Abstract
In this study, a new proportional-integral-derivative controllers (PID) system was designed to analyze chiller energy demand (CED) in accordance with current criteria for lowering energy consumption in buildings (TED). By defining parameters of cooling setpoint (CSP) and cooling set back (CSB) schedule, the activity of the air conditioning system along with mechanical ventilation was adjusted well-ordered by the PID controllers. In the first step, it was found that a one-degree change in the CSP parameter had a much superior effect than a three-degree change in CSB. In this study, the heat recovery potential in Riyadh was evaluated and it was found that adding this system with a yield of 0.5 to 0.8, diminished TED in the range of 33.4 to 50%. With the development of a system of PID controllers, the economizer decreased CED by 1 kWh/m2 during CSB. Although the heat recovery system was much more successful than the economizer, to benefit the advantage of both devices simultaneously, a suitable PID system was designed to activate the economizer in CSB time and heat recovery in CSP. Due to the proper combination of these two devices, TED was reduced by 54.3%.