Concurrent and countercurrent flow mode comparison in the tube in tube heat exchanger

The “pipe in pipe” heat exchanger efficiency at concurrent and countercurrent flow mode analytical studied. It is established that at concurrent flow mode with increasing of water equivalent simplex temperature difference on the output decreases and at countercurrent flow mode it increases. Performance indicator with convenient limits , which allow to assess the degree of heat transfer from the hot to the cold coolant, is introduced. It is established that there is a maximum along for temperature difference on the tube space outlet at concurrent and countercurrent flow modes. At sufficiently small and large values of water equivalent simplexes the difference between the flow modes is practically omited.