Development of an Efficient Low- and Medium-Temperature Vacuum Flat-Plate Solar Thermal Collector

Abstract

Production of heat accounts for over half of our overall primary energy consumption in domestic and industrial applications. Despite the great scope for deployment of solar thermal collectors to provide low- and medium-temperature heat, there is relatively little uptake of this technology. The requirements for heat provision are studied, and the desired characteristics of potential solutions considered. Application areas are discussed in addition to the potential for system integration. An assessment is made of the shortcomings of solar thermal collectors and the requirements for new technologies suggested. This leads to a design approach for a collector that is effective across a range of applications and provides further supplementary benefit for system or building integration.

A vacuum flat-plate (VFP) solar thermal collector is proposed as a solution to the requirements for domestic and industrial heat at the low- to medium-temperature range. VFP solar thermal collectors have several potential advantages over other collector types: they may deliver heat efficiently at 150–250 °C, and they may be made much thinner than the existing collectors, offering new application opportunities in industrial process heat and for building integration. VFP collectors achieve this by combining the optical properties of flat-plate (FP) collectors with the heat loss characteristics of evacuated tubes. This chapter considers the development of a micro/mini-channel absorber plate and vacuum enclosure for a VFP collector.