Design Optimization of a Sorption Integrated Sydney Type Vacuum Tube Collector

In order to reach the targets on emissions set by the European Commission, both new and existing buildings must reduce their fossil fuel inputs. Solar thermal cooling supplying on-site renewable heating and cooling could potentially contribute toward this goal. In this paper, a novel concept for solar thermal cooling providing efficient coproduction of cooling and heating based on sorption integrated vacuum tube collectors is proposed. A prototype collector has been constructed and tested in a solar laboratory based on a method developed specifically for sorption integrated collectors. From the test results, the key performance parameters have been determined and used to calibrate a mathematical model for trnsys environment. System simulation has been conducted to optimize the collector and sorption module configuration by performing a parametric study where different vacuum tube center–center (C–C) distances and sorption module designs are tested for a generic hotel in Ankara, Turkey. The parametric study showed that the heating and cooling output per year can be as high as 1000 kWh/m² for solar fractions above 50%, and that the output per sorption module compared to the prototype can more than double with an optimized design. Furthermore, cooling conversion efficiencies defined as total cooling output per total solar insolation can be as high as 26% while simultaneously converting 35–40% of the incident solar energy into useful hot water.