Question

In a two-fluid heat exchanger, the inlet and outlet
temperature of the hot fluid are 65°C and 40°C
respectively. For the cold fluid, these are 15°C and
42°C. The heat exchanger is a:
(1) Parallel flow heat exchanger
(2) Counter flow heat exchanger
(3) Heat exchange device where both parallel flow and
counter flow operations are possible
(4) None of the above

Answer 1

I think 3 rd option is right

Answer 2

The heat exchanger used is a counter flow heat exchanger.

• A heat exchanger is a device that transfers heat from one working fluid to another. Both cooling and heating operations employ heat exchangers.
• The fluids may be in direct touch or separated from one another by a solid wall to prevent mixing.  They are extensively employed in sewage treatment, natural gas processing, power plants, chemical and petrochemical factories, air conditioning, refrigeration, and space heating.
• The most common instance of a heat exchanger is found in internal combustion engines, where an engine coolant circulates through radiator coils while air passes by, cooling the coolant and heating the incoming air.
• A heat exchanger that uses counter-flow technology has one of the working fluids flowing in the opposite direction from the other fluid. In a heat exchanger with a parallel flow, both fluids move in the same direction.

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