Analysis on Potential of Energy Demand Reduction for Heating and Cooling with Underground U Type Heat Exchanger (A Case Study in Commercial Building in Pulchowk)

Abstract

In the world, there is an aim to promote sustainable energy thinking and implementation. In commercial buildings with significant cooling and heating loads, it is critical to consider long-term solutions in the design phase that help to reduce energy usage. Recently, the variable refrigerant flow has a high Coefficient of Performance (COP) in the heating, ventilation, and air conditioning area, which has made enormous progress in demand for energy reduction. However, the conventional commercial HVAC system has a lower COP than the ground source heat pump system (GSHP), so this study presents a heating and cooling load calculation and details analysis of system design and financial Analysis of GSHP to existing commercial VRF systems. In this study heating load for the winter season and the cooling load for the summer season of the commercial building are calculated and also the required bore length for the GSHP system. It is found that the cooling load for the project is almost 2.67 times the heating load and the required bore length for cooling is 1.5 times higher than the heating length. For designing the system ground floor is taken into consideration and the Samsung DVMS water system is selected for GSHP looping. So an outdoor unit of 20HP is selected and an indoor unit 2units of 8TR and one unit of 4TR indoor unit duct able type is selected. The initial investment is high for the GSHP system as compared to VRF and other split and VRF systems which is almost double of VRF systems. Because of the high expense of drilling and installing the looping system, the cost is significant. However, because COP is more valuable in a long-running hour, it has a shorter payback period and a higher internal rate of return. For the fluid heat transfer to the ground from the ANSYS software it is found that in heating conditions there is a change of temperature by around 90C and for cooling conditions, there is a change of temperature around 140C. As a result, there is a noticeable temperature difference, resulting in improved system performance. Under this study, financial analysis is carried out in two scenarios: 18 hours per day and 24 hours per day. In scenario1, there is an energy demand reduction by 35307KWhr annually and in scenario 2, there is an annual saving of energy 47076KWhr annually. For scenario 1, the payback period is of 12.3years with an

internal rate of return of 14% and for scenario 2, the payback period is 7.7 years with an internal rate of return of 20%. So the above result shows GSHP is feasible for the project having high cooling and heating load having a high running hour. The findings reveal that GSHP offers better potential for energy savings and greenhouse gas reduction.