Analysis of building-integrated solar desiccant air cooling systems considering the dynamic sensible and latent cooling loads

The growing global demand for thermal comfort drives continuous growth in air-conditioning, primarily reliant on environmentally harmful refrigerants. This research work presents a comparative thermodynamic and energy performance analysis of two different configurations of building-integrated solid desiccant cooling systems in subtropical climate conditions, examining their suitability as sustainable cooling systems. Configuration-1 consists of a solar-integrated solid desiccant dehumidifier with a specifically developed indirect regenerative evaporative cooler with innovative materials referred to as SDI-IREC. In contrast, configuration-2 consists of a solar-integrated solid desiccant dehumidifier with direct evaporative cooling referred to as SDI-DEC, and it will act as a baseline system for performance comparison. Simulation models of both systems are developed in the transient energy simulation program TRNSYS and validated with experimental data from test rigs at the Center for Renewable Energy Research, UET Taxila, Pakistan. Afterwards, a robust transient seasonal performance analysis of building-integrated systems is conducted to demonstrate the energy advantages and performance limitations of both air- conditioning systems. The SDI-IREC system demonstrates a coefficient of performance (COP) on average 50 % higher than the SDI-DEC system. This enhancement is attributed to the high dew-point effectiveness of its regenerative indirect evaporative cooler. Additionally, the system achieves an 87 % solar fraction, highlighting its superior energy efficiency and renewable energy utilization. The auxiliary energy share of the SDI-DEC is 60 % as compared to only 13 % for SDI-IREC.