Dynamic Response Analysis of Start-Up Transient in Air Conditioning System

Abstract

Dynamic models of the heating, ventilation and air-conditioning (HVAC) systems in a temperature controlled room are very useful for controller design, commissioning, and fault detection and diagnosis. A transient model is a set of time differential equations in mass, energy and momentum balances. These transient equations contain parameter values for validation. The parameter such as thermal capacitances of the room chamber, heat transfer coefficient of room panel, heat transfer coefficient of evaporator are difficult to determine because they are related to unsteady condition and have to be considered to account for room energy storage. Many researchers have been studied the transient model for HVAC system by setting an assumption that there parameters are already known. None of them has been investigated into the parameter identification. This research work focused into the parameter identification technique to determine the thermal capacitances of the room chamber, heat transfer coefficient of room panel, and heat transfer coefficient of evaporator. The transient model of a refrigeration unit for an air-conditioned room was analyzed. Block diagram technique along with computer simulation technique were applied for the task. Experimental tests were setup to validate this model.