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Thermal solar energy and energy efficiency in existing buildings for residential use.
Introduction and general concepts:
When making the energy certificate of an existing building in most of the dwellings that are the subject of it, since they are constructions prior to the Technical Code, they do not have any type of energy contribution with the contribution of renewable energy, in any case the The Certifying Technician will mention them if he deems it appropriate, within the improvement proposals to reduce energy consumption and improve his qualification.
Solar thermal energy is mandatory in Spain from the entry into force of the Technical Building Code , so that according to it, a total percentage of the demand for domestic hot water is required to be generated with this system (and the rest with a support team), this percentage according to DB HE-4 and according to the climatic zone It varies between 30 and 70 percent in the general case and between 50 and 70 when it has a source of support based on electricity, although new buildings that must benefit from the new modification of the DB HE recently approved must meet other requirements.
The approach to this type of energy as a possible improvement in the energy certificate implies that, for the property that is the object thereof, the implementation of this type of installation is viable both technically and economically (this aspect is specified in Royal Decree 390/2021 itself ) and that allows you to achieve a reasonable reduction in the energy bill that will lead you to achieve a reasonable amortization of the investment or the cost necessary to carry out the installation.
As the main advantage, these homes, by having a support energy of renewable origin that cover part of our demand for DHW, heating and / or cooling, reduces both energy consumption and CO2 emissions, in this case and according to the percentage of demand that our system covers, our rating will be improved.
Technical catalogs to help in the design, calculation and dimensioning of the solar thermal installation.
For the calculation and dimensioning of a solar thermal energy installation there are help tools, among them we will highlight the following:
1.- From the SOLARGE page, tool in Excel format to calculate DHW demand according to the Technical Building Code, as well as a checklist for the estimation of technical parameters of solar systems that you can download at the following link HERE (It no longer works).
2.- From the IDAE (Institute for the Diversification and Saving of Energy) and ASIT (the Solar Thermal Industry Association) page, the CHEQ4 tool is a computer program in order to facilitate the application, compliance and evaluation of section HE4 included in the basic requirement HE Energy saving of the Technical Building Code (CTE), for low temperature solar thermal energy installations, and can be downloaded from the following link HERE. (Automatic download)
3.- From the valentin.de page, you have an online application based on the TSOL software, which allows you to simulate an ACS solar thermal energy installation. Available from the following link HERE.
4.- In the Konstruir.com portal they have an online tool to calculate solar panels to cover the minimum ACS solar contribution required by CTE DB-HE-4. It can be accessed from the following link HERE.
Aid contemplated by the PAREER Program
We already know that with regard to the aids contemplated by the PAREER program recently approved by the Ministry of Industry (Resolution of September 25, 2013, of the Secretary of State for Energy, by which the one of June 25 is published 2013, of the Board of Directors of the Institute for the Diversification and Saving of Energy - IDAE, which establishes the regulatory bases and call for the aid program for the energy renovation of existing buildings in the residential sector (housing and hotel use) For this type of action, only the aids established in action 2 are considered: Improvement of the energy efficiency of thermal and lighting installations, within Annex 1 of said standard.
In this case, said regulation establishes a reimbursable loan aid that may be up to 90% of the eligible cost of the action, calculated in accordance with the sixth section of the resolution and with the limitation in its amount indicated in point 2 , which for the case that interests us, corresponding to solar installations for the production of sanitary hot water and / or air conditioning of open and / or covered swimming pools.
Maximum repayable loan amount (€) = 1,170 * Ps (0.9).
In addition, it is required that to qualify for these aids, solar thermal installations must meet the following requirements:
- They will respond to the definition of the basic requirement HE4 of the Technical Building Code.
- The facilities and equipment will comply with current regulations established in the RITE, the IDAE Technical Specifications for solar thermal installations-Revision 2009 as well as the recognized document of the RITE "ASIT Guide to Solar Thermal Energy", prepared by ASIT and available on the website of the Ministry of Industry, Energy and Tourism.
- Solar collectors must be certified by the Ministry of Industry, Energy and Tourism.
- Only collectors with a global loss coefficient lower than 9 W / (m2 ºC) will be admitted.
- Solar installations with a power greater than 14 kW will have a system for measuring the energy supplied in order to verify compliance with the energy management program and periodic energy efficiency inspections.
Conclusion.
The implementation of solar thermal energy to improve energy efficiency is obviously one of the strengths to achieve this objective, since when we talk about existing residential buildings, the implementation of this type of installation as renewable energy and especially if it is accompanied by the The substitution of air conditioning equipment for other more efficient ones will result in significant savings in energy consumption and in the final qualification of the building, despite the fact that the current situation regarding the legislative framework that contemplates the aid and that should contribute to promoting this renewable energy leaves much to be desired.
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Article prepared by José Luis Morote Salmeron. Access to its website HERE, in collaboration with OVACEN.
