Control and prevention of ice formation and accretion on heat exchangers for ventilation systems

In cold climates, the application of mechanical ventilation systems with heat recovery like are airto-air exchangers is used for reducing energy consumption for heating buildings by transferring heat exhausted air to supply air. However, increase efficiency of heat exchanger results in lower exhaust air temperatures and Ice formation on heat exchanger fins, which can cause problem and is not favourable. Therefore, prevention and control of ice formation on heat exchangers is necessary. The existing methods are divided into two different methods: active and passive ice control methods. The active methods are e.g. bypass, recirculation, preheating. The passive methods relate to the surface characteristics of the heat exchanger fins as they have effect on ice formation in initial phase. All these methods have varying levels of success, cost, and effectiveness, which are depending on the heat exchangers operating condition and construction. Since, the active method are reducing efficiency of heat exchanger and the passive methods are not permanent solution it can be suggested that the optimum ice protection method may be a combination of both methods. The aim of this paper is to review and evaluate the current methods to provide new insight of concern for the ice formation problem