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Institute of Nanostructures, Nanomodelling and Nanofabrication - Portugal
Solar thermal collection, storage and distribution system for greenhouses
L.H. Godinho 1*, M.P.F. Graça 1,2
1) Prirev, Lda, Zona Industrial de Vagos, Lt.61, 3840-385 Vagos – Portugal2) Physics Department, I3N - Institute of Nanostructures, Nanomodelling and Nanofabrication,
Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
*Corresponding Author, [email protected]
AbstractThe main purpose of a greenhouse is to create and maintain a controlled artificial environment that will favour the crop production with the maximum profit. Late increase on fuel prices, together with colder than normal seasons, make heating costs a significant burden on greenhouse operations. Therefore, the use of renewed energy systems, namely solar thermal systems, to control the inner environment of agricultural greenhouses becomes an economical and technological topic of unquestionable interest. This publication is related with the analytical analysis of the possibility of using a solar thermal system to control the climate environment of a greenhouse. Preliminary calculations show that, in certain climate conditions, a solar greenhouse can collect sufficient solar energy to feed, at least, another standard thermally optimised greenhouse of the same size. This project, which is based on the Portuguese Utility Model nº10218 – “Thermal Solar System for Collection, Storage and Distribution of Heat at Low Temperature”, was submitted and waits for approval of the Seventh Framework Programme (PRODER) for a prototype to be built that will verify the technological and economical viability of the patented idea.
ConclusionsFrom these results we can assume that, in our climate conditions – temperature and radiation – the energy gain from a set of 3 x (36 m2) solar thermal panels installed inside a simple 300 m2 greenhouse glazed with structured PC plates, can exceed its needs if thermal properties are optimized. Therefore, a single module like this can eventually supply energy to one or two more standard modules with equivalent area.
Aveiro University - Portugal
Prirev, Lda – Departamento de Energias Renováveis – Portugal.
At the energy level, the goals of this project are:- pre-study of thermal properties in the design phase of the project;- design of energy monitoring systems;- data analysis and presentation of results.
Intended results are:- substantially improved production conditions (quantity and quality);- increased effectiveness of the heating using thermal efficient greenhouses;- lower fuel consumption and, consequently, less air pollution;- promotion of specialized agriculture, more competitive and with better work conditions.
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AknowledgementsThe authors thank Professor Dr John Rekstad, from the Physics Department of Oslo University, for his help in the project discussion
Figure. Thermal energy storage tank: 1) transparent structured PC plate; 2) upper metal support structure; 3) lower (buried) metal structure; 4) soil; 5) bottom EPS plates; 6) side EPS plates; 7) top (floating) EPS plate; 8) inner reinforced PVC bag; 9) water.
Figure. Monthly energy requirements and solar energy collectedFigure. Solar radiation profile as function of the solar panel tilt.
