ENERGY ANALYSIS OF GSHP SYSTEM FOR SPACE HEATING

Abstract

In the present energy scenario of fast depletion of fossil fuels, in the past decades continuous efforts are being made to explore the possibility of alternate energy sources. However, due to increase, in pollution and the awareness on sustainability of energy sources, the current focus is on the development of renewable and green energy sources. As the pollution due to green house gases has increased to alarming levels worldwide, there are a number of protocols being proposed by international agencies to keep CO2 emission well within limit. In order to minimize CO2 emission from centralized power stations research attempts are being focused on the reduction of electricity consumption in many energy intensive applications. One such application is space heating, where there is a lot of scope for reducing electricity consumption by substituting with other sources of heat. Ground source heat pump (GSHP) is considered as one of the alternate energy sources for space heating since it is environmental friendly and sustainable. As part of the present work, conservation equations for mass, energy, entropy and exergy balance are derived for a GSHP system with a U-tube ground heat exchanger. The performance characteristics of this GSHP .system are evaluated in terms of energetic and exergetic aspects. After successfully validating the equations and the procedure, the analysis has been extended for the application of GSHP for space heating a class room with a heat load of about 4 kW. In the present work a research is also carried out to identify the operating parameters that will give rise to higher COP and less CO2 emission. In order to identify the optimum operating conditions for the GSHP, Taguchi optimization technique has been employed using L9 orthogonal array. The conditions of larger the better for COP and lower the better for CO2 emission have been considered. An Experimental analysis of GSHP for apace heating is also performed for Roorkee weather conditions. Experimental results indicate that total % reduction in CO2 emission and electricity consumption using GSHP system for space heating is 69% for both, that is 19.1% lesser than theoretical reduction of CO2 emission. According to the Taguchi optimization method condenser outlet temperature plays a major role in controlling the value of COP and CO2. All thermodynamic results and effect of space heating can be achieved more efficiently- during the morning time and it is shown that the room temperature can be increased by 22°C using the proposed GSHP system, at the same time, with significant reduction in CO2 emission.