Systematic review of solar air collector technologies: Performance evaluation, structure design and application analysis

A solar air collector (SAC) is a main device of solar-thermal system, which can absorb radiation and transfer the absorbed thermal energy to air. This paper presents systematic review three basic types SAC, namely, flat-plate SAC (FPSAC), evacuated tube (EVTSAC), concentrated SAC. High efficiency, low heat loss simple structure have always been goals SACs development research. Enhancement methods applied in SACs, including enhanced-surface technology, absorber materials, airflow reorganization, internal component integrated systems storage PV/T, are reviewed. Performance comparisons among different each type conducted. The analysis indicates that FPSACs, with groove half conical, enable performance evaluation criterion about 2. An micro-heat pipe arrays provide efficiency up 73 %. Among linear concentrating an open Brayton cycle achieve highest outlet temperature 350 °C, corresponding 75% efficiency. It recommended consider use high-efficiency optimal design SACs. Some suggestions for future research proposed.