Life cycle cost analysis of near zero energy buildings benefited from earth-sheltering

Abstract

Using passive solutions to take advantage of ambient energy sources would be more credible by considering the economic aspects of the project. Compared to aboveground buildings, Earth-Sheltered buildings (ESBs) have better energy efficiency. However, they might not be economically justifiable due to the escalation in construction costs. This paper presents a comprehensive analytical framework to compare the ESB options in the early design stage by the life cycle costs, including the cost/benefits of becoming a Net Zero energy building. An under-construction earth-sheltered hotel has been simulated using DesignBuilder® software to validate the method. Simulations were carried out to estimate the changes in energy consumption and cooling/heating loads for different wall structures, architectural forms, and soil cover depths. To evaluate the sensitivity of the results, Latin hypercube sampling (LHS) simulation was used. The results show that reducing energy consumption by earth sheltering is significant. Also, the Net present value (NPV) is statistically significantly positive, and forms are meaningfully influential. According to the results, the highest NPV is obtained when the depth of the building is seven meters. The uncertainty analysis results indicate that electricity price, interest rate, cooling setpoint, ground reflectance, and equipment consumption play a key role in NPV.