Performance Analysis of Evaporation and Heat Wheel-Based Building Air Conditioning Systems

Abstract

Air conditioning in composite weather is relatively more challenging and also carries importance as it resembles conditions of hot-dry, cold, and warm-humid climates. Bifurcation of cooling and ventilation tasks happens to be one of the attractive techniques to design energy-efficient air-conditioning systems. It deals with the concept of providing a dedicated outdoor air system (DOAS) in conjunction with the air-conditioning unit. This study establishes the electrical energy consumption behavior of a building air-conditioning unit when modifications are done along the air pathway of the desiccant-integrated DOAS. For a 511 m2 building situated in composite weather, simulations in energyplus are carried out after necessary validations with the available standards. Here, two modes are discussed: in the first one, an indirect evaporation cooler (IEC)-based system is analyzed, while in the second mode, a heat wheel has been studied. For regeneration, a solar collector and supplementary electrical heater are provided. For the dynamic pattern of site environmental conditions, variations of room air temperature, humidity, thermal load, electricity, thermal energy, and solar fraction have been studied. Current analysis demonstrates that approximately 2994 kWh of the total thermal energy delivered by solar collector and supplementary electrical heater system can be saved through heat wheel instead of IEC. The usage of a heat wheel in the airflow pathway of the desiccant-integrated DOAS can offer energy savings up to 5.04% of the electrical energy with respect to IEC-integrated DOAS. Furthermore, the suggested design delivers a higher solar fraction.