stage of building a house, the heating will be almost invisible.

This circumstance makes us close our eyes to the need for a circulation pump to maintain pressure, and manual venting of air from the pipes. In addition, bottom-connected batteries are much easier to install and maintain.

Ideal for heating a two-story house would be a scheme with an upper wiring. It differs from the previous one in that the coolant is distributed through pipes from the very top of the circuit - from an expansion tank installed on the top floor or attic.

The disadvantages include something for which many people sacrifice efficiency in favor of aesthetics - in order to hide pipes, you will have to sacrifice a useful amount of space, and in some cases this cannot be done at all. If the number of floors is high, a circulation pump may also be required.

There is also the most modern and at the same time the most expensive type of two-pipe scheme - the beam (collector). With this approach, each radiator is independent of the others, which provides ample scope for local temperature control.

This method makes it possible to connect underfloor heating.However, the need to supply pipes to each battery by means of supply and exhaust manifolds significantly increases the cost of such systems, which is their main drawback. Otherwise, many experts call such schemes the best.

Classification of water heating systems according to the principle of operation

According to the principle of operation, heating has natural and forced circulation of the coolant.

with natural circulation

Used to heat a small house. The coolant moves through the pipes due to natural convection.

Photo 1. Scheme of a water heating system with natural circulation. Pipes must be installed at a slight slope.

According to the laws of physics, a warm liquid rises. Water, heated in the boiler, rises, after which it descends through pipes to the last radiator in the system. Cooling down, the water enters the return pipe and returns to the boiler.

The use of systems operating with the help of natural circulation requires the creation of a slope - this simplifies the movement of the coolant. The length of the horizontal pipe cannot exceed 30 meters - the distance from the outermost radiator in the system to the boiler.

Such systems attract with their low cost, no additional equipment is required, they practically do not make noise when they work. The downside is that the pipes need a large diameter and should be laid as evenly as possible (there is almost no coolant pressure in them). It is impossible to heat a large building.

Forced circulation scheme

The scheme using the pump is more complicated. Here, in addition to heating batteries, a circulation pump is installed that moves the coolant through the heating system. It has higher pressure, so:

• It is possible to lay pipes with bends.
• It is easier to heat large buildings (even several floors).
• Suitable for small pipes.

Photo 2. Scheme of a heating system with forced circulation. A pump is used to move the coolant through the pipes.

Often these systems are made closed, which eliminates the ingress of air into the heaters and coolant - the presence of oxygen leads to metal corrosion. In such a system, closed expansion tanks are required, which are supplemented with safety valves and air vent devices. They will heat a house of any size and are more reliable in operation.

Mounting methods

For a small house consisting of 2-3 rooms, a single-pipe system is used. The coolant moves sequentially through all the batteries, reaches the last point and returns through the return pipe back to the boiler. Batteries connect from below. The downside is that the distant rooms warm up worse, as they receive a slightly cooled coolant.

Two-pipe systems are more perfect - a pipe is laid to the far radiator, and taps are made from it to the rest of the radiators. The coolant at the outlet of the radiators enters the return pipe and moves to the boiler. This scheme evenly heats all rooms and allows you to turn off unnecessary radiators, but the main disadvantage is the complexity of installation.

Collector heating

The main disadvantage of a one- and two-pipe system is the rapid cooling of the coolant; the collector connection system does not have this drawback.

Photo 3. Water collector heating system. A special distribution unit is used.

The main element and basis of collector heating is a special distribution unit, popularly called a comb.Special plumbing fittings necessary for the distribution of the coolant through separate lines and independent rings, a circulation pump, safety devices and an expansion tank.

The manifold assembly for a two-pipe heating system consists of 2 parts:

• Input - it is connected to a heating device, where it receives and distributes hot coolant along the circuits.
• Outlet - connected to the return pipes of the circuits, it is necessary to collect the cooled coolant and supply it to the boiler.

The main difference between the collector system is that any battery in the house is connected independently, which allows you to adjust the temperature of each or turn it off. Sometimes mixed wiring is used: several circuits are connected independently to the collector, but inside the circuit the batteries are connected in series.

The coolant delivers heat to the batteries with minimal losses, the efficiency of this system increases, which makes it possible to use a boiler of lower power and consume less fuel.

But the collector heating system is not without drawbacks, these include:

• Pipe consumption. You will need to spend 2-3 times more pipe than when connecting batteries in series.
• The need to install circulation pumps. Requires high pressure in the system.
• Energy dependence. Do not use where there may be power outages.

Varieties and equipment

Batteries are divided into large and small photovoltaic installations. For small batteries, the battery voltage ranges from 12 to 24 V .: this electricity is enough to operate a TV and lighting fixtures.A large installation will provide electricity and heat to a medium-sized house.

Equipment

The complete set for heating on standard solar panels includes:

• vacuum collector, the calculation of the power of which is repelled from the area of ​​\u200b\u200bthe house;
• tanks from 500 to 1000 liters for heating water (water heaters);
• a device that controls the process of work;
• heating element or heat pump;
• a pump that delivers the coolant from the collector to the storage tank.

Residential heating options

The well-known and most common way to heat your own house or apartment is to make a water system. Principle of operation: the coolant is heated by a boiler or other source, then it is transferred through pipes to heating devices - radiators, underfloor heating (abbreviated as TP) or baseboard heaters.

A heat exchanger placed inside the stove heats the water sent by the pump to the batteries

Now we list alternative heating options:

1. Furnace. A metal potbelly stove is being installed or a full-fledged brick oven is being built. If desired, a water circuit is built into the furnace or smoke channels of the stove (shown above in the photo).
2. Purely electric - convectors, infrared and oil heaters, spiral fan heaters. A more modern way is the installation of heating floors using resistive cables or a polymer film. The latter is called infrared, carbon.
3. Air. The heat source warms up the filtered outdoor air, which is forced into the rooms by a powerful fan. A simpler and cheaper option is the installation of gas convectors in residential premises.
4. Combined - wood-burning stove + electric heaters of any type.

Bathroom heating scheme with electric underfloor heating

To move on, you need to decide which type of heating is better - more profitable, more efficient, more convenient. We definitely recommend choosing a water system. The reasons:

• to heat water, you can use any energy carrier or combine several types of fuel by installing 2-3 boilers;
• with high requirements for interior design, piping is mounted in a hidden way, baseboard heaters or TP circuits are used instead of batteries;
• the ability to organize hot water supply (DHW) - install a double-circuit boiler or an indirect heating boiler (depending on the amount of water consumed);
• alternative energy sources can be connected to the system - solar collectors, heat pump;
• if necessary, heating in a private house is made completely autonomous - pipes are laid according to a gravity (gravitational) scheme, plus a boiler unit is installed that does not require connection to the mains;
• the system lends itself well to adjustment, automation and remote control via cellular communication or the Internet.

The only drawback of water networks is the cost of installation, equipment and valves. Purchase and connection of electric heaters will cost less, but the restriction in terms of fuel choice will increase operating costs.

The device in a country cottage of full-fledged air heating will cost even more than building a stove. It is necessary to purchase a ventilation unit with a heat exchanger, which plays the role of a blower, purifier and air heater. Then organize the supply and exhaust - to conduct air ducts to all rooms.The expert will tell about the pitfalls of air heating in the video:

Dimensions

Calculating the size of solar panels requires parameters such as the exact area of ​​​​the house and the monthly consumption of electricity from the family. So, an average family of 3 people spends about 250-450 kW when using household appliances. To this it is necessary to add water heating, depending on the volume of the tank.

To meet the cost of electricity per 1 person, a battery area of ​​1m2 is required, and to heat 10 m2 of floor space, 1 m2 of a solar panel is also needed. The calculation of battery irradiation should be carried out, focusing on 1000 kW / h per 1 m² per year. The electricity produced will be equal to the energy consumed by 100 liters of gas.

Solar collectors with an area of ​​5 m² are able to provide hot water to a medium-sized house. They produce electricity equal to approximately 2100 kWh per year.

It is not worth turning off the public heating completely - in the cold season, the solar heat feeds the batteries passively, you cannot rely on the weather. It is better to combine solar heating with another type: if the batteries cannot get the required amount of solar energy, then it can be easily replaced.

The choice of coolant

When studying the question of how the heating system in a private house is arranged, it is necessary to consider the coolant separately. Most often, filtered demineralized water is used for this. In order to avoid freezing in the case of periodic use of the system, special antifreeze additives are introduced into its composition - antifreezes. This involves replacing all rubber gaskets with fluoroplastic ones, which are more resistant to chemical attack.

It is also important to note that some boilers are not designed to heat non-freezing liquids.

Usually, the coolant is poured into the system directly from the water supply using a make-up valve and a check valve. In the course of this procedure, air is released through automatic air vents and Mayevsky manual taps. A manometer is used to control the pressure of closed systems; open systems need constant checking of the water level in the tank. If make-up runs out of the overflow pipe, it must be closed.

To pump antifreeze into a closed system, a special manual or automatic pump is used, which has a built-in pressure gauge. To ensure the continuity of the procedure, the liquid is prepared in advance in a special capacious tank, from which it is pumped into the pipe. To fill an open system with antifreeze, simply pour it into the expansion tank.

Do-it-yourself heating in a private house can be organized subject to strict adherence to all recommendations and the availability of appropriate skills. There is no need to rush, and after the work is completed, it is recommended to conduct a thorough testing.

Mounting

Heating installation from solar panels can be made with your own hands, but it is better to turn to specialists - solar panels are expensive, and its durability and efficiency depend on the correct installation.

The solar collector itself is placed on a well-lit side with a deviation from the south of a maximum of 30 ° to the east or west.The storage system can be installed in the basement of the house: it is disassembled into parts and mounted directly in the room where it is planned to be installed. Often the installation is mounted from several small drives.

In this case, it is better to choose a panel type of heating in combination with good home insulation.

Collector selection criteria

When choosing a collector, pay attention to the quality of solar panels, system components and the life of the absorber (surface exposed to sunlight).

The cost of a solar system depends on its performance, which is determined by the collector area, geographic latitude, time of year, and a number of other characteristics. The cheapest are Chinese, German panels are more expensive, but their service life is usually higher, and they can be recommended for important tasks, for example, year-round hot water supply.

An accurate calculation of the system should be done by an experienced specialist. Simplified, we can assume, for example, that a system with a collector with a usable area of ​​3 m² in the middle zone and in winter can provide about 150 liters of hot water (with a temperature of about 50 ° C) in 2-3 hours in 2-3 hours. Practice shows that for a small family (two or three people) a solar system with a collector area of ​​​​2-4 m² and a boiler with a capacity of 200-300 liters is enough. Such a system will cost about 100-300 thousand rubles. The cost of one module (with an area of ​​approximately 2 m²) of the collector ranges from 20-25 thousand rubles. (Chinese manufacturers) up to 50-60 thousand rubles. (Ariston, Buderus, Viessmann and other European manufacturers); another 40-60 thousand rubles. you will have to pay for the boiler and 10-20 thousand rubles. for the controller, pump and materials needed for installation.

In a small house, solar energy makes it possible to provide up to 60% of the energy needed to produce hot water.

Viessmann

Thermosiphon solar system Vitosol 111-F (Viessmann) for providing hot water in summer. The thermosiphon principle provides the possibility to carry out heat transfer using the natural convection of the heat carrier. Such a system does not require the use of a pump and any complex control system.

Partitions

The interior of the kitchen and living room begin to think over from the docking of the two zones.

• Here are some of the ways and objects that delimit space:
• installation of a bar counter;
• kitchen island;
• big table;
• installation of a low partition.

Designers advise installing a wide rack, since it will be possible to sit at it like at a regular table, and high chairs are quite suitable for the whole family.
However, narrow racks are installed in small rooms (16 sq m). Kitchen islands are convenient to use, but are only suitable for large kitchen-dining rooms (25 sq m or 30 sq m). Capital low partitions are installed only if it is decided in advance what they will be used for (for example, as a TV stand).

Criteria for choosing a heating system

Given the ease of installation and the availability of materials, many craftsmen carry out the installation with their own hands, observing the rules and norms of SNiP.

Fuel type

Autonomous heating of a private house requires taking into account the availability of fuel, climatic conditions, heat loss of the building. Heating with main gas is considered the most convenient solution.

An alternative is liquefied gas supplied through a gas tank and allowing you to install a compact chimney, a small boiler.

Replace gas:

• Liquid fuel, which allows to automate the operation of the boiler and ensure the availability of an energy source.
• Electricity is an environmentally friendly, safe, silent heating option. You will need separate wiring that can withstand a power of 9 kW - a three-phase network of 380 V. A well-insulated room is heated with an electric convector, an infrared emitter.
• Solid fuel, requiring a storage area (utility room or building) for firewood, pellets, coal, coke, and put up with the formation of soot, soot, frequent cleaning.
• Combined heating options.

Why solar plants are not visible on the roofs of our houses

The Internet is replete with promotional materials with beautiful pictures that tell about the extraordinary benefits of solar systems. Craftsmen post videos on youtube on the topic “heating from the sun with their own hands” about their own know-how, collected on their knees from improvised materials. The web is swollen with rave articles reposting about the miraculous benefits of solar heating. However, how many houses with solar collectors on the roof have appeared in recent years near your home? No one? What are the reasons why solar energy heating is not recognized in our area?

Unfortunately, solar energy for home heating does not come when and where it is needed. It is cold closer to the poles, in winter and at night. And the maximum solar radiation falls on the equatorial regions, in the summer and during the day. Heat accumulators at the very least help smooth out daily, but not seasonal fluctuations.

Map of the intensity of the distribution of sunlight over the territory of Russia. In the Western part of the country, where the lion's share of the population lives, there is little sun.And in eastern Siberia, where the proportion of radiation is noticeably higher, it is cold, which makes it difficult to use active systems. By the way, solar panels that generate electricity are not so sensitive to severe frosts. Quite powerful solar power plants have already been built and are successfully operating in cold but sunny Yakutia.

Passive heating with solar energy is inefficient and is not able to seriously heat the house in the conditions of the Russian winter. “Windows facing south” is a really useful design method that costs nothing but helps to optimize heating costs. But once relatively popular in the United States, solar greenhouses, Trombe walls and their derivatives gradually faded away even in their homeland.

Active solar heating systems for a private house are very expensive, a lot of money will have to be paid for equipment. Operation, contrary to some statements, is by no means free: electricity is consumed, maintenance of equipment is required. At current prices, compared not only with cheap natural gas, but even with rather expensive pellets, diesel fuel, the installation of a vacuum solar collector in the vast majority of the territory of the Russian Federation will never pay off at all, the payback period exceeds the life of the equipment. Only in some southern regions of the country, solar heating systems for a private house may not be unprofitable under certain conditions.

Scientific station on Olkhon Island (Russia). The use of vacuum collectors (on the right on the roof) for preparing hot water and solar panels (on the left) for generating electricity makes sense, because there are no central communications on this rocky Baikal island.However, for full-fledged heating in the climate of Buryatia, solar systems are not enough, “normal” stoves heat the house, the fuel for which is imported from the “mainland”, because it is impossible to harass the local forest for firewood