Ali Malkawi

Distributed temperature control via Geothermal Heat Pump systems in energy efficient buildings

Geothermal Heat Pump (GHP) systems are heating and cooling systems that use the ground as the temperature exchange medium. GHP systems are becoming more and more popular in recent years due to their high efficiency. Conventional control schemes of GHP systems are mainly designed for buildings with a single thermal zone. For large buildings with multiple thermal zones, those control schemes either lose efficiency or become costly to implement requiring a lot of real-time measurement, communication and computation. In this paper, we focus on developing energy efficient control schemes for GHP systems in buildings with multiple zones. We present a thermal dynamic model of a building equipped with a GHP system for floor heating/cooling and formulate the GHP system control problem as a resource allocation problem with the objective to maximize user comfort in different zones and to minimize the building energy consumption. We then propose real-time distributed algorithms to solve the control problem. Our distributed multi-zone control algorithms are scalable and do not need to measure or predict any exogenous disturbances such as the outdoor temperature and indoor heat gains. Thus, it is easy to implement them in practice. Simulation results demonstrate the effectiveness of the proposed control schemes.

Decentralized temperature control via HVAC systems in energy efficient buildings: An approximate solution procedure

This paper presents a real-time decentralized temperature control scheme via Heating Ventilation and Air Conditioning (HVAC) systems for energy efficient buildings, which balances user comfort and energy saving. Firstly, we introduce a thermal dynamic model of building systems and its approximation. Then a steady-state optimization problem is formulated, which aims to minimize the aggregate deviation between zone temperatures and their set points, as well as the building energy consumption. Because this problem is nonconvex, a convex relaxation approach is proposed, and the tightness of the relaxation is proved. We next develop a real-time decentralized algorithm to regulate the zone flow rate, so that the thermal dynamics can be driven to an equilibrium point which is the optimal solution of the steady-state optimization problem. Finally, a numerical example is proposed to illustrate the effectiveness of the control scheme.