Cost optimum design of a tropical near zero energy house (nZEH)

Housing development, as part of economic development, must be supported by energy availability in order to achieve sustainable growth. One of the approaches to supporting renewable energy promotion is to design and build energy efficient housing. However, the optimal design of such buildings faces two conflicting requirements, namely the consideration of cost effectiveness and minimum environmental impact. The high costs of energy efficient buildings, such as the near Zero Energy House (nZEH), are due to the high price of the materials and equipment used, such as photovoltaic (PV) panels, insulation and other supporting materials. Indonesia is situated on the equator and benefits from sunlight throughout the year. Nonetheless, this potential has not been fully realized, as the solar-generated energy technology for housing comes at a high price. Therefore, the objective of this study is to find the cost optimum combination of validated design variables for an nZEH which suit the tropical climate conditions of Indonesia. Experiments and a case study are employed in the study to validate the design variables for an optimum nZEH design, which include building orientation, PV panels, fenestration, and passive design. The study finds that the cost optimum nZEH design achieved 72 percent site-energy savings and 21 percent savings in the total Net Present Value (NPV) of life cycle costs, with insignificant incremental initial construction costs in enhancing the design.