Points out that to-date, the overall effectiveness of run-around heat exchangers has been limited to about 50%, making them uneconomical in many HVAC applications. Also, improvements to system performance have proved difficult due to the complexity and number of physical variables and economic considerations involved. Describes an accurate computer model for the simulation of a run-around heat exchanger, which has led to improvement of system performance through known optimisation techniques by enabling important physical and economic factors to be considered. Notes the effectiveness can be increased to more than 66%. Investigates a large run-around system, where the payback period could be less than three years. The life cycle net savings are expected to increase by more than 45% in the optimised system compared to the installed system.

KEYWORDS: Heat recovery, run around coils, heat exchangers, designing, optimisation, performance, economics, calculating, payback period, service life, costs