PVT Solar Collectors Research Articles

PVT type of the two-phase loop mini tube thermosyphon solar water heater

In this paper, the performance study is performed in order to verify the new design of the photovoltaic (PV) panel combined with type of the wickless heat pipe solar water heater. In this enhanced design, each wickless heat pipe is assumed in the shape of the loop mini tube comprised of the flow boiling process inside it. Without considering the PV panel, this design was reported in our prior published work (Ziapour et al., 2016). Here, the performance of the proposed passive PVT solar collector is numerically performed using EES software. The solar cell packing factor (i.e. fraction of the absorber plate area which is covered by the solar cells) is important parameter for designing a PVT system. The simulation results show that the thermal efficiency of the passive PVT solar system increases with increase of the solar cells packing factor. Through the simulation results it is found that the optimal numbers of the wickless heat pipes may be five loops. By selecting the five loops, the maximum value of the tank water temperature is obtained near to 72°C in the evening. Also the maximum values of ηth and ηpv are found as 70% and 80% at noon time, respectively.

Approximations to the CPC—a comment on recent papers by Canning and by Shapiro

Innovative concentrating PVT solar collector concepts based on a CPC geometry concept were developed to outperform the asymmetric Solarus CPVT collector and therefore decrease the energy/performance gap between CPVT and PV/ST solar collectors.The updated reflector geometry proved to be the most suitable reflector geometry for CPVTs, where the electrical peak efficiency per gross area reached 10.6%, which is +16.5%rel higher than the electrical peak efficiency of the Solarus CPVT. Optical efficiencies of η0 = 62.3% and η0 = 61.8% for CPC 1 and CPC 2 have been achieved, respectively.A PV module (0.5 m2) combined with an ST solar collector (0.5 m2) system to be able to deliver the same overall energy yield as the newly developed CPVT collector (1 m2) requires on average +0.02 m2 (at 45 °C), −0.06 m2 (at 55 °C) and −0.15 m2 (at 65 °C) of installed area, for a wide range of latitudes.A CPC-PVT system to increase its competitiveness requires a material cost reduction and at the same time an increased overall efficiency. Nevertheless, the energy/performance gap between a system composed of PV + ST technologies and a CPC-PVT decreased significantly.