Gutter and solar collector made of plastic bottles. Homemade solar water heater made from plastic bottles Solar heater made from plastic bottles

It's nice that the magazine sectionHomius“Stories” is becoming more and more popular and some authors even send continuations of their articles and reviews. Today is exactly such a case. The editor received another letter from Vladimir Alekseev from the city of Klin, Moscow region, already familiar to us from the review of methods of use. This time Vladimir decided to continue the topic and talk about several more useful options.

In my last review I reported on several ways to use plastic bottles for household needs. And so, I couldn’t resist, I decided to continue the topic. After all, there are a lot of options on how to usefully use such material. Today I will try to describe the most interesting ways, which will help the summer resident in his difficult work. I would like to start by making a drainpipe that can be turned into solar collector For summer shower.

The version of the drainpipe, when one is inserted almost halfway into the other, is known to everyone. It's not difficult to make. One problem is that this method requires a decent amount of material, and there is a lot of waste in the form of cut bottoms. As it turns out, there is a less expensive method.

To implement it you will need:

drill with a diameter of 8 mm;
nib 12 mm wide;
drill or screwdriver.

The volume of the bottle can be any, but the neck must be narrow. A wide one will require a different nib.

Preparing plastic bottles for joining

First, in the bottom of the bottle, exactly in the center, you need to drill a hole with a diameter of 8 mm. In order not to constantly swap the drill and the pen, it is better to immediately decide on the number of bottles that will be required to obtain required length gutter

Next, the pen comes into play. Here you should not press too hard when drilling. It's better to spend a little more time, but still get a neat straight hole. In fact, for a regular drain, the work done will be enough. All that remains is to screw the neck of one bottle into the hole drilled in the bottom of the other. After all, special tightness is not needed in the manufacture of such a drainpipe. But this design can also be used for other purposes. At the dacha, summer showers are especially in demand. Further we will talk about him.

Continuing the topic: solar collector for heating running water

Imagine that several rows of dark bottles, assembled in the manner described, are laid out parallel to each other on the roof of a barn, and a container of water is located on a small elevation. A hose runs from the bottom bottle of one row, connected to the bottom of the adjacent line. We get some semblance of a snake. The fact that the container is located higher provides the necessary pressure. It turns out that the water, before entering the shower tap, passes through several rows of dark bottles and warms up thoroughly. Now I’ll tell you how to make a sealed line that can withstand slight pressure.

Making a sealed connection: what is needed for this

In order for the connection to be not only tight, but also strong (after all, the water pressure will not be strong, but sufficient), you need to prepare some tools. To work, you will need an M27 cutting die (also called a “cutter”) and a ¾″ (inch) pipe tap. Another necessary tool– a hot glue gun that will help seal the joints.

New carving on the neck of the bottle, over the old one

The neck of each bottle must be driven with a straight edge to the limiter. There is no need for a die holder here; the plastic is very soft and easy to process. But you should be careful so that the spoon fits evenly onto the neck. Otherwise, when laying the collector on the roof, the curvature may lead to a crack at the connection point, and hence water leakage.

Internal thread in the bottom of a plastic bottle

Now you need to do internal thread in the bottom of the bottle, where the neck will be screwed. To do this we use a ¾ inch pipe tap. It is very important that the thread pitch of the die and tap match. Otherwise, nothing good will come of our venture.

For this cutting, a tap holder is also not required. To begin with, we take the tap in one hand, and with the other we hold the plastic bottle by the side, as close as possible to the bottom, where its density is greater. Slowly turn the tap clockwise. Plastic is very soft, so there is no need to unscrew the tap after every 1-2 turns (as is the case with metal). On average, one bottle takes no more than a minute. The number of plastic bottles may vary, depending on the parameters of the roof on which the collector will be located. It is also worth noting that the longer the line of plastic bottles is, the stronger and faster the water will heat up in sunny weather.

Assembling a solar collector line from plastic bottles

Once the internal and external threads on all bottles are ready, you can begin assembling the solar collector. It's not more complicated here children's construction set. We simply screw the neck of one bottle into the bottom of another.

Having calculated the length of how many plastic blanks are needed, we assemble several strips, laying them out parallel on the ground. Thus, you can decide on the width of the future collector. The highways will also be located on the roof in a certain order. Water from the container should be supplied to the hole at the bottom of the first line. The second line will be located in the opposite direction. It turns out that the flow of water should always be directed from the bottom to the neck. The number of lines matters only to the owner; it does not have any effect on the water pressure.

Many may ask why it is necessary to respect the direction of the bottles. The main problem here is that various debris, branches, leaves get into the tank during dacha downtime(autumn-spring). If the bottles are positioned the other way around, and water along with debris goes from the neck to the bottom, the hole will simply become clogged, and flushing the line will become quite problematic. In our case, it is enough to fill and drain one container at the beginning summer season to get rid of garbage completely.

Now let's cut off a few pieces garden hose and connect the stripes into a single highway. Although this work can be done on the roof, as they say “on site”. It's time to start sealing the connections. Hot melt adhesive works great for this. We carefully coat each connection with molten polyethylene, paying special attention to Special attention places where the hose meets the plastic bottle. After the procedure is completed and the glue has hardened, it will even be possible to place each line at an angle from the ground to the roof - there will be no kinks. This design is quite durable and will last at least 4-5 seasons (judging by how hot-melt adhesive behaves under temperature changes).

In order for the solar collector made from plastic bottles to last longer, you should not leave the valve closed in the fall, otherwise the water remaining inside the line will freeze and simply crush the walls. But when the tap is open, it will flow out. Maybe not all of it, but what remains will no longer be able to cause harm to the structure. And, when he arrives next season, the summer resident will be sure that he will definitely not be left without a shower.

When it's hot outside, the amount of garbage such as plastic bottles increases significantly in the world. These are bottles for mineral water, juices, beer and much more. One author proposed a way to use this material to create a very useful homemade product. We are talking about such a device as a solar collector, which allows you to receive free hot water from solar energy.

The author of this homemade product was a Brazilian named Jose Alano. Its peculiarity is that such a collector is capable of active operation both at sunrise and sunset. The whole point is that Sun rays penetrate the bottle and heat the water. If we talk about collectors with glass, then the sun's rays are reflected from the surface, unless they pass at an angle close to 90 degrees.

Materials and tools for homemade work:
- plastic bottles (their number depends on the scale of the collector);
- tetra pack from juice or milk;
- PVC pipes and with an outer diameter of 20 mm and tees (can be used copper tube, but this is expensive material);
- cardboard;
- stationery knife;
- black heat-resistant paint;
- scissors;
- storage tank.

Manifold manufacturing process:

Step one. Bottle preparation
To create a collector you need bottles of the same shape, so you need to try a little and find the right number of them. This is necessary so that the bottles can be inserted into each other, thus forming a chain of bottles.

Once the bottles are found, you need to wash them and remove the labels. Next, cardboard is taken and a template is made from it. Subsequently, using this template, you need to cut off the bottom of the bottles at a given level. This is convenient to do with a stationery knife.

Step two. Making an absorber
To make an absorber you will need milk or juice containers (tetra packs). The bags need to be rinsed thoroughly, since the contents will turn sour when heated and will emit bad smell. After drying, the material is cut as shown in the pictures. After this, it needs to be painted with black paint (heat-resistant).

Step three. Assembling the collector
The heat exchanger is assembled from PVC pipes with a diameter of 20 mm. For these purposes, you should use only those pipes that are intended for hot water supply. The corners and tees at the top are connected using PVC glue. To increase the efficiency of the collector, the pipes need to be painted black.

The structure is assembled as follows. First you need to take the bottle and put it on the bottle with the neck first. Then take an absorber (Tetra Pak) and insert it into the bottle until it stops. The length of the pipe is about 105 cm, and the number of bottles collected on it in this way should not be more than five.

Step four. Collector installation
To install the collector you will need a wooden or metal support. It needs to be turned so that the sun falls on it, it needs to be oriented towards the south.

In order for water to circulate naturally, the tank must be placed at a level above the collector. Now cold water will fall down, since it is heavier, and the hot one will expand and enter the tank. The distance from the collector to the tank must be at least 30 cm, then circulation will occur with the required intensity. Thanks to this approach, no pumps will be needed. The tank must be insulated to reduce heat loss.

The system can also be equipped with a turbulent reducer. It is needed in order to hot water entered the tank smoothly and without pressure, while smoothly mixing with the cold water. It is made from a bottle with a closed bottom; you need to make a number of holes in it.

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. For production you will need Building tools, ingenuity and available means.

What can a solar system be made from?

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

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 pipes OK;
HDPE and PVC pipes.

Judging by the diagrams, modern “Kulibins” give preference 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

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 self-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 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. On preparatory stage The labels are removed from the bottles and the surface is thoroughly washed. Except 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 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 color. 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 minimum costs 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 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 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.

From metal-plastic pipe solar systems are not made due to the rubber seals of the fittings, which 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 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. Polyethylene pipes low pressure They 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. Availability large quantity corners, tees, American females and other fittings facilitate 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?

Make a solar collector at home that can technical specifications and it is impossible to compare the indicators with factory products. 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 rotating mechanism, automatically adjusting 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

About solar water heaters (solar water collectors) in general...

Meanwhile, probably every schoolchild knows that for every square meter surface perpendicular to the sun's rays, 600-1000 watts of energy fall per hour! Well, it’s just a sin not to use it in the summer! It’s especially nice to take a shower before bed after a hot day, and it doesn’t hurt to freshen up during the day. But not ice water from a well or a well.

Those who have been to Greece or Italy have probably noticed that almost every house has a solar collector-water heater. Although their structure is quite simple in principle, there are many nuances in their operation. For example - constant water supply, thermal insulation storage tank, organizing water circulation between the tank and the collector itself, etc.

But self-production Such systems are extremely labor-intensive and expensive, and in general, with an amateurish approach, they promise more trouble than benefits.

In fact, it is necessary to make a sealed collector, organize water circulation and its regular replenishment, and avoid mixing already heated water with fresh cold water. And for the winter, drain the whole thing (we don’t have Greece here with +12 in January). And for what? Tolley's business is dear iron barrel! Filled it up - it warmed up, drained it for the winter - no problem. So what if it only works 10-15 times a year... But without any hassle.

It’s all these problems that keep summer residents from creating a normal and efficient solar collector for a water heater.

But it seems to me that when using plastic bottles, many problems are solved. All the “charms” of the simplicity of a primitive “barrel” solar water heater remain and the advantages of a real collector with water circulation are added. And these advantages will become obvious as we describe the water heater.

Solar water heater collector made from plastic bottles.

If you pour water into such a bottle and place it in the sun, the water in it will heat up quite quickly. But the bottle has a very limited volume! 2-2.5 liters maximum. To take a decent shower, you need at least 50-60 liters, preferably more than 100.

The main problem of creating a solar water heater is connecting many plastic bottles into a single container and organizing them to have some kind of flow! So that cold water can flow into them, and warm water can flow out. Having solved this problem, we simply get a small transparent tank that perfectly heats water using solar energy. Taking, for example, 100 such mini-reservoirs, i.e. bottles, we will already get 200 liters warm water!

Having measured the diameter of the thread on the neck of the bottle, I selected a drill that would be used to drill a hole in the bottom of another bottle. The best drill was a hole saw for drilling holes. large diameter for wood by 26 mm (sets of such files are available in abundance and cost 70-100 rubles). With this diameter, the neck of the bottle is screwed quite tightly into the hole in the bottom of the other. Sometimes you have to work with a large round file. Yes, and it is advisable to first drill a hole strictly in the center of the bottle with a regular drill 6-8 mm. I will say that this is not easy to do, because... It is in the center of the bottom that there is a very hard and smooth tide - a pimple. Therefore, for mass precision drilling, it would be better to make a simple template so that the drill does not wander.

The next problem was the sealing issue. Generally speaking, nothing seems to stick or stick to PET. But it turned out that this was not entirely true. Even with drilled hole, the bottom of the bottle retained absolute rigidity, and this gave hope for the use of silicone sealants. After thoroughly degreasing the surfaces with acetone, I coated the threads of the bottle and screwed it into the bottom. And then I generously covered the joint with sealant from the outside as well. To be safe, I left the bottles motionless for 3 days (the fermentation rate of the sealant is 3-4 mm/day, as stated in the instructions).

Since I was just going to work out the technology and conduct an experiment, I limited myself to connecting only 3 bottles in series.

The tightness of the joints turned out to be absolute! In the photo, the water bottles are lying on cardboard and as you can see, there are no water drips! By the way, the silicone stuck to the PET so much that you couldn’t pick it off with a knife!

During the day in the sun (or rather, in just a few hours), the water heated up perfectly even without any additional tricks. Thus, a certain conventional cell of the collector - water heater was obtained, with dimensions of 0.1 meters (bottle diameter) by 1 meter (bottle length approx. 35 cm). Those. The collector area was 0.1 kiloV. meter, and the capacity is approx. 6 liters. It is easy to calculate that per 1 kiloV. A meter will fit approximately 10 such modules, the capacity of which will be 60 liters of water. The sun will pour almost a kilowatt of energy onto these 60 liters of water every hour! Not only can you heat this water, you can boil it! Well, of course, it will never boil, if only because of heat loss. But you can heat 60 liters of water to 40-45 degrees 2-3 times exactly. Which is more than enough for country needs.

Now about the water heater project itself.

To connect all our modules in parallel, you will need a pipe of fairly large diameter (50 millimeters, or better yet 100, for example, polypropylene). All modules crash into it in the same way as bottles are joined together in a module. Perhaps it will be possible to do it simpler. Having glued or screwed a bottle cap to the pipe with a self-tapping screw and ensuring a tight seal, drill a hole in the cap (and the pipe at the same time) and simply screw the module into the cap.

The modules, of course, must be located at an angle (the lower side faces south, the common pipe is at the lowest point of the collector). In the topmost bottle of the module you need to drill a small hole, 2-3 mm. Install a valve on both sides of the pipe. Supply water to one of them (for example, from a pump or water tank, in the figure Vent.2). And the other valve will be collapsible, warm water will drain through it (in the picture Vent. 1).

The solar water heater collector works as follows. Valve 1 is closed, and we begin to fill the collector with water by opening valve 2. Water fills the bottles from the bottom up. The air then comes out of the holes at the top of the modules. Of course, as in communicating vessels, the water level in the modules is the same.

Having visually determined that the bottles are full, we close valve 2 and the water heater starts working.

If we need warm water, we open valve 1 and the heated water begins to flow out of the collapsible pipe.

That's all. Everything is exactly the same as in a barrel, only such a collector will heat water an order of magnitude more efficiently than a barrel, due to its large area.

A little about the design.

Of course, it is advisable to place the modules in a “box” to add rigidity to the structure. It is advisable to make the bottom of the box from a dark material that absorbs sunlight. For example, smoking a sheet of iron. It would be a good idea to place a heat insulator under the sheet, for example thin polystyrene foam or foamed polyethylene (“penoplex”). Cover the top of the box with plastic wrap or glass to prevent the wind from cooling the bottles.

The angle of inclination is minimal, 10-20-30 degrees, no more. Firstly, in summer this is the most optimal angle of inclination relative to the Sun (almost perpendicular), but in winter this collector is not used. Secondly, this will ensure a minimum drop in water pressure (height of the water column), which is important when there are many bottle joints. Although during testing I placed my 3-bottle module even vertically and it “kept” a pressure of 0.1 atm, I would not take risks during operation.

The size of the entire water heater is up to the taste of the creator. For 200 liters you will need approx. 110 bottles, which will take up an area of approx. 3 kiloV.meters. True, the power of such a heater will already be approximately 3 kW!

You can use the heater in the “pour-pour” mode. Or you can arrange a thermally insulated storage tank for warm water next to it. On a good sunny day, a 2-meter, excuse me, 2-kilowatt water heater will heat you half a ton of water.

Such a water heater is not afraid of frost (except for the water shut-off valves), and the sun is not afraid of it either (PET does not decompose well in the sun).

Of course, such a solar water heater also has disadvantages (for example, poor automation), but a lot of it pays off because it is practically free. Judge for yourself what the money will be spent on here. Well, a pipe, a couple of valves and 2-3 tubes silicone sealant 45-50 rub/piece. And you will receive water bottles as a bonus when purchasing water in the store. By involving your acquaintances in collecting them, by the next season you will have collected several dozen, or even hundreds of bottles and will be able to make yourself a very decent and productive solar water heater. Total: 300-500 rubles maximum (!!!), and you hot water all season!

Konstantin Timoshenko, www.delaysam.ru

SOLAR WATER HEATER FROM PLASTIC BOTTLES

About solar water heaters (solar water collectors) in general...

The vast majority of summer residents would like to have a shower with solar heated water at their dacha. But things usually don’t go beyond a primitive barrel installed on the roof of a shower stall. 99% do not think of building even the simplest frame around this barrel and covering it with plastic film (which would increase the use of solar energy by at least 2 times! Try entering a closed film greenhouse on a sunny day!). The most advanced ones insert a heating element (thermoelectric heater) into this barrel and diligently heat the atmosphere with it.
Meanwhile, probably every schoolchild knows that for every square meter of surface perpendicular to the sun's rays, 600-1000 watts of energy fall per hour! Well, it’s just a sin not to use it in the summer! It’s especially nice to take a shower before bed after a hot day, and it doesn’t hurt to freshen up during the day. But not ice water from a well or a well.

Those who have been to Greece or Italy have probably noticed that almost every house has a solar collector-water heater. Although their structure is quite simple in principle, there are many nuances in their operation. For example - constant water supply, thermal insulation of a storage tank, organization of water circulation between the tank and the collector itself, etc.

But making such systems yourself is extremely labor-intensive and expensive, and in general, with an amateurish approach, it promises more trouble than benefit.
In fact, it is necessary to make a sealed collector, organize water circulation and its regular replenishment, and avoid mixing already heated water with fresh cold water. And for the winter, drain the whole thing (we don’t have Greece here with +12 in January). And for what? Tolley is a native iron barrel! Filled it up - it warmed up, drained it for the winter - no problem. So what if it only works 10-15 times a year. But no hassle.

It’s all these problems that keep summer residents from creating a normal and efficient solar collector for a water heater.
But it seems to me that when using plastic bottles, many problems are solved. All the “charms” of the simplicity of a primitive “barrel” solar water heater remain and the advantages of a real collector with water circulation are added. And these advantages will become obvious as we describe the water heater.

Solar water heater collector made from plastic bottles.

There is no need to explain to you what a plastic PET bottle is. Any transparent carbonated drinking water bottle is suitable for the solar collector. Although I don’t know, I haven’t experimented with dark bottles.
If you pour water into such a bottle and place it in the sun, the water in it will heat up quite quickly. But the bottle has a very limited volume! 2-2.5 liters maximum. To take a decent shower, you need at least 50-60 liters, preferably more than 100.
The main problem of creating a solar water heater is connecting many plastic bottles into a single container and organizing them to have some kind of flow! So that cold water can flow into them, and warm water can flow out. Having solved this problem, we simply get a small transparent tank that perfectly heats water using solar energy. Taking, for example, 100 such mini-reservoirs, i.e. bottles, we will already get 200 liters of warm water!

At first I wanted to organize the flow of the bottle by creating a special stopper. For example, with coaxial tubes. It flows into one and flows out into the other. But making a mass of such tubes (for example, 100 or 200) is no easier than creating a normal classic solar collector. Therefore, I decided to take a different route - by connecting bottles and creating from them a kind of transparent pipe, which will be both a reservoir and a collector itself. Well, like a barrel, only flat and transparent.

Having measured the diameter of the thread on the neck of the bottle, I selected a drill that would be used to drill a hole in the bottom of another bottle. The best drill was a hole saw for drilling large-diameter holes in 26 mm wood (sets of such files are available in abundance and cost 70-100 rubles). With this diameter, the neck of the bottle is screwed quite tightly into the hole in the bottom of the other. Sometimes you have to work with a large round file. Yes, and first it is advisable to drill a hole strictly in the center of the bottle with a regular 6-8 mm drill. I will say that this is not easy to do, because... It is in the center of the bottom that there is a very hard and smooth tide - pimples. Therefore, for mass precision drilling, it would be better to make a simple template so that the drill does not wander.

The next problem was the sealing issue. Generally speaking, nothing seems to stick or stick to PET. But it turned out that this was not entirely true. Even with a drilled hole, the bottom of the bottle remained absolutely rigid, and this gave hope for the use of silicone sealants. After thoroughly degreasing the surfaces with acetone, I coated the threads of the bottle and screwed it into the bottom. And then I generously covered the joint with sealant from the outside as well. To be safe, I left the bottles motionless for 3 days (the fermentation rate of the sealant is 3-4 mm/day, as stated in the instructions).

Since I was just going to work out the technology and conduct an experiment, I limited myself to connecting only 3 bottles in series. The tightness of the joints turned out to be absolute! In the photo, the water bottles are lying on cardboard and as you can see, there are no water drips! By the way, the silicone stuck to the PET so much that you couldn’t pick it out with a knife!
During the day in the sun (or rather, in just a few hours), the water heated up perfectly even without any additional tricks. Thus, a certain conventional cell of the collector - water heater was obtained, with dimensions of 0.1 meters (bottle diameter) by 1 meter (bottle length approx. 35 cm). Those. The collector area was 0.1 sq. meter, and the capacity is approx. 6 liters. It is easy to calculate that per 1 sq. A meter will fit approximately 10 such modules, the capacity of which will be 60 liters of water. The sun will pour almost a kilowatt of energy onto these 60 liters of water every hour! Not only can you heat this water, you can boil it! Well, of course, it will never boil, if only because of heat loss. But you can heat 60 liters of water to 40-45 degrees 2-3 times exactly. Which is more than enough for country needs.

Now about the water heater project itself.

For example, we make 10-20 such modules and the length is not 3, but 5-6 bottles (in general, as long as the roof area facing south allows). You can, of course, use hoses to organize full flow of all modules, but I think this is pointless. Because anyway, all the water is heated at the same time and receives the same amount of heat at any point in the collector. Therefore, we will connect our modules in parallel! And we will use it in barrel mode: poured - heated - used (or poured into a thermally insulated storage tank).
To connect all our modules in parallel, you will need a pipe of fairly large diameter (50 millimeters, or better yet 100, for example, polypropylene). All modules crash into it in the same way as bottles are joined together in a module. Perhaps it will be possible to do it simpler. Having glued or screwed a bottle cap to the pipe with a self-tapping screw and ensuring a tight seal, drill a hole in the cap (and the pipe at the same time) and simply screw the module into the cap.

The modules, of course, must be located at an angle (the lower side faces south, the common pipe is at the lowest point of the collector). In the topmost bottle of the module you need to drill a small hole, 2-3 mm. Install a valve on both sides of the pipe. Supply water to one of them (for example, from a pump or water tank, in the figure Vent.2). And the other valve will be collapsible, warm water will drain through it (in the picture Vent.1).
The solar water heater collector works as follows. Valve 1 is closed, and we begin to fill the collector with water by opening valve 2. Water fills the bottles from the bottom up. The air then comes out of the holes at the top of the modules. Of course, as in communicating vessels, the water level in the modules is the same. Having visually determined that the bottles are full, we close valve 2 and the water heater starts working.
If we need warm water, we open valve 1 and the heated water begins to flow out of the collapsible pipe.

That's all.
Everything is exactly the same as in a barrel, only such a collector will heat water an order of magnitude more efficiently than a barrel, due to its large area.

A little about the design.
Of course, it is advisable to place the modules in a “box” to add rigidity to the structure. It is advisable to make the bottom of the box from a dark material that absorbs sunlight. For example, smoking a sheet of iron. It would be a good idea to place a heat insulator under the sheet, for example thin polystyrene foam or foamed polyethylene (“penoplex”). Cover the top of the box with plastic wrap or glass to prevent the wind from cooling the bottles.

The tilt angle is minimal, 10-20-30 degrees, no more.
Firstly, in summer this is the most optimal angle of inclination relative to the Sun (almost perpendicular), but in winter this collector is not used.
Secondly, this will ensure a minimum drop in water pressure (height of the water column), which is important when there are many bottle joints. Although during testing I placed my 3-bottle module even vertically and it “kept” a pressure of 0.1 atm, I would not take risks during operation.

The size of the entire water heater is up to the taste of the creator. For 200 liters you will need approx. 110 bottles, which will take up an area of approx. 3 sq. meters. True, the power of such a heater will already be approximately 3 kW!
You can use the heater in the “pour-pour” mode. Or you can arrange a thermally insulated storage tank for warm water next to it. On a good sunny day, a 2-meter, excuse me, 2-kilowatt water heater will heat you half a ton of water.

Such a water heater is not afraid of frost (except for the water shut-off valves), and the sun is not afraid of it either (PET does not decompose well in the sun).
Of course, such a solar water heater also has disadvantages (for example, poor automation), but a lot of it pays off because it is practically free. Judge for yourself what the money will be spent on here. Well, a pipe, a pair of valves and 2-3 tubes of silicone sealant for 45-50 rubles per piece. And you will receive water bottles as a bonus when purchasing water in the store. By involving your acquaintances in collecting them, by the next season you will have collected several dozen, or even hundreds of bottles and will be able to make yourself a very decent and productive solar water heater. Total: 300-500 rubles maximum (!!!), and you have hot water all season long!
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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) It was assumed that shielding the back (unlit part of the bottle) aluminum foil will reflect IR rays not absorbed by water and reflect them back into the bottle.

2) Blackening the back of the bottle (with rubber-bitumen mastic from aerosol can) will allow you to “absorb” 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. Clear water itself 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 back wall bottles also have 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 this 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.

"Encyclopedia of Technologies and Methods" Patlakh V.V. 1993-2007