Feasibility study of an electricity delivering Fresnel greenhouse
The objective of this study is to investigate the possibilities for a significant reduction of energy consumption of greenhouses by using available solar energy. Energy use of greenhouses can be very high (more than 25% of natural gas consumption in The Netherlands). In northern Europe, with colder winter climate conditions, energy saving is an important issue. Moreover during summer cooling is needed by natural ventilation to remove excess energy. In the southern countries with higher global radiation and higher outdoor temperatures during summer, cooling of greenhouses is even more important. This new type of electricity delivering Fresnel Greenhouse with triple junction cells and different Fresnel lenses is evaluated. The modular design simplifies calibration and avoids torsion errors of the tracking system. The position of each module will be controlled with two electric stepping motors. The properties of flat and spherical Fresnel lenses are compared and a higher optical efficiency combined with a smaller focal distance was found for the spherical Fresnel lenses. The addition of secondary optics will diminish the sensitivity for tracking errors. This can result in a cost reduction of the tracking system. Calculations based on radiation data of Wageningen, in The Netherlands, show a maximum yield of 120 kW m-2 of electrical energy and 180 kW m-2 of thermal energy. This type of greenhouse can be applied in The Netherlands for the growth of potted plants. These are typical shadow plants who do not like direct radiation. Removing all direct radiation will drastically reduce the need for cooling under summer conditions and the need for screens or lime coating of the glass. In Mediterranean and more tropical climate conditions this type of greenhouse can probably also be applied for fruit and vegetables, where a part of the direct radiation will be transmitted to the crops.
Sonneveld, P.J., van der Sluys, M., van Rhijn, A. and Hebbink, M. 2017. Feasibility study of an electricity delivering Fresnel greenhouse. Acta Hort. (ISHS) 1170:477-484
concentrators, energy options, PV system, solar cell