Algorithm and Software for Existing HVAC Systems to Provide Ancillary Services to the Power Grid

Technology #14469

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Prabir Barooah
Sean Meyn
Managed By
Richard Croley
Assistant Director 352-392-8929
Patent Protection
US Patent Pending US-2014-0339316-A1

Designed as a software retrofit for existing HVAC systems in commercial buildings

This control algorithm, which can be incorporated into software, works with a building’s existing HVAC (heating, ventilation, and air conditioning) system to provide ancillary services to the power grid. It exploits the inherent flexibility of power demand in HVAC systems so that a desired power consumption profile over time can be achieved without inconveniencing occupants. In an electrical power grid, power generation and transmission are continuously adjusted to compensate for supply-demand imbalances that result from fluctuating customer loads or, increasingly, from fluctuating solar and wind power generators. To balance energy supply and demand and maintain reliable power grid operation, ancillary services are required. University of Florida researchers have developed a system that provides ancillary services to the power grid from loads instead of gas turbine and hydro generators (the traditional sources). The algorithm, which manipulates airflow rates, changes the amount of power consumed by a building’s HVAC system without affecting indoor temperature, in such a way that the power consumption profile matches what is desired by the grid.


An algorithm that works with existing HVAC systems to provide ancillary services to the power grid


  • Requires no changes to the HVAC system, only a software add on, facilitating widespread adoption
  • Increases overall grid efficiency, reducing national power consumption and energy costs


This algorithm manipulates airflow rates to reduce the amount of power consumed by a building’s HVAC system without affecting indoor temperature. Because commercial buildings have large thermal inertia, changes to the air flow rate can be made in certain ranges without affecting indoor climate. Controllable loads are already allowed to compete in the market for ancillary service in certain parts of the country. With higher use of fluctuating renewable energy sources, much more ancillary services will be required. When incorporated into software, this algorithm will provide large amounts of ancillary services to the power grid at low cost.

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