Controller and System Design for HVAC with Thermal Energy Storage

Energy consumption by Heating Ventilation and Air Conditioning (HVAC) systems is usually heaviest when electricity prices are at their highest, presenting significant opportunities for the improvement of the underlying control algorithms. The idea being that thermal energy storage can be used to time-shift power consumption away from periods of high power demand to periods of low power cost. In this work, we present a supervisory control scheme, known as Market Responsive Control (MRC), which has the objective of minimizing the expenditure required for the cooling of a given building. The design of this controller is achieved by a fairly simple convex optimization problem. The MRC method is then embedded within an equipment design algorithm. This extended algorithm, known as MRC Embedded Equipment Design (MRC-EED), has the objective of maximizing Net Present Value (NPV) in an effort to size the storage unit and cooling device. Under the economic assumptions of this study, it is concluded that the NPV of installing Thermal Energy Storage (TES) can be significant if electric price variability is sufficiently large.