DIY water heater from plastic bottles. Homemade solar water heater made from plastic bottles

C solar collector made from PET bottles

Konstantin Timoshenko
Source: delaysam.ru

Two years ago, I was experimenting with PET bottles to make a solar water heater from them - a collector that would supply my family with hot water for both washing and household needs during the summer season. And finally this year he got around to it.

Having accumulated quite a lot of PET drinking water bottles over the winter, I decided to make a solar collector out of them - a water heater. I also bought a polypropylene pipe with a diameter of 50 mm, a couple of plugs and plugs and got to work. The length of the pipe accommodated 20 PET bottles of 2 liters each. Thus, the volume of the solar collector should have been about 40 liters of water. The volume is quite sufficient for daily needs in terms of washing dishes and washing up.

Having drilled the required number of holes for bottles in the pipe, I was faced with the problem of sealing the joint between the bottle and the polypropylene pipe. Silicone and acrylic sealants flatly refused to stick to it and flew off like leaves from a cabbage head. It seems to be holding tightly, but if I pressed a little, it comes off completely. The solution was found in using hot melt glue. But even here there were some surprises. The glue seemed to adhere well, but also peeled off in layers. I had to take a soldering iron and carefully rub (melt) the glue into the polypropylene around the perimeter of the hole. I had to do the same with bottles. The glue had to be melted into their neck. After this, we managed to glue the bottles into the pipe quite firmly and reliably.

In one of the end plugs I cut a fitting for connecting to the water supply. The water heater was supposed to be storage. Those. when the tap was opened, it was filled with water (40 liters), the water was heated and poured into a thermos storage tank. The bottles had to be positioned at an angle of about 20-30 degrees, with the neck down. To prevent the air in the bottles from interfering with filling them with water, a small hole (2-3 mm) was made in the very top of all bottles.

To prevent the collector from “moving apart” under the weight of the water filling it, a box was made from a board 150 mm wide. A layer of 50 mm polystyrene foam was laid at the bottom of the box and covered with household foil on top. This is done to thermally insulate PET bottles and to improve the efficiency of the solar collector.

So, the entire system was placed in a box and connected to the plumbing system. I covered the bottles with matte black spray paint, remembering my experiments with PET bottles for heating water (Read below for solar flow-storage water heater). After filling the solar collector with water, I inserted a sensor from an electronic thermometer into one of the bottles to monitor the temperature of the water and air.

The solar collector body itself was oriented to the east (alas, the roof was already ready...). But since its inclination is quite small (about only 20-25 degrees), the loss of efficiency should have been small. In fact, it could be considered that the collector is located almost horizontally.

The first day of the collector's work turned out to be partly cloudy. But there was quite a lot of sun and the water heated up to 48-50 degrees by 14:00. The collector body was not covered with anything, and since the wind was blowing with medium strength, I understood that the bottles were both heated by the sun and cooled by the wind. And 50 degrees for hot water is not so much. Taking a bath and washing the dishes is normal. But without a “reserve”, even such water poured into a thermos will quickly cool down even the next day.

So I decided to make windproof bottles using several pieces of glass that I had lying around since time immemorial. I glued the glass to several points with silicone sealant, but left micro-slits for ventilation in case it fogged up.

The day turned out to be not clear, but also partly cloudy. But the air was clear, almost without haze. Therefore, the sun shone brightly, although not “100%”. With the installation of glass, heating began to occur much more intensely than without them... A temperature of 50 degrees (the initial water temperature was about 15 degrees) was reached at about one o'clock in the afternoon and then continued to rise, although the sun had crossed the “perpendicular” to the plane of the solar collector.

At about 4 p.m., “a terrible thing happened.” When the water temperature reached 65 degrees (which I never dreamed of), the collector simply began to collapse! The hot-melt adhesive softened so much that it could no longer withstand even minimal water pressure and the junction of the PET bottles and the polypropylene pipe began to “cry”. But that's not so bad. The PET bottles themselves began to warp! It is clear that the temperature of their “body” exceeded the limit for PET and was higher than the temperature of water. I knew that PET warps at high temperatures, but I did not expect that this temperature would be reached in a solar collector with a primitive design. Thus, my solar water heater ceased to exist during the "testing".

What conclusions can be drawn from this experiment?

1. You can make a simple and extremely cheap solar water heater - a collector from PET bottles. Its cost will not exceed $10! Bottles - shareware, a pipe 2 meters 50 mm - 60 rubles, a pair of caps - another 40 rubles. A pair of hot melt glue rods - 30 rubles. fitting for connecting to the water supply, cuttings of foam plastic, boards, glass or plastic film...

The only drawback is that the temperature of the water heated by it should not exceed 50-55 degrees. Otherwise, the solar collector will be destroyed. The problem of hot-melt adhesive can be solved by making fittings. For example, take a tube (aluminum or copper) and cut a thread on its outer side. And use a couple of nuts to secure the bottle cap to the water supply manifold. And just screw the bottle into its own cork.

In principle, this water temperature (50 degrees) is sufficient for domestic needs. It may not be worth increasing the efficiency of your solar water heater during the hottest months of summer. It’s better to let it underheat a little than to melt. And in the demi-season months, it is worth covering the collector with glass.

2. The solar collector - water heater has potential even in central Russia! And the potential is huge! From April-May to September inclusive (virtually the entire summer season), a solar collector - water heater of the proper size and design can provide hot water to an ordinary family, while saving hundreds (and maybe thousands) of rubles from the family budget, which are spent on electric water heaters and their operation .

Of course, we should come up with something more reliable and heat-resistant than PET bottles for use in a solar collector - water heater. And of course - budget. For example - aluminum cans...

Solar instantaneous storage water heater made from PET bottles

While experimenting with elements of a flow-storage solar water heater made from plastic PET bottles, I once noticed that the temperature of a dark (brown) beer bottle was even higher to the touch than that of a transparent water bottle. This gave me the idea to do a simple experiment with different colors and types of bottles to see which ones were the most efficient in terms of heating.

At the very beginning, I believed that there was no better water bottle than a transparent one. The sun heats the water directly, without intermediaries. How wrong I was! The very first experimental results dispelled my theories to smithereens.

The experimental conditions were simple. I simply placed a row of bottles against the wall of the barn, which faces approximately southeast. Since the conditions for all the bottles were exactly the same, I did not insulate or orient them in any way. Those. This is exactly how, in spartan conditions, this used PET container was supposed to show its true character.

Bottles were prepared according to the list in the table. In doing so, I used the following considerations.

1. The idea was that shielding the back (unlit part of the bottle) with aluminum foil would allow the IR rays not absorbed by the water to be reflected back into the bottle.

2. Blackening the back of the bottle (with rubber-bitumen mastic from an aerosol can) will allow you to “absorb” the IR rays passing through the bottle. One of the bottles was completely blackened, i.e. on all sides and became black and matte.

Everything was done the day before and the next day all the bottles greeted the dawn at the experiment site. The ambient air temperature (in the shade nearby) and the wind blowing the bottles were also taken into account.

The sun that day shone through a slight haze, i.e. did not give full intensity, but since everyone was on equal terms, this can be ignored.

The results of this experiment are shown in the table. By the way, if someone thinks that water at 52 degrees is “so-so” - try holding your hand in it for at least 2 minutes... Just stock up on more post-burn ointment... And at the same time, measure the temperature of the hot water from the tap in the apartment . It is unlikely that it will be much higher.

What conclusions can be drawn?

1. In fact, clear water is a very poor absorber of IR rays. They practically pass through it without stopping. As you can see, the transparent bottle remained the “coldest”. The heating can be safely attributed to the non-absolute transparency of the bottle itself, and not to the direct heating of the water in it.

2. The presence of foil on the back wall of the bottle also has little effect on heating. I don't know why. Perhaps heating occurs only on the front wall of the bottle; perhaps the foil, in addition to the reflector lens, also acts as a radiator - cooler.

3. The transparent one with a blackened bottom looks much better (by 8%). But obviously, the change in the angle of illumination by the sun began to have an effect. As the illumination angle changed, the area of ​​the rear absorbing surface also changed.

4. It was the completely blackened bottle that performed best. The black matte surface almost completely absorbed IR rays. And since the PET bottle is round, the lighting angle is not of fundamental importance.

5. Bottles made of dark plastic also performed quite well. This suggests that heat absorption by PET bottles occurs mainly on the side facing the sun. And very weakly - with the actual “insides” of the bottle (water). And not at all - with the back side.

This allows us to draw a conclusion about WHAT a solar collector made from plastic PET bottles should actually be.

This should be a box with a well-insulated bottom, where PET bottles are placed. The side of the bottles facing the sun should be blackened with some kind of matte paint (the same “Kuzbass-varnish” or rubber-bitumen mastic). Cover the top of the box with either thin glass or cover it with plastic film to protect it from the wind.

This design of a solar flow or storage heater made from PET bottles will be the most effective. By the way, these same results allow us to estimate the design of the most efficient “classic” water heater. It is quite obvious that its “mirror” does not necessarily have to be transparent. And if it is transparent, then the “bottom” must be absolutely heat-absorbing.

Now let's talk about the “place” of such a heater in a country water supply system with hot water.

Of course, having a heater like this on your roof does not guarantee that you will have hot water. There are also prolonged bad weather, and at night, especially in the mid-season, the water in such a heater will cool down greatly.

I think that such a water heater performs 2 functions.

A)Allows you to make sure for “mere pennies” that solar water heating is possible and it is a reality. After all, not everyone will decide to build a solar collector like this out of the blue, investing substantial money for the sake of ephemeral savings in electricity, firewood, and money. This water heater for 500 rubles will pay for itself within a season and will let you feel the beauty of the moment.

B)This water heater will allow you to REALLY save money in the form of firewood, electricity, gas, etc. working as a water treatment system for ANY industrial water heater.

Each family has its own hot water consumption. But in any case, it should always be there. Therefore, as soon as the heating of water in the solar collector ends, it should immediately be sent to a well-insulated storage tank, from which hot water is consumed. A heating element should also be installed in the same storage tank, which will provide hot water during periods of prolonged bad weather. Or you can connect a wood-burning water heater to it.

But in any case, the solar water heater itself is only part of the hot water preparation system. Then there will be hot water in the house or shower always and around the clock. Although of course it can be used on its own. Just hot water will be ready for lunch.

Alternative sources of renewable energy are extremely popular. In some EU countries, autonomous heating supplies cover more than 50% of energy needs. In the Russian Federation, solar collectors have not yet become widespread. One of the main reasons: the high cost of equipment. For a solar panel from a domestic manufacturer you will need to pay at least 16-20 thousand rubles. Products from European brands will cost even more, starting from 40-45 thousand rubles.

Making a solar collector with your own hands will be at least half cheaper. A homemade solar collector will provide enough heat to heat shower water for 3-4 people. To make it you will need construction tools, ingenuity and available materials.

What can a solar system be made from?

First, you need to understand what operating principle a solar water heater uses. The internal structure of the block contains the following components:

• frame;
• absorber;
• a heat exchanger within which the coolant will circulate;
• reflectors to focus the sun's rays.

The factory solar water heating collector works as follows:

• Heat absorption - the sun's rays pass through the glass located on top of the body or through vacuum tubes. The internal absorbent layer in contact with the heat exchanger is painted with selective paint. When sunlight hits the absorber, a large amount of heat is released, which is collected and used to heat water.
• Heat transfer - the absorber is located in close contact with the heat exchanger. The heat accumulated by the absorber and transferred to the heat exchanger heats the liquid moving through the tubes to the coil inside the heat storage tank. Water circulation in the water heater is carried out by forced or natural means.
• DHW - two principles of heating hot water are used:
  1. Direct heating - hot water after heating is simply discharged into a thermally insulated container. In a monoblock solar system, ordinary household water is used as a coolant.
  2. The second option is to provide hot water supply with a passive water heater based on the principle of indirect heating. The coolant (often antifreeze) is sent under pressure to the solar collector heat exchanger. After heating, the heated liquid is supplied to a storage tank, inside of which a coil (playing the role of a heating element) is built, surrounded by water for the hot water supply system.
     The coolant heats up the coil, thereby transferring heat to the water in the container. When the tap is opened, heated water from the heat-storing tank flows to the water collection point. The peculiarity of a solar system with indirect heating is its ability to operate throughout the year.

The operating principle used in expensive factory-made solar systems is copied and repeated in do-it-yourself collectors.

The working designs of solar water heaters have a similar structure. They are only made from scrap materials. There are schemes for the production of collectors from:

• polycarbonate;
• vacuum tubes;
• PET bottles;
• beer cans;
• refrigerator radiator;
• copper tubes;
• HDPE and PVC pipes.

Judging by the diagrams, modern “Kulibins” prefer homemade systems with natural circulation, thermosiphon type. The peculiarity of the solution is that the storage tank is located at the top point of the hot water supply system. Water circulates through the system by gravity and is supplied to the consumer.

Polycarbonate manifold

They are made from honeycomb panels with good thermal insulation properties. Sheet thickness from 4 to 30 mm. The choice of polycarbonate thickness depends on the required heat transfer. The thicker the sheet and the cells in it, the more water the installation can heat.

To make a solar system yourself, in particular a homemade solar water heater made of polycarbonate, you will need the following materials:

• two threaded rods;
• propylene corners, the fittings must have an external threaded connection;
• PVC plastic pipes: 2 pcs, length 1.5 m, diameter 32;
• 2 plugs.

The pipes are laid parallel to the housing. Connect to the hot water supply via shut-off valves. A thin cut is made along the pipe into which a sheet of polycarbonate can be inserted. Thanks to the thermosiphon principle, water will independently flow into the grooves (cells) of the sheet, heat up and go into the storage tank located at the top of the entire heating system. To seal and fix the sheets inserted into the pipe, thermally resistant silicone is used.

To increase the thermal efficiency of a cellular polycarbonate collector, the sheet is coated with any selective paint. Heating of water after applying selective coating accelerates approximately twice.

Vacuum tube manifold

In this case, it will not be possible to get by solely with improvised means. To make a solar collector you will have to buy vacuum tubes. They are sold by companies involved in the maintenance of solar systems and directly by manufacturers of solar water heaters.

For independent production, it is better to choose flasks with feather rods and a heat-pipe thermal channel. The tubes are easier to install and change if necessary.

You also need to purchase a concentrator block for a vacuum solar collector. When choosing, pay attention to the performance of the node (determined by the number of handsets that can be simultaneously connected to the device). The frame is made independently by assembling a wooden frame. Savings when manufacturing at home, taking into account the purchase of ready-made vacuum tubes, will be at least 50%.

Solar system made from plastic bottles

To prepare you will need about 30 pcs. PET bottles. When assembling, it is more convenient to use containers of the same size, 1 or 1.5 liters. At the preparatory stage, the labels are removed from the bottles and the surface is thoroughly washed. In addition to plastic containers, you will need the following:

• 12 m of hose for watering plants, diameter 20 mm;
• 8 T-adapters;
• 2 knees;
• roll of Teflon film;
• 2 ball valves.

When making solar collectors from plastic bottles, a hole is made at the bottom of the base equal to the diameter of the neck, into which a rubber hose or PVC pipe is inserted. The collector is assembled in 5 rows of 6 bottles on each line.

On a clear day, within 15 minutes. the water will heat up to a temperature of 45°C. Considering the high performance, it makes sense to connect a solar water heater made from plastic bottles to a storage tank of 200 liters. The latter is well insulated to prevent heat loss.

Aluminum beer can collector

Aluminum has good thermal characteristics. It is not surprising that metal is used to make heating radiators.

Aluminum cans can be used in the manufacture of homemade solar systems. Cans made of tin or any other metal are not suitable for production.

For one solar panel the following components will be required:

• jars, about 15 pcs. per line, the body accommodates 10-15 rows;
• heat exchanger - a collector made of a rubber hose or plastic pipes is used;
• glue for gluing cans together;
• selective paint.

The surface of the cans is painted dark. The box is covered with thick glass or polycarbonate.

A solar collector made of aluminum cans is often made for air heating. When using water coolant, the thermal efficiency of the device decreases.

Solar system from the refrigerator

Another popular solution that requires minimal time and money. The solar collector is made from the radiator of an old refrigerator. The coil is already painted black. It is enough just to place the grille in a wooden case with insulation and connect it to the hot water supply using soldering.

There is an option for making an air conditioner from a condenser. To do this, several radiators are connected into a single network. If it is possible to purchase cheaply about 8 pcs. capacitors, manufacturing a collector is quite possible.

Copper tube collector

Copper has good thermal properties. In the manufacture of a copper solar collector, the following is used:

• pipes with a diameter of 1 1/4", used in the installation of heating and hot water supply systems;
• 1/4" pipes used in air conditioning systems;
• gas-burner;
• solder and flux.

The radiator grille body is assembled from copper pipes with a large diameter. Holes equal to 1/4" are drilled into the surface. Pipes of the appropriate diameter are inserted into the resulting grooves. The radiator is covered with glass or polycarbonate. The copper is painted with selective paint.

Solar boiler made of HDPE pipes and PVC hoses

In the production of solar systems, almost any available material is used. There are solutions that allow you to make a collector from corrugated hose, a rubber hose used for watering plants.

Solar systems are not made from metal-plastic pipes due to rubber fitting seals that cannot withstand strong heat. With intense solar radiation, heating in the collector reaches 300°C. If overheated, the gaskets will definitely leak.

It is possible to manufacture a solar collector from corrugated stainless pipe. The popularity of the solution is due to the speed and ease of installation. Corrugated stainless steel pipe is laid in rings or snakes. The disadvantage is the relative high cost of stainless corrugated pipes.

Despite the existing options described above, solar collectors made of propylene and HDPE pipes remain the most popular. Each option has its own advantages:

• Solar collector made of HDPE pipes- for manufacturing, choose a material that is resistant to heat. A large number of fittings are sold to facilitate the assembly of a heat storage radiator. Pipes made of low-density polyethylene are initially black or dark blue in color, so they do not require painting.
• Solar collector made of PVC pipes- the popularity of the solution lies in the ease of installation of the structure, carried out using soldering. The presence of a large number of angles, tees, American females and other fittings facilitates the assembly process. Using soldering, you can create a collector heat exchanger of any configuration.

Making a solar hot water collector from PEX pipe:

All the pipes described are used with varying efficiency as a core in the manufacture of a homemade solar collector from plastic bottles and aluminum cans.

How to make selective coating

A highly efficient collector has a high degree of solar energy absorption. The rays hit a dark surface and then heat it up. The less radiation is repelled from the solar collector absorber, the more heat remains in the solar system.

To ensure sufficient heat accumulation, it is necessary to create a selective coating. There are several production options:

• Homemade selective collector coating- use any black paints that leave a matte surface after drying. There are solutions when an opaque dark oilcloth is used as a collector absorber. Black enamel is applied to the heat exchanger pipes, the surface of cans and bottles, with a matte effect.
• Special absorbent coatings- you can go the other way by purchasing a special selective paint for the collector. Selective paints and varnishes contain polymer plasticizers and additives that provide good adhesion, heat resistance and a high degree of absorption of sunlight.

Solar systems used exclusively for heating water in summer can easily get by by painting the absorber black using regular paint. Homemade solar collectors for heating a house in winter must have a high-quality selective coating. You can't skimp on paint.

Homemade or factory solar system - which is better?

It is unrealistic to make a solar collector at home that can be compared with factory products in terms of technical characteristics and performance. On the other hand, if you simply need to provide enough water for a summer shower, solar energy will be enough to operate a simple homemade water heater.

As for liquid collectors operating in winter, not even all factory solar systems can operate at low temperatures. All-season systems are most often devices with vacuum heat pipes, with increased efficiency, capable of operating at temperatures down to –50°C.

Factory solar collectors are often equipped with a rotating mechanism that automatically adjusts the angle of inclination and direction of the panel to the cardinal points, depending on the location of the Sun.

An effective solar water heater is one that fully meets its intended purpose. To heat water for 2-3 people in the summer, you can get by with an ordinary solar collector, made with your own hands from improvised materials. For heating in winter, despite the initial costs, it is better to install a factory solar system.

Video course on making a panel solar water heater

Ecology of consumption. Science and technology: Imagine a solar collector made from plastic bottles. It can help disadvantaged communities gain a reliable source of energy and, at the same time, a recycling system.

Imagine a solar collector made from plastic bottles. It can help disadvantaged communities gain a reliable source of energy and, at the same time, a recycling system.

Such a project was implemented in Garina, a town 40 kilometers north of the Argentine capital Buenos Aires. There is a group of volunteers called "Sumando Energias" who are trying to equip poor people with solar energy systems for heating water.

“This is a poor area and sometimes we don’t have electricity. No water. This solar panel made from recycled material is very helpful because we have children... This is how we get warm water when we have no electricity,” says a local resident.

How does this system work? She is brilliant and simple at the same time. It is made from used drink bottles, plastic containers and milk cartons after they have been recycled.

The sun heats the solar energy receiver, hot water flows into the container. Volunteers painted the pipes black to attract solar radiation. The collector maintains the temperature of the heated water all night, without gas or electric heating.

“In my opinion, rational environmental development is an important trend in which we must develop. We throw away too much today, and not just in developing countries. I believe that developed countries should also follow the path of thoughtful development. Developed countries are the largest polluters,” says Julien Laurenson, a participant in the Sumando Energias project.

A third of Argentines live below the poverty line. Almost 17% of the population lacks water, says a study by the Argentine Statistics Agency last September.

The project provides access to renewable energy to poor people and has the potential to significantly improve the living conditions of the South American nation, which has large natural resources. With more and more volunteers, Sumando Energias hopes to build panels for 3,000 families a year.

“Argentina has huge potential for solar and wind energy. To explain better: if we had the same opportunities as in Germany, in the province of Santa Cruz - in Buenos Aires or in the north, where there is a lot of sun, we could produce energy and provide it not only to Argentina, but also to neighboring country,” says Pablo Castano, co-founder of Sumando Energias.

Since 2014, the non-governmental organization has installed 36 panels and offers two-day training for those who want to learn the technology of recycling salvaged materials into solar heaters. Volunteers involve local families in the process of building the mechanism and teach them how to recycle waste.

“There are such things, garbage that we throw away, and it pollutes the environment, but we can use it for practical purposes, for example, for hot water in the house. It is very good to recycle waste. I've never done this before. I just threw everything away, bottles and stuff. Previously, garbage stood in plastic bags for a long time, because the municipal service did not come to pick it up,” says Angel Guelari, a resident of Garin.

Argentina appears to be on the right track. In 2005, Buenos Aires became the first Latin American city to vote for a "No Waste" policy. The Argentine capital has pledged to recycle between 4 and 5,000 tons of trash that people throw away every day. published

Engineers from the distant Argentine province of Tucuman have developed a simple and cheap solar water heater from several dozen plastic bottles. And they wrote detailed instructions, which became so popular that they were used by thousands of people from different parts of the Spanish-speaking world.

This device will absolutely freely provide 80 liters of warm water to a family of 4 people. And all you need for this: 6 plastic bottles and 2 meters of hose.

Step-by-step instructions on how to make a solar water heater from plastic bottles

1. Collect at least 30 soft disposable 1-1.5 liter bottles and remove the label.

2. Buy in the store 12 meters of black irrigation hose (precisely black) 2 cm in diameter, 8 “T-shaped” adapters and two elbows, a roll of Teflon and two ball valves 2 cm in diameter.

3. At the base of each bottle we make holes equal to the diameter of the hole in the neck. You can use a drill, or you can use a hot screwdriver.

Then we thread the bottles onto the hose so that there are 6 bottles per row. You should have 5 rows of bottles with a hose length of 2 meters.

4. Connect the hoses with T-shaped adapters.

5. We lay out the entire structure in a box insulated with foam plastic and connect it with pipes to an 80-liter barrel. (For a better thermal effect, you can line the box with foil. And you can coat plastic bottles with matte spray paint.)

6. We position the collector at an angle of 45 degrees on the south side of the roof. (For wind protection, you can cover the collector with glass and transparent polycarbonate.)

Pour in water and... voila! After just 15 minutes, the water in the tubes will heat up to a temperature of 45-50 degrees and begin to circulate according to the thermosiphon principle. To store warm water, you can use a 200-liter barrel, which can be insulated.

The concept of alternative energy for many owners of private houses and summer cottages is associated with expensive solar panels, wind turbines or heat pumps. No one even realizes that in just a few hours, for mere pennies, you can build a solar collector from plastic bottles to supply yourself with hot water throughout the warm season.

We will tell you how to make an effective sanitary water treatment system from waste materials. In our article you will find a detailed description of the designs and methods of manufacturing systems, the operation of which has been tested in practice. Taking into account our recommendations, you will assemble a useful household device without any hassle.

The main difference between a solar collector and various types of heat generating systems is the cyclical nature of its operation. In other words, in the absence of the sun there will be no thermal energy.

Obviously, in the dark, the performance of an autonomous hot water system with a solar collector is reduced to zero. Heat production by a solar collector is determined by the length of daylight hours, which depends on latitude and time of year.

A homemade solar collector will solve not only the issue of supplying hot water to a house not connected to central networks, but also heating problems

The climatic features of the area also have a significant impact on the performance level of the solar collector. If the area is characterized by frequent fogs or the sun is often hidden behind clouds, then the performance of the solar collector is significantly reduced.

However, even in this case, water heating remains effective due to the ability to capture even scattered rays.

Design features and principle of operation

The main element of the standard version of the solar collector is an adsorber in the form of a copper plate with a tube. The plate quickly heats up under the influence of sunlight, transferring heat to the tube and the liquid in it. Thanks to free or forced circulation, the resulting heat is further transported throughout the system.

Under the influence of sunlight, the copper plate is heated, from which heat is transferred to the coolant located in the tube

To increase the efficiency of the adsorber, it should be endowed with the necessary physical properties. First of all, it is necessary to increase the absorption capacity of the adsorber and minimize the reflection of sunlight. The simplest solution would be to apply black paint to the adsorber.

To increase the efficiency of the adsorber, it must be covered with transparent glass. Ordinary glass reflects some of the sun's rays.

It is best to use special glass with a low iron content or use an anti-reflective coating. To avoid contamination of the glass, the body of the solar collector should be made airtight.

Despite the many ways to improve the operation and increase the productivity of a solar collector, due to imperfections in the design, this indicator is far from ideal. Taking into account the principle of operation of a solar collector and methods for increasing its efficiency, we will try to create a primitive and inexpensive model from scrap materials.

Assembling the unit from scrap materials

In addition to being cheap and easy to assemble, the option made from plastic bottles differs from standard solar devices in that flat solar collectors do not work well in the morning and evening hours.

The convex shape of the bottles ensures almost vertical penetration of rays even during sunset and dawn, thereby ensuring the efficiency of the device both in the morning and in the evening.

There are several distinctive ways to construct a perfectly working hot water system from plastic bottles:

• The solar collector plays the role of a storage tank in which water is heated and then drained;
• The solar collector is connected to a storage tank to ensure water heating and natural circulation;
• Plastic collector bottles act as a water reservoir;
• Plastic bottles act as sealed containers to retain heat.

Also, solar collectors may differ in their design features. First of all, this is due to both the method of fastening the bottles and the methods of their arrangement.

Option with heated water storage

To make a solar collector, you will need a diameter of 50 mm, to which plastic bottles will be connected, the number of which is determined by the diameter of the pipe. For the template, 15 plastic bottles were taken, so the working capacity of the solar collector was 30 liters.

To connect the bottles into a single system, holes must be drilled in a propylene pipe intended for hot water supply. The ideal solution was to use a 26mm wood drill bit.

With these dimensions, maximum joint density is ensured, and the bottle is screwed into the hole with force along its thread. To ensure maximum sealing of the connection, the joints can be coated with silicone sealant, but it is better to use hot melt adhesive.

To achieve the effect of communicating vessels, holes with a diameter of about 2 mm must be made in the upper part of each bottle.

After connecting the bottles, a fitting is cut into one side of the pipe, which will later be connected to the water supply for water supply. On the other side, you should install a tap through which the heated water will drain into the storage tank.

However, under the weight of filled water, such a device for household use may lose its integrity. Therefore, it would be advisable to install a box. To make it you will need a board 150 mm wide.

To increase the efficiency of the solar collector, you can lay foam plastic or polystyrene foam 50 mm thick on the bottom of the box and cover it with foil.

After installing the solar collector at the place of its further use, plastic bottles must be painted black to more effectively absorb sunlight.

It is better to use matte paint and apply it by spraying from an aerosol can. All that remains is to cover the box with glass, thereby increasing its tightness and connect it to the cold water supply system and the system for draining warm water prepared for use into the storage tank.

From practical experience it is known that plastic does not tolerate high temperatures, which lead to its deformation. On bright sunny days, the temperature of the heated water can exceed 65 degrees, which will lead to deformation of the plastic.

In this regard, it is better to refuse additional sealing of the box with glass at all or to use it exclusively in cloudy weather.

Method with circulation of heated water

The solar collector system is similar to the first option, but has a number of design differences.

To create a collector you will need the following tools and materials:

• PVC pipe with a diameter of 20 mm with corners and tees;
• Roller pipe cutter;
• Chamfer cutters;
• Primer (cleaning agent);
• Plastic bottles;
• Tetrapacks for milk or juice;
• Stationery knife;
• Cardboard;
• Heat-resistant matte black paint;
• Storage tank.

For installation we will need a PVC pipe with a diameter of 20 mm. The horizontal part of the pipe should be cut into sections into which angles and tees will be attached by cold welding. The bottom of the solar collector will look exactly the same. The end result is a closed system, but first things first.

Features of gluing PVC pipes

To obtain a high-quality cut, it is better to use one equipped with rollers. After cutting, the inside of the pipe must be chamfered using special chamfer cutters.

After measuring the depth of the tees and angles, you need to place a mark on the end of the pipe being connected and treat the ends of the pipes and fittings with a primer (cleaning agent).

The next step is to apply and spread the glue around the outside of the pipe and the inside of the fitting. The glue must be applied with a brush, and its size should be smaller than the diameter of the pipes. All that remains is to insert the pipe into the prepared tee or corner and turn it a quarter turn to evenly distribute the glue.

It should be taken into account that the work of gluing one corner or tee should be completed in no longer than 30 seconds. After fixing, it is necessary to remove any remaining adhesive.

The procedure for manufacturing a solar collector

After preparing the top pipe and attaching the vertical pipes to it, you can begin preparing the plastic bottles. The presented solar collector model has 4 vertical pipes 105 cm long; this length of pipe can accommodate 5 plastic bottles. That is, to assemble the collector you will need 20 identical plastic bottles.

The bottom must be removed from each bottle. To do this, you should make a simple template from a piece of cardboard 30 cm long rolled into a tube. Using the template and a stationery knife, remove the bottom of the bottles. After preparing the bottles, you can begin making an absorber that will absorb solar energy.

Using a simple cardboard template allows you to quickly cut and get bottles of the same size

We use used juice or milk tetra packs as an absorber. They must be cut, thoroughly washed and dried. To improve their absorption capacity, apply matte black paint. The easiest way to do this is to use spray paint from a can.

Sequential stringing of plastic bottles makes it easy to place folded tetra packs in them

After preparing the bottles and tetrapacks, you can begin assembling the solar device. First, you need to string a plastic bottle, neck first, onto a vertical tube and insert a Tetra Pak into it. In a similar way, all the bottles are strung on vertical tubes, which then must be connected to the tees and corners of the lower pipe, similar to the upper one.

To give rigidity to the manufactured solar collector, it is necessary to make a support for it.

You can, as in the first case, place the collector in a wooden box, but there is no longer any need to insulate it. Since each of the plastic bottles is a kind of small insulated reservoir, which, heating up from the inside, transfers heat to the water circulating through the tubes.

Features of placement and connection

For maximum possible absorption of sunlight, the collector must be oriented in a southerly direction. A small tilt angle of 10-15 degrees is enough for the collector to work effectively in almost any position of the sun.

The lower part of the pipe must be connected to the bottom of the storage tank, and the upper part - approximately to its central part. Cold water from the polymer container will flow through the lower pipe into the collector, where it will heat up and rise through the upper tube into the tank.

Thus, there will be natural circulation of water through the homemade system. To ensure high intensity of water circulation, the tank should be placed just above the solar collector at a distance of at least 0.3 m from it.

It should be taken into account that when cold water enters the tank from the water supply system, it is actively mixed, which reduces the efficiency of the collector. This can be avoided by equipping the inlet to the tank with a turbulent reducer, which is a plugged tube with multiple holes.

Water flows smoothly through the reducer, which allows cold water to remain in the lower layers, from where it is taken into the solar collector.

Obviously, the solar collector provides water heating only during the daytime in sunny weather. Therefore, it is important to save hot water for use during the day and evening. To do this, it is necessary to insulate the storage tank.

Conclusions and useful video on the topic

Video 1. This is how the first solar systems from plastic bottles appeared:

Video 2. Almost free water heating device in action:

A solar collector made from plastic drink containers is a cheap solution for producing hot water. However, in case of prolonged bad weather, especially in spring and autumn, it is advisable to install a heating element in the storage tank. In this case, the solar collector will become part of a complete system, allowing, under favorable conditions, to save money.

Tell us about your experience in building a homemade solar system from plastic bottles. It is possible that you have information and design options in your arsenal that may be useful to site visitors. Please write comments in the block form below, ask questions, share photos and useful information.