Solar panels for heating a private house. "In step with the times" - reliable solar heating of a private house Heating in a private house from a solar collector

20.06.2020

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.

The relevance of creating solar heating for a private house with your own hands

To get full autonomy is the dream of every owner who starts 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 give from 50 W/sq.m on a cloudy day to 1400 W/sq.m in 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 saved 3 tons of firewood for a solid fuel boiler!

on average for square meter devices accounted for 900 watts;
to raise the temperature of the water, it is necessary to spend 1.16 W;
taking into account also the heat loss of the collector, 1 sq.m will be able to heat about 10 liters of water per hour to a temperature of 70 degrees;
to provide 50 l hot water, necessary for one person, you will need to spend 3.48 kW;
after checking the data of the hydrometeorological center on the power of solar radiation (W / sq.m) in the region, it is necessary to divide 3480 W by the resulting solar radiation power - this will be the required area of \u200b\u200bthe solar collector to heat 50 liters of water.

As it becomes clear, effective heating system it is rather problematic to implement it exclusively with the use of solar energy. After all, in the gloomy winter season there is very little solar radiation, and to place a collector with an area of 120 sq.m. doesn't always work out.

So are solar collectors non-functional? Don't discount them ahead of time. So, with the help of such a drive, you can do without a boiler in the summer - there will be enough power to provide the family with hot water. In winter, it will be possible to reduce energy costs by supplying already heated water from a solar collector to an electric boiler.
In addition, the solar collector will be an excellent assistant to the heat pump in a house with low-temperature heating (warm floors).

So, in winter, the heated coolant will be used in underfloor heating, and in summer, excess 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” is formed in the thickness of 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 -2C. When heated, the initial temperature rises to +15 C, and by the end of the heating season does not fall below +2C.

Homemade solar collector device

For a self-confident master, it is not difficult to assemble a thermal collector. You can start with a small device for providing hot water in the country, and in case of a successful experiment, move on to creating a full-fledged solar station.

Flat solar collector made of metal pipes

The simplest collector to perform is a flat one. For his device you will need:

welding machine;
pipes made of stainless steel or copper;
steel sheet;
tempered glass or polycarbonate;
wooden boards for the frame;
non-combustible insulation that can withstand metal heated to 200 degrees;
black matte paint resistant to high temperatures.

The assembly of the solar collector is quite simple:

Pipes are welded to steel sheet- it acts as an adsorber of solar energy, so the fit of the pipes should be as tight as possible. Everything is painted matte black.

A frame is placed on the sheet with pipes so that the pipes are on the inside. Holes are drilled for the entry and exit of pipes. The heater is installed. If a hygroscopic material is used, you need to take care of waterproofing - after all, wet insulation will no longer protect pipes from cooling.

The insulation is fixed OSB sheet, all joints are filled with sealant.
On the side of the adsorber, transparent glass or polycarbonate with a small air gap is placed. It serves to prevent the steel sheet from cooling down.
You can fix the glass using wooden window glazing beads, after laying the sealant. It will prevent cold air from entering and protect the glass from compressing the frame when heated and cooled.

For the full functioning of the collector, you will need a storage tank. It can be made from a plastic barrel, insulated from the outside, in which a heat exchanger connected to a solar collector is laid in a spiral. The hot water inlet should be at the top and the cold outlet at the bottom.

It is important to place the tank and manifold correctly. To ensure natural circulation of water, the tank must be above the collector, and the pipes must have a constant slope.

Solar heater from improvised materials

If it was not possible to make friendship with the welding machine, you can make a simple solar heater from what is at hand. For example, from tin cans. To do this, holes are made in the bottom, the banks 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 a frame under glass in the same way as ordinary pipes.

Solar house facade

Why not decorate the house with something useful instead of ordinary siding? For example, by making a solar heater on the south side of the entire wall.

Such a solution will allow to optimize heating costs in two directions at once - to reduce energy costs and significantly reduce heat losses due to additional insulation of the facade.

The device is simple to disgrace and does not require special tools:

a painted galvanized sheet is laid on the insulation;
a stainless corrugated pipe, also painted black, is laid on top;
everything is covered with polycarbonate sheets and fixed with aluminum corners.

If this method seems complicated, the video shows a tin option, polypropylene pipes and films. How much easier!

Good owners of private houses are always looking for ways to save money on water heating and heating. This is especially true in recent times, when prices for public utilities have a strong upward trend almost every quarter. Nature itself comes to the rescue with its inexhaustible source of energy - solar radiation. By putting the laws of physics into practice, craftsmen find interesting ways to save money by designing and assembling solar collectors, which, probably, any homeowner can do on their own - you just have to put a little effort and skill.

A do-it-yourself solar collector can be made in multiple ways and from a variety of materials, sometimes even from those that simply “roll around underfoot.” They are constructed from ordinary old beer cans, plastic bottles, hoses or pipes, using glass, polycarbonate panels and other materials.

Some of the ways to make collectors will be discussed below, but first you should study the connection diagrams - they, as a rule, are approximately common to any solar water heating systems.

Solar Water Collector Wiring Diagrams

The effective operation of the solar water heating system depends not only on what the collector is made of, but also how correctly it will be installed and connected. There are a lot of options for connection schemes, but you should not look for the most complex ones, since it is quite possible to use the basic ones, which are accessible and understandable.

"Summer" version of hot water supply from a solar collector

This simple solar collector connection scheme is applicable for both domestic and domestic water heating. If hot water is needed outside in a summer building, then the tank for it is also installed in the air. In the case when hot water is distributed around the house, and the storage tank is installed there.

"Summer" collector connection option

This scheme usually provides for the natural circulation of water, and in this case, the collector battery is installed 800 ÷ 1000 mm lower than the tank level, where hot water will flow - this should be ensured by the difference in density of the cold and heated liquid. To connect the manifold to the tank, pipes with a diameter of at least ¾ inch are used. To keep the water in the storage tank in a hot state, which it will reach from heating by the daytime sun, the walls must be well insulated, for example, mineral wool 100 mm thick and polyethylene (if a roof is not installed over the boiler). But still, it is better to provide a stationary shelter for the container, since if the insulation gets wet from rain, it will significantly reduce its thermal insulation properties.

Natural circulation is not very good for use in a system with a solar collector, as it creates a slight inertia in the movement of water in the circuit. And if the battery and the tank are far enough from each other, then the water, having passed this path, will gradually cool down. Therefore, to increase efficiency, circulation is often installed. This option is suitable for heating water only in the warm half of the year, and for the winter the water from the system will have to be drained, otherwise, freezing, it will easily break t tons of ruby.

"Winter" scheme for connecting solar water heating

If you plan to use the solar collector year-round, then so that in extreme cold the water does not freeze in the pipes, a special one is poured into the circuit instead of it - antifreeze, that is, non-freezing liquid. The scheme takes on a completely different look - an indirect heating boiler is installed. In this case, the antifreeze heated in the solar collector will pass through the coil-heat exchanger of the boiler, warming the water in the tank.

A "security group" is necessarily built into this system - automatic air vent, pressure gauge and safety valve, designed for the desired pressure. For the constant movement of the coolant is usually used circulation pump.

Solar heating option

When using solar thermal energy for heating a house, an indirect heating boiler connected to the collector is also used, as well as for additional heating of the coolant - running on solid fuel or gas. On autumn or spring days, when the sun is able to heat the coolant to the desired temperature, the boiler can simply be turned off.

Solar collector - a good help for home heating

If the winters in the region are very cold, then one should not expect great efficiency from the collector, since during this period there are few sunny days, and the luminary itself is low to the horizon. Therefore, additional heating of the coolant and hot water is simply necessary. The only way a solar battery will help save on fuel is that not cold, but already somewhat heated water will flow into the boiler, which means that to bring it to the desired temperature, it will take less gas or wood to burn.

You also need to know that the larger the area to make a solar thermal collector, the more energy he will be able to absorb. Therefore, in order for such a system to be able to generate enough heat to heat the house, the size of the collector area must be increased to 40 ÷ 45% of the total area of the house.

Option for hot water supply and heating from a solar collector

In order to use the solar collector for both heating and hot water supply, it is necessary to combine both previous options in the system, and use a special boiler for water with an additional tank having a coil through which the coolant heated by the solar battery circulates. Due to the fact that the inner tank is much smaller than the main one, the water in it heats up from the coil much faster and gives off heat to the general tank.

The collector can be included in the general system "heating - hot water supply"

In addition, the boiler must be connected to an additional heating source - it can be either an electric boiler or a solid fuel heat generator.

The temperature instability created by the solar battery can contribute to overheating of the coolant or, conversely, to its too rapid cooling in the heating and water supply circuits. To prevent this from happening, the entire system must be controlled by automation. Installed in the wiring controller temperature, which can either redirect coolant flows, or turn on or off circulation pumps, or perform other control operations.

In the diagram above, such a temperature controller is designated as a regulator.

So, with connection diagrams (strapping) in in general terms there is clarity. Now it makes sense to consider several options self-manufacturing solar collectors.

Prices for solar collectors

Solar collectors

Solar collector from hose or flexible pipe

Those who have private house with a garden or a dacha, of course, they know that the water remaining in the temporary light mains after watering the beds heats up quickly. This is positive quality hoses or flexible pipes and used by craftsmen, creating solar heat exchangers from them. It should be noted that such a collector will cost many times cheaper than bought in a store, but in order for the manufacturing process to be successful, some effort must be made.

On the roof - a whole battery of solar collectors

Such a collector may consist of one or more sections, in which hoses tightly coiled in a spiral “snail” are laid and fixed.

"Snail" - heat exchanger

This design can be called the simplest both in design and installation. Its main disadvantage can be called the fact that it is practically impossible to use it without the use of forced circulation, since if the pipe contours are too long, the hydraulic resistance will exceed the pressure force created by the temperature difference. However, solving the issue of installing a circulation pump is not difficult at all. And such a system installed in a country house will become great help and will quickly pay off, including the costs (very insignificant) for the power supply of the pump.

Similar collectors are also used for heating water in pools. They are connected to a filtration system, which is necessarily equipped with a pump. Water, circulating through the pipes of the collector, has time to heat up before entering the pool.

In some cases, creating the entire system, you can do without installing a storage tank. This is possible when hot water is only used for daytime and in small quantities. For example, in a circuit of 150 m of pipe having inner diameter 16 mm, holds 30 liters of water. And if five or six of these “snails” from pipes are assembled into a single battery, then during the day each family member can take a shower several times, and there will still be a lot of hot water for household needs.

If someone still has doubts about the effectiveness of such water heating, we recommend watching a video that shows a test of a hose collector:

Video: the efficiency of a simple solar collector

Materials for manufacturing

To make such a solar water collector, you need to prepare some materials. It is not at all excluded that some of them can be found in a barn or garage.

A rubber hose or a flexible black plastic pipe with a diameter of 20 ÷ 25 mm is, in fact, the main element of the system in which heat exchange will occur when water circulates. The number of hose will depend on the size of the solar battery - it can be 100 or 1000 meters. The black color of the hose is preferred because it absorbs heat more than all other shades.

It should be noted right away that metal-plastic pipes are not particularly suitable for the manufacture of a collector, even if they are covered with black paint. The fact is that their plasticity in this case is insufficient - they break at bends of a small radius and thus, even if the integrity of the walls is not violated, the intensity of the water flow will decrease.

Hoses are sold in coils of 50, 100 or 200 meters. If you plan to make a large volume battery, then you will have to purchase several bays. In the event that it is planned to use, for example, 50 or 100 m of hose in each section, then you should not buy a whole 200-meter bay, it is better to purchase a ready-made measured hose. This will save time during installation.

The hose can be laid not only in a round spiral, but also oval, as well as in the form of a coil.

As a good alternative, you can also try modern PEX pipes. They have good plasticity, but how to give them a black color if it is not on sale is easy to figure out.

If the slope of the roof on which the collector battery will be installed is steep, then special boxes are made for hose spirals - from bars, plywood or metal sheet. This will require bars 40 × 40 or 40 × 50 mm, plywood 6 mm thick, or a metal sheet in 1.5–2 mm.

The blanks of the future module are processed (wood) or anti-corrosion compounds (metal). Then a box is assembled from them into one or more spirals.

By the way, as the sides of the box, you can use old window frames, on which the bottom part is simply mounted.

For pre-treatment of metal and wood, it is necessary to purchase antiseptic, anti-corrosion and priming compounds.
Hoses (pipes) will experience considerable loads both from the mass of the coolant and from temperature extremes and internal pressure. Therefore, they will try to break the laying, deform, sag, so you need to provide special fasteners to maintain them in the initially set position.

It can be a metal strip, which is fixed between the pipes with self-tapping screws.

Another option is a loose bundle with a tight cord or plastic tie-tie with a cross or crossbar. But still, this fastening method is more suitable for a plastic pipe than for a hose, since it can sag on the cord when the rubber expands. If a reinforced rubber hose is chosen for the collector, then this method is quite suitable for fixing.

Another fastening option suitable for a plastic pipe or reinforced hose can be wide-head nails. They can be hammered either into the bottom of the box (in this case it must have a thickness of at least 10 mm), or onto a kind of cross made of a bar.

It will be necessary to prepare the connecting elements for the hose or pipes. There are a lot of varieties of such fittings, but you need to choose exactly those that are intended for selected for manufacturing material collector.

In addition to such connectors, threaded fittings will be required to switch from a plastic or rubber pipe to a common metal one. Such a connection will be necessary if the collector will consist of several modules.

To know how many connecting elements are required, you need to draw in advance circuit diagram created system and calculate their number on it.

To combine all the modules into a single battery, two collector - cut metal pipe. Through one of them, fixed at the bottom of the battery, cold water will flow into the heat exchangers, and in the second, fixed at the top, warm water will be collected.

The upper pipe will be connected to the storage tank, that is, it will go to the consumer. It should have a diameter of 40 ÷ 50 mm.

Battery installation

Having prepared everything you need, you can get to work.

First you need to process antiseptic all wooden parts of the future structure.
Further, if the bottom of the modules is made of a metal sheet, it must be coated with an anti-corrosion compound. Usually, mastic is used for this purpose, designed to cover the bottoms of cars.

Known to all motorists "anticorrosive" - what you need

After the compositions have dried on the prepared elements, single or common modules are assembled from them.
Then hoses are laid in them, for which holders are fixed.

For free passage of pipes through the sides of the modules, holes are drilled for them - in its upper part and lower. Accordingly, the inlet pipe is led into the lower hole cold water, and at the top - heated outlet.
If several modules are mounted vertically, or one common one, into which several “snails” of the pipe are also placed, one above the other, then the lower end of each of the spirals is connected to the upper output of the underlying one - and the entire “column” is switched according to this sequential principle. The lowest end is connected to a common metal manifold through which cold water will flow. All adjacent vertical rows are mounted in the same way - with a common connection to the supply manifold.

Accordingly, the upper ends of the hoses of the uppermost horizontal row of modules are connected to a metal collector pipe, through which hot water is drained for consumption.
The spiral collector circuit can also be mounted on a metal sheet installed not on the roof, but near the house, on its south side, or near the pool, if it requires heating. In this case, the metal base will contribute to faster heating of water and heat retention in pipes, as it has good thermal conductivity and heat capacity.

Another option for a thermal solar collector can be laying the circuit on the roof plane in special boxes in long parallel rows along the entire length of the roof.

Prices for XLPE pipes

XLPE pipes

Video: simple linear tube solar collector

Enhance the effect with plastic bottles

The figure shows a solar collector made of hoses (pipes), the efficiency of which is greatly increased through the use of ordinary plastic bottles. What is the "feature" here? And there are several of them:

The action of a plastic bottle as a casing - schematically

Bottles play the role of a transparent casing, and do not allow air currents to take away heat during absolutely unnecessary mutual heat exchange. Moreover, the air chambers themselves become a kind of heat accumulators. On the face - the greenhouse effect, which is actively used in agricultural technology.
The rounded surface of the bottle plays the role of a lens that enhances the effect of sunlight.
If the bottom surface of the bottle is covered with a reflective foil material, then the effect of focusing the rays in the zone of the pipe passage can be achieved. Heating will only benefit from this.
Another important factor. Plastic transparent surface to some extent reduce the destructive negative impact ultraviolet rays, which neither rubber nor plastic "like". Such a circuit should last longer.

To make such a solar collector you will need:

1 - Rubber hose, black metal or plastic pipes - as a heat exchanger.

2 - Plastic bottles that will become a casing around the pipes of the circuit.

3 - In the bottles, in their half, which will be adjacent to the base, foil or other reflective material may be inserted. The reflective part should look towards the sun.

4 - It will be quite easy to mount the stand from a bar or a metal pipe.

5 - Storage tank for heated water, which must be connected to the intake point - faucet, shower, etc.

6 - Cold water tank that can be connected to the water supply system.

Installation of a solar collector

The assembly of the version shown in the upper diagram is as follows:

To begin with, a stand is mounted from a metal pipe or bar. If it is made of wood, then it must be covered antiseptic composition if made of metal, then it must be treated with an anti-corrosion agent. It is necessary to calculate the length so that an even number of bottles is installed between the two racks.
On racks, at a distance the width of the bottles, horizontal strips are fixed, on which it will be possible to make additional fastening for the coil. In addition, they will betray the frame additional rigidity.
Next, the required number of plastic bottles is prepared - the bottom part is cut off from them so that one bottle with the side of the neck fits snugly into the resulting hole.

A hose (pipe) of the required length is taken, which will be enough for laying coil circuit on a ready-made frame-stand.

Stepping back from the edge of the hose 100 ÷ 150 mm, make a mark of the place of its fastening. Then, through this edge, the required number of prepared bottles is put on the pipe, which will be enough to completely close the area to the opposite rack. The bottles are installed tightly one to the other, so that the neck of the second one enters the hole cut in the bottom of the previous one.

When the pipe section for laying the upper section of the coil is completely covered with a bottle box, its edge is fixed on top of the left rack of the frame. For fastening, you can use clip-holders for plastic pipes with a latch, the desired size.

If necessary, the position of the bottles is adjusted so that their foil half is at the bottom, near the collector frame.
Then the pipe is given a smooth turn, and it snaps back onto the clip.
The next step is to put bottles on the pipe again, and it is already fixed on the left rack. This follower is continued until the entire frame is filled with a collector coil.
Now it remains only to “pack” the fittings through which the resulting manifold will be inserted to the cold water supply and to storage capacity hot.

Here's what can happen in the end - you can't imagine it easier!

Such a collector, as you can see, absolutely not difficult in manufacturing, but it can become a good "helper" in a private house, taking on the functions of heating water.

By the way, solar energy can be used not only for heating water, but also for supplying heated air to rooms. For example, how to make it yourself, you can find out if you follow the link to a special publication of our portal.

Video - do-it-yourself solar power plant assembly

In most regions of Russia for heating residential buildings huge sums are being spent. This forces homeowners to look for additional opportunities in this area. The energy of solar radiation is environmentally friendly and free heat. Applying modern technologies, you can use solar energy for space heating in the regions of central and southern Russia.

Possibilities of modern technologies

The surface of the earth receives a different amount of solar energy, it all depends on the location of the territory relative to the equator and the season. For example, in the Arctic, the sun is much less than in the equatorial part. In addition, solar radiation is more intense in summer than in winter period. When calculating the average values, experts determined that in one hour a square meter of the earth's surface receives about 160 W of solar energy. Modern systems are highly productive, making it possible to use the energy of solar radiation almost anywhere.

To obtain maximum efficiency when using solar energy, two methods are used:

Direct heating of thermal collectors. Direct sunlight heats the thermal collectors, which in turn transfer heat to the liquid in the heating circuit and the hot water supply system. Thermal collectors can be of open and closed type, they can have a flat or spherical shape. thermal energy obtained from the collectors can be used to heat the working medium in the water supply system and the coolant in the heating system.
The use of solar panels. In this case, solar energy is converted into electricity, which is subsequently transmitted to the consumer through a special system.

The development of solutions for the collection, accumulation and use of solar energy is progressing quite rapidly. However, there are many positives and negatives in this area.

Advantages and disadvantages of using solar collectors and batteries

The main advantage in using solar heating systems is the general availability. In second place is the absence of emissions. Solar energy is considered the most environmentally friendly and natural form of energy.

In addition, the operation of solar panels and collectors is quiet, and the location on the roof of the building saves usable space.

The main inconvenience in the use of solar energy for the home, consumers experience from intermittent lighting. For example, at night there is no possibility of collecting energy, and in winter time when required a large number of warm, daylight hours are short.

In addition, it is necessary to constantly monitor the cleanliness of the panels so as not to reduce the efficiency. It should also be taken into account that the depreciation of equipment, the operation of the circulation pump and the control electronics require constant costs.

Solar collectors of open type

The design of open solar collectors is made in the form of a system of tubes, unprotected from external influences. Inside this system, a coolant circulates, which is heated directly from the sun's rays. The tubes are fixed on the carrier panel in the form of a snake or with parallel stacking of rows and exit to the branch pipe. The tubes can be filled with water, gas, air or antifreeze.

The simple design and lack of insulation makes open collectors affordable for almost all consumers. In addition, home craftsmen have the opportunity to make solar heating of a private house with their own hands.

The lack of insulation on the tubes of the system does not allow to store the received solar energy, therefore, such systems have a very low efficiency. Their main use is for heating water in swimming pools and showers in summer time. Most often, open-type collectors are used by residents of warm and sunny regions, where the temperature of the air and heated water does not have significant differences. The highest efficiency of work was noted in sunny weather in the absence of wind.

Solar collectors of tubular type

To assemble a tubular solar collector, separate tubes filled with water, gas or steam are used. This design is one of the types of open solar systems, but with a more coolant, more protected from the negative effects of external factors. This includes vacuum installations, arranged according to the principle of a thermos.

In a tubular solar collector, the tubes are arranged in parallel with individual connections to common system. This allows you to replace a failed tube with a new element without compromising the operation of the entire structure. In addition, the system can be assembled directly on the roof of the building, which greatly simplifies the installation process.

The main advantage of a tubular solar collector is the cylindrical shape of the main elements. Thanks to this, solar energy is collected throughout the daylight hours, and this does not require the installation of additional devices that monitor the movement of the sun.

Depending on the design features, solar collectors are divided into two types: feather and coaxial.

Tubes of coaxial type have some resemblance to a conventional thermos. Their design consists of two flasks with air pumped out between them. The surface inside the first flask is coated with a highly selective substance that is able to absorb solar energy to the maximum. It is this layer that serves as a kind of conductor of thermal energy to the internal heat exchanger, consisting of aluminum plates. However, this stage is characterized by a large number of unwanted heat losses.

Feather-type tubes are made of glass and have a cylindrical shape; a feather absorber is located inside the glass cylinder. The absence of air inside the tube significantly increases the thermal insulation characteristics. The amount of heat transferred from the absorber is practically not reduced, therefore, the efficiency of such collectors is much higher.

Heat transfer is carried out by a direct-flow system and by means of a thermotube.

A thermotube is a sealed container, inside which an evaporating liquid is poured, which is most often water under low pressure. Heated from the inner walls of the container or feather absorber, the liquid boils, and its vapors rise up. After the transfer of thermal energy to the coolant of the heating system or hot water supply, the vapor condenses into a liquid, which flows down the walls.

The direct-flow system is a U-shaped tube with a coolant circulating inside.

A cold coolant is located in one half of the tube, and a heated liquid is discharged through the second part. When the temperature rises, the coolant expands, and it enters the storage tank to ensure natural circulation.

The main condition for the location of the thermotube and direct-flow system is the creation of a certain angle of inclination, which should not be less than 20 degrees.

Direct-flow systems are characterized by the greatest efficiency, since the coolant is directly heated in them.

Advantages and disadvantages of heating systems

Like any system, tubular solar collectors have their pros and cons. The advantages of the system include the following:

Minor heat loss.
Possibility of use at rather low air temperature, up to -30 degrees.
High efficiency throughout the daylight hours.
High performance performance in regions with cold and temperate climates.
Low windage, which is explained by the fact that tubular systems pass through themselves the main amount of air masses.
The ability to heat the coolant to a high temperature.
Long service life.

Of the shortcomings of the system, the following attracts special attention:

The system is not capable of clearing snow, ice and frost on its own.
High price level.

As for the high cost, it should be noted here that tubular collectors pay off in a fairly short time.

Closed flat solar collectors

The design of the flat collector is aluminum frame with a special absorbent layer and a transparent coating. It also includes piping and insulation.

The absorbent layer is blackened copper sheet with excellent thermal conductivity, ideal for building solar systems. The absorber absorbs the energy of solar radiation and transfers it to the coolant, which circulates through the adjacent pipeline.

The outer part of the panel has a protection in the form of a transparent coating, for the manufacture of which tempered glass was used, which is resistant to mechanical damage. This allows you to create reliable protection against hail. The bandwidth of such glass is 0.4-1.8 microns, which is sufficient for maximum solar radiation. Inner side the panel has a good heat-insulating layer.

Closed flat panels have a number of undeniable advantages:

Simple construction.
High efficiency when used in warm regions.
The presence of a device for changing the angle of the panel, allowing you to choose the optimal location of the structure.
Self-cleaning of frost and snow.
Acceptable cost.
Long service life, high-quality products can last up to half a century.

If the use of the system was included in the design of the building, then in this case, you can get a big benefit.

Of the shortcomings, attention is drawn to the following:

High heat loss.
Quite a large mass of the structure.
High windage of inclined panels.
Low performance with temperature changes up to 40 degrees.

Scope of flat closed panels for heating a house with solar panels is wide enough:

In summer, the systems fully meet the needs for hot water.
Between heating seasons they can replace gas appliances heating and electric heaters.

Comparative characteristics of some types of solar collectors

The main characteristic of any solar collector is its performance. Depending on the design features and the temperature difference, the efficiency of the system is determined. it should be taken into account that the cost of flat-plate collectors is much lower than that of tubular systems.

When choosing a solar collector, you should carefully study the parameters on which the efficiency of solar water heating and the power of the structure depend.

Solar collectors have a number of rather important characteristics:

The ratio of the total and absorbed energy of solar radiation can be determined from the adsorption coefficient.
The ratio of the amount of transferred heat and absorbed energy is determined by the emission factor.
The ratio of the total and aperture area.
Efficiency.

The aperture area should be understood as the working area of the collector. Flat-type systems are characterized by the maximum values of this indicator. The aperture area corresponds to the area of the absorbent layer.

Ways to connect to the heating system

One of the disadvantages of solar collectors is the impossibility of a constant supply of energy. Therefore, when connecting, it is important to choose a system that is capable of operating in a limited mode.

In the regions of central Russia, solar collectors are used as an additional source of heat, as they do not guarantee a constant flow of energy. Connecting solar collectors and batteries to a functioning heating and hot water supply system has some differences that must be taken into account.

Connection of heat collectors

The connection scheme is determined by the direct purpose of the design, most often two options are used:

For heating water in the summer.
For heating the coolant in winter in heating and hot water systems.

The first option is distinguished by its simplicity, its operation is based on the natural movement of the coolant. Therefore, such a scheme for the use of solar energy for a private house can be used without a circulation pump. The principle of operation is as follows: when heated by sunlight, the water in the collector expands and enters the storage tank. A cold liquid is sucked in to replace the outgoing water.

However, it should be borne in mind that for greater efficiency of the system with natural circulation, it is necessary to create a certain angle of inclination. In addition, it is important to place the storage tank at a higher level than the solar collector.

To maintain a high temperature of the coolant, the storage tank requires additional thermal insulation.

Maximum effective work solar collector requires the use of a more complex connection scheme.

A non-freezing coolant is poured into the system and a circulation pump is inserted. To control its operation, a controller and temperature sensors are installed. The first sensor shows the temperature of the water in the storage tank, the second sensor is installed on the pipe supplying the hot coolant from the solar collector. Such a scheme works according to the following principle: when the water in the tank is heated above the specified parameters, the circulation pump is turned off, and the movement of the coolant stops. When the temperature drops to the control values, the controller turns on the heating boiler.

How solar panels are connected

The solar collector connection scheme, in which the energy of solar radiation is accumulated, cannot be used to connect solar panels. In this case, you will have to additionally install an expensive battery pack. Therefore, another option must be used.

Energy from the solar panels is transferred to the charge controller, which is designed to constantly supply energy to the batteries and stabilize the voltage. When electricity is supplied to the inverter, the direct current is converted into alternating single-phase current 220 V.

Obtaining a universal type of energy for heating a house from the sun makes solar panels more profitable, but do not forget about the lower efficiency of this system. It should also be noted that the solar collector cannot store energy, as solar panels do.

Power calculation

To profitably use solar collectors, it is important to consider the following recommendations from manufacturers:

The system should provide hot water only by 70%.
No more than 30% of energy can enter the heating system from solar collectors.

Only in this case it is possible to achieve savings in heating and hot water supply costs by almost 40%.

When calculating the power of the collector for heating a house with solar energy, one should also take into account the location of the system, the angle of the panels and the average annual temperature in the region.

Is it possible to provide your home with solar thermal energy? Today we will discuss the prospect of using solar systems as the main source of heating, consider the issue of economic feasibility and efficiency of solar collectors.

The main components of the heating system

Solar collectors serve as the heating source of the solar system, the purpose of which is the most efficient transfer of energy from the infrared spectrum of solar radiation to the heat carrier. The thermal range of sunlight is 40-45% of the total radiation flux, in specific figures it is 200-500 W / m 2, depending on latitude, time of year and day.

In principle, collectors alone are enough to build the simplest solar system. Through their channels, ordinary water used for household needs and heating of housing can circulate. However, this approach is not effective enough for a number of reasons, the first of which is the lack of replenishment of energy losses for a full day. Therefore, one of the most important elements of the solar heating system is a heat accumulator - a container with water.

The scheme of heating the house with solar collectors: 1 - cold water supply; 2 - heat exchanger; 3 - heat accumulator; 4 - temperature sensor; 5 - coolant circuit; 6 - pumping station; 7 - controller; eight - expansion tank; 9 - hot water; 10 - three-way valve; 11 - solar collector

Also a limitation is technical device solar collector. Its channels have a rather small flow area, due to which there is a risk of clogging with mechanical impurities. There is also a high probability of freezing of the coolant at night, while the upper limit of the operating temperature range is 200-300 °C. The collectors are designed for fast continuous circulation of the coolant, which enters at a low temperature, is quickly heated by sunlight and just as quickly gives off heat to the battery.

Tubes of the vacuum U-shaped solar collector

For these reasons, for direct heating in heat pipes, it is customary to use propylene glycol with a set of special additives. So, the third obligatory element of a solar heating system is a special coolant and an exchange circuit, which is often structurally included in the heat accumulator, or may be part of the collector itself.

Varieties and differences of collectors

If you do not go into the technical details of the device, the main difference between flat and vacuum collectors lies in the expediency of their use in different climatic zones. Flat collectors are best used in southern latitudes with prevailing temperatures above zero, vacuum - closer to the north.

The design of a flat solar collector: 1 - coolant outlet; 2 - collector frame; 3 - structured hail-resistant glass; 4 - absorber; 5 - copper tubes; 6 - thermal insulation; 7 - coolant inlet

The expediency of using certain types of solar collectors is due to a number of features:

the inability of vacuum collectors to independently clear snow;
high heat losses of flat solar collectors, growing together with the temperature difference;
low resistance of flat collectors to wind loads;
high cost of the project on vacuum solar collectors;
low temperature range of effective use of flat-plate collectors.

Vacuum collector design with indirect heat transfer: 1 - cooled coolant inlet; 2 - heat exchanger (collector); 3 - sealed plug; 4 - vacuum tube; 5 - aluminum plate (absorber); 6 - heat pipe; 7 - working fluid; 8 - output of the heated coolant; 9 - heat sink housing; 10 - heat pipe capacitor; 11 - insulation

One of the most important differences lies in the installation process. Flat-plate collectors require delivery to the roof in assembled form, while vacuum collectors can be assembled on site. Also, flat-plate collectors usually do not have their own heat storage and exchange circuit.

Problems of solar energy

Heating solar systems are not without disadvantages, the most important of which is the inconstancy of the energy source. At night, the system does not heat up, and in prolonged overcast weather, expecting clear skies to heat the house is below average pleasure. If the battery, with a sufficiently large volume, is able to maintain the required amount of heat at least until the morning, then several days of battery life in low light conditions can only be expected with a significant expansion of the solar farm. This, in turn, causes the opposite problem: when reaching the maximum power mode (for example, on a clear spring day), such a solar system will require more intensive heat removal or temporary shutdown of several absorbers with their shading.

It is important to understand that solar systems in the realities of the Russian climate cannot be used as the only or main source of heating. However, they can significantly reduce energy consumption during the heating period. Hybrid collectors work especially effectively, in which the heaters are combined with photocells. If the cloudiness delays most of the IR radiation, then the losses of the photoelectric part of the spectrum are not so significant.

Another disadvantage of solar collectors lies in the need for forced circulation of the coolant in the collector-accumulator system. Some vacuum collectors are equipped with a tank designed for natural circulation and located above the absorber. Such installations are usually used in hot water supply systems with cold water intake under pressure. But there are still ways to establish joint work of such solar collectors with a heating system.

Integration into the heating system

There are two ways to combine solar collectors with an arbitrarily complex liquid heating system. The main source of energy can be either gas or electricity - there is no significant difference.

The first option is to heat the common daily battery. The accumulator is connected to the boiler jointly and sequentially; if the temperature is not high enough, the latter is put into operation and heats up the liquid. A properly designed system of this kind can work effectively even without forced circulation.

1 - heating circuit; 2 - heating fluid; 3 - temperature sensor; 4 - pumping station; 5 - controller; 6 - pump; 7 - expansion tank; 8 - sanitary water; 9 - cold water; 10 - hot water supply; 11 - solar collector; 12 - heating boiler

The second type of combination involves the use of a heat accumulator with two circuits. Through one, heat is removed from the collector, through the second, the coolant in the system is heated, water from the accumulator serves as a source of hot water. Since the circuits are isolated from each other, warmer liquids or antifreeze can be used in the heating system and the heat exchange cycle from the solar collector. The main disadvantage is the volatility of the system, because in both circuits the circulation is forced.

1 - cold water supply; 2 - temperature sensor; 3 - solar collector heat exchanger; 4 - boiler heat exchanger; 5 - collector coolant circuit; 6 - pumping station; 7 - controller; 8 - expansion tank; 9 - circulation pump; 10 - hot water outlet; 11 - heating boiler; 12 - solar collector

Power calculation and installation steps

The transition to solar energy does not accept haste and a superficial approach. Often, conclusions about the expediency of installing a solar system can be made only after several years of observations and calculations.

Unfortunately, relying on insolation maps does not make much sense, because local weather conditions can greatly distort the average. Therefore, the first thing to do is to independently compile a report on the intensity of solar radiation at the installation site of the collectors. Pyranometers are used for measurements; within 5 thousand rubles, you can purchase a budget device with a sufficient set of functions.

Measurements should be carried out at different times of the day with a frequency of about a week throughout the year. In the course of measurements it is necessary to take into account the angle of inclination and the orientation of the collectors. The data obtained are finally compared with the statistics of the hydrometeorological center on the percentage of cloudy days in a year.

In order to ensure high efficiency of the solar plant, the most negative scenario should be considered, that is, the longest period with the lowest light should be taken as the starting point. Ideally, you can make an adjustment for the likelihood of even worse weather conditions using meteorological statistics for the last 15-20 years. The obtained data on the incoming solar energy will help to determine the required total area of the absorption field and determine the number of collectors that need to be purchased.

As mentioned, collectors are very rarely used as the main source of heating, usually they play an auxiliary role. But the share of participation can be calculated, it is indicated as a percentage of the total power of the house's energy system or its heat loss. Having received the required number of kilowatts, it is multiplied by the optical efficiency of the absorbers, several coefficients are added - corrections for orientation, inclination, temperature conditions, as well as a safety margin.

Based on the "net" value of the generated power, the following is selected:

the required number of collectors of a certain model and, on average, one backup solar collector per 10-15 in operation;
piping system with manufacturer's recommended capacity and heat resistance;
circulation group, shut-off valves, other auxiliary devices;
volume and location of the battery tank. In systems with a daily storage or a heat extraction power of more than 20 kW, it makes sense to build insulated concrete tanks with a volume of 15-20 m3.

For independent installation and maintenance, it is necessary to draw up a system project, allocate space for auxiliary devices and fix the solar collector on the southern (for the northern hemisphere) slope of the roof, taking into account the recommendations of the equipment supplier regarding wind loads. Do not forget that by purchasing a full range of equipment from one distributor, you get the opportunity to compile for free, if not a design of a solar heating system, then at least a list of well-compatible equipment and components.

Is a heat pump necessary?

One of the main disadvantages of solar heating systems is the high cost. While flat-plate collector technology is well established, vacuum absorbers remain expensive and, under certain weather conditions, are the only ones that can be successfully operated. But there is another alternative - air-type collectors.

In view of more simple device their cost is less, plus there is the possibility of battery life. The efficiency of the air collectors is increased with the installation of a blower powered by an integrated solar panel. Due to the accelerated, but proportional to the heating, cooling of the channels, the return heat losses through the collector are minimized. Power limitation can be achieved by controlling the fan speed or by simply blocking the flow - air collectors are not afraid of thermal shock, and it is also easy to set up natural recirculation.

The lack of air systems in a small degree of heating of the coolant. The heat capacity of air is less, plus the absorber is almost always heated without focusing. To be able to integrate into the heating system (which is most often necessary due to the impossibility of laying a ventilation duct in a heated room), a heat pump or a split system is really needed.

But air source heat pumps can also be used to increase the efficiency of air conditioning. With them, the circulation rate can be raised to values that are not acceptable in household ventilation systems, which gives a 2-3-fold increase in output due to the high temperature difference. During the night, the collector will also have a small share of output over the operating temperature range.

The air used as a heat carrier can be dried or replaced with carbon dioxide or another more heat-intensive gas. However, it makes no sense to use heat pumps with a water primary circuit: they are initially designed to work with a high temperature difference, and therefore the increase in power is not enough to justify the installation cost.

The cost of a solar heating installation

For the pleasure of using clean energy in general, you have to pay quite a lot, at least for today. To be fair, there is also positive news: over the past five years, the cost of manufacturing flat-plate collectors has fallen by 2-2.5 times, and this can soon be expected from devices with vacuum absorbers.

The cost of flat-plate and vacuum collectors is determined by the volume of production - the value of solar radiation in ideal lighting conditions, that is, power density. On average, you will have to pay about $350-500 for 1 kW of flat-type solar collectors, and about $800-1000 for a complete installation with an external battery. The cost of vacuum solar collectors fluctuates in a higher range - from $600 to $1000-1200 per complex, depending on the quality of workmanship, tube material, heat exchanger insulation and other features.

For capacitive collectors, the measurement standard is in liters of water heated to the highest possible temperature. The amount of electricity generated can be calculated either by the total area of the absorber, or by expressing it in terms of the specific heat capacity of water. Depending on the complexity of the system, the cost varies greatly, the price of one of the examples from the middle market segment reaches $1,500 per 300 liters (for 4-5 residents) with a temperature difference of about 50 °C, which is equivalent to 2.5 kW of specific power.

The use of "green" energy supplied by natural elements can significantly reduce utility costs. For example, by arranging solar heating of a private house, you will supply low-temperature radiators and systems with virtually free coolant. warm floors. Agree, this is already saving.

You will learn everything about “green technologies” from our article. With our help, you can easily understand the types of solar installations, how they are constructed and the specifics of operation. Surely you will be interested in one of the popular options that are intensively working in the world, but not yet very popular with us.

In the review presented to your attention, design features systems, connection schemes are described in detail. An example of the calculation of a solar heating circuit to assess the realities of its construction is given. Photo collections and videos are attached to help independent masters.

On average, 1 m 2 of the earth's surface receives 161 watts of solar energy per hour. Of course, at the equator this figure will be many times higher than in the Arctic. In addition, the density of solar radiation depends on the time of year.

In the Moscow region, the intensity of solar radiation in December-January differs from May-July by more than five times. However, modern systems are so efficient that they can work almost anywhere on earth.