Energy assessment methods for solar chimney in buildings: A review

Solar chimneys as cost-effective renewable energy systems offer significant energy saving in buildings through the enhanced natural ventilation. Previous studies have focused on the fluid dynamics of the solar chimney itself. Still, few studies were found in the literature on its assessment on the energy performance in buildings, such as addressing how many percentages of energy can be saved based on it in buildings. This is mainly due to the relevant challenges of the assessment methods, such as absent functions, modeling accuracy, experimental validation, and the capability of addressing many influencing factors. To overcome the constraints, five typical energy assessment methods were critically reviewed through this review, including hydrostatic pressure, thermal network, zonal model, theoretical/empirical models, and computational fluid dynamics (CFD) modeling. This is the first review paper specified for the energy assessment methods of solar chimneys. The major influencing factors of solar chimney include configuration, installation conditions, material usage, and environment. The current energy assessments for solar chimneys are primarily based on the thermal network and zonal model (or the combination) but not CFD modeling. The current challenge for hydrostatic pressure analysis is its applications in multiple chambers, especially with those large openings (e.g., doors and windows). The thermal network could overcome this challenge, but its modeling accuracy and generality still require effort. Due to many influencing factors, a single assessment method may not be viable for practical implementation. Future research on energy assessment could be in several directions, such as a combined zonal and CFD modeling, the validity and uncertainty of those energy assessments in practical building applications, and detailed and comprehensive experimental tests for the validation.