Buildings Optimal Insulation Thickness Effects on Air Conditioning Capacity and PV Self-Consumption Share Level

Abstract

Energy conservation projects and renewable energy power generation are the future of sustainable energy supply. Combining both is very effective and maximizes benefits. PTs building sector is the highest consumer, constitute 48.6% of the total Palestinian energy balance. Until now, there is no specific Palestinian engineering building code. As a result, building insulation is still mandatory. There are few performed studies about optimal building insulation thickness economic and environmental benefits. Regarding renewable energy national share increase, the PA developed many ambitious plans, most of which concentrated on increasing PV systems installed capacity due to its high potential. PTs enjoy 3000 sunshine hours per year, 5.4 kWh/m2/day average solar radiation. Few studies are targeting Palestinian building's renewable energy share increase through the principle of self-consumption. This research presents a novel approach in investigating the economic feasibility of installing optimal insulation thickness in buildings. Practically, insulation layers are assumed to be installed during the building phase, before mechanical building systems. However, the insulation effect will reduce AC required capacity as a result of reducing summer CL, thus, reduce initial investment. For that reason, the P1-P2 method has been used to generalize the optimal insulation thickness approach for the West Bank area considering different Tb values. It has been found that at Tb=18 °C, optimal thickness values, total cost, energy saved, and Np values are 10-11 cm, 18 $/m2, 175-375 $/m2, and 5-14 years, respectively. Then, a commercial building in Ramallah city was taken as a case study; it has a 1,700m2 roof area for PV installation. PVsyst software is used to design a 173 kWp system. It is estimated to generate 320MWh per year for building self-consumption. The insulation effect raised renewable energy share from 62.6% to 64.1%, and reduced AC rated capacity by 20 refrigeration ton (saved $20,000 as an initial investment).