EXPERIMENTAL STUDY ON UTILIZATION OF GROUND SOURCE ENERGY FOR SPACE HEATING/COOLING

Abstract

In the present energy scenario of fast depletion of fossil fuels and increased green gas emission, there is a concern worldwide to find alternate energy sources which are sustainable as well as non-polluting. Alternate energy sources such as solar energy, wind energy, biomass energy and ocean energy are being seriously considered as green and sustainable energy sources of future. However, the cost per unit kWhr of such energy sources are still very high compared to the conventional energy sources obtained from fossil fuels. Hence now the focus is shifted towards looking at the option of reducing the electricity consumption in intensive energy consuming sectors. Space heating/cooling is one of the intensive energy consuming energy sectors, especially in countries like India where there is a fast urbanization in the last two decades. Utilization of ground source energy is considered as one of the best options to reduce electricity consumption for space heating/cooling processes. In this dissertation report an attempt is made to analyze the utilization of a ground source heat pump (GSHP) for space heating/cooling processes for Roorkee weather condition. An experimental setup is installed with a reversing valve before the compressor, which will make the condenser to act as an evaporator in summer and condenser in the winter in the room side to provide coolipg and heating respectively. Similarly the evaporator is made to act as condenser during winter and as evaporator during summer by rejecting and absorbing heat to the room. During summer the ground heat exchanger rejects heat to the ground whereas during winter the ground heat exchanger absorbs heat from the ground for space heating. A number of experimental test runs were made during winter and summer and based on the observations and calculations, results were obtained for the variation of COP and exergy destruction in various components of the heat pump system. The change in calculated values of COP with increasing ambient temperature for space heating and cooling has no significance. The COP calculation is based on energy analysis and it does not include any effect of irreversible losses which is taking place in other components. It is observed that minimum exergy destruction takes place in the compressor and fan unit for both heating and cooling followed by ground heat exchanger. The maximum exergy destruction is found for condenser and evaporator both for heating and cooling thus giving scope for improving the performance of these systems. Based on experimental observations, the average COPs during winter and summer respectively were calculated as 4.33 and