DE-2531 -- A Truck Exhaust Gas-Operated Absorption Refrigeration System

A truck absorption refrigeration system wh~ch utilizes the exhaust gas waste heat as the power source is studied. Ammonia-water system is chosen since it is suitable for the required low temperature application. The exhaust gas characteristics of a typical long haul di~se1 truck, such as SCFM and exhaust temperature vs rpm, indicate that at full load and 2,000 rpm, the refrigeration potential of 20 tons is available. This value is arrived at by assuming that only half of the waste heat is collected through the heat exchanger and that the COP of the system is 0.5.

A refrigeration storage tank or plate is designed into the system to eliminate the fluctuation of the refrigeration output and to store the excess refrigeration capacity for use when the truck engine stops or operates at low speed. Preliminary calculations indicate that the additional pressure drop in the exhaust system due to friction caused by the additional surfaces is two order of magnitude smaller than the pressure drop that occurs normally in the exhaust system of a typical truck. Hence, the heat exchanger for energy extraction is not likely to affect the truck engine performance. Operating cost of the proposed system is negligible. It is very quiet and is practically maintenance free. The novel feature of the exhaust gas operated absorption system is that it will help conserve precious energy resources (liquid petroleum in this case) at a time when the supply of these resources is diminishing fast.