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How to make a solar collector with your own hands? Solar water heater Do-it-yourself solar water heater.

The sun is the largest source of safe and free energy. And if earlier people could not use it, now there are technologies that help to provide the house with heat and hot water only due to the sun. Using collectors is a cost-effective and affordable way to make a country house more comfortable. You just need to choose the right solar collector (or make it yourself), and then introduce it into the existing heating system.

What is a solar water heater

A collector (water heater) is a device that collects the energy of the sun's rays and turns it into heat. The sun heats the coolant in the collector, which is then used for hot water supply and heating or electricity generation.

Devices associated with the energy of the sun, it is correct to call solar installations or solar collectors (on behalf of the ancient Greek god of the sun Helios).

Modern solar water heaters can be complex, but any owner of a private house can make a device for their own needs. The main thing is to figure out what this device is for.

Three manifolds fully meet the needs of the family in hot water and heating

Scope of solar installations

In our country, the phrase solar water heater is still associated with a black tank on the roof of a summer shower booth, but this technology is successfully used all over the world. Solar collectors are common in the southern regions of Europe. Residents of private homes in Italy, Spain and Greece are required by law to use solar water heaters. Not far behind the West and China. There, solar water heaters are installed on the roofs of skyscrapers and provide hot water to all apartments. In 2000, there were so many solar plants in the world that, put together, they would take more than 71 million m 2. Almost 15 million m 2 of them would be European.

Solar vacuum collectors almost completely occupy the roofs of Chinese new buildings

Such devices are used for hot water supply of domestic premises and industrial buildings, heating of private houses, administrative buildings, workshops. They are most in demand in the food and textile industries, since it is in this area that there are many production processes using hot water.

In the private sector, for every person from Germany there is 0.14 m 2 of solar collector area, from Austria - 0.45 m 2, from Cyprus - 0.8 m 2, and from Russia - 0.0002 m 2. The intensity of solar lighting in Russia is only 0.5 kWh/m 2 less than in southern Germany. This means that the low popularity of solar collectors in the northern regions is not due to geographical reasons.

With an extensive manifold system, even pool water can be heated

Types of solar collectors

Engineers have developed flat, tubular vacuum concentrators with parabolic trough reflectors, air towers, solar towers and other types of installations. The most popular for domestic purposes are flat and vacuum water heaters.

Table: Comparative characteristics of flat and vacuum collectors

flat collector	vacuum manifold
Easy to do with your own hands from improvised materials.	Produced in industrial conditions or assembled from factory parts.
Pays off quickly.	It pays off three times longer than a flat one.
Less likely to overheat in hot weather.	Does not allow the return of accumulated heat to the environment.
Effectively works in the summer or in countries with a hot climate.	Suitable for cold regions, works in winter at temperatures down to -30 ° C.
It has a high windage, so a strong gust of wind can rip it off the roof.	The wind passes freely between the vacuum tubes, so the probability that the collector will not be affected by a storm is higher.
It clears itself of snow, frost and ice.	Performance is 2-3 times higher than that of a flat collector (with equal areas).

Features of Flat Solar Water Heaters

The device is a panel, inside of which there are copper tubes with a dark coating. They heat water, which is then collected in a tank and used for DHW (hot water supply). If you make a collector yourself, then expensive components can be replaced with available materials:

instead of copper pipes, you can take steel, polyethylene or just a radiator from an old refrigerator;
a wooden frame can become a replacement for a metal one, although it weighs more;
chrome absorber will replace the usual black paint;
a sheet of glass or cellular polycarbonate will serve well as a protective cover, and polystyrene foam will serve as a heater.

The main thing is to ensure the tightness of the panel, but for this it is enough to seal all the seams with building silicone. The main disadvantage of such devices is that the heated coolant radiates heat into the air and cools slightly before entering the storage tank. The use of thermal insulation and sealing of seams are designed to combat this effect.

Expensive parts of an industrial manifold can be replaced with cheaper counterparts, for example, use steel pipes instead of copper pipes, and make the device frame wooden

If water is not taken from a flat-plate collector, on a hot sunny day it can heat up to 190–210 ° C, which can lead to rupture of coolant pipes or connecting elements. For those who use a solar water heater on an occasional basis, it is important to install a storage tank that can eliminate excess pressure in the pipes. Another option is to use mineral oil instead of water as a heat sink. Its boiling point is higher, which reduces the risk of damage to the system. In this case, you need a heat exchanger in which the oil will transfer the accumulated heat to the water without direct contact.

Flat-plate solar collectors are cheaper and easier to manufacture, but are only suitable for summer operation in a country house or as an auxiliary water heater. Use them only for domestic hot water.

Features of vacuum manifolds

Solar water heaters of this type consist of separate tubes, each of which is in an airless environment. This design made it possible to reduce heat losses on the way from the collector to the storage tank and increase the efficiency of the system. Thanks to this, vacuum collectors work perfectly during the change of seasons (autumn, spring) and in winter.

Vacuum solar water heaters also use copper tubes, as this material provides good heat transfer and is hygienic at the same time. The remaining elements are similar: glass (borosilicate for better heat transmission), under it is a black absorbing layer, a tube with a coolant and a substrate. It is easier to ensure the tightness of the system, since there is only one seam - the connection between the tube and the storage tank.

Cold water gradually heats up from alternate contact with hot copper pipes. The heat from the vacuum solar system is only removed in this way, so it is important to ensure that it has a regular supply of cold water, that is, to use hot water throughout the day. To increase the stability of the system, antifreeze is used as a coolant in vacuum solar collectors. It tolerates heat well up to 300 ° C and does not freeze when the temperature of the device drops to -40 ° C on a cloudy day.

For year-round hot water supply and heating of a country house, a vacuum solar collector is required. It is more expensive, but more efficient and more reliable than a flat one.

It is impossible to create a full-fledged vacuum solar collector with your own hands: the manufacture of a thick-walled tube from borosilicate glass is unthinkable in artisanal conditions. Therefore, a more reliable option would be to purchase factory flasks (coaxial and feather varieties are offered) and assemble the solar water heater on site. But since even such work requires remarkable locksmith skills, it is better to buy a finished product with a guarantee from the manufacturer.

In which system to integrate a solar water heater

In order for hot water to start flowing from the tap, it is important not only to choose a collector, but also to create a whole system for it from a storage tank, connecting pipes, taps and other elements.

Circulation types

It is necessary to determine whether you can install the storage tank above the level of the collector. It depends on which of the two types of circulation will be in the system.

Natural circulation is created due to the difference in density of cold and hot water.. The heated liquid tends to rise, which causes such an arrangement of the storage tank. If the roof has a complex structure, choose a well-lit place to place the collector and place the tank under the ridge.
Forced circulation systems work thanks to a pump that pumps warm water into a prepared tank. In this case, it becomes possible to place the elements of the system far from each other, for example, to put a storage tank in the attic or in the basement. This is better for the exterior, requires less effort on the thermal insulation of the tank itself. But the pipes leading from the collector to the tank must be provided with thermal insulation, otherwise there is a risk of losing all the heat along the way. Forced circulation requires the use of electricity, so if there is no or often no electricity in the country, this option will not work.

If you decide to use a coolant oil in the manifold, provide a pump for forced circulation. Otherwise, due to the low expansion coefficient of the oil, the system simply will not work.

Selecting the type of circulation circuit

Three types of systems are common:

Open loop. This is the easiest way to supply hot water to your home. Its main difference is that the coolant in the collector is necessarily water. First, it is heated in tubes, then it enters the storage tank, and then directly to the faucet in the kitchen or bathroom. That is, water does not circulate in a circle, but in an open circuit, a new portion is heated each time.
Single-circuit. It is preferable when using solar heat it is supposed to heat the house or make the operation of electric heating cheaper. Its difference is that the water heated by the sun enters the heating pipes. The coolant moves in the system in a circle. This is the closed circulation cycle. Since the solar collector is used in winter and off-season, choose vacuum models and include an additional heater in the system. An electric or gas boiler helps to bring the coolant to the desired temperature on cold and cloudy days, as well as at night.
Dual circuit. This option involves the transfer of heat from the collector to the system through a special heat exchanger. Since there is no direct contact between the coolant and water, oil or antifreeze is used in the collector. The system is optimal for country houses in which people live throughout the year. In it, the collector is used for both hot water supply and heating at the same time. As a rule, a boiler and / or boiler for additional heating of water is also integrated into it, and several collectors are used (depending on the number of residents and the climatic characteristics of the region).
In a two-circuit circulation system, there is no direct contact between the solar water heater and water

The circulation system with an open circuit is effective for the hot water supply of a summer residence, a double-circuit one - for the complete supply (hot water supply and heating) of a country house.

How to make a flat solar collector with your own hands

For this you need a drawing. You will also need to calculate the area of the water heater in accordance with the needs of the family. This parameter is determined by the formula: A=K*F*SF/(G*η)AW=1/(G*η)A=K*F*SF*AW, where:

A - area of collectors, m2;
AW - reduced area, which is capable of generating 1 kW*hour per day, m2*day/(kW*hour);
Η – efficiency of one collector, %;
G - total solar radiation per day, typical for the area, kW*h/(m2*day);
K - coefficient taking into account the magnitude of the angle of inclination of the collectors and their orientation relative to the cardinal points;
F is the energy required to heat water for a day, kWh/day;
SF is the share of solar energy in covering the heat demand, %.

For the construction of the collector, you will need a detailed drawing indicating the number and size of parts

Tools and materials for work

For the manufacture of a flat solar collector measuring 2.28x1.9x0.1 m with metal-plastic pipes and a wooden frame, you will need:

hacksaw or jigsaw for cutting wood and plywood;
scissors for metal-plastic pipes;
screwdriver;
brushes and spray gun or spray paint for blackening mounted pipes.

Sequencing:

Assemble a box for the base of the collector from two sheets of plywood measuring 1.52x1.52 m 1 cm thick. Cut one of them to create sides for parts: 0.76x0.38 m - 4 pcs. 1 PC.
Paint the inner surface of the resulting box with black matte paint, and the outer surface with white or cover it with a protective varnish.
Create a frame for attaching the box from a bar with a section of 5x5 cm, according to the attached diagram. In total, 60 m of timber will be needed. Before assembly, it is important to treat the parts with a wood preservative to protect the material from precipitation and temperature changes. Fasten the parts together with wood screws using metal corners 5x5 cm.
Fix the box on the prepared stand and carry out further assembly on this inclined stand.
Make a markup where the pipes will pass, and in the right attachment points for them. Paint them black too so as not to increase heat loss.
Cut 0.5 inch thick metal-plastic pipes into pieces of the required length. In order not to make a mistake, use the first fragment as a reference sample. You should get 45 pieces of 2.14 m each.
Assemble the snake from the pipes on the stand, using fittings for metal-plastic pipes on the turns. In total, 44 angled elbows of the "mother-mother" and "mother-father" types and 88 adapters from a metal-plastic pipe to a fitting are needed. Use sealing thread to seal the connections. At the beginning and end of the snake, fix the adapters for connecting the water supply and drainage hoses.
Paint the structure black with an airbrush or spray can.
The collector coil is painted black
Connect the coil to the pump and make sure that no leakage occurs when pumping water. If any connection is not tight enough, drain the water and reassemble it, and then check again.
Cover the top of the box with clear glass or solid polycarbonate. If it is not possible to use a single sheet, make an aluminum frame in the size of the existing fragments (preferably no more than four) and securely fasten the panels. Treat each joint carefully with transparent silicone so that the water heater is airtight.

According to the described scheme, a collector with a power of 1.6–2 kW is assembled.

To reduce the cost of the device, a flexible pipe made of cross-linked polyethylene is used. It is originally black and mounted with a snake using just two fittings. But in this case, the water will come into contact not with hygienic metal (as in the case described), but with plastic. This is undesirable if the water is also intended for cooking.

Video: how to make a flat solar water heater with copper tubes

Solar collector installation

The device is installed on the roof. This option is suitable for country houses and high-rise buildings. It is better if the roof is pitched and the angle of inclination is close to the latitude of this region. In this case, you will need to attach brackets to the boards on its south side through the roofing material. The collector will be placed 15–20 cm above the roof level, parallel to the slope. This is the most harmonious solution, especially if several water heaters are used in the house. Sometimes the collector is recessed into the roof so that the protective screen is flush with the decorative roofing. But this method is much more expensive and can weaken the roof structure.

It is best to mount the flat-plate collector system on a pitched roof

On flat roofs, collectors are mounted on special structures that hold them at a given angle. Stands can be purchased ready-made or welded independently from the corners. The metal structure is attached to the base with large anchor bolts.

On a flat roof, collectors are mounted on special structures

In dachas, solar collectors are installed next to the house or swimming pool in an open sunny area. In this case, they choose a place on an already created site or equip a reliable base separately. To do this, you need a rectangular platform with a compacted bulk cushion, waterproofing and paving slabs, porcelain stoneware, and other durable, hard and weather-resistant material. Subsequently, a metal or wooden easel stand is mounted on it, on which the solar collector is attached.

Installing a solar collector on supports that do not have a common base is considered a less reliable option, but helps save space

Solar collector maintenance

Like any other equipment, the device requires maintenance. Most common jobs:

If the collector was purchased, at the first breakdown, you should call the master, and during the warranty period, contact the manufacturer's representative. A homemade solar water heater will have to be repaired on its own, but finding a breakdown and fixing it in a homemade product is much easier than in a factory one. The experience of collector repairers suggests that the condition of the valves, sensors, storage tank and pump should first be checked, as they are less reliable than the solar plant itself.

In DHW systems with a solar collector, valves and sensors most often fail.

Video: instructions for assembling a solar collector from aluminum cans

The owners of solar collectors are sure: once you evaluate the capabilities of this device, it will simply be impossible to do without it. Now you can provide your home or cottage with cheap and safe heat.

The level of development of modern technologies and materials is so high that not using solar energy is unreasonable from the financial side and criminal in relation to the environment. Unfortunately, the purchase of industrial installations for generating electricity and heat is irrational due to their high cost. Nevertheless, there is a way out: to make a productive solar collector with your own hands from materials that can be found in the nearest hardware store.

The purpose of the solar collector, its advantages and disadvantages

A solar water heater (liquid solar collector) is a device that heats a coolant with the help of solar energy. It is used for space heating, hot water supply, water heating in swimming pools, etc.

The solar collector will provide the house with hot water and heat

The prerequisite for using an eco-friendly water heater is the fact that solar radiation falls on the Earth all year round, although it differs in intensity in winter and summer. So, for middle latitudes, the daily amount of energy in the cold season reaches 1–3 kWh per 1 sq.m, while in the period from March to October this value varies from 4 to 8 kWh/m 2. If we talk about the southern regions, then the figures can be safely increased by 20-40%.

As you can see, the efficiency of the installation depends on the region, but even in the north of our country, the solar collector will provide the need for hot water - the main thing is that there are fewer clouds in the sky. If we talk about the middle lane and the southern regions, then the solar-powered installation will be able to replace the boiler and cover the needs of the heating system coolant in winter. Of course, we are talking about productive water heaters of several tens of square meters.

A solar battery will help save money from the family budget. The following material will help to make it yourself:

Table: distribution of solar energy by region

Average daily amount of solar radiation, kW * h / m 2
Murmansk	Arkhangelsk	Saint Petersburg	Moscow	Novosibirsk	Ulan-Ude	Khabarovsk	Rostov-on-Don	Sochi	Nakhodka
2,19	2,29	2,60	2,72	2,91	3,47	3,69	3,45	4,00	3,99
Average daily amount of solar radiation in December, kW*h/m2
0	0,05	0,17	0,33	0,62	0,97	1,29	1,00	1,25	2,04
Average daily amount of solar radiation in June, kW*h/m2
5,14	5,51	5,78	5,56	5,48	5,72	5,94	5,76	6,75	5,12

Home-built solar collectors are no match for factory-made solar collectors, but a home-made solar installation will cut domestic water heating costs and save electricity when connected to a washing machine and dishwasher.

Advantages of solar water heaters:

relatively simple design;
high reliability;
efficient operation regardless of the season;
long service life;
the possibility of saving gas and electricity;
no permission is required to install equipment;
small mass;
ease of installation;
complete autonomy.

As for the negative points, not a single installation for obtaining alternative energy can do without them. In our case, the disadvantages are:

high cost of factory equipment;
dependence of the solar collector efficiency on the time of year and geographic latitude;
susceptibility to hail;
additional costs for the installation of a heat storage tank;
dependence of the energy efficiency of the instrument on cloudiness.

Considering the pros and cons of solar water heaters, one should not forget about the environmental side of the issue - such installations are safe for humans and do not harm our planet.

The factory solar collector resembles a construction set, with which you can quickly assemble the installation of the required performance

Types of solar water heaters: the choice of design for self-production

Depending on the temperature that solar heaters develop, there are:

low-temperature devices - designed for heating liquids up to 50 ° C;
medium temperature solar collectors - increase the outlet water temperature up to 80 °C;
high-temperature installations - heat the coolant to the boiling point.

At home, you can build a solar water heater of the first or second type. To manufacture a high-temperature collector, industrial equipment, new technologies and expensive materials will be needed.

By design, all liquid solar collectors are divided into three types:

flat water heaters;
vacuum thermosyphon devices;
solar concentrators.

A flat solar collector is a low heat-insulated box. A light-absorbing plate and a tubular circuit are installed inside. The absorbing panel (absorber) has an increased thermal conductivity. Due to this, it is possible to achieve maximum energy transfer to the coolant circulating around the water heater circuit. The simplicity and efficiency of flat installations is reflected in numerous designs developed by craftsmen.

Inside a flat solar collector - a light-absorbing plate and a tubular circuit

The principle of operation of vacuum solar water heaters is based on the thermos effect. The design is based on dozens of double glass flasks. The outer tube is made of impact-resistant, tempered glass that resists hail and wind. The inner tube has a special coating to increase light absorption. Air is evacuated from the space between the elements of the flask, which makes it possible to avoid heat losses. In the center of the structure there is a copper thermal circuit filled with low-boiling coolant (freon) - it is the heater of the vacuum solar collector. In the process, the process fluid evaporates and transfers heat energy to the main circuit working fluid. In this capacity, antifreeze is most often used. This design allows the system to operate at temperatures down to -50 °C. It is difficult to build such an installation at home, so there are a few self-made vacuum-type structures.

The design of the vacuum solar collector is based on a set of double glass flasks

The solar concentrator is based on a spherical mirror capable of focusing solar radiation to a point. The liquid is heated in a spiral metal circuit, which is placed at the focus of the installation. The advantage of solar concentrators is the ability to develop high temperatures, but the need for a tracking system for the Sun reduces their popularity among DIYers.

Building a productive solar concentrator at home is not an easy task

For home fabrication, flat plate solar heaters built using thermal insulation materials, high transmittance glass and copper absorbers are best suited.

The device and principle of operation of a flat solar collector

A homemade solar water heater consists of a flat wooden frame (box) with a blank back wall. At the bottom is the main element of the device - the absorber. Most often it is made of a metal sheet attached to a tubular collector. The efficiency of energy transfer depends on the contact of the absorber plate with the heat exchanger pipes, so these parts are welded or soldered with a continuous seam.

The fluid circuit itself is an array of vertically mounted tubes. In the upper and lower parts, they are connected to horizontal pipes of increased diameter, which are intended for the supply and withdrawal of the coolant. The inlet and outlet for the liquid are located diagonally - due to this, complete heat removal from the heat exchanger elements is ensured. Antifreeze for heating systems or other antifreeze solutions are used as a heat carrier.

The absorber is covered with light-absorbing paint, glass is placed on top, and the box is protected with a layer of thermal insulation. To simplify the task, the glazing area is divided into parts, and in order to increase productivity, double-glazed windows are used. The closed design creates the effect of a thermos in the solar collector and at the same time prevents heat loss due to wind, rain and other external factors.

The solar water heater works like this:

The non-freezing liquid heated in the solar collector rises through the tubes and enters the heat storage tank through the coolant withdrawal branch.
Moving through the heat exchanger installed inside the storage tank, the antifreeze gives off heat to the water.
The cooled working fluid enters the lower part of the solar water heater circuit.
The water heated in the tank rises and is taken for the needs of hot water supply. The replenishment of the liquid in the heat storage tank occurs due to the water pipe connected to the bottom. If the solar collector works as a heating system heater, then a circulation pump is used to circulate water in a closed secondary circuit.

The constant movement of the coolant and the presence of a heat accumulator allows you to accumulate energy while the sun is shining, and gradually spend it even when the luminary is hiding behind the horizon.

The scheme for connecting a solar collector to a storage tank is not so complicated.

Options for homemade solar installations

A feature of do-it-yourself solar water heaters is that almost all devices have the same design of a heat-insulated box. Often the frame is assembled from lumber and covered with mineral wool and a heat-reflecting film. As for the absorber, metal and plastic pipes are used for its production, as well as ready-made components from unnecessary household equipment.

From a garden hose

A snail-shaped garden hose or PVC plumbing pipe has a large surface area, which makes it possible to use such a circuit as a water heater for the needs of an outdoor shower, kitchen or pool heating. Of course, for these purposes it is better to take black materials and be sure to use a storage tank, otherwise the absorber will overheat during the peak of the summer heat.

A flat-plate garden hose collector is the easiest way to heat your pool water

From the condenser of an old refrigerator

The external heat exchanger of a used refrigerator or freezer is a ready-made solar collector absorber. All that remains to be done is to retrofit it with a heat-absorbing sheet and install it in the case. Of course, the performance of such a system will be small, but in the warm season, a water heater made from refrigeration equipment parts will cover the hot water needs of a small country house or cottage.

The heat exchanger of an old refrigerator is an almost ready-made absorber for a small solar heater

From a flat radiator heating system

The manufacture of a solar collector from a steel radiator does not even require the installation of an absorbing plate. It is enough to cover the device with black heat-resistant paint and mount it in a sealed casing. The performance of one installation is more than enough for a hot water supply system. If you make several water heaters, you can save on heating the house in cold sunny weather. By the way, a solar plant assembled from radiators will heat utility rooms, a garage or a greenhouse.

The steel radiator of the heating system will serve as the basis for the construction of an environmentally friendly water heater

From polypropylene or polyethylene pipes

Pipes made of metal-plastic, polyethylene and polypropylene, as well as fittings and devices for their installation, allow you to build solar circuits of any size and configuration. Such installations have good performance and are used for space heating and hot water for household needs (kitchen, bathroom, etc.).

The advantage of a solar collector made of plastic pipes is low cost and ease of installation

From copper pipes

Absorbers constructed from copper plates and tubes have the highest heat transfer, therefore they are successfully used for heating the coolant of heating systems and in hot water supply. The disadvantages of copper collectors include high labor costs and the cost of materials.

The use of copper pipes and plates for the manufacture of the absorber guarantees a high efficiency of the solar plant

Solar collector calculation method

The performance of a solar solar collector is calculated based on the fact that 1 sq.m of installation on a clear day accounts for from 800 to 1 thousand W of thermal energy. The losses of this heat on the reverse side and walls of the structure are calculated according to the thermal insulation coefficient of the insulation used. If expanded polystyrene is used, then for it the heat loss coefficient is 0.05 W / m × ° C. With a material thickness of 10 cm and a temperature difference of 50 °C inside and outside the structure, the heat loss is 0.05/0.1 × 50 = 25 W. Taking into account the side walls and pipes, this value is doubled. Thus, the total amount of outgoing energy will be 50 W per 1 sq.m of solar heater surface.

To heat 1 liter of water by one degree, 1.16 W of thermal energy is required, therefore, for our model of a solar collector with an area of 1 sq.m and a temperature difference of 50 °C, it will be possible to obtain a conditional performance coefficient of 800/1.16 = 689.65/kg × ° C. This value shows that a 1 sq.m installation will heat up 20 liters of water by 35 °C within an hour.

The calculation of the required performance of a solar water heater is carried out according to the formula W = Q × V × δT, where Q is the heat capacity of water (1.16 W/kg × °C); V - volume, l; δT is the temperature difference at the inlet and outlet of the installation.

Statistics say that one adult needs 50 liters of hot water per day. On average, for hot water supply, it is enough to raise the water temperature by 40 °C, which, when calculated using this formula, requires energy costs W = 1.16 × 50 × 40 = 2.3 kW. To find out the area of the solar collector, this value must be divided by the amount of solar energy per 1 sq.m of surface at a given geographical latitude.

Calculation of required solar system parameters

Making solar water heater with copper absorber

The solar collector proposed for production on a sunny winter day heats water to a temperature above 90 ° C, and in cloudy weather - up to 40 ° C. This is enough to provide the house with hot water. If you want to heat your home with solar energy, you will need several such installations.

Required materials and tools

To make a water heater you will need:

sheet copper with a thickness of at least 0.2 mm and dimensions of 0.98 × 2 m;
copper tube Ø10 mm, length 20 m;
copper tube Ø22 mm, length 2.5 m;
thread 3/4˝ - 2 pcs;
plug 3/4˝ - 2 pcs;
soft solder SANHA or POS-40 - 0.5 kg;
flux;
chemicals for absorber blackening;
OSB board 10 mm thick;
furniture corners - 32 pieces;
basalt wool 50 mm thick;
sheet heat-reflecting insulation 20 mm thick;
rail 20x30 - 10m;
door or window seal - 6 m;
window glass 4 mm thick or double-glazed window 0.98x2.01 m;
self-tapping screws;
dye.

In addition, prepare the following tools:

electric drill;
a set of drills for metal;
"crown" or cutter for woodworking Ø20 mm;
pipe cutter;
gas-burner;
respirator;
paint brush;
a set of screwdrivers or a screwdriver;
electric jigsaw.

To pressurize the circuit, you will also need a compressor and a pressure gauge designed for pressure up to 10 atmospheres.

For soft soldering, a simple gas torch is suitable

Instructions for the progress of work

Using a pipe cutter, the copper tube is cut into pieces. You will get 2 parts Ø22 mm 1.25 m long and 10 elements Ø10 mm 2 m long.
In thick pipes, a margin of 150 mm is made from the edge and 10 holes Ø10 mm are made every 100 mm.
Thin tubes are inserted into the resulting holes so that they protrude inward by no more than 1–2 mm. Otherwise, excessive hydraulic resistance will appear in the radiator.
Using a gas burner, hot air gun and solder, all parts of the radiator are interconnected.
The solar collector circuit works under pressure, so special attention is paid to the tightness of the connections

To assemble the radiator, you can use special fittings, but in this case, the cost of the solar system will increase significantly. In addition, collapsible connections do not guarantee the tightness of the structure under variable thermodynamic loads.
Plugs and threads are soldered in pairs along the radiator diagonals to 3/4˝ pipes.
Having closed the outlet thread with a plug, a fitting is screwed onto the inlet of the assembled manifold and the compressor is connected.
The compressor is connected with a fitting
The radiator is placed in a container with water and a pressure of 7–8 atm is pumped up by the compressor. The bubbles rising at the joints are used to judge the tightness of the soldered joints.
If a suitable container for checking the collector could not be found, then you can assemble it yourself. For this, a box or a simple barrier is made from improvised means (trimming of lumber, brick, etc.) and covered with plastic wrap.
After checking the tightness, the radiator is dried and degreased. Then proceed to the soldering of the copper sheet. Solder the absorber sheet to the tubes with a continuous seam along the entire length of each element of the copper circuit.
Soldering of the absorber sheet is carried out with a continuous seam
Since the solar collector absorber is made of copper, chemical blackening can be used instead of painting. This will allow you to get a real selective coating on the surface, similar to what is obtained in the factory. To do this, a heated chemical solution is poured into the container for leak testing and the absorber is placed face down. During the reaction, the temperature of the reagents is maintained by any available method (for example, by constantly pumping the solution through a vessel with a boiler).
Blackening of copper is one of the most critical stages in the manufacture of an absorber.

As a liquid for chemical blackening, you can use a solution of sodium hydroxide (60 g) and potassium persulfate or ammonium persulfate (16 g) in water (1 l). Remember that these substances are dangerous to humans, and the process of copper oxidation itself is associated with the release of harmful gases. Therefore, it is imperative to use protective equipment - a respirator, goggles and rubber gloves, and the work itself is best done outdoors or in a well-ventilated area.
Parts are cut out from the OSB sheet for assembling the solar collector housing - the bottom 1x2 m, the sides 0.16x2 m, the top 0.18x1 m and the bottom 0.17x1 m panels, as well as 2 supporting partitions 0.13x0.98 m.
A 20x30 mm rail is cut into pieces: 1.94 m - 4 pcs. and 0.98 m - 2 pcs.
Holes Ø20 mm are made in the side walls for the inlet and outlet pipes, and 3-4 holes Ø8 mm are drilled in the lower part of the collector for microventilation.
Holes needed for micro-ventilation
Cutouts are made in the partitions for the absorber tubes.
A support frame is assembled from slats 20x30 mm.
Using furniture corners and self-tapping screws, the frame is sheathed with OSB panels. In this case, the side walls should rest on the bottom - this will prevent the deflection of the body. The bottom panel is lowered 10 mm from the rest to cover it with glass. This will prevent precipitation from getting inside the frame.
Install interior partitions.
When assembling the case, be sure to use a building square, otherwise the design may turn out to be lopsided
The bottom and sides of the body are insulated with mineral wool and covered with rolled heat-reflecting material.
It is better to use mineral wool with moisture-repellent impregnation.
The absorber is placed on the prepared space. To do this, one of the side panels is dismantled, which is then put in place.
Scheme of the internal "pie" of the solar collector
At a distance of 1 cm from the upper edge of the box, the inner perimeter of the structure is sheathed with a wooden lath 20x30 mm so that its wide side touches the walls.
A sealing gum is glued around the perimeter.
For tightness, use a conventional window seal.
Glass or a double-glazed window is laid, the contour of which is also pasted over with a window seal.
The structure is pressed with an aluminum corner, in which holes for self-tapping screws are pre-drilled. At this stage, the collector assembly is considered complete.
When assembled, the thickness of the solar collector is about 17 cm

To prevent moisture ingress and heat leakage, at all stages the joints and mating points of the parts are treated with silicone sealant. To protect the structure from precipitation, the wood is coated with a special compound and painted with enamel.

Features of installation and operation of liquid heating collectors

To place the solar collector, choose a spacious place that is not shaded all daylight hours. The mounting bracket or subframe is made of wooden slats or metal in such a way that the inclination of the water heater is adjustable from 45 to 60 degrees from the vertical axis.

Connection diagram for a solar heater in a forced circulation system

The storage tank to reduce heat losses is placed as close as possible to the installation. Depending on the conditions, natural or forced circulation of the coolant is organized. In the latter case, a controller is used with a temperature sensor embedded in the outlet pipe. The pumping of the working fluid along the circuit will turn on when its temperature reaches the programmed value.

A seasonally operating system is filled with water, while year-round use of a solar water heater requires the use of an antifreeze fluid. The ideal option is a special antifreeze for solar systems, but to save money, liquids intended for car radiators or domestic heating systems are also used.

Video: do-it-yourself solar water heater

Building a solar collector is not only an interesting and exciting activity. A solar water heater will save your family budget and will prove that you can protect the environment not only in words, but also in real deeds.

Thanks to my versatile hobbies, I write on various topics, but my favorite ones are engineering, technology and construction. Perhaps because I know a lot of nuances in these areas, not only theoretically, as a result of studying at a technical university and graduate school, but also from the practical side, since I try to do everything with my own hands.

The solar collector is a group of metal plates that are usually installed on the south side of the roof. They are painted black, since it is the black surface that heats up faster and keeps heat longer. These metal plates are placed in a plastic frame.

Usually several such metal collector sheets are installed on the roof, since when the sun's rays touch the surface of the roof, the energy contained in these rays is evenly distributed over the entire surface of the roof. Therefore, the more sheets are installed on the roof slope, the more energy they accumulate.

The whole principle of operation of solar installations can be represented as follows:

The coolant-water moves through the collector through special pipes. Water circulation can be carried out both naturally and artificially, that is, with the help of circulation pumps. First, the collector is heated by sunlight, then this heat is transferred to the coolant. The heated liquid then flows through the pipes and enters the storage tank, which is a special water tank.

The walls of this tank have good thermal insulation so that it does not lose heat. Also, additional electric heaters can be mounted in this tank, which will automatically come into the working phase, if suddenly there is a long cloudy weather outside, and the collectors do not heat up. The water in this tank can stand for as long as you like, until the owners prefer to use it for their own purposes.

Based on the foregoing, we can conclude that the whole principle of operation of solar installations is to convert solar energy into heat.

Kinds

There are several types of solar collectors:

Flat. Today, representatives of this category are very popular in the field of use. Such a solar plant consists of a platinum sheet, which is painted black. This sheet is enclosed in a metal frame, the outer side of which is covered with glass for better light transmission. In devices of this type, everything is done to reduce the heat loss to a minimum.

Glass for such structures is made in such a way that the iron content in it is as low as possible. This contributes to a better transmission of solar energy. Solar energy passes through the glass and heats the surface of the collector in which the coolant moves. Further, this coolant is heated by platinum plates.

Collectors that accumulate solar energy in solar installations are also called absorbing plates. They are made not only from platinum. Instead, metals such as copper and aluminum, which have high thermal conductivity, can be used.

Liquid. In installations of this type, a liquid is used as a heat carrier. Heat exchangers are installed under the absorbent element and are attached to it from below. They can take the form of a coil, or separate tubes running parallel to each other. The serpentine is of course a convenient option, as the risk of possible leakage is minimized. Liquid solar plants can be divided into two subspecies:

Open. In such systems, water is used as the heat carrier. It is heated in the installation, and sent to the tank, from where it goes to use. It is inconvenient to use such systems, since during periods of low temperatures, water freezes and can break pipes.
Closed. In systems of this type, the role of the coolant is played not by water, but by a special non-freezing liquid. In the installation, it is heated by solar energy and enters the heat exchanger, which is a tank, inside of which there is a hermetically sealed water tank. The heated non-freezing liquid transfers its heat to the water, which immediately heats up and goes to use.

Air. If water has a number of disadvantages, such as freezing and boiling, then the use of air as a heat carrier will help to completely eliminate these disadvantages. Indeed, air does not freeze at low temperatures, and also does not boil at high temperatures. Due to these advantages, air is an excellent heat carrier. In addition, inexpensive materials are used in air solar installations, and maintenance work is carried out very easily.

The design of solar solar installations includes several collectors, the role of which is played by metal plates. The coolant moves between them by natural convection (there is an option where fans are used). Then the heated air enters the room. The downside is that air is a poor heat carrier.

Scheme and design

The design of the solar collector itself is only part of a massive undertaking. The fact is that for the correct operation of the entire system, you need to design the correct harness. Here we will consider a scheme in which the solar plant operates on two tanks. One of the tanks is a heat accumulator, which is used for heating, and the other is for hot water.

Check valves. The main function of non-return valves is to prevent water from flowing back, that is, it forces water to flow in one direction. In this scheme, check valves are installed in the path of the liquid exiting the manifold so that the liquid does not flow back into the device. Two more check valves are installed at the outlet of the tanks.
circulation pumps. They are essential. This diagram shows the use of two pumps. One of them is installed at the outlet of the DHW tank, and the other at the outlet of the heat accumulator. If only the pump located near the DHW works, then the entire system will work only for heating the DHW, and if only the pump next to the storage tank works, then the system works only for this element. You can also turn on both pumps.
Stop valve. In this scheme, in the storage tank, the coolant flows in two coils: in the upper and lower. The fact is that in the upper coil, the resistance is greater than in the lower one, so most of the water flows in the lower coil. In order to balance the flow of the coolant, it is necessary to install a shut-off valve at the liquid inlet to this tank.
Filter. It must be present in any system. Its function is to trap large particles of debris that are present in the liquid.
Flow meter. It is needed in order to see how many liters of water flows in one minute. This indicator is regulated by a shut-off valve.
Pressure indicator. With this element, you can determine the level of pressure in the system. A blast valve is installed nearby in case the pressure suddenly exceeds the norm.
Expansion tank. In the system, the water will begin to expand due to heating. The excess flows into the expansion tank, and when cooled, they will begin to circulate again. If this tank is not there, then the excess will come out through the blast valve, and when it cools down, there will not be enough water in the system.
Air vents. In solar systems, automatic air vents are used. They are installed at the top of the system. It is needed in order to automatically remove accumulated air from the system.
Drain tap. Through this tap, the coolant can be drained from the system.

These are the elements of the system of this scheme.

There are other designs, but the whole principle of operation remains the same, only some valves and gates may need more or less, depending on the scheme.

Necessary materials and tools

Solar installations can be purchased in special establishments, but you can also do it yourself, since the purchase will be very expensive. Solar collectors at home can be made from different materials, such as plastic bottles, a hose, polypropylene, but the most economical in material terms and the easiest is the process of making a solar battery from a radiator of a strictly refrigerator.

For this you will need the following materials:

Rubber mat.
Scotch
Foil.
Ordinary glass.
Wooden bars for making a frame.
Soldering device.

All of these materials can be purchased at no extra cost. If they are already available, then you can get down to business.

How to make a solar collector with your own hands - step by step instructions

If the old refrigerator is already in a non-working condition, then you should not throw it away, as its capacitor can be an excellent material for assembling a collector. In the manufacture of this device, you should be guided by the following step-by-step instructions:

It is necessary to dismantle the condenser, rinse thoroughly, clean it of freon, and measure it.
After you have made the necessary measurements, you should proceed to the manufacture of a wooden frame, that is, the body. To do this, use wooden bars.
Now you need to take the foil and lay it on the bottom of the manufactured case. This is done so that the heat exchanger can heat up not only from the front side, but also from the back.
Now, armed with adhesive tape, you should glue all the cracks around the entire perimeter of the case.
Then you need to nail additional bars on the back of the device. This is done so that the heat exchanger is firmly fixed.
Now small holes are made in the frame for the removal of pipes.
On the underside of the frame, you need to mount a few screws so that the glass is held securely and does not slip.
Now they cover it all with glass, and with the help of adhesive tape they seal all the holes.

That's all! It remains only to install it somewhere on the roof, and tie it with the rest of the elements of the heating system at home.

Nuances

In the manufacture and operation of the collector, you should pay attention to the following points:

Water heated through such a collector should be used only for technical needs, since freon still remains in the condenser.
It is not necessary to use a refrigerator condenser, you can also take a radiator from a car.
If the use of a circulation pump is envisaged, then the water storage tank can be installed absolutely anywhere. Instead of a high power circulation pump, you can take a regular aquarium pump. If the system provides for natural circulation of the liquid, then the tank must be located above the collector itself.

Energy resources. Free solar energy will be able to provide warm water for household needs at least 6-7 months a year. And in the remaining months - also help the heating system.

But most importantly, a simple solar collector (unlike, for example, from) can be made independently. To do this, you will need materials and tools that can be bought at most hardware stores. In some cases, even what is found in an ordinary garage will be enough.

The solar heater assembly technology presented below was used in the project "Turn on the sun - live comfortably". It was developed specifically for the project by a German company Solar Partner Sued, which is professionally engaged in the sale, installation and service of solar collectors and photovoltaic systems.

The main idea is that everything should turn out cheap and cheerful. For the manufacture of the collector, fairly simple and common materials are used, but its efficiency is quite acceptable. It is lower than that of factory models, but the difference in price fully compensates for this shortcoming.

The sun's rays pass through the glass and heat up the collector, while the glazing prevents heat from escaping. The glass also impedes the movement of air in the absorber; without it, the collector would quickly lose heat due to wind, rain, snow or low outside temperatures.

The frame should be treated with an antiseptic and paint for outdoor use.

Through holes are made in the housing for supplying cold and removing heated liquid from the collector.

The absorber itself is painted with a heat-resistant coating. Conventional black paints at high temperatures begin to peel off or evaporate, which leads to darkening of the glass. The paint must be completely dry before you set the glass cover (to prevent condensation).

A heater is laid under the absorber. The most commonly used mineral wool. The main thing is that it can withstand fairly high temperatures during the summer (sometimes over 200 degrees).

From below, the frame is covered with OSB boards, plywood, boards, etc. The main requirement for this stage is to make sure that the bottom of the collector is reliably protected from moisture getting inside.

To fix the glass in the frame, grooves are made, or strips are attached to the inside of the frame. When calculating the dimensions of the frame, it should be taken into account that when the weather (temperature, humidity) changes during the year, its configuration will change slightly. Therefore, a few millimeters of margin are left on each side of the frame.

A rubber window seal (D- or E-shaped) is attached to the groove or bar. Glass is placed on it, on which a sealant is applied in the same way. From above, all this is fixed with galvanized tin. Thus, the glass is securely fixed in the frame, the seal protects the absorber from cold and moisture, and the glass will not be damaged when the wooden frame "breathes".

The joints between the sheets of glass are insulated with sealant or silicone.

To organize solar heating at home, you need a storage tank. The water heated by the collector is stored here, so you should take care of its thermal insulation.

As a tank you can use:

non-working electric boilers
various gas cylinders
barrels for food use

The main thing to remember is that pressure will be created in a sealed tank depending on the pressure of the plumbing system to which it will be connected. Not every container is able to withstand a pressure of several atmospheres.

Holes are made in the tank for the inlet and outlet of the heat exchanger, the inlet of cold water, and the intake of heated water.

The tank houses a spiral heat exchanger. For it, copper, stainless steel or plastic are used. The water heated through the heat exchanger will rise up, so it should be placed at the bottom of the tank.

The collector is connected to the tank using pipes (for example, metal-plastic or plastic) drawn from the collector to the tank through the heat exchanger and back to the collector. Here it is very important to prevent heat leakage: the path from the tank to the consumer must be as short as possible, and the pipes must be very well insulated.

The expansion tank is a very important element of the system. It is an open reservoir located at the highest point of the fluid circulation circuit. For the expansion tank, you can use both metal and plastic containers. With its help, the pressure in the manifold is controlled (due to the fact that the liquid expands from heating, pipes can crack). To reduce heat loss, the tank must also be insulated. If air is present in the system, it can also exit through the tank. Through the expansion tank, the collector is also filled with liquid.

The rise in the cost of traditional energy sources encourages owners of private houses to look for alternative options for heating housing and water heating. Agree, the financial component of the issue will play an important role in choosing a heating system.

One of the most promising ways of energy supply is the conversion of solar radiation. For this, solar systems are used. Understanding the principle of their device and the mechanism of operation, making a solar collector for heating with your own hands will not be difficult.

We will tell you about the design features of solar systems, offer a simple assembly scheme and describe the materials that can be used. The stages of work are accompanied by visual photographs, the material is supplemented with video clips about the creation and commissioning of a self-made collector.

Modern solar systems are one of heat production. They are used as auxiliary heating equipment that converts solar radiation into useful energy for home owners.

They are able to fully provide hot water supply and heating in the cold season only in the southern regions. And then, if they occupy a sufficiently large area and are installed on open areas not shaded by trees.

Despite the large number of varieties, the principle of their work is the same. Any one is a circuit with a serial arrangement of devices, both supplying thermal energy and transmitting it to the consumer.

The main working elements are or solar collectors. The technology on photographic plates is somewhat more complicated than on a tubular collector.

In this article we will consider the second option - a collector solar system.

Solar collectors still serve as an auxiliary energy supplier. It is dangerous to completely switch the heating of the house to the solar system due to the inability to predict a clear number of sunny days

Collectors are a system of tubes connected in series with the outlet and inlet lines or laid out in the form of a coil. Technical water, air flow or a mixture of water with any non-freezing liquid circulates through the tubes.

Circulation is stimulated by physical phenomena: evaporation, changes in pressure and density from the transition from one state of aggregation to another, etc.

The collection and accumulation of solar energy is carried out by absorbers. This is either a solid metal plate with a blackened outer surface, or a system of individual plates attached to the tubes.

For the manufacture of the upper part of the housing, the cover, materials with a high ability to transmit light flux are used. It can be plexiglass, similar polymeric materials, hardened types of traditional glass.

In order to eliminate energy losses from the back of the device, thermal insulation is placed in the box

I must say that polymeric materials do not tolerate the influence of ultraviolet rays quite well. All types of plastic have a fairly high coefficient of thermal expansion, which often leads to depressurization of the case. Therefore, the use of such materials for the manufacture of the collector housing should be limited.

Water as a heating medium can only be used in systems designed to supply additional heat in the autumn/spring period. If year-round use of the solar system is planned, before the first cold snap, process water is changed to a mixture of it with antifreeze.

If a solar collector is installed to heat a small building that is not connected to the independent heating of the cottage or to centralized networks, a simple single-circuit system is built with a heating device at the beginning of it.

The chain does not include circulation pumps and heating devices. The scheme is extremely simple, but it can only work in sunny summer.

When the collector is included in a double-circuit technical structure, everything is much more complicated, but the range of days suitable for use is significantly increased. The collector processes only one contour. The predominant load is assigned to the main heating unit, powered by electricity or any type of fuel.

Home craftsmen invented a cheaper option - a spiral heat exchanger made of.

An interesting budget solution is the absorber of a solar system made of a flexible polymer pipe. Suitable fittings are used to connect to the inlet and outlet devices. The choice of improvised means from which a solar collector heat exchanger can be made is quite wide. It can be the heat exchanger of an old refrigerator, polyethylene water pipes, steel panel radiators, etc.

An important criterion for efficiency is the thermal conductivity of the material from which the heat exchanger is made.

For self-manufacturing, copper is the best option. It has a thermal conductivity of 394 W/m². For aluminum, this parameter varies from 202 to 236 W / m².

However, the large difference in thermal conductivity parameters between copper and polypropylene pipes does not mean at all that a heat exchanger with copper pipes will produce hundreds of times larger volumes of hot water.

Under equal conditions, the performance of a heat exchanger made of copper pipes will be 20% more efficient than the performance of metal-plastic options. So heat exchangers made of polymer pipes have the right to life. In addition, these options are much cheaper.

Regardless of the pipe material, all connections, both welded and threaded, must be tight. Pipes can be arranged both parallel to each other, and in the form of a coil.

The coil-type circuit reduces the number of connections - this reduces the likelihood of leaks and provides a more uniform movement of the coolant flow.

The top of the box, in which the heat exchanger is located, is covered with glass. Alternatively, modern materials can be used, such as an acrylic analogue or monolithic polycarbonate. The translucent material may not be smooth, but corrugated or matte.

Conclusions and useful video on the topic

The manufacturing process of an elementary solar collector:

How to assemble and commission a solar system:

Naturally, a self-made solar collector will not be able to compete with industrial models. Using improvised materials, it is quite difficult to achieve the high efficiency that industrial designs have. But the financial costs will be much less compared to the purchase of ready-made installations.