Absorption chiller and heat exchanger tube used the same

Abstract

An absorption chiller that uses an aqueous salt solution as an absorbent and water as a refrigerant, the absorption chiller including an evaporator that allows the water to trickle or flow downward onto the outer surface of a heat exchanger tube installed horizontally or approximately horizontally, an absorber that allows the aqueous salt solution to trickle or flow downward onto the outer surface of a heat exchanger tube installed horizontally or approximately horizontally, and a condenser that allows the water to be supplied onto the outer surface of a heat exchanger tube installed horizontally or approximately horizontally. At least one of the heat exchanger tubes is provided, on the inner surface thereof, with protruded threads formed in a spiral fashion. A plurality of rows of projections of a height of 0.2 to 0.4 mm with flat portions on the top is provided on the outer surface of the tube successively at a pitch of 0.4 to 0.8 mm between projections. The plurality of rows of projections is arranged in a spiral fashion in a direction opposite to that of the protruded threads and separated from each other at a pitch of 0.7 to 1.4 mm. Furthermore, the present invention provides the heat exchanger tube constructed in the forgoing manner.