Thermal performance of an oil engine driven heat pump for greenhouse heating

Abstract The thermal performance of an oil engine driven water-to-water heat pump for greenhouse heating was analysed. The temperature of the ground water used as the heat source was about 14°C. The primary energy ratio (the ratio of heat energy made available to energy input of fuel) was 2·16 at an engine rotational speed of 1250 rev/min, and 1·76 at an engine speed of 1980 rev/min. The heat produced at the condenser and the heat recovered from the engine accounted, respectively, for about 75% and about 25% of the heat output. By using the engine driven heat pump instead of a conventional oil heater, the fuel oil consumption can be reduced by half.