Development and analysis of a new multi-function heat recovery split air conditioner with parallel refrigerant pipe

Abstract

This study developed a heat recovery air conditioner to supply on-demand air conditioning and reclaim waste heat during operation. In addition to the conventional refrigerant pipe, a plate heat exchanger was designed and connected in parallel to the condenser and evaporator. While refrigerant with high pressure and high temperature flows through the plate heat exchanger, the refrigerant flow is cooled down and condensed by cooling water from a water tank, and condensation heat in the exchanger is absorbed by the cooling water and stored in the water tank. In this study, solenoid valves were installed in the pipe to regulate the refrigerant volume in parallel connected pipes based on the tank water temperature by duty control logic. This multi-function heat recovery air conditioner has various operation modes. In summer, the air conditioner not only provides on-demand cooled air to air-conditioned rooms but also reclaims waste condensation heat through the plate heat exchanger. In winter, the air conditioner supplies on-demand heated air to indoor spaces and heats the water tank by simultaneously reclaiming waste condensation heat. According to an experimental operation test, the value of average water heating efficiency (COPh) of this air conditioner can reach 3.77 in the summer operating mode and 1.91 in the winter operating mode.