A coupled optical-thermal-electrical model to predict the performance of hybrid PV/T-CCPC roof-top systems

W Li,M.C Paul,M Rolley,T Sweet,M Gao,H Baig,E.F Fernandez,T.K Mallick,A Montecucco,J Siviter,A.R Knox,G Han,D.H Gregory,F Azough,R Freer

doi:10.1016/j.renene.2017.05.012

Abstract

A crossed compound parabolic concentrator (CCPC) is applied into a photovoltaic/thermal (PV/T) hybrid solar collector, i.e. concentrating PV/T (CPV/T) collector, to develop new hybrid roof-top CPV/T systems. However, to optimise the system configuration and operational parameters as well as to predict their performances, a coupled optical, thermal and electrical model is essential. We establish this model by integrating a number of submodels sourced from literature as well as from our recent work on incidence-dependent optical efficiency, six-parameter electrical model and scaling law for outdoor conditions. With the model, electrical performance and cell temperature are predicted on specific days for the roof-top systems installed in Glasgow, Penryn and Jaen. Results obtained by the proposed model reasonably agree with monitored data and it is also clarified that the systems operate under off-optimal operating condition. Long-term electric performance of the CPV/T systems is estimated as well. In addition, effects of transient terms in heat transfer and diffuse solar irradiance on electric energy are identified and discussed.

Highlights

Flat-plate photovoltaic/thermal (PV/T) hybrid solar collectors, first-time proposed in 1978 [1] and later tested by Ref. [2], have been developed over the years for efficient solar energy utilization e excellent reviews of this subject were provided in Refs. [3,4]
We aim to develop a coupled lumped optical, thermal and electrical model to examine the electrical performance of the concentrating PV/T (CPV/T) roof-top systems installed in three different geographical locations which operate under variable outdoor climate conditions
A coupled lumped optical, thermal and electrical model is developed for roof-top PV/T systems with and without crossed compound parabolic concentrator (CCPC) and applied to predict the electrical performance of such systems installed in Glasgow, Penryn and Jaen

Summary

Introduction

Flat-plate photovoltaic/thermal (PV/T) hybrid solar collectors, first-time proposed in 1978 [1] and later tested by Ref. [2], have been developed over the years for efficient solar energy utilization e excellent reviews of this subject were provided in Refs. [3,4]. Flat-plate photovoltaic/thermal (PV/T) hybrid solar collectors, first-time proposed in 1978 [1] and later tested by Ref. [2], have been developed over the years for efficient solar energy utilization e excellent reviews of this subject were provided in Refs. [5], a Solarex MSX60 polycrystalline flat-plat PV module was integrated with a heat collecting plate to form a PV/T module and both the electrical and thermal performances of the module were tested. The module showing its primary-energy saving efficiency exceeds 0.6 in comparison with a pure solar thermal collector. [8] to improve the electrical and thermal performances of a flat-plat PV/T hybrid air collector. Effects of water flow rate and packing factor on the energy performance of a façadeintegrated PV/T system were predicted and clarified by using a lumped thermal model [9]

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