Fresh air dehumidification systems enable a healthy and comfortable building environment by controlling indoor humidity and replacing indoor air with fresh air. However

the fresh air dehumidification heat pump equipped in the system is limited by the installation space

resulting in low dehumidification efficiency and insufficient capacity. A new air dehumidification system based on a configuration comprising four heat exchangers is proposed herein to fully recover heat from indoor and outdoor air such that the dehumidification capacity and energy efficiency can be improved. Furthermore

it features various operation modes by switching the air and refrigerant flow paths

which satisfies the requirements of fresh air dehumidification in various application scenarios. Simulation and experimental results of the prototype show that the maximum specific moisture extraction rate(SMER) is 3.27 kg/(kW?h) under the rated cooling conditions

which is 35.2% and 59.6% higher than those of systems comprising three and two heat exchanger systems

respectively.