An Experimental comparison of two solar photovoltaic thermal (PVT) energy conversion system for production of heat and power

Abstract Two solar photovoltaic-thermal (PVT) energy conversion systems are described and their performance tested under laboratory conditions. One of these was a simple Flat Plate (FP-PVT) design, with headers and risers for heat removal the other a fixed linear axis Compound Parabolic Concentrating solar PVT (CPC-PVT) energy conversion system with a heat-pipe for removal of solar gain. Both had a low iron glass cover for high transmissivity of solar radiation, and polycrystalline silicon solar photovoltaic cells adhered to the absorber. Heat loss coefficient for the FP-PVT collector was measured as 4.1W/m 2 /K and 3.5W/m 2 /K for the CPC-PVT solar collector. These solar collectors were tested under steady state conditions using the solar simulator facility at the University of Ulster's Centre for Sustainable Technologies. The FP-PVT and the CPC-PVT had a combined efficiency of 66.8% and 53.4% respectively producing both heat and power

Open multistate Majorana model

The multistate Majorana model in the presence of dissipation and dephasing is considered. It is proven that increasing the Hilbert space dimension the system becomes more and more fragile to quantum noise. The impossibility to recast the problem in the form of a set of independent spin-$1/2$ problems because of the presence of the noise is pointed out