Judicious design solutions for zero energy school buildings in hot climates

The concept of net-zero energy, with its holistic consideration of energy-efficient passive, active, and renewable energy systems, is a critical step toward decarbonizing the built environment. This work aims to assess the feasibility of net-zero energy schools in hot climates and propose practical and realistic design solutions. The design of a net-zero energy school was developed and analyzed using DesignBuilder software in hot-humid, hot-dry, and warm-humid climatic zones in Oman. A multiphase methodology was followed, including data collection, an energy audit, fieldwork measurements, and energy simulation modeling. Integrating judicious passive design strategies such as thermal insulation for walls and roofs besides high-performance windows resulted in moderate potential reductions in energy cost and consumption in all climatic zones. Considering active design strategies like light-emitting diode (LED) lights, lighting control, and variable refrigerant volume/variable refrigerant flow (VRV/VRF) air conditioning systems resulted in additional reductions in energy cost and consumption. For the energy cost, the reductions were estimated at 29.9%, 29.5%, and 25.9% in the hot-humid, hot-dry, and warm-humid climatic zones, respectively. The corresponding reductions in energy consumption reached 28.53%, 27.90%, and 25.14%. Integrating a photovoltaics (PV) system aiming to reach the net-zero energy status supplied the school with demanded energy and managed to export 42.78%, 43.53%, and 45.75% to the national grid in the hot-humid, hot-dry, and warm-humid climatic zones, respectively. Similar reductions were achieved for CO₂ emissions and energy costs.