Air to air heat exchanger performance

Proper ventilation is obligatory in buildings where humans spend 70% of their life. Humidity, pollutant particles, smoke and harmful gases lower indoor air quality and cause sicknesses. To create an adequate air inside, dirty indoor air shall be exhausted and fresh air shall be taken from outdoors. To obtain controlled ventilation, buildings HVAC systems are designed by using mechanical ventilation. Mechanical ventilation is done with the help of an exhaust air fan, supply air fan and proper ventilation.Exhausted indoor air is conditioned air, for summer it is cooled and in winter it is heated to design temperatures. To transfer heat between exhaust air and supply air, air to air heat exchangers (heat recovery exchangers) are used in modern ventilation systems. By the help of air to air heat exchangers, fresh air from outdoors is pre-heated or pre-cooled by the help of exhausted air thus decreases the energy used to condition indoor air.Air to air heat exchangers are rated according to their efficiency which varies according to indoor and outdoor air temperatures. The same heat exchanger shall be evaluated according to the climate in which it is going to be installed.In this research, a sample heat recovery ventilator has been examined according to its energy savings. Outdoor air temperatures received from Devlet Meteoroloji Enstitusu has been evaluated by means of average values and hourly values. Energy savings in heating and cooling seasons are considered in different climates including warm, cold and extremely cold climates.