Heating by solar energy. Do-it-yourself solar heating of a private house. Features of solar collectors

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With rising energy prices, the use of alternative energy sources is becoming increasingly important. And since heating is the main expense item for many, we are talking about heating first of all: you have to pay practically all year round and considerable amounts. When you want to save money, the first thing that comes to mind is solar heat: a powerful and completely free source of energy. And it’s quite possible to use it. Moreover, although the equipment is expensive, it is several times cheaper than heat pumps. Let's talk in more detail about how solar energy can be used to heat a house.

Solar heating: pros and cons

If we talk about using solar energy for heating, we need to keep in mind that there are two different devices to convert solar energy:

If the counter hot water you have, then you know the volumes of hot water that you spend monthly. Display the average consumption data for the month or calculate based on the maximum consumption - it’s whatever you want. You should also have data on heat losses at home.

Take a look at the solar heaters you would like to install. Having data on their performance, you can roughly determine the number of elements needed to cover your needs.

In addition to determining the number of components of the solar system, you will need to determine the volume of the tank in which hot water for hot water will accumulate. This can be easily done if you know your family's actual expenses. If you have a DHW meter installed and you have data for several years, you can display the average consumption per day (divide the average consumption per month by the number of days). This is approximately the volume of tank you need. But the tank needs to be taken with a reserve of 20% or so. Just in case.

If there is no hot water supply or meter, you can use consumption standards. One person spends on average 100-150 liters of water per day. Knowing how many people permanently live in the house, you will calculate the required tank volume: the norm is multiplied by the number of residents.

It must be said right away that it is rational (from the point of view of payback) for middle zone Russia has a solar heating system that covers about 30% of heat demand and fully supplies hot water. This is an average result: in some months, heating will be 70-80% provided by the solar system, and in some months (December-January) only 10%. Again, a lot depends on the type solar panels and from the region of residence.

Moreover, it’s not just a matter of “north” or “south”. It's a matter of the number of sunny days. For example, in very cold Chukotka, solar heating will be very effective: the sun almost always shines there. In the much milder climate of England, with eternal fogs, its effectiveness is extremely low.

Results

Despite many critics who say solar energy is inefficient and too long term payback, more and more people are at least partially switching to alternative sources. In addition to saving, many are attracted by independence from the state and its pricing policy. In order not to regret the wasted amounts of money invested, you can first conduct an experiment: make one of the solar installations with your own hands and decide for yourself how attractive it is to you (or not).

With rising energy prices, the use of alternative energy sources is becoming increasingly important. And since heating is the main expense item for many, we are talking about heating first of all: you have to pay considerable amounts almost all year round. When you want to save money, the first thing that comes to mind is solar heat: a powerful and completely free source of energy. And it’s quite possible to use it. Moreover, although the equipment is expensive, it is several times cheaper than heat pumps. Let's talk in more detail about how solar energy can be used to heat a house.

Solar heating: pros and cons

If we talk about using solar energy for heating, then you need to keep in mind that there are two different devices for converting solar energy:

Both options have their own characteristics. Although it must be said right away, whichever one you choose, do not rush to abandon the heating system that you have. The sun rises, of course, every morning, but your solar cells will not always get enough light. The most rational decision- do combined system. When the sun's energy is sufficient, the second heat source will not work. With this you will protect yourself and you will live in comfortable conditions, and save money.

If there is no desire or opportunity to install two systems, your solar heating should have at least a double power reserve. Then we can say for sure that you will have warmth in any case.

Advantages of using solar energy for heating:

Flaws:

Dependence of the amount of incoming heat on the weather and region.
For guaranteed heating, you will need a system that can operate in parallel with a solar heating system. Many heating equipment manufacturers provide this possibility. In particular European manufacturers wall-mounted gas boilers are designed to work together with solar heating (for example, Baxi boilers). Even if you have installed equipment that does not have this capability, you can coordinate the work heating system using a controller.
Solid financial investment at the start.
Periodic maintenance: tubes and panels must be cleaned of adhering debris and washed from dust.
Some of the liquid solar collectors cannot work under very low temperatures Oh. On the eve of severe frosts, the liquid must be drained. But this does not apply to all models and not all liquids.

Now let's take a closer look at each type of solar heating element.

Solar collectors

Solar collectors are used for solar heating. These installations use the heat of the sun to heat the coolant fluid, which can then be used in a water heating system. The specificity is that a solar water heater for heating a house produces only a temperature of 45-60 o C, and the most high efficiency shows at 35 o C at the outlet. Therefore, such systems are recommended for use in conjunction with warm water floors. If you don’t want to give up radiators, either increase the number of sections (approximately twice as much) or heat up the coolant.

To provide the house with warm water and for water heating, you can use solar collectors (flat and tubular)

Now about the types of solar collectors. Structurally there are two modifications:

flat;
tubular.

In each of the groups there are variations in both materials and design, but they have the same operating principle: a coolant runs through the tubes, which is heated by the sun. But the designs are completely different.

Flat-plate solar collectors

These solar heating systems have simple design and therefore they can be made with your own hands if desired. A durable bottom is secured to a metal frame. A layer of thermal insulation is laid on top. The housing walls are also insulated to reduce losses. Then there is a layer of adsorber - a material that absorbs solar radiation well, turning it into heat. This layer is usually black in color. The adsorber is equipped with pipes through which the coolant flows. From above, this entire structure is closed with a transparent lid. The material for the cover can be strained glass or one of the plastics (most often it is polycarbonate). In some models, the light-transmitting material of the cover may undergo special treatment: to reduce reflectivity, it is made not smooth, but slightly matte.

Pipes in a flat-plate solar collector are usually laid in a snake pattern, and there are two holes - inlet and outlet. Single-pipe and two-pipe connection. This is what you like. But for normal heat exchange a pump is needed. A gravity-flow system is also possible, but it will be very inefficient due to the low speed of the coolant. It is this type of solar collector that is used for heating, although it can be used to efficiently heat water for hot water supply.

There is a variant of a gravity collector, but it is used mainly for heating water. This design is also called a plastic solar collector. These are two plates made of transparent plastic, hermetically fixed to the body. There is a labyrinth inside to move water. Sometimes the bottom panel is painted black. There are two holes - inlet and outlet. Water is supplied inside, warmed by the sun as it moves through the labyrinth, and comes out warm. This scheme works well with a water tank and easily heats water for domestic hot water. This is a modern replacement for a conventional barrel mounted on summer shower. Moreover, a more effective replacement.

How efficient are solar collectors? Among all domestic solar systems today they show top scores: their efficiency is 72-75%. But not everything is so good:

they do not work at night and do not work well in cloudy weather;
large heat losses, especially in windy conditions;
low maintainability: if something breaks down, then a significant part, or the entire panel, needs to be replaced.

However, heating a private house from the sun is often done with the help of these solar installations. Such installations are popular in southern countries with active radiation and positive temperatures in winter period. They are not suitable for our winters, but in summer season show good results.

Air manifold

This setup can be used for air heating Houses. Structurally, it is very similar to the plastic collector described above, but air circulates and heats up in it. Such devices are hung on walls. They can operate in two ways: if the solar air heater is sealed, air is taken from the room, heated and returned to the same room.

There is another option. It combines heating with ventilation. There are holes in the outer housing of the air manifold. Through them, cold air enters the structure. Passing through the labyrinth, it is heated by the sun's rays, and then warmed up it enters the room.

Such heating of the house will be more or less effective if the installation occupies the entire southern wall, and there is no shadow on this wall.

Tubular manifolds

Here, too, the coolant circulates through pipes, but each of these heat exchange pipes is inserted into a glass flask. They are all connected in a manifold, which is essentially a comb.

Diagram of a tubular collector (click to enlarge the picture)

Tubular collectors have two types of tubes: coaxial and feather. Coaxial - a pipe in a pipe - are nested one inside the other and their edges are sealed. A rarefied airless environment is created inside between the two walls. That is why such tubes are also called vacuum tubes. Feather tubes are just a regular tube sealed on one side. And they are called feather ones because, to increase heat transfer, an adsorber plate is inserted into them, which has curved edges and is somewhat reminiscent of a feather.

In addition, heat exchangers can be inserted into different housings different types. The first are the Heat-pipe thermal channels. This is a whole system for converting sunlight into thermal energy. A heat-pipe is a small-diameter hollow copper tube sealed at one end. On the second there is a massive tip. A substance with a low boiling point is poured into the tube. When heated, the substance begins to boil, part of it turns into a gaseous state and rises up the tube. Along the way from the heated walls of the tube, it heats up more and more. Fall into top part, where he has been for some time. During this time, the gas transfers part of the heat to the massive tip, gradually cools, condenses and settles down, where the process is repeated again.

The second method is U-type, which is a traditional tube filled with coolant. There's no news or surprises here. Everything is as usual: the coolant enters on one side, passes through the tube, and is heated by sunlight. Despite its simplicity, this type of heat exchanger is more efficient. But it is used less often. And all because solar water heaters of this type form a single whole. If one tube is damaged, the entire section must be replaced.

Tubular collectors with a Heat-pipe system are more expensive, show lower efficiency, but are used more often. And all because a damaged tube can be changed in a couple of minutes. Moreover, if a coaxial flask is used, then the tube can also be repaired. It is simply disassembled (the top plug is removed) and the damaged element (thermal channel or the bulb itself) is replaced with a working one. The tube is then inserted into place.

Which collector is better for heating?

For southern regions with mild winters and big amount sunny days a year the best option- flat collector. In such a climate it shows the highest productivity.

For regions with harsher climates, tubular collectors are suitable. Moreover, systems with Heat-pipe are more suitable for harsh winters: they heat even at night and even in cloudy weather, collecting most of the spectrum solar radiation. They are not afraid of low temperatures, but the exact temperature range needs to be clarified: it depends on the substance located in the thermal channel.

These systems, when properly calculated, can be basic, but more often they simply save heating costs from another, paid source of energy.

Another auxiliary heating could be an air manifold. It can be made to cover the entire wall, and it can be easily done with your own hands. It is perfect for heating a garage or cottage. Moreover, problems with insufficient heating may arise not in winter, as you expect, but in autumn. In frost and snow, the sun's energy is many times greater than in cloudy, rainy weather.

Solar panels

When we hear the words “solar energy,” we first think of batteries that convert light into electricity. And this is done by special photoelectric converters. They are produced by industry from various semiconductors. Most often, we use silicon photocells for household use. They have the lowest price and show fairly decent performance: 20-25%.

Solar panels for a private home are common in some countries

Solar panels can be used directly for heating only if the boiler or other heating device on electricity you connect to this current source. Also, solar panels in combination with electric batteries can be integrated into the home’s electricity supply system and thus reduce monthly bills for used electricity. In principle, it is quite possible to fully meet the family’s needs from these installations. It just takes a lot of money and space. On average, you can get 120-150W per square meter of panel. So count how many squares of roof or local area should be occupied by such panels.

Features of solar heating

The feasibility of installing a solar heating system raises doubts among many. The main argument is that it is expensive and will never pay for itself. We have to agree that it is expensive: the prices for equipment are quite high. But no one is stopping you from starting small. For example, to evaluate the effectiveness and practicality of the idea of making a similar installation yourself. The costs are minimal, and you will have a first-hand idea. Then you will decide whether to get involved with all this or not. Here's the thing: all the negative messages are from theorists. Not a single one was encountered from practitioners. There is an active search for ways to improve and alterations, but no one said that the idea is useless. This says something.

Now let's talk about the fact that installing a solar heating system will never pay off. While the term is paying off

There is a lot of bridges in our country. It is comparable to the service life of solar collectors or batteries. But if you look at the dynamics of price growth for all energy resources, you can assume that it will soon decrease to a completely acceptable time frame.

Now let’s talk about how to make the system. First of all, you need to determine the needs of your home and family for heat and hot water. The general methodology for calculating a solar heating system is as follows:

Knowing what region the house is located in, you can find out how much sunlight falls on 1m2 of area in each month of the year. Experts call this insolation. From this data, you can then estimate how many solar panels you need. But first you need to determine how much heat will be needed for DHW preparation and heating.
If you have a hot water meter, then you know the volume of hot water you use monthly. Display the average consumption data for the month or calculate based on the maximum consumption - whoever wants it. You should also have data on heat losses at home.
Take a look at the solar heaters you would like to install. Having data on their performance, you can roughly determine the number of elements needed to cover your needs.

It must be said right away that a solar heating system, which covers about 30% of the heat demand and fully supplies hot water, is rational (from the point of view of payback) for central Russia. This is an average result: in some months, heating will be 70-80% provided by the solar system, and in some months (December-January) only 10%. Again, a lot depends on the type of solar panels and the region of residence.

Results

Despite many critics who talk about the inefficiency of solar energy and the long payback period, more and more people are at least partially switching to alternative sources. In addition to savings, many are attracted by independence from the state and its pricing policy. In order not to regret the wasted amounts of money invested, you can first conduct an experiment: make one of the solar installations with your own hands and decide for yourself how attractive it is to you (or not).

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, and consider the issue of economic feasibility and efficiency of solar collectors.

Main components of the heating system

The source of heating for the solar system is solar collectors, the purpose of which is to transfer the energy of the infrared spectrum of solar radiation to the coolant as efficiently as possible. The thermal range of sunlight is 40-45% of the total radiation flux, in specific figures it is 200-500 W/m2 depending on latitude, time of year and day.

In principle, to build the simplest solar system, only collectors are sufficient. Ordinary water used for household needs and home heating can circulate through their channels. 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 essential elements A solar heating system uses a heat accumulator - a container of water.

Scheme for heating a house with solar collectors: 1 - supply cold water; 2 - heat exchanger; 3 - heat accumulator; 4 - temperature sensor; 5 - coolant circuit; 6 - pumping station; 7 - controller; 8 - expansion tank; 9 - hot water; 10 - three-way valve; 11 - solar collector

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

Vacuum U-shaped solar collector tubes

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

Types and differences of collectors

Without going into technical details devices, the main difference between flat and vacuum collectors lies in the advisability of their use in different climatic zones. Flat-plate collectors are best used in southern latitudes with prevailing temperatures above zero, vacuum collectors - closer to northern latitudes.

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 feasibility 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-plate solar collectors, growing along 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.

Design of a vacuum manifold 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 heated coolant; 9 — heat sink body; 10 — heat pipe condenser; 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 ones can be assembled locally. Also, flat-plate collectors usually do not have their own heat accumulator and exchange circuit.

Problems of solar energy

Heating solar systems are not without their drawbacks, the most important of which is the inconstancy of the energy source. At night, the system does not heat up, and during prolonged cloudy weather, waiting for clear skies to heat the house is below average. If the battery, with a sufficiently large volume, is able to retain the required amount of heat at least until the morning, then for several days battery life in low light conditions can only be calculated with a significant expansion of the solar farm. This, in turn, causes the opposite problem: when reaching maximum power mode (for example, on a clear spring day), such a solar system will require more intense 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 season. Hybrid collectors, in which heaters are combined with photocells, work especially effectively. If cloudiness blocks most of the IR radiation, then the loss of the photoelectric part of the spectrum is not so significant.

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

Integration into the heating system

There are two ways to combine solar collectors with as many complex system heating with liquid coolant. 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 storage device communicates with the boiler jointly and sequentially; if the temperature is not high enough, the latter comes into operation and heats the liquid. A properly designed system of this kind can operate effectively even without forced circulation.

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

The second type of combination involves the use thermal battery with two circuits. Through one, heat is removed from the collector, through the second, the coolant in the system is heated, water from the battery serves as a source of hot water. Since the circuits are isolated from each other, more heat-intensive liquids or antifreeze can be used in the heating system and the heat exchange cycle from the solar collector. The main disadvantage is the energy dependence of the system, because circulation in both circuits 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 feasibility 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 statistical indicators. Therefore, the first thing you need to do is to independently compile a report on the intensity of solar radiation at the place where the collectors are installed. 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 in different time days with a frequency of about a week throughout the year. During the measurement process, it is necessary to take into account the angle of inclination and orientation of the collectors. The data obtained is ultimately checked against the statistics of the hydrometeorological center on the percentage of cloudy days per year.

To ensure high efficiency of the solar installation, the worst-case scenario should be considered, that is, the longest period with the lowest illumination should be taken as the starting point. Ideally, you can adjust for the likelihood of even more unfavorable weather conditions using meteorological statistics over the past 15-20 years. The obtained data on incoming solar energy will help to establish 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; they usually play a supporting 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, tilt, temperature regime, as well as a margin of safety.

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 for 10-15 in operation;
piping system recommended by the manufacturer throughput and heat resistance;
circulation group, shut-off valves, other auxiliary devices;
volume and location of the battery tank. In systems with a daily storage tank 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 design, allocate space for placing 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. Don’t forget that by purchasing a full range of equipment from one distributor, you get the opportunity to draw up for free, if not a project for 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 the production technology of flat-plate collectors is well mastered, vacuum absorbers remain expensive, and under certain conditions weather conditions You can successfully use only them. But there is another alternative - air-type collectors.

Due to the simpler device, their cost is lower, plus there is the possibility of autonomous operation. The efficiency of air collectors is increased with the installation of a blower fan powered by an integrated solar panel. Due to the accelerated, but proportional to heating, cooling of the channels, return heat loss through the collector is minimized. Power limitation can be achieved by controlling the fan speed or simply shutting off the flow - air collectors are not afraid of thermal shock, and natural recirculation is easy to set up.

Flaw air systems to a small degree of heating of the coolant. The heat capacity of air is less, plus the absorber almost always heats up 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 into the heated room), a heat pump or split system is really needed.

But air 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 times increase in output due to the high temperature difference. At night, the collector will also have a small share of output at the operating temperature range.

The air used as a coolant 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 operate with a high temperature difference and therefore the increase in power is not enough to justify the cost of the installation.

Cost of solar heating installation

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

The cost of flat and vacuum collectors is determined by the volume of production - the value of solar radiation in ideal conditions lighting, that is, specific power. On average, for 1 kW of flat-type solar collectors you will have to pay about $350-500, and for a complete installation with an external battery - about $800-1000. The cost of vacuum solar collectors ranges 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 standard measurement is in liters of water heated to the maximum possible temperature. The amount of electricity generated can be calculated either by the total area of the absorber, or by expressing it through the specific heat capacity of water. Depending on the complexity of the system, the cost varies greatly, the price of one example from the middle segment of the market reaches $1500 for 300 liters (for 4-5 residents) with a temperature difference of about 50 ° C, which is equivalent to 2.5 kW of power density.

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

You will learn everything about “green technologies” from our proposed article. With our help, you can easily understand the types of solar installations, the methods of their construction and the specifics of operation. You will probably be interested in one of the popular options that are actively working in the world, but are not yet in great demand here.

In the review presented to your attention, the design features of the systems are analyzed and the connection diagrams are described in detail. An example of solar calculation is given. heating circuit to assess the realities of its construction. To help independent craftsmen Attached are photo selections and videos.

On average, 1 m 2 of the earth's surface receives 161 W 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 so effective that they can work almost anywhere on earth.

Building solar heating for a private house with your own hands is not difficult task, as it seems to the ignorant layman. This will require welding skills and materials available at any hardware store.

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

Gaining complete 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 storing it is assembled in the garage?

Depending on the region, the solar flux can range from 50 W/sq.m on a cloudy day to 1400 W/sq.m with a clear summer sky. With such indicators, even a primitive collector with low efficiency (45-50%) and an area of 15 sq.m. can produce about 7000-10000 kWh per year. And this is 3 tons of firewood saved for a solid fuel boiler!

on average, there are 900 W per square meter of device;
to increase the water temperature, it is necessary to spend 1.16 W;
taking into account also the heat loss of the collector, 1 sq.m can heat about 10 liters of water per hour to a temperature of 70 degrees;
to provide 50 liters of hot water needed by one person, you will need to spend 3.48 kW;
Having checked 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 power of solar radiation - this will be the required area of the solar collector to heat 50 liters of water.

As it becomes clear, effective heating system It is quite problematic to implement it exclusively using solar energy. After all, during the gloomy winter season there is very little solar radiation, and it is impossible to place a collector with an area of 120 sq.m. on the site. it won't always work out.

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

So, in winter the heated coolant will be used in warm floors, 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” forms in the soil. For example, in a conventional geothermal circuit at the beginning 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 +2 C.

Construction of a homemade solar collector

For a master who is confident in his abilities, assembling a heat collector will not be difficult. You can start with small device to provide hot water at the dacha, and if the experiment is successful, move on to creating a full-fledged solar station.

Flat-plate solar collector made of metal pipes

The simplest collector to make is a flat one. For its device you will need:

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

Assembly of the solar collector is quite simple:

The pipes are welded to a 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 facing inside. Holes are drilled for the inlet and outlet of the pipes. Insulation is being installed. If a hygroscopic material is used, you need to take care of waterproofing - after all, once wet, the insulation will no longer protect the pipes from cooling.

The insulation is fixed OSB sheet, all joints are filled with sealant.
On the adsorber side it is placed clear glass or polycarbonate with a small air gap. It serves to prevent the steel sheet from cooling.
You can fix the glass using wooden window beads, after applying sealant. It will prevent cold air from entering and protect the glass from shrinking the frame when heating and cooling.

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

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

Solar heater made from scrap materials

If with welding machine It was not possible to establish a friendship, 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 cans themselves are fastened to each other with sealant, and they are seated on it at the junction with PVC pipes. They are painted black and placed in 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 entire wall on the south side.

This solution will allow optimizing heating costs in two directions at once - reducing energy costs and significantly reducing heat loss due to additional insulation of the facade.

The device is incredibly simple and does not require special tools:

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

If this method seems complicated, the video shows a version made from tin, polypropylene pipes and films. Much easier!