Analysis of Influencing Factor on Supply Fan Temperature Rise of Air Handling Unit in Variable Air Volume System

An economizer system reduces the energy consumed by an air-handling unit while maintaining indoor comfort.The economizer system reduces the cooling load and energy consumption by adjusting the amount of outside air introduced when the outside temperature is lower than the indoor temperature.The fan operation in the air-handling unit causes pressure losses, such as heat, vibration, and noise.The heat generated from the air supply fan causes a temperature difference between the front and rear ends of the fan, and the actual supplied air temperature differs from the set temperature of the system.In this study, the factors affecting the temperature rise of the air supply fan were analyzed experimentally, and the terminal damper opening rate and fan speed were selected as variables to check the heat generation of the air supply fan owing to the changes in the air flow rate and differential pressure in the variable air flow system.The experiment confirmed the temperature difference according to the changes in the air flow rate and differential pressure.Additionally, using multiple regression analysis, a model was developed for predicting the increase in the air supply fan temperature.The terminal damper opening rate and fan speed were set as the independent variables, and the temperature difference was set as the dependent variable.A comparison of the predicted and experimental values using the developed prediction model revealed that was 0.95.