Reducing carbon footprint and cooling demand in arid climates using an integrated hybrid ventilation and photovoltaic approach

Abstract

A hybrid ventilation system combining both natural and mechanical ventilation has proven very promising in moderating indoor climate, based on its ability to ensure indoor air qual- ity with low energy consumption. The system maintains indoor thermal comfort conditions by switching to mechanical mode whenever natural ventilation is not possible. However, the application of such a system in severe arid climates is still very limited and challenging, and almost half the urban peak load for energy demand is used to supply cooling and air- conditioning in summer. This paper assessed the application of the hybrid ventilation mode for an educational building in a hot, arid climate, with the aim of reducing the building’s energy consumption without compromising the occupants’ thermal comfort. A dynamic simulation was conducted using Integrated Environmental Simulation in a Virtual Environ- ment building energy software, and the outcomes were validated against actual consump- tion data over one year. The results were then evaluated for indoor thermal comfort and energy reduction and showed the potential of the hybrid system to provide energy savings of 23% across the year. Better energy performance was achieved during the cooler seasons (33.5%) compared to hot (17.1%). When photovoltaic systems were incorporated, by exam- ining diferent inclination angles and locations for energy savings and carbon emissions (CO2) reductions, the outcomes proved that photovoltaic south and a 25° tilt angle recorded the maximum energy and minimum CO2 emissions annually. This integration of hybrid ventilation and photovoltaics reduced the building’s energy consumption from 106.1 MWh to 36.6 MWh, saving almost 85% in total annual energy and cut down the carbon emissions from 55,227 kgCO2 to 6390 kgCO2