A dynamic simulation study of temperature and humidity independent control system for temperate semi-humid continental monsoon climate regions

Abstract

A temperature and humidity independent control (THIC) system is a promising solution for hot and humid indoor working environments. This study proposes a dual-source heat pump air-conditioning (DSHPAC) system composed of a dual-source heat pump (DSHP) and air handling unit (AHU) as a THIC system. The proposed THIC system indirectly adjusts the cooling capacity of the high-temperature evaporator (Eva1) and low-temperature evaporator (Eva2) by controlling the refrigerant mass flow rate of the system to meet the cooling and dehumidifying requirements under different operational conditions. The proposed THIC system can switch among three operational modes by using the designed operational strategy, ensuring that the requirements for indoor temperature and humidity are met. In addition, the mathematical model and equilibrium equations of the THIC system are established. This study uses an office building in Xi'an on a typical summer day as a simulation case in dynamic simulations. The coefficient of performance (COP), cooling capacity, and compressor power consumption of the proposed DSHP system are analyzed. The results demonstrate that the COP of the proposed system increases with the temperature of Eva1 (TEva1), the COP of the proposed system varies from 1.76 to 3.62, and the cooling capacity increases from 1.19 kW to 3.38 kW when TEva1 increases from 6.24 °C to 36.4 °C. The analysis of different values of φR (refrigerant mass ratio) shows that the highest COP is achieved at φR = 0.1. The results prove the application potential of the dual-source heat pumps to the THIC air-conditioning systems.