20 September 2011

EVALUATION OF BOREHOLE GSHP PERFORMANCE FOR GREENHOUSE IN JAPAN


A ground source heat pump (GSHP) system with 78 boreholes has been installed in huge existing orchid greenhouses in Akabira city in Hokkaido. Two GSHP units with the same characteristics have been set up simultaneously to work in this system. To evaluate the performance of the system, temperature, electricity consumption and flow rate were measured from Oct.1st 2010 to Dec.31st in 2010. The results obtained showed that the average heat extraction rate of the system was about 35W/m of borehole length, and average temperature declined 5oC. COP and SCOP were 3.0 and 2.7, respectively.