A computer system with a software was designed to obtain air temperatures, velocities and solar radiation data in the classroom. Seven temperature readings were recorded. The graph in Figure 13, shows temperature readings for inside the classroom and air entering – existing the collector. The top vent air (air existing) temperature of the collector on […]

Beside the collection efficiency, other optical characteristics have been monitored to evidence how much they are affected by geometrical deformations of the solar trough profile. The second study combines the consequences of mirror deformations with misalignment and tracking errors. The crucial optical features to be considered in examining alignment and sun tracking are angular misalignment […]

R. Casasola1*, D. Romero1, J. Alonso1, J. M. Cejudo2. 1 Isofoton, C/ Severe Ochoa n° 50, 29590 Malaga, Spain2 ETSII, Universidad de Malaga, Plaza de El Ejido s/n, 29071 Malaga, SpainCorresponding Author, r. casasola@lsofoton. com Abstract A possible way of increasing the efficiency of solar collectors is to optimize the heat transfer between the fluid […]

In thermotropic systems with fixed domains scattering particles, which exhibit a sudden change of refractive index with temperature, are statically embedded in a matrix material. At low temperatures the layer is translucent, as the refractive indices of matrix and domain are almost equal. The differing temperature dependence of the refractive index for the components above […]

Thermal stagnation and risk for overheating is generally aimed to be avoided in any collector sys­tems if these have metal-based – or polymeric collectors. The intention with a built-in overheating mechanism for polymeric collectors is to be able to use low-cost commodity plastics in glazed col­lectors. High operational temperatures in polymeric collectors can be avoided […]

In general there are two types of applications for solar thermal air collectors. Open systems in which outdoor air can be heated up directly and circulation systems with a closed loop. In a closed loop application the heat can be used directly or if needed transferred to another medium by means of a heat exchanger […]

1.1. Stagnation temperatures in reference – and ventilated collector (set-up A) The measurements of the maximum temperatures in the reference – (Tr) and the ventilated collector (Tv) are shown in Fig. 2 for different days and tilt angles. The difference between these temperatures gives the reduction of the maximum temperature, which can be obtained by […]

Klemens Schwarzer, Jan Kroker, Markus Rusack Fachhochschule Aachen / Campus JulichSolar-Institut Julich (SIJ) Heinrich-Mufimann-Str. 5, D-52428 Julich, GermanyCorresponding Author: schwarzer@sij. fh-aachen. de Abstract Throughout an earlier research project the Solar-Institut Julich (SIJ) developed a small sin­gle axis tracking modular parabolic trough collector with an evacuated absorber tube, a high – reflective aluminium mirror, an anti-reflective […]