Experimental Study on Heating Performance of a Vapor Injection ASHP for Electric Buses
Abstract
In this paper, the heating performance and flow distribution of a vapor injection air source heat pump (ASHP) designed for electric buses is experimentally investigated under different working conditions by adjusting the opening of main-branch electronic expansion valve (EEV1) and injection-branch electronic expansion valve (EEV2). Under the condition of fixed EEV1 opening, the injection mass flow rate increases nearly linearly with the increasing of EEV2 opening and the main-branch mass flow rate has slight increase about 8.5%. The heating capacity increases with the increasing of injection ratio and there exists an optimum injection ratio to get the maximum COP 1.90. Under the condition of fixed EEV2 opening, the injection ratio decreases with the increasing of EEV1 opening. The heating capacity and COP both reach the maximum at 0.193 injection ratio, corresponding to 3.8ï‚°C superheat of evaporator.
Keywords
electric buses, vapor injection, heat pump
DOI
10.12783/dteees/iceee2018/27785
10.12783/dteees/iceee2018/27785
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