Retrofit of a standard split-type air conditioner into an air-to-water heat pump

Abstract

In the context of the rising prices of energy and especially of natural gas, the interest in heat pumps has grown steadily over the last period, as they are a very convenient alternative to low and medium power thermal plants. Although the price of heat pumps has dropped a lot recently, these systems are still very expensive compared to the wall-mounted natural gas fuelled power plants found in the vast majority of residential buildings in Romania. In this context, the authors proposed the conversion of an inverter type air conditioner into an air-water heat pump with minimal costs, maintaining and even improving the global performance of the system. The newly made heat pump was tested at variable regimes in the Cogeneration Trigeneration Laboratory of the Faculty of Mechanical Engineering of Iasi. The external unit was inserted into a climatic chamber capable of simulating variable climatic conditions for any region in Europe. Later, the same heat pump was tested in real operating conditions, being inserted in the heating circuit of a medium-sized house in the Iasi area. Its operation was then monitored during an entire winter season, being instrumented to measure the energetic balance and determine the coefficient of performance (COP) continuously throughout the season, in accordance with the weather conditions and also to measure the seasonal coefficient of performance (SCOP).