Energy savings and economics of advanced control strategies for packaged air conditioners with gas heat

• Energy and cost savings from the advanced control of packaged units are estimated.
• Economic analysis is performed using the maximum cost of a replacement controller.
• Building energy is simulated with EnergyPlus plus customized system control.
• Simulation and economic analysis are made for 4 building types in 15 climate zones.

This paper presents an evaluation of the potential energy savings from adding advanced control to existing packaged air conditioners. Advanced control options include an air-side economizer, multi-speed fan control, demand control ventilation and staged cooling. The energy and cost savings from the different control strategies individually and in combination are estimated using the EnergyPlus energy simulation program for four building types, namely, a small office building, a stand-alone retail building, a strip mall building and a supermarket. For each of the four building types, the simulation was run for 16 locations covering all 15 climate zones in the U.S. Simulation results show that simply adding multi-speed supply-fan control and DCV leads to 14–42% energy savings and 27–59% cost savings. The maximum installed cost of a replacement controller that provides acceptable payback periods to owners is also estimated.