Transpired Solar Collector
A conventional solar thermal collector in essence consists of a glass cover, a black absorption plate and an insulated back cover. If however there is large blind facade available, it may be considered to eliminate the expensive glass cover and compensate the loss of thermal efficiency by an enlarged collector area. These Unglazed Air Collectors or Transpired Solar Collectors are typically used to heat ambient air in commercial, industrial, agriculture and process applications. According to wikipedia:
It is typically the most cost-effective out of all the solar technologies, especially in commercial and industrial applications, and it addresses the largest usage of building energy in heating climates, which is space heating and industrial process heating.
[wikipedia.org] – Solar air heat
Space heating is a universal need in cold climates, as well as a major user of energy – some 13% of U.S. energy is used for heating residential and commercial buildings alone. By reducing this energy use, transpired air collectors can also reduce building operations costs, reliance on imported fossil fuels, pollution, and greenhouse gas generation. In addition to being maintenance free, transpired collectors help eliminate temperature stratification where that is a problem.
Transpired air collector systems can be used to pre-heat air for standard commercial and industrial building ventilation systems. They pay for themselves quickly and produce substantial environmental and economic benefits with no negative side effects. They provide a highly effective means for substituting renewable energy for fossil fuel consumption.
[nrel.gov] – Transpired Air Collectors – Ventilation Preheating (U.S. Department of Energy)
Transpired solar collectors can be combined with solar panels, with the additional benefit that performance decreasing heat is drawn away from the solar panels.
[noorderlichtsolar.nl] – Dutch representative SolarWall
See book “Solar Energy Technologies and Project Delivery for Buildings“, p200 and beyond, for mathematical modelling “Solar Ventilation Air Preheating”.