An analysis into the alternative strategies of substantial energy saving for the facilities of University of Jeddah, Khulais branch

Abstract

The main objective of this study is to develop strategies which aim to improve the energy saving and the sustainability at the University of Jeddah (UJ) - Khulais branch. The energy saving can be improved by reducing -indirectly- the cooling load, while the sustainability can be improved by recycling the sewage water, generating energy from the solar irradiance and improving land-use efficiency. Initially, the main reasons for increasing energy consumption in the buildings were identified. The most important reasons were large heat gain through the flat rooftops and sidewalls, infiltration and exfiltration, partial damage to the insulation materials of walls and ceilings, and thermal mass. To reduce the heat gained through buildings' rooftops, it is proposed to shade the rooftops by tilted and ventilated airgap Building Integrated Photovoltaic (BIPV). BIPV also help to improve the shading efficiency, land use efficiency, natural cooling of the rooftops and PV modules, Energy Efficiency Rating (EER) of the air-cooled ac system, and efficiency of night ventilation system. To reduce heat gained through the sidewalls, it is proposed to shade the walls by planting long-stemmed trees (Eucalyptus) around the buildings. Irrigating the trees by gray water will improve the sustainability and improve Leed Credit Point. Previous studies and current measurements of solar radiation under shaded surfaces have shown that shading the building is an appropriate strategy to reduce solar heat gain. Startup load of air conditioning system is another source of increasing energy use and it forms around 10-20% of the total cooling load due to high indoor temperature at the morning. As the buildings are not occupied after 3:00 PM, and during weekends, it is proposed to use mechanical night ventilation to reduce the indoor temperature and to improve the air quality. Connecting the ventilation system with a separate control system and the BMS at the buildings help to reach to the possible minimum indoor temperature.