Abstract

Solar assisted Solid Desiccant Cooling (SDC) systems are effective solutions for hot and humid climates. Unlike conventional cooling systems that cool and dehumidify simultaneously, SDC systems handle sensible and latent load separately, assuring more accessible, economical and efficient air conditioning. Air-based flat-plate Photovoltaic Thermal (PV/T) collectors can provide low grade thermal energy for SDC operation. However, PV/T collectors optimized for increasing the outlet air temperature adversely affect the electrical performance and material integrity of the photovoltaic (PV) modules. As a result, an auxiliary heater (AH) is commonly employed to boost the outlet air temperature to the required level to support the SDC system’s operation; increasing the input power requirements of the integrated system.
This research investigates a Photovoltaic Thermal Solar Air Heater (PVT SAH) assisted Solid Desiccant Cooling (SDC) system for daytime operation in hot and humid climates. The objective of the research is to develop an integrated design methodology for the complex system.
An integrated energy model of a roof mounted PVT-SAH assisted SDC system for an archetypical low-rise mixed-use building in India is developed. First, three configurations of the integrated system are compared and an appropriate configuration is identified. A sensitivity analysis is conducted to investigate the correlation between the design parameters and the objective functions, and specify the ranges of inputs for the optimization study. A multi-objective optimization study is conducted to investigate the design solutions that reduce the solar assisted SDC system’s reliance on auxiliary heater, and optimize the solar energy gains (electrical and thermal) for space cooling application.
The integrated system configuration with proposed modifications achieved upto 135% improvement in COPth and upto 48% reduction in unmet hours over the typical system configurations. As per the sensitivity analysis, the collector area, air mass flow rate, and channel height are the most important design parameters. The optimization study results show that AH energy consumption is more sensitive to the air mass flow rate for larger collector areas. In contrast, the PV electrical energy gain is more sensitive to the collector areas.
The integrated PVT-SAH assisted SDC system shows a great potential to reduce both energy consumption and peak demand. The design methodology proposed in this study will facilitate the design and application of an integrated PVT-SAH assisted SDC system in hot and humid climates.