02 July 2009

Application of ground source heat pumps for air conditioning of greenhouses

High energy costs for heating greenhouses have been a serious problem in Japan due to increased oil prices. Field tests have been carried out in a greenhouse since 2007 in order to evaluate the applicability of ground source heat pump (GSHP) systems to greenhouses. The system consists of two heat pumps of 10 kW heating/cooling capacity and four vertical ground heat exchangers of total 240 m. COPs of heating and cooling operations ranged between 4-6 and 4-5 respectively, demonstrating that the systems could signifi cantly reduce CO2 emission and energy costs.