How To Build A DIY Solar Thermal System

Here is everything you need to know to build a DIY solar thermal system, except for the installation and commissioning of the system.

Unlike solar photovoltaics, the solar thermal system is based on a much more elementary technology; as a result, DIY solar panels are easier to make. In the next paragraphs we will illustrate the scheme of a do-it-yourself solar panel , indicating the components necessary to build it on your own, but before proceeding with the topic it is very important to make a clarifying premise on the actual convenience, from an economic point of view, and on the intrinsic limitations posed by this type of project.

The do-it-yourself solar system and tax breaks


The premise relates to the fact that both solar photovoltaic and thermal systems can access the tax concessions provided for by the energy requalification bonus. Searching on the internet it is possible to find numerous articles that explain how to make a DIY photovoltaic system or a DIY solar thermal system , all more or less exhaustive on the subject; Most of them report among the various advantages offered by this type of solution, both that of being able to save on purchase and installation costs and the fact of being able to take advantage of tax breaks.

In fact it must be emphasized that this information is misleading; in our article, however, we would like to clarify that this information is misleading, because to access the energy redevelopment bonus specific requirements must be met, and one of these is the obligation to purchase the system from an authorized dealer in able to provide the serial numbers of the various components, panels included, and all the manufacturer’s documentation with the guarantee, the technical data sheets, the energy efficiency label with the class to which they belong and all other data that testify that the system it was manufactured in full compliance with the standards in force in Europe.

A further fundamental requirement for accessing the Bonus also concerns payments, which must be made using fiscally traceable instruments, such as credit and debit cards, checks and wire transfers. Solar panels and do-it-yourself photovoltaic panels therefore, being made independently, make it impossible to comply with the required obligations, consequently they cannot benefit from the tax deduction; however, this in no way undermines the possibility of saving offered by the do-it-yourself solution, especially in the event that there are no conditions to be able to benefit from the energy requalification bonus.

DIY hot water solar panel


So we come to the focal point of our article and that is the construction of a DIY hot water production system based on thermal solar panels. Also in this regard it is necessary to make some clarifications, namely that the only part of the system that can be built independently are the panels, or manifolds; the rest of the components instead, therefore the pipes, the pump unit, the expansion tank, the degasser, the storage tank, the heat exchanger and the control unit, must necessarily be purchased separately and then assembled together according to the needs of the case.

Unlike the DIY photovoltaic panel , which is more complicated to make because it requires a good knowledge of electronics, solar thermal panels are much easier to build.

The first step is to build the panel structure using wood or aluminum profiles; the pieces must be shaped in such a way as to take into account the thickness of the gaskets, and to ensure a perfect seal against rain and humidity, they must also be equipped with flashings. Furthermore, the bottom of the panel must be insulated by laying a bed of rock wool, in order to prevent the heat collected by the collector from being dispersed.

For the assembly of the profiles you can use bolts and an impact wrench , or a welding machine, the important thing is that the structure is perfectly waterproof and well insulated; if drills are used to drill the bolt seats, moreover, care must be taken to insert ring gaskets of the appropriate size to guarantee watertight integrity even in those points. Once the panel structure has been completed, the absorber can then be laid on the rock wool layer.

The absorber is nothing more than the grid of copper pipes that makes up the water circuit, which once positioned will be fixed to the panel and then welded to sleeves placed at its ends, which will in turn be connected to the water inlet and outlet.

Once the absorber has been fixed in place and connected to the sleeves, the panel can be closed definitively by applying a polarized glass plate on the upper side, always paying attention to guarantee maximum sealing. The polarized glass has a smooth and a prismatic face, to mount it in the right direction it must be placed so that the smooth surface faces outwards and the prismatic one faces the inside of the panel. When all the panels are finished, it will be possible to connect them together and install them on the roof.

The completion of the plant


As we mentioned previously, the realization of the panels and the do-it-yourself solar tube allows you to save on the overall cost for the system; the economic advantage, however, is tangible almost exclusively for those who have a well-equipped home laboratory and a fair amount of experience in the hobby field at their disposal.

As you may have guessed while reading the previous paragraph, in fact, apart from the raw material, various tools and the necessary experience are also needed to use them well, otherwise you risk doing an approximate and patchy job.

If the construction and installation of the panels on the roof can be done by yourself, furthermore, for the completion of the system it is necessary to contact a qualified and authorized technician; even in the event that an application for access to tax deductions does not have to be presented, in fact, the legal obligation remains with regard to the construction of the system in a workmanlike manner and the subsequent implementation for testing.

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