Packaged air conditioners and heat pumps serve over 60% of the commercial building floor space in the U.S. and contribute to about 230 trillion BTUs of energy consumption annually.
Even a small increase in unit operational efficiency can lead to significant reductions in energy use and carbon emissions for commercial buildings.
Pacific Northwest National Laboratory (PNNL) has evaluated a number of control strategies that can be implemented and retrofitted into an existing unit to improve the operational efficiency of HVAC equipment.
The results from the detailed simulation analysis show significant energy savings around 24-35%.
Cost savings around 38% were documented from fan, cooling, and heating energy consumption when packaged units are retrofitted with advanced control packages.
The study also identified several other findings, including:
- Integrated differential enthalpy economizer, multi-speed supply fan, differential dry-bulb economizer, single- and two-stage capacity control, and demand-controlled ventilation offer the strongest opportunities for savings.
- Based on current utility rates, the maximum controller cost capable of providing payback periods of no more than three years for all U.S. locations are $2,103 per controller for stand-alone retail, strip mall, and supermarket buildings and $540-$1,350 for small office buildings.
- Individual control strategies have different degrees of impact on energy and cost savings and vary according to the square footage allotted per controller and the climate zone.
If only half of the packaged HVAC units in the U.S. are retrofitted with the modified control package option, it could result in annual savings of approximately 55 trillion BTUs.
The energy savings are equivalent to removing over 16 coal-powered power plants generating 200 megawatts each.