Environmental problems constantly dictate new living conditions. This is due to both the cleanliness of the environment and the shortage of energy resources. According to world organizations, their number is not unlimited, and a huge amount of resources are allocated to solve this problem. These include financial investments, scientific projects, and many other activities. This approach bears fruit, and as a result, qualitatively new devices, tools and methods appear in the life of society, introduced both into production processes and into the everyday life of people.
One of these innovations is energy-saving systems that use alternative energy sources, the main and most powerful of which is solar radiation. Like all energy sources, its use is accompanied by a number of problems, the most pressing of which is the short period of use in cold climate zones. However, despite this, there are a number of effective methods using the principles of solar energy storage.
Solar water heaters from antiquity to modern times
There are many ways to use solar energy. One of the most popular methods used in both domestic and industrial settings is solar water heaters. These devices have been used for centuries, and with the use of modern technologies they have gained a new round of popularity. From ancient times until recently, water, like other liquids, was heated with the help of the sun in open or closed dark-colored containers, which contributed to rapid heating.
Now, in the electronic age, more modern elements are increasingly being used, which make it possible not only to heat water with the help of the sun, but also to maintain a given temperature of the coolant. They include a lot of technical developments regarding both the structural elements used and control methods. Their design is varied and mostly depends on the intended purpose of the device, as well as the technologies and materials used. Some of them are produced only industrially, but others can also be performed in artisanal conditions.
Types and classification of devices
In practice, a number of principles have been implemented that allow the use of solar energy. There are several design options, regardless of whether the solar water heater is made by hand or not. The main classification criterion is the coolant. It can be liquid and metallic. Vacuum can be used as a heat insulator. Solar water heaters can be direct or indirect. In the first case, the water is heated directly by the sun, and in the second case, this occurs by converting solar energy into electrical energy, and then into thermal energy, which heats the liquid.
In a closed or open loop, it can also move in two ways, depending on the type of structure - forcibly with the help of pumps and other pressure-injecting installations or by gravity. They can also be divided by area of application. For example, solar water heaters for homes are low-efficiency devices. They are characterized by their small size. A solar water heater for a swimming pool or other temporary facility, designed for constant multi-purpose heating of water in large quantities, has appropriate dimensions and also belongs to a different class.
Producers and consumers
There are a number of manufacturers on the market who have experience in such developments and create such products en masse. The main competing companies are VIESMANN, SOLVIS, VAILANT. The main consumer states are Saudi Arabia, Israel, Malta and many EU countries. In addition, this direction is actively popularized in China, the Russian Federation, the USA and Australia.
Pricing policy and materials for production
A solar water heater, the price of which is high, will not be in demand, so the models of promoted products are either made from cheap materials, or their power is maximized so that the product can pay for itself in a short time. In southern China they save on heat conductors. They are made lamellar, but the result does not suffer - the products have enough power, since the Sun here is much more active than in the northern regions. In cold countries, more expensive thermally insulated systems based on solar panels are used. They are more energy efficient and cost accordingly.
The solar collector market also offers consumers various modifications of ready-made systems. For example, a simple model for home costs from 300 USD. But there are also models with additional equipment that greatly simplifies operation. These can be pumps and various sensors. The price of such devices starts from 550 USD.
Do-it-yourself home solar water heater: design diagram
There is an opinion that solar heating devices have a complex design. However, you can make your own solar water heater. The circuit of the collector included in its composition is simple. It can be assembled from existing parts or constructed from new ones. It is a coil made of thin, easily heated metal, installed on a platform and protected by glass. You can build a solar water heater with your own hands in a day. To do this, you will need to prepare the installation site in the form of a concrete or tiled covering. Mount a platform on it from existing light but durable materials, for example, wood. And install it using anchors at an angle to the site.
The platform with mountings for the coil is painted black. Pipes are installed on top and connected together. They are also painted. An ordinary single or double glass with a thickness of 4 mm or more is installed on top, which is fixed in guides on the platform. Taps are installed on the removed pipes of the coil and connected to the pump using short hoses.
Vacuum model and its features
The design of a vacuum-based solar water heater is completely different. It is much more complex and requires professional design skills. Its structure includes: a heat exchanger with external insulation and a valve, vacuum tubes connected to it, an expansion tank installed inside the heat exchanger, an electric heater, connecting pipes and a drain valve.
It may also include a workstation, controllers and sensors depending on the type selected.
Vacuum tubes have a multicomponent structure, consisting of the tubes themselves, made of impact-resistant glass, absorbers located inside the tubes, and a number of other auxiliary elements. A variant of this design is assembled mainly from a ready-made kit. Once you buy it, you can easily install a solar water heater. The price for it varies depending on the output power (number of kW).
Advantages and disadvantages of passive and active types
Solar water heaters with gravity flow of coolant are called passive. When choosing this option, you should take into account the problem of its placement. The movement of water here occurs due to the difference in density of the cold and heated coolant. Therefore, such a system must include a storage tank and a well-thought-out piping system. Such solar systems have a low rate of accumulation of heated liquid and this is their main drawback. But all the advantages of other solar systems are present in them. These are low energy consumption, absence of harmful fumes and emissions, and economic feasibility. Therefore, solar water heaters in the case of using elements for activating the flow of liquid become almost irreplaceable. However, this requires additional energy sources to power them, so they are not energy independent, unlike gravity-fed passive models.
Results
The middle class cannot afford highly efficient solar water heaters. Their design includes a number of expensive components, the payback period of which is measured in years. But a self-made energy-independent solar water heater is not a fiction. It can be made at home without any problems. In addition, the market offers a wide range of boilers using solar energy from global manufacturers. Most of these solar systems use collectors installed on the roofs of buildings and in the surrounding area at an angle optimally selected for a given climatic zone. Some of these products are completely energy independent from other energy sources. The selection of the model occurs solely according to the requirements for the power of the device and the possibility of its installation in the given conditions. Their use may be temporary or permanent in nature for heating water for a specific purpose or for general use.
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 provide the house with heat and hot water only from 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 integrate 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 located in the collector, which is then used to provide hot water supply and heating or generate electricity.
Devices related to the energy of the sun are correctly called solar installations or solar collectors (on behalf of the ancient Greek sun god Helios).
Modern solar water heaters can be complex, but any owner of a private home can make the device for his own needs. The main thing is to understand why this device is needed.
Three collectors fully meet the family's needs for hot water and heating
Scope of use of solar power plants
In our country, many people still associate the phrase solar water heater 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. China is not lagging behind the West. There, solar water heaters are installed on the roofs of high-rise buildings and provide hot water to all apartments. In 2000, there were so many solar power plants in the world that, taken together, they would have taken up more than 71 million m 2. Almost 15 million m2 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, and 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 each person from Germany there is 0.14 m2 of solar collector area, from Austria - 0.45 m2, from Cyprus - 0.8 m2, and from Russia - 0.0002 m2. The intensity of solar lighting in Russia is only 0.5 kWh/m2 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 with vacuum, concentrators with parabolic cylindrical reflectors, air, solar towers and other types of installations. Flat and vacuum water heaters remain the most popular for domestic purposes.
Table: comparative characteristics of flat and vacuum collectors
| Flat-plate collector | Vacuum manifold |
|---|---|
| Easily made with your own hands from scrap materials. | It is produced in an industrial environment or assembled from factory parts. |
| Pays for itself quickly. | Pays for itself three times longer than a flat one. |
| Less likely to overheat in hot weather. | Prevents the return of accumulated heat to the environment. |
| Works effectively in summer or in countries with hot climates. | Suitable for cold regions, works in winter at temperatures down to -30 o C. |
| It has a high windage, so a strong gust of wind can tear it off the roof. | Wind passes freely between the vacuum tubes, so there is a higher chance that the collector will not be damaged by a storm. |
| It cleans itself of snow, frost and ice. | Productivity is 2–3 times higher than that of a flat-plate collector (with equal areas). |
Features of flat-plate solar water heaters
The device is a panel containing copper tubes with a dark coating. They heat water, which is then collected in a tank and used for domestic hot water supply (hot water supply). If you make the collector yourself, then expensive components can be replaced with affordable materials:
- instead of copper tubes, 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;
- the chrome absorber will be replaced by ordinary black paint;
- a sheet of glass or cellular polycarbonate would serve well as a protective cover, and polystyrene foam would serve as insulation.
The main thing is to ensure the tightness of the panel, but to do this it is enough to seal all the seams with construction 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 precisely this effect.
Expensive parts of an industrial manifold can be replaced with cheaper analogues, for example, steel tubes can be used instead of copper tubes, and the frame of the device can be made of wood.
If water is not taken from a flat-plate collector, on a hot sunny day it can heat up to 190–210 o C, which can lead to rupture of coolant tubes or connecting elements. For those who use a solar water heater occasionally, it is important to install a storage tank that can eliminate excess pressure in the tubes. Another option is to use mineral oil rather than water as a heat sink. Its boiling point is higher, reducing the risk of system damage. In this case, you will 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 use in the country or as an auxiliary water heater. Use them only for domestic hot water.
Features of vacuum manifolds
This type of solar water heater consists of individual tubes, each of which is in an airless environment. This design made it possible to reduce heat loss on the path from the collector to the storage tank and increase the efficiency of the system. Thanks to this, vacuum collectors work perfectly during the changing 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), a black absorbing layer underneath, a coolant tube 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 tubes. This is the only way heat is removed from a vacuum solar system, so it is important to provide it with a regular supply of cold water, that is, use hot water throughout the day. To increase the durability of the system, antifreeze is used as a coolant in vacuum solar collectors. It tolerates heat up to 300 o C well and does not freeze when the temperature of the device drops to -40 o 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 reliable than a flat one.
It is impossible to create a full-fledged vacuum solar collector with your own hands: making a thick-walled tube from borosilicate glass is unthinkable in home-made conditions. Therefore, a more reliable option would be to purchase factory-made flasks (coaxial and feather varieties are offered) and assemble the solar water heater on site. But since even such work requires remarkable metalworking skills, it is better to buy a finished product with a guarantee from the manufacturer.
Which system should I integrate a solar water heater into?
In order for hot water to start flowing from the tap, it is important not only to choose a collector, but also to create an entire system for it from a storage tank, connecting pipes, taps and other elements.
Types of circulation
It is necessary to determine whether you can install the storage tank above the level of the collector. This determines 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 determines this 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 operate 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 place a storage tank in the attic or basement. This is better for the exterior and requires less effort to insulate 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 frequent loss of electricity at the dacha, this option will not be suitable.
If you decide to use 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 simplest option for supplying hot water to your home. Its main difference is that the coolant in the collector is necessarily water. First, it is heated in the tubes, then it goes into a storage tank, and then directly into the tap in the kitchen or bathroom. That is, the 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 to heat a house or to make the operation of electric heating cheaper. Its difference is that water heated by the sun enters the heating pipes. The coolant moves in a circle in the system. This is a closed circulation cycle. Since the solar collector is used in winter and in the off-season, choose vacuum models and include an additional heater in the system. An electric or gas boiler helps bring the coolant to the desired temperature on cold and cloudy days, as well as at night.
- Double circuit. This option involves transferring 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 where 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 is also integrated into it for additional heating of water, and several collectors are used (depending on the number of residents and the climatic characteristics of the region).
In a double-circuit circulation system, there is no direct contact between the solar water heater coolant and water
An open-circuit circulation system is effective for domestic hot water supply, while a double-circuit circulation system is effective for full supply (DHW and heating) of a country house.
How to make a flat-plate solar collector with your own hands
For this you need a drawing. You will also need to calculate the area of the water heater according to 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 - collector area, m2;
- AW - reduced area that 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 a given area, kW*hour/(m2*day);
- K is a coefficient that takes into account 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, kW*hour/day;
- SF is the share of solar energy in covering the heat demand, %.
To build a collector you will need a detailed drawing indicating the number and size of parts
Tools and materials for work
To make 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;
- shears for metal-plastic pipes;
- screwdriver;
- brushes and a spray gun or a can of aerosol paint for blackening installed 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 on the part: size 0.76x0.38 m - 4 pieces, size 1.52x0.76 m - 1 PC.
- Paint the inner surface of the resulting box with matte black paint, and the outer surface with white or coat it with protective varnish.
- Create a frame for fastening the box from timber with a cross-section of 5x5 cm, according to the attached diagram. In total you will need 60 m of timber. Before assembly, it is important to treat the parts with a wood antiseptic to protect the material from precipitation and temperature changes. Fasten the parts together with wood screws using 5x5 cm metal corners.
- Attach the box to the prepared stand and carry out further assembly on this inclined stand.
- Make markings where the pipes will go and where they need to be attached. 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. To avoid making a mistake, use the first fragment as a reference sample. You should get 45 pieces of 2.14 m each.
- Assemble a snake of pipes on a stand, using fittings for metal-plastic pipes at the turns. In total, 44 female-to-female and female-to-male angle elbows and 88 adapters from a metal-plastic pipe to a fitting are required. Use sealing thread to seal connections. At the beginning and end of the snake, attach adapters to connect the water supply and drainage hoses.
- Paint the structure black using a spray gun or spray can.
The collector coil is painted black
- Connect the coil to the pump and make sure that there is no leakage when pumping water. If any connection is not tight enough, drain the water and reassemble it, and then test again.
- Cover the top of the box with transparent glass or monolithic polycarbonate. If it is not possible to use a solid sheet, make an aluminum frame to the size of the existing fragments (preferably no more than four) and securely fasten the panels. Carefully treat each joint with transparent silicone to ensure 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 initially black and is mounted with a snake using just two fittings. But in this case, the water will not come into contact with hygienic metal (as in the described case), but with plastic. This is undesirable if the water is also intended for cooking.
Video: How to make a flat-plate 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 the house uses several water heaters. Sometimes the collector is recessed into the roof so that the protective screen is flush with the decorative roof covering. But this method is much more expensive and can weaken the roof structure.
It is best to install a flat-plate collector system on a pitched roof
On flat roofs, collectors are mounted on special structures that hold them at a given angle. The stands can be purchased ready-made or welded yourself from corners. The metal structure is attached to the base with large anchor bolts.
On a flat roof, collectors are mounted on special structures
At dachas, solar collectors are installed next to the house or pool in an open sunny area. In this case, choose a place on an already created site or equip a reliable foundation separately. To do this, you will need a rectangular platform with a compacted bulk cushion, waterproofing and a coating of paving slabs, porcelain stoneware, and other durable, hard and weather-resistant material. Subsequently, a metal or wooden easel stand is mounted on it, onto 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. The most common jobs:
If the collector has been purchased, you should call a repairman at the first breakdown, and during the warranty period, contact a manufacturer’s representative. A homemade solar water heater will have to be repaired on your own, but finding a breakdown and fixing it in a homemade product is much easier than in a factory-made one. The experience of collector repair technicians suggests that you first need to check the condition of the valves, sensors, storage tank and pump, since they are less reliable than the solar installation itself.
In DHW systems with a solar collector, valves and sensors most often fail
Video: instructions for assembling a solar collector from aluminum cans
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.
An excellent homemade product for a summer house, which on a good summer day will provide you with hot water, heated by absolutely free solar energy. Hot water can be useful for washing dishes, hands and for other needs. A solar water heater is easy to manufacture, does not require the strict use of certain materials, everything can be replaced if desired or lacking.
Making a Solar Water Heater
As we describe the manufacture, I will offer alternative options for replacing materials, since you may not be able to find some of them.So, let's start with the fact that you need to cut a square out of thick plywood of any brand, be it chipboard, fibreboard, OSB, etc.
The side size of the square is approximately 60 cm.
Next, from a thin sheet of stainless steel, cut out a square equal to a square of plywood. This will be a solar energy reflector.
If you don’t have thin stainless steel, take regular aluminum foil and cover a square of plywood with it.
I take a sheet of stainless steel and place it on top of a square of plywood. I put wooden slats around the perimeter and secure it all with small nails.
Now I need a copper tube 5-6 m long. The thinner its walls, the better. The metal of the tube can also be aluminum. We roll it up in one layer, but so that the dimensions of the rolling circle do not exceed the dimensions of the plywood square.
We paint the tube with aerosol paint from a black can. First one side, then when dry, the other.
From a U-shaped aluminum profile we make a body-contour around the perimeter of the square.
Drill a hole in the center. We also nail four limiters from the rail for the copper coil.
We install a copper coil. At the beginning of the curl we put a silicone tube. And we pass it through the hole in the center.
The other end of the copper tube comes out from the side.
We cut the glass to the size of the plywood square. Here it is better to use plexiglass or plexiglass, as they transmit infrared rays well.
The solar panel is almost ready.
We make a stand from a square steel profile.
A rectangle with a soldered rectangle on top.
We weld semicircular rods that will hold the water bottle.
Now take a 20 liter bottle. We make a hole in the lid for the tap.
We place the tap on the sealant.
Place the bottle on the stand.
We also glue the neck of an unnecessary bottle onto the sealant on top so that you can easily add water to the tank.
We glue the tube on the side.
And glue the tube from below. This should be done for better circulation.
Install the solar panel at an angle.
We connect the side tube of the solar collector to the side tube of the bottle.
And the central one from the collector - to the bottom of the bottle.
Good owners of private houses are always looking for opportunities to save on water heating and heating costs. This has become especially relevant lately, when utility prices have a consistent upward trend almost every quarter. Nature itself comes to the rescue with its inexhaustible source of energy - solar radiation. Applying the laws of physics in practice, craftsmen find interesting ways to save money by developing and assembling solar collectors, which probably any homeowner can do on their own - they just need to apply a little effort and skill.
A do-it-yourself solar collector can be made in multiple ways and from a wide variety of materials, sometimes even from those that are simply “lying under your feet.” They are constructed from ordinary old beer cans, plastic bottles, hoses or pipes, using glass, polycarbonate panels and other materials.
Some of the methods for manufacturing collectors will be discussed below, but first it is worth studying the connection diagrams - they, as a rule, are approximately common for any solar water heating systems.
Solar water collector connection diagrams
The effective operation of a solar water heating system depends not only on what the collector is made of, but also on how correctly it is installed and connected. There are quite a lot of options for connection diagrams, but you shouldn’t look for the most complex ones, since you can quite easily use the basic ones, which are accessible and understandable.
“Summer” option of hot water supply from a solar collector
This simple solar collector connection diagram is applicable both for heating water for and for domestic needs. If hot water is needed outside in a summer building, then the tank for it is also installed in the air. In the case when hot water supply is distributed throughout the house, and the storage tank is installed there.
“Summer” option for connecting the collector This scheme usually provides for natural circulation of water, and in this case the battery-collector is installed 800 ÷ 1000 mm below the level of the tank where the hot water will flow - this should be ensured by the difference in the density of the cold and heated liquid. To connect the collector to the tank, pipes with a diameter of at least ¾ inch are used. To keep the water in the storage tank in a hot state, which it will reach from heating by the daytime sun, the walls must be properly insulated, for example, with 100 mm thick mineral wool and polyethylene (if there is no roof over the boiler). But it is still better to provide a permanent shelter for the container, since if the insulation gets wet from rain, it will significantly reduce its thermal insulation properties.
Natural circulation is not very good for use in a system with a solar collector, since it creates a weak inertia in the movement of water in the circuit. And if the battery and the tank are far enough from each other, then the water, having passed this path, will gradually cool down. Therefore, to increase efficiency, a circulation system is often installed. This option is suitable for heating water only in the warm half of the year, and in winter the water from the system will have to be drained, otherwise, when it freezes, it will easily burst T t rubles
“Winter” connection diagram for solar water heating
If you plan to use the solar collector all year round, then in order to prevent the water in the pipes from freezing during extreme cold, a special antifreeze, that is, a non-freezing liquid, is poured into the circuit instead. The scheme takes on a completely different form - an indirect heating boiler is installed. In this case, the antifreeze heated in the solar collector will pass through the boiler’s heat exchanger coil, warming the water in the tank.
A “security group” is necessarily built into this system - automatic air vent, pressure gauge and safety valve designed for the required pressure. For constant movement of the coolant, a circulation pump is usually used.
Solar heating option
When using solar thermal energy for heating a house, an indirect heating boiler connected to the collector is also used, as well as for additional heating of the coolant - one that runs on solid fuel or gas. On autumn or spring days, when the sun is able to heat the coolant to the desired temperature, the boiler can simply be turned off.
A solar collector is also a good help for heating a house If the winters in the region are very cold, then you should not expect great efficiency from the collector, since during this period there are few sunny days, and the star itself is low to the horizon. Therefore, additional heating of the coolant and hot water is simply necessary. The only way a solar battery will help you save on fuel is that the boiler will receive not cold, but already somewhat heated water, which means you will need to burn less gas or wood to bring it to the desired temperature.
You also need to know that the larger the solar thermal collector is, the more energy it will be able to absorb. Therefore, in order for such a system to generate enough heat to heat a house, the size of the collector area must be increased to 40–45% of the total area of the house.
Option for hot water supply and heating from a solar collector
To use a solar collector for both heating and hot water supply, it is necessary to combine both previous options in the system, and use a special boiler for water with an additional tank having a coil through which the coolant heated by the solar battery circulates. Due to the fact that the internal tank is much smaller than the main one, the water in it heats up from the coil much faster and transfers heat to the general tank.
The collector can be included in the general “heating - hot water supply” system In addition, the boiler must be connected to an additional heating source - this can be either an electric boiler or a solid fuel heat generator.
The temperature instability created by the solar battery can contribute to overheating of the coolant or, conversely, to its too rapid cooling in the heating and water supply circuits. To prevent this from happening, the entire system must be controlled automatically. Installed in the wiring controller temperature, which can either redirect coolant flows, or turn circulation pumps on or off, or perform other control operations.
In the diagram presented above, such a temperature controller is designated as a regulator.
So, in general terms there is clarity with the connection diagrams (piping). But now it makes sense to consider several options for making solar collectors yourself.
Prices for solar collectors
Solar collectors
Solar collector made from a hose or flexible pipe
Those who have a private house with a garden or a dacha, of course, know that the water remaining in the temporary light mains after watering the beds quickly heats up. This positive quality of hoses or flexible pipes was used by craftsmen to create solar heat exchangers from them. It should be noted that such a collector will cost many times less than one bought in a store, but for the manufacturing process to be successful, some effort must be made.
On the roof there is a whole battery of solar collectors Such a manifold may consist of one or several sections into which hoses tightly coiled in a spiral “snail” are laid and secured.
"Snail" - heat exchanger This design can be called the simplest, both in design and installation. Its main disadvantage is that it practically cannot be used without the use of forced circulation, since if the pipe contours are too long, the hydraulic resistance will exceed the pressure force created by the temperature difference. However, solving the issue of installing a circulation pump is not at all difficult. And such a system installed in a country house will be an excellent help and will quickly pay for itself, including the costs (very insignificant) for powering the pump.
Similar collectors are also used to heat water in swimming pools. They are connected to a filtration system, which is necessarily equipped with a pump. Water, circulating through the collector pipes, has time to heat up before entering the pool.
In some cases
By creating the entire system, you can do without installing a storage tank. This is possible when hot water is used only during the day and in small quantities. For example, a circuit of 150 m of pipe with an internal diameter of 16 mm holds 30 liters of water. And if five or six such “snails” from pipes are collected into a single battery, then during the day each family member can take a shower several times, and there will still be a lot of hot water left for household needs.If anyone has any doubts about the effectiveness of such water heating, we recommend watching a video that shows testing a hose collector:
Video: efficiency of a simple solar collector
Materials for production
To make such a solar water collector, you need to prepare some materials. It is not at all impossible that some of them will be found in a barn or garage.
- A rubber hose or a flexible black plastic pipe with a diameter of 20 ÷ 25 mm is essentially the main element of the system in which heat exchange will occur during water circulation. The amount of hose will depend on the size of the solar panel - it can be 100 or 1000 meters. The black color of the hose is preferable because it absorbs heat more than all other shades.
It should be noted right away that metal-plastic pipes are not particularly suitable for making a collector, even if they are coated with black paint. The fact is that their plasticity in this case is insufficient - they break when bending a small radius and thus, even if the integrity of the walls is not violated, the intensity of the water flow will decrease.
Hoses are sold in coils of 50, 100 or 200 meters. If you plan to make a large-volume battery, you will have to purchase several bays. If you plan to use, for example, 50 or 100 m of hose in each section, then you should not buy a whole 200-meter coil, it is better to purchase a ready-made measured hose. This will help save time during installation.
The hose can be laid not only in a round spiral, but also oval, and also in the form of a coil.
As a good alternative, you can try modern PEX cross-linked polyethylene pipes. They have good plasticity, but it’s not hard to figure out how to give them black color if it’s not on sale.
- If the slope of the roof on which the collector battery will be installed is steep, then special boxes are made from bars, plywood or metal sheets for the hose spirals. To do this, you will need bars 40×40 or 40×50 mm, plywood 6 mm thick, or a metal sheet 1.5–2 mm thick.
The blanks of the future module are treated (wood) or with anti-corrosion compounds (metal). Then a box is assembled from them into one or more spirals.
By the way, you can use old window frames as the sides of the box, onto which the bottom part is simply mounted.
- For pre-treatment of metal and wood, it is necessary to purchase antiseptic, anti-corrosion and primer compounds.
- Hoses (pipes) will experience considerable loads both from the mass of the coolant and from temperature changes and internal pressure. Therefore, they will try to disrupt the installation, deform, and sag, so it is necessary to provide special fastenings to maintain them in the initially specified position.
This can be a metal strip that is secured between the pipes with self-tapping screws.
Another option is a loose bundle with a tight cord or a plastic clamp-“tie” with a cross or crossbar. But still, this fastening method is more suitable for a plastic pipe than for a hose, since it can sag on the cord when the rubber expands. If a reinforced rubber hose is chosen for the collector, then this method is quite suitable for fixation.
Another fastening option suitable for a plastic pipe or reinforced hose can be nails with wide heads. They can be driven either into the bottom of the box (in this case it must have a thickness of at least 10 mm), or onto a kind of cross made of a block.
- It will also be necessary to prepare connecting elements for the hose or pipes. There are quite a lot of varieties of such fittings, but you need to choose exactly those that are intended for the one selected for production material collector.
In addition to such connectors, threaded fittings will be required to transition from a plastic or rubber pipe to a common metal one. Such a connection will be necessary if the collector consists of several modules.
To know how many connecting elements are required, you need to draw in advance a schematic diagram of the system being created and calculate their number on it.
- To combine all modules into a single battery, two collector - cut metal pipe. Through one of them, fixed at the bottom of the battery, cold water will flow into the heat exchangers, and in the second, fixed at the top, warmed water will be collected.
The upper pipe will connect to the storage tank, that is, go to the consumer. It should have a diameter of 40 ÷ 50 mm.
Battery installation
Having prepared everything you need, you can start working.
- First you need to treat all wooden parts of the future structure with an antiseptic.
- Next, if the bottom of the modules is made of metal sheet, it must be coated with an anti-corrosion compound. Typically, mastic designed to cover the undersides of cars is used for this.
Known to all motorists, “anticorrosive” is what you need - After the compositions have dried on the prepared elements, single or common modules are assembled from them.
- Then the hoses are laid in them, for which the holders are secured.
- To allow pipes to pass freely through the sides of the modules, holes are drilled for them - in the upper and lower parts. Accordingly, the cold water inlet pipe is led into the lower hole, and the heated water outlet into the upper hole.
- If several modules are mounted vertically, or one common one, into which several pipe “snails” are also placed, one above the other, then the lower end of each of the spirals is connected to the upper outlet of the underlying one - and according to this sequential principle, the entire “column” is switched. The lowest end is connected to a common metal collector through which cold water will flow. All adjacent vertical rows are mounted in the same way - with a common connection to the supply manifold.
- Accordingly, the upper ends of the hoses of the uppermost horizontal row of modules are connected to a metal collector pipe through which hot water is discharged for consumption.
- The spiral-shaped collector circuit can also be mounted on a metal sheet installed not on the roof, but near the house, on its southern side, or near the pool, if it requires heating. In this case, the metal base will contribute to faster heating of water and heat retention in the pipes, since it has good thermal conductivity and heat capacity.
- Another option for a thermal solar collector can be laying the circuit on the roof plane in special boxes in long parallel rows along the entire length of the roof.
Prices for cross-linked polyethylene pipes
XLPE pipes
Video: a simple solar collector with a linear pipe arrangement
We enhance the effect with plastic bottles
The figure shows a solar collector made of hoses (pipes), the efficiency of which is significantly increased through the use of ordinary plastic bottles. What's the "trick" here? And there are several of them at once:
The effect of a plastic bottle as a casing - schematically - The bottles act as a transparent casing and prevent air flows from taking away heat during absolutely unnecessary mutual heat exchange. Moreover, the air chambers themselves become a kind of heat accumulators. There is a greenhouse effect, which is actively used in agricultural technology.
- The rounded surface of the bottle acts as a lens, enhancing the effect of sunlight.
- If the bottom surface of the bottle is lined with reflective foil material, you can achieve the effect of focusing the rays in the area where the pipe passes. Heating will only benefit from this.
- Another important factor. A transparent plastic surface will to some extent reduce the destructive negative effects of ultraviolet rays, which neither rubber nor plastic “like”. This circuit should last longer.
To make such a solar collector you will need:
1 – Rubber hose, black metal or plastic pipes – as a heat exchanger.
2 – Plastic bottles that will become a casing around the circuit pipes.
3 - In the bottles, in their half, which will be adjacent to the base, foil or other reflective material can be inserted. The reflective part should face the direction of the sun.
4 – It will be quite easy to mount the stand from a block or metal pipe.
5 - Storage tank for heated water, which must be connected to the point of collection - tap, shower, etc.
6 - A container for cold water that can be connected to the water supply system.
Solar collector installation
The assembly of the option shown in the top diagram is as follows:
- To begin with, a stand is mounted from a metal pipe or bar. If it is made of wood, then it must be coated with an antiseptic composition, but if it is made of metal, then it must be treated with an anti-corrosion agent. It is necessary to calculate the length so that an even number of bottles are installed between the two racks.
- On racks, at a distance width of the bottles, horizontal strips are fixed on which additional fastening for the coil can be made. In addition, they will give the frame additional rigidity.
- Next, the required number of plastic bottles is prepared - the bottom part is cut off from them so that one bottle, with the side of the neck, fits tightly into the resulting hole.
- Take a hose (pipe) of the required length, which will be sufficient for installation coil circuit on a ready-made frame-stand.
Stepping back 100 ÷ 150 mm from the edge of the hose, mark the place where it is attached. Then, through this edge, the required number of prepared bottles is put on the pipe, which will be enough to completely cover the area to the opposite rack. The bottles are placed tightly next to each other, so that the neck of the second one fits into the hole cut in the bottom of the previous one.
- When the section of pipe for laying the upper section of the coil is completely covered with a box of bottles, its edge is secured on top of the left frame post. For fastening, you can use clip holders for plastic pipes with a latch of the desired size.
- If necessary, the position of the bottles is adjusted so that the foil half of them is at the bottom, near the collector frame.
- The pipe is then given a smooth turn and snapped back onto the clip.
- The next step is to put bottles on the pipe again, and it is fixed on the left rack. This pattern is continued until the entire frame is filled with the collector coil.
- Now all that remains is to “pack” the fittings through which the resulting collector will be connected to the cold water supply and to the hot storage tank.
This is what can happen in the end - it couldn’t be simpler! Such a collector, as can be seen, absolutely not complicated in manufacturing, but it can become a good “helper” in a private home, taking on the functions of heating water.
By the way, solar energy can be used not only to heat water, but also to supply heated air to rooms. For example, you can find out how to make it yourself by following the link to a special publication on our portal.
Video - DIY solar power plant assembly
Today, modern technologies and materials make it possible to use alternative energy sources as efficiently as possible. One such source is the sun. Converting its energy into electricity and heat is an economical (almost free) way to heat rooms. This way you can protect the environment from pollution. To heat water, you can make a solar water heater with your own hands.
Scope of use
Solar solar collectors are used to heat water in swimming pools, space heating or hot water supply. The essence of the work is to use the sun's energy to heat the coolant. Although the sun has different intensity in winter and summer, heating water in this way is possible all year round. This is the prerequisite for using this method.
For example, per square meter in winter you need from 1 to 3 kW/hour of generated electricity, and in summer this figure increases to 6-8 kW/hour. In the northern regions, all indicators can be increased by 30% or more. Even in the northern regions, solar heaters are actively used and help solve the problem of supplying hot water, heating, and the like. In the southern regions and the middle zone, such devices will fully provide the house with hot water and heat, of course, this means large units of several square meters. They can completely replace the boiler.
How to heat water at the dacha. DIY solar collector
The advantages of the system include:
The disadvantages of such a system are:
- high price when purchasing factory equipment;
- the efficiency directly depends on the location and time of year;
- dependence of efficiency on sunlight and cloud cover;
- despite the fairly high power, the panels are susceptible to hail;
- the need to install a heat storage tank.
DIY solar collector water heater Part 1
Types of solar collectors
Solar collectors can be classified according to many parameters. First of all, mention should be made of the temperature at which heteroheaters operate. So, devices are divided into:
- low temperature - operate at 50 degrees;
- medium temperature - temperature range 80−90 degrees;
- high-temperature - capable of bringing the coolant to a boiling state.
There are high-temperature devices that can operate at temperatures of 200-300 degrees, but these are used exclusively for production purposes. You can make a solar water heater with your own hands only in the first and second groups. To produce high-temperature collectors, you will need expensive and professional equipment.
If we divide devices by design, we can distinguish three main types:
- vacuum devices;
- flat water heaters;
- solar concentrators.
Vacuum water heaters operate on the principle of a thermos. The design is based on several dozen glass flasks with two chambers. The outer one is made of high-strength glass, which is “not afraid” of hail and wind. The inner one is made with a special cut to increase the ability to absorb sunlight. A vacuum is created between the chambers to avoid heat loss.
The inner tube contains a copper circuit in which a coolant circulates - low-boiling freon, which heats the structure of the vacuum solar collector. The heating process is realized due to the evaporation of the process fluid and the transfer of heat to the working fluid, which is located in the main circuit. As a rule, antifreeze is used for these purposes.
DIY solar collector
Such a system can provide operation at temperatures up to 50 degrees. It is quite difficult to build this structure on your own. In this regard, there are very few homemade devices of this type.
A flat-plate water heater looks like a low, insulated box. The solar energy absorption panel has increased thermal conductivity. Thanks to this, it is possible to achieve maximum heating of the coolant that moves along the tubular circuit.
The principle of operation of a solar concentrator is to heat a certain point using a spherical mirror. Direct heating of the coolant occurs in a spiral metal circuit, which is located under the focus of the mirror. The main advantage of solar collectors with the concentration of sunlight at one point is the ability to heat the coolant to a high temperature. But such a system is not popular among beginners and experienced craftsmen, since there is a need to monitor the location of the sun.
In order to make a solar collector for a summer shower with your own hands, a flat design is ideal. You also need to take into account the presence of thermal insulation, copper absorbers and glass, which has a high light transmittance.
Do-it-yourself solar collector - review, wiring.
Device and principle of operation
A flat-plate water heater consists of a wooden frame with a tightly sewn back wall. The main heating element, the absorber, is mounted on the bottom. It is often made from a metal sheet onto which a manifold of tubes is attached in the form of a coil or in a parallel position. The tubes are welded or soldered to the metal plate carefully; the seam should not be interrupted. This is necessary to ensure maximum heat transfer.
The fluid circuit consists of vertically arranged tubes. They are attached to a horizontal circuit with a large diameter. The inlet and outlet holes are located diagonally. This scheme allows you to extract heat from the heat exchanger as efficiently as possible. Antifreeze is often the main coolant. But you can choose other non-freezing substances.
The absorber must be painted with light-absorbing paint. The box is insulated with insulating materials, and tempered glass or plexiglass is installed on top. You can simplify the task by dividing the glazing area into two parts. For higher performance, double-glazed windows are used.
This design creates the effect of a thermos, which reduces heat loss from wind, rain and other weather phenomena.
The operating principle is as follows:
Modern technologies make it possible to use heated coolant even after the sun disappears behind the clouds. This happens due to the constant movement of the coolant and the presence of a heat-storing tank.
Independent production from improvised means
Heating water from the sun with your own hands can be done in different ways. But they all have one feature: the same design of the thermal insulation of the box. Often the base is made of wood, chipboard and similar materials. The top of the structure is covered with antiseptic substances, and then with varnish and reflective film. Insulation occurs due to the installation of mineral wool. The absorber is made from metal and plastic tubes. All other elements of the product can be made from unnecessary scrap materials.
One of the cheapest options for a solar collector for a summer shower is to use a garden hose or PVC pipe. They fold into a snail shape on a metal or wooden surface. The effectiveness of their use lies in the large heating area. It is imperative to install a heat storage tank. If this is not done, the absorber will overheat on very hot summer days. It is better to take the hose itself black. Thus, the sun's rays will heat the coolant as much as possible. This option can be used not only to heat water for a summer shower, but also for heated floors or a swimming pool.
To build a solar collector, the condenser of an old refrigerator is often used. The heat exchanger on the outside will be a ready-made absorber for the solar collector. You just have to install it on a heat-absorbing sheet of metal, and also mount it into the body. Of course, the efficiency factor is small, but it is just right to meet the needs for supplying warm water in the summer for a small country house.
Using an old radiator is another option for producing a solar collector yourself. It is more convenient to manufacture, since it does not even require the installation of an additional heat-reflecting plate. It is enough to mount it into the casing and pre-coat it with heat-resistant paint. One radiator can cover the need for hot water supply in the summer. If you install several units, then in cold sunny weather it is quite possible to do without additional sources of water heating.
Copper, metal-plastic, and polyethylene tubes for creating a collector with your own hands have also become very popular lately. They all have their pros and cons. For example, copper tubes require a lot of labor to install, as well as a large budget for their purchase.
Installation Features
To install the unit, you must carefully select the location. It cannot be shaded, since the solar collector must receive the maximum amount of sunlight throughout the day. The mounting rails that hold the base are made of wooden strips or metal. Their location and length must be calculated in such a way that the inclination of the slab towards the sun can be adjusted from 45 to 60 degrees.
To reduce heat loss, the storage tank should be placed as close to the installation as possible. Coolant circulation can be natural or forced. It depends on certain conditions. For the latter case, an additional circulation pump and a temperature sensor are used, which will monitor the water temperature and turn on the engine when the degree reaches the programmed level.