Desiccant-based AHU interacting with a CPVT collector: Simulation of energy and environmental performance

In this paper, a desiccant-based AHU has been coupled with a novel CPVT, consisting of a parabolic trough concentrator and a linear triangular receiver. In order to analyze the system, a TRNSYS project based on models available in literature (some of them were calibrated and validated with experimental tests) has also been developed. Electricity produced by the CPVT collector is used to power the auxiliaries of the AHU, the chiller and also to balance the electric load of users, while thermal energy is used to heat the regeneration air flow during the summer period and the process air in the winter. Electricity in excess is sold to the grid, whereas the thermal energy in excess is used for production of domestic hot water (DHW). Eventual integrations of electricity and thermal energy are provided by the electric grid and by a gas-fired bolier, respectively. Energy and environmental performance of the overall system in terms of Primary Energy Saving and emission reduction with respect to a reference case are evaluated. The heat provided by the CPVT covers about 60% of thermal energy required by regeneration air and 30% of process air in winter operating mode. On an annual basis, the analyzed system obtains a Primary Energy Saving between 81% and 89%, depending on the DHW required.