Performance evaluation of desiccant-coated heat pump AC system using different metal-organic frameworks for automobile application

The high energy consumption of automotive air conditioning systems significantly impacts the driving range of electric vehicles (EVs) and increases fuel consumption in internal combustion engine (ICE) vehicles. A promising strategy to address this challenge involves the use of desiccant-coated heat exchangers (DCHE) to control humidity and improve system efficiency. However, the additional weight and volume introduced by conventional DCHEs limit their practicality in vehicle applications. To overcome these constraints, this study presents a novel desiccant-coated heat pump (DCHP) configuration specifically designed for automotive use, wherein desiccant materials are directly coated onto the surfaces of the evaporator and condenser, eliminating the need for a separate heat exchanger and significantly reducing system complexity and weight. A numerical simulation was performed to evaluate the thermal and moisture removal performance of the proposed DCHP system using five different desiccant materials: silica gel and four MOFs—CPO-27(Ni), aluminum fumarate, MIL-100(Fe), and MIL-101(Cr). Among them, MIL-101(Cr) demonstrated the highest performance, achieving COP of 8.03 and compressor work of 1.10 kW, corresponding to an 80 % increase in COP and a 39.56 % reduction in compressor work compared to a conventional heat pump system. The study also examined the effects of evaporating temperature, desiccant coating thickness, and outlet air conditions to ensure thermal comfort within the cabin environment. Results confirmed that the DCHP system can operate at higher evaporating temperatures without the need for reheating, delivering supply air within ASHRAE-defined comfort zones. This work is the first to investigate the application of MOF-based DCHP systems in automotive air conditioning, offering a novel, sustainable climate control solution that enhances energy efficiency while maintaining occupant comfort without adding system mass.