연구홍보포털

논문 초록 (Abstract)

The primary objective of a greenhouse is to produce good plant-growth conditions such as temperature and humidity. One of the hot issues fo r the greenhouse is to provide an appropriate heating system which can achieve favorable temperature condition and save energy. In this stu dy, the performance of a ground-coupled multi-heat pump system for the greenhouse heating was investigated. The ground-coupled multi-heat pump system was composed of GLHX (ground loop heat exchanger) and multi -heat pump unitwhich had one outdoor unit and two or more indoor units. The temperature distribution within the greenhouse using the ground-co upled multi-heat pump system was represented relatively uniform comparin g to when the conventional heating system and GCHP system were adopted, because the capacity of each indoor unit could be changed linearly according to the variation of load.The temperature difference bet ween the maximum and minimum temperatures and the standard deviation of inside temperature for the greenhouse were 2.1 degrees C and 1.2 degrees C, respectively. It is necessary to develop the multi-he at pump unit which can be operated with high performance at relatively l ow temperature setting conditions. The system COP of the ground-cou pled multi-heat pump unit decreased greatly at part load condition du e to relatively high power consumption of the ground circulation pump . Therefore, it is suggested that a control algorithm of the groun d circulation flow rate has to be developed to maximize energy sav ing by applying the ground-coupled multi-heat pump system to the greenh ouse. (C) 2013 Elsevier Ltd. All rights reserved.