Effect of Exhaust Gas Temperature on the Performance of Automobile Adsorption Air-Conditioner

Abstract

An adsorption air conditioning unit of two beds was designed and built. Each bed was constructed from two concentric copper pipes sets, the length of the pipes in each set was 1500 mm pipe. The inner pipe was 50 mm in diameter while the outer pipe was of 100 mm diameter. The inside surface of the outer pipe and the outside surface of the inner pipe were covered by two active carbon layers which were separated from each other by a 5 mm space, to allow for methanol vapour penetration through the two layers. Each bed was inserted in a metal pipe to convey the hot stream of exhaust gases, to form a two passes heat exchanger. To complete the adsorption air conditioner cycle, an evaporator and condenser were connected to the two beds. Exhaust gases were produced by a propane burner, which can be adjusted to deliver hot gases at a temperature range of 80 to 140°C. The work showed that there was direct relationship between the hot gas temperatures that was used to heat the bed and the chilled water temperature. When the hot gases temperature exceeded 120°C, the whole cycle time increased along with a slight increase in chilled water temperature with a reduction in COP. A minimum chilled water temperature of 7.6°C was obtained. This chilled water was supplied to a fan coil unit to maintain an inside temperature of 24.2°C for a 600 Watt conditioned space load. The maximum cycle COP was about 0.31 when the hot gas temperature was 120°C.