A carton paper overhanging part is added to the bottom of the selective coated collector. An artificial suction effect is tried to be constituted by using two fans. In this case, air pressure in the chambers is increased but isn’t enough to provide air flow by convection. As seen in Table 1, the surface temperatures […]

A trough collector with parabolic profile has been simulated and studied by means of ray tracing analyses. The first study examines the geometrical deformations of the parabolic profile and their effects on solar light collection. For the application to solar light exploitation, the essential quantity to be considered is the collection efficiency. It is obtained […]

Marco Bakker1, Jochem Nijs2, Wim van Helden1, Angele Reinders21 ECN, Energy Research Centre of the Netherlands, P. O. Box 1, 1755 ZG Petten, The Netherlands,telephone: +31 224 56 8079, fax: +31 224 56 8966, email: m. bakker@ecn. nl2 University of Twente, Faculty of CTW, Department of Design, Production and Management,P. O.Box 21, 7500 AE Enschede, […]

Thermotropic hydrogels are chemically or physically cross-linked polymer networks which are poured with appropriate water content. At low temperatures the aqueous solution is dissolved homogeneously on the molecular level, so that a clear state is achieved. Above the switching temperature scattering domains are formed by an aggregation of the polymers and/or by separation of free […]

Example (a) in Fig. 8 shows a thermosiphon collector with blow-moulded absorber of PE. (b) and (c) are flat-plate collectors with 10 mm PC twin-wall sheets as collector cover. In example (b) is the absorber made of silicone rubber tubing partly compressed between metal plates. A drain-back collector with stiff, extruded absorber plate of polyphenylene […]

Advantages of a solar air collector system in general • Air is for free. • Air cannot freeze. • No deterioration of the heat-transfer-fluid. • No high pressure thrusts during a stagnation situation. • No costs for secure systems, e. g. safety valves, membrane expansion vessels. • No environmental or security problems in case of […]

If ventilation should be applied as an overheating mechanism in polymeric collectors, it is necessary to limit heat losses when the collector is operative. Hence a flap at the top of the collector frame was introduced, which should be opened when a critical temperature in the collector/of the absorber is reached (Fig. 1). Due to […]

Our first prototype collector was installed in Freiburg, Germany in Dec 2005 [1]. The evaluation of measurements that were performed during summer 2006 confirmed the theoretically derived performance parameters [3]. In summer 2006 the second linear Fresnel process heat collector with 132 m2 aperture area (66 kWp, th) was installed on the roof of a […]