Building integrated solar air heating with waste heat utilization

A novel waste heat utilization system, which consists of transpired solar collector panels and capillary tube heat exchanger, is studied; its function principle is described, and its experimental performance is presented for the first time. A test unit of capillary tubes was installed at the solar wall air heater at the factory of an automotive company in Turkey in 2012. Capillary tubes utilized waste heat energy which is obtained from heat recovery unit of an air compressor. Thermal power output, ambient temperature, temperature rise, collector cavity temperatures, and water supply temperatures were monitored over the course of two winters. The results showed that capillary tubes can provide 15 °C temperature rise during night-time operation. The heat exchange effectiveness in air cavity is found to be maximum 0.7. The results also show that waste heat energy utilization can reach up to 85% depending on operating conditions.