Regimes of ﬂuid ﬂow in heat exchangers
There are many different types of heat exchangers available to the building services industry. Plate heat exchangers and heat pipes which have been in use in other industries for many years are now used in heat ventilating and air conditioning (HVAC) systems for extracting low grade heat from return air in ventilation and air conditioning systems, for example. The thermal wheel is also used for this purpose. The cooling tower employed for cooling condenser water in an air conditioning plant allows the two ﬂuids, atmospheric air and condenser water, to come into direct contact for heat transfer to take place.