Engineers at Lithuanian solar panel manufacturer Solitek (a division of ophthalmic lens manufacturer Global BOD) introduced the M40, a translucent glass-to-glass monocrystalline solar module with an output of 235W for use in agrita.

The module is being produced in Lithuania at a recently launched 180 MW annual production facility.

“The M40 panel has 235 watts and a transparency factor of 40%, which means that up to 40% of its surface transmits natural light – more than in our previous modules,” said Julius Sakalauskas, head of Solitek.

The new solar module has 40 cells and an energy conversion efficiency of 12.6%. The device can operate with a maximum system voltage of 1,500 V. Its no-load voltage is 26.60 V and the short-circuit current is 11.01 A.

The dimensions of this frameless solar panel are 1,770 x 1,049 x 7.1 mm and the weight is 30 kg. The thickness of the front and back glass is 3 mm. The operating temperature range is -40 to 85 degrees Celsius, and the temperature coefficient of power loss is -0.47% per degree Celsius.

The manufacturer offers a 30-year linear power output warranty and a 30-year product warranty. Its output power is guaranteed at 87% of original efficiency for 30 years.

Solitek said the M40 is nearly half the price of previous versions of the panel.

Sakalauskas explained that the company gained a lot of experience from a 1.5-MW rooftop agroelectric project in Malaysia, for which it provided its conventional double-glass modules.

“Even then, it was clear that growing peppers in drier, hotter locations in the shade of the solar modules resulted in much higher yields and significantly reduced the amount of water needed for irrigation. Yields of vegetables and fruits can increase two to three times compared to conventional farming, with crops ripening 30% faster than under conventional conditions,” said the head of the company, adding that water loss has been reduced by 65%.

Solitek currently assembles solar modules at its facility in Lithuania. The company sold its IBC solar cell production lines to Finnish manufacturer Valoe in December 2020.

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But most importantly, a simple solar collector (as opposed to, for example, solar panels) can be made your own. To do this you will need materials and tools that you can buy in most construction stores. In some cases, even what you can find in a normal garage will be enough.

The following technology for assembling a solar heater was used in the project “Turn on the sun – live comfortably”. It was developed specifically for the project by the German company Solar Partner Sued, which is professionally engaged in the sale, installation and service of solar collectors and photovoltaic systems.

The main idea is that everything should be cheap and sulphuric. For the manufacture of the collector uses fairly simple and common materials, but its efficiency turns out to be quite acceptable. It is lower than the factory models, but the price difference fully compensates for this disadvantage.

There are different types of solar water heaters, but they are all based on a simple principle: the dark surface “absorbs” solar energy, then this heat is transferred to the heat carrier (water). The simplest models can be built from available materials and do not require pumps or other electrical equipment. An efficient solar collector can even be used in winter due to the use of non-freezing fluids – antifreeze.

The described solar collector system is passive and does not depend on electricity. It does not need any electrical appliances. The hot liquid moves between the collector and the tank according to the principle of convection, thanks to a simple rule: the heated liquid always rises up.

The working principle of such a solar collector is as follows:

The sun heats the liquid in the collector
The heated liquid rises through the collector and the pipe into the storage tank
When the hot liquid enters the heat exchanger installed in the water tank, the heat is transferred from the heat exchanger to the water
The fluid in the heat exchanger, as it cools, travels downward in a spiral and flows from the hole in the bottom of the tank back to the manifold
The water heated in the tank accumulates in the upper part of the tank
Cold water from the water mains / reservoir flows into the bottom of the tank
Heated water is withdrawn through the outlet at the top of the tank.
While the sun is shining on the collector, the liquid in the absorber pipes is heated, moving into the tank and thus constantly circulating. This process ensures that the water in the tank is heated in just a few hours with intense solar radiation.

schematic diagram of a solar collector

The main element of the heating collector is the absorber. It consists of a metal sheet welded to metal pipes. Several pipes are installed vertically and are welded to two larger diameter pipes located horizontally. These thicker pipes for the fluid inlet and outlet must be parallel to each other. And the fluid inlet (bottom of the absorber) and the outlet (top of the absorber) should be on different sides of the panel (diagonally). For connections in thick pipes, holes must be drilled to match the diameter of the vertical pipes.

For better heat transfer from the metal plate to the pipes, it is very important to ensure maximum contact between the plate and the pipes. Welding should be along the entire element. It is important that the metal plate and pipes fit tightly together.

pipes for the solar water heater

Absorber is placed in a wooden frame and covered with glass, which protects the collector and creates a greenhouse effect inside. Normal window glass is used. The optimum thickness is 4 mm, while maintaining a good ratio of reliability to weight. It is desirable to divide the desired area of glass into several parts. It is more convenient and safer to work with it.

Using several layers of glass or double-glazed glass will give an increase in efficiency, but will increase the weight of the construction and the cost of the system.
The sun’s rays pass through the glass and heat the collector, and the glazing prevents heat from escaping. Glass also prevents air movement in the absorber without it, the collector would quickly lose heat to wind, rain, snow, or low outside temperatures.

Through-holes are made in the casing to allow the cold liquid to flow in and the heated liquid to flow out of the collector.

The absorber itself is painted with a heat-resistant coating. Ordinary black paints begin to flake or evaporate at high temperatures, causing the glass to darken. The paint must dry completely before you fix the glass coating (to prevent condensation).

Under the absorber, insulation is placed. Most often mineral wool is used. The main thing is that it can withstand quite high temperatures during the summer (sometimes over 200 degrees).

From below, the frame is closed with OSB board, plywood, boards, etc. The main requirement for this step is to make sure that the bottom of the collector is securely protected from moisture inside.

To fix the glass in the frame, make grooves, or attach strips on the inside of the frame. When calculating the size of the frame, keep in mind that as the weather changes (temperature, humidity) during the year, its configuration will change slightly. Therefore, on each side of the frame leave a few millimeters of reserve.

A rubber window seal (D- or E-shaped) is attached to the groove or bar. On it the glass is put, on which in the same way the sealant is applied. On top of it all is secured with galvanized sheet metal. Thus, the glass is firmly fixed in the frame, the seal protects the absorber from cold and moisture, and the glass will not be damaged when the wooden frame is “breathing”.

The joints between the sheets of glass are insulated with a sealant or silicone.
To organize the solar heating of your home, you will need a storage tank. This is where the water heated by the collector is stored, so it is worth taking care of its thermal insulation.

As a tank can be used:

non-working electric boilers
various gas cylinders
barrels for food use
The main thing – remember that in a sealed tank will create pressure, depending on the pressure of the water system, to which it will be connected. Not every tank is capable of withstanding pressure of several atmospheres.

The tank makes holes for the inlet and outlet heat exchanger, the input of cold water, and the intake of heated water.

Diagram of the storage tank for a solar collector

A spiral heat exchanger is placed in the tank. Copper, stainless steel or plastic is used for it. The water heated through the heat exchanger will rise up, so it should be placed in the bottom of the tank.

The manifold is connected to the tank with pipes (e.g. metal or plastic pipes) routed from the manifold to the tank through the heat exchanger and back to the manifold. Here it is very important to prevent heat leakage: the path from the tank to the consumer should be as short as possible, and the pipes should be very well insulated.

solar collector installation

The expansion tank is a very important element of the system. It is an open tank, located at the highest point of the fluid circulation circuit. For the expansion tank can be used as a metal or plastic tank. With its help to control the pressure in the manifold (because the liquid from the heat expands, it can crack the pipes). To reduce heat loss, the tank must also be insulated. If there is air in the system, it can also escape through the tank. The expansion tank also fills the manifold with fluid.

tank

More details about building a cheap solar collector, a list of necessary materials and rules of installation of the heater can be found by downloading the Practical guide on the construction of solar collectors for hot water.

The post Making a simple solar collector with their own hands, step by step instructions appeared first on Solargcc.

“Today, it is relatively easy and inexpensive to give up 90 percent of fossil fuels. In my opinion, there are two promising sources of green energy: the first is solar power and the second is wind power. SolteQ specializes in developing and manufacturing clean energy products, so in addition to innovative wind energy solutions, we have developed SolteQ’s highly efficient solar roofs, which generate up to 36% more energy than conventional solar power plants,” Bayer says.

Although solar shingles have been developed for a long time, they were not ready for large-scale mass production and were only sold in limited quantities. Thanks to our many years of experience in the industrial sector, we have developed a roof covering that is 100 percent compliant with German building regulations, and all panels come with safety systems already integrated into them.”

German solar roofing

According to the manufacturer, its solar roofs are very easy to install and maintain systems, and roofers can work with them in the same way as, for example, Frankfurt shingles. High sales figures, however, are not SolteQ’s primary goal. The company says it wants to make its contribution to a cleaner planet and make Germany the No. 1 manufacturer in the global market for energy-generating roofs – a product with a future.

Solar roof tiles in different colors

The company focuses on German quality and boasts that its products do not use cheap components from Asian countries. The variety of options available is ensured by the availability of shingles in a variety of colors and styles.

“We do not offer Chinese dumping products, we offer great products, maximum power generation at a reasonable price that is affordable for anyone who can afford a new roof with the installation of solar panels on it,” explains the head of the comany.

A house with a solar panel roof

SolteQ has developed complete roofing solutions for houses. This means that solar cells are installed on the southern (sunny) side of the roof, while the northern (shaded) side is covered with a covering which has no built-in photovoltaic cells but is completely identical in appearance. In addition, according to the manufacturer, the SolteQ roof generates not only electricity, but also thermal energy: in addition to the photovoltaic system, the entire roof area is used as a large thermal collector.

The company hopes that in the future, every home will be able to cover its own energy needs, or at least most of them. And because SolteQ solar shingles are easy to install and low in price, they offer significant advantages over traditional rooftop photovoltaic systems.

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Price
The cost of a solar panel depends on its characteristics, size, brand, durability, availability of special certificates. Therefore, the price of the photomodule should be considered in connection with other parameters, focusing on the final benefit. Expensive, but highly efficient and high quality panel can pay off faster and last longer than a cheap equivalent.

Quality
This parameter largely depends on the manufacturing company. Before buying, it is worth studying the history of the brand and reviews of its products. It is better to give preference to firms that independently control all production stages, invest in scientific development and have many satisfied customers.

Energy Efficiency
The efficiency of a photovoltaic panel is determined by the amount of solar energy that is converted into electricity. As the efficiency of the module increases, so does its cost. Therefore, this characteristic should be considered with the intended use of the solar panel in mind. Overpaying for maximum energy efficiency may not pay off.

Temperature coefficient
The nominal performance of the photovoltaic panel is determined at +25 °C. As the module’s temperature increases, its output power decreases, and the faster the higher the temperature coefficient.

Longevity
The longevity of solar panels is easiest to determine by the warranty period, during which the manufacturer claims to maintain a certain level of power. For reliable solar panels, this period is usually at least 25 years.

Size and capacity
The size of a solar panel is directly related to its capacity. The first indicator is mainly determined by the area of space for the installation of the photovoltaic system, and the second – the demand for electricity.

Type of photovoltaic cells
Photovoltaic panels are manufactured using different technologies. Monocrystalline ones have high energy efficiency and good thermal resistance, but they are not cheap. Polycrystalline are inferior to monocrystalline in characteristics, but more affordable, so they are most often installed in private homes. Rather rare thin-film (amorphous) modules have a modest nominal efficiency, but work more efficiently at high temperature and low light.

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