Countercurrent Heat Exchanger (HEX)

In cross flow type of heat exchangers, the fluids flow in directions normal to each other. Cross flow heat exchangers made in aluminum are common as radiators in vehicles. A vehicle needs more power and space for comfort purpose. So, a countercurrent heat exchanger (HEX) is need to be shifted. It may be shift on the roof of the vehicle compartment. That’s why, a new material, graphite foam with high thermal conductivity and low density, is a potential material for HEXs in vehicles. To increase the size of the heat exchanger in vehicles, Placing the heat exchanger at the roof or the underbody. A new position of the heat exchangers has to be developed after changing the position. In this study, a countercurrent heat exchanger is used. A new

Johnson [3] found out for a typical 3.0 lt. gas engine with a maximum mechanical output power of 115 kW, the total waste heat dissipated can be from 20 kW to as much as 400 kW across the range of a typical engine operation. The corresponding energy efficiency of the vehicles might be from 30 % to 15 %. If the exhaust gases enter into the surroundings directly, they will not only waste energy but also cause heat pollution of the environment. Reusing the waste heat of the exhaust gas has a great potential for reducing the fuel consumption of vehicles. There are several methods to reuse the energy of the exhaust gases. These methods

When the flow directions are parallel, the streams may flow in the same or in opposite sense. So there are three primary flow arrangements for a plate fin heat exchanger – (i) parallel flow, (ii) counter-flow and (iii) cross flow. Thermodynamically, the counter-flow arrangement provides the highest heat (or cold) recovery, while the parallel flow geometry gives the lowest. While the cross flow arrangement, gives an intermediate thermodynamic performance, by offering superior heat transfer properties and easier mechanical layout. Under some circumstances, a hybrid cross – counter-flow geometry provides greater heat (or cold) recovery with superior heat transfer performance. Thus in general engineering practice, there are three main configurations for the plate fin heat exchangers: (a) cross flow, (b) counter-flow and (c) cross-counter