Design of cascade analysis for renewable and waste heat recovery in a solar thermal regeneration unit of a liquid desiccant dehumidification system

Liquid desiccant dehumidification (LDD) system is an emerging technology with energy-saving benefit in HVAC applications. It removes moisture from the inlet air stream and handles the latent load without overcooling and reheating. The most energy-intensive process of the LDD system, the desiccant regeneration process, can be driven by renewable solar thermal energy with a temperature lower than 100 degrees C. However, the integration of solar heat needs to consider the inconsistent availability of solar radiation and regeneration heat demand. In this study, a pinch-based Cascade Analysis (CA) approach is used to optimally size the solar thermal collectors and thermal energy storage (TES) water tanks, which are the main components of the solar thermal system. From the analysis, the overall system efficiency, minimum area of solar thermal collectors and total TES volume are 78.8%, 59.83 m(2) and 7.10 m(3), respectively, with an average daily regeneration heat demand of 213.48 kWh. The overall system installation and operating cost is approximately 14219.98 USD or 948.00 USD annually over 15 years. This work serves as a preliminary study to provide an overview of the implementation of solar thermal systems for decision-makers who intend to implement solar-based LDD systems in HVAC or drying applications. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Liquid desiccant dehumidification (LDD) system is an emerging technology with energy-saving benefits, and the integration of solar thermal collectors and thermal energy storage tanks can optimize system efficiency, reduce energy consumption, and overall cost.