Method for Optimizing System Efficiency and Demand Response Performance of Variable-Speed/Variable-Capacity Furnaces, Heat Pumps and Air Conditioners

Tech ID: 27596 / UC Case 2017-548-0

Abstract

Researchers at the University of California, Davis have developed a methodology which maximizes the overall efficiency of variable-speed heat pumps, furnaces and air conditioner systems with minimal hardware changes.

Full Description

Current control methods for variable-capacity unitary heating and cooling equipment fail to take into account interactions between equipment operation and the performance of the duct system. Reducing fan speed and heating/cooling capacity often results in dramatically sub-optimal performance at the supply grilles. This affects the overall system efficiency and negatively impacts comfort due to non-uniform impacts between different supply grilles.

Researchers at the University of California, Davis have developed a methodology that improves efficiency and comfort by characterizing duct system performance with a few readily accessible factors. By using a simple algorithm to adjust equipment operating parameters (fan speed, capacity, and damper positions), with the addition of perhaps only one additional temperature sensor, the methodology results in a 20-300% improvement in efficiency (depending upon conditions). By taking into account thermal losses, this simple and inexpensive approach dramatically improves the energy efficiency and comfort performance of existing variable-speed heating and cooling equipment. Moreover, this approach facilitates successful system performance during utility demand-response events.

Applications

  • Maximizing system efficiency for variable-speed/variable-capacity furnaces, heat pumps, and air conditioners

Features/Benefits

  • Accounts for performance changes with the associated duct system
  • Minimal hardware changes required to the system
  • Simplified algorithm to adjust equipment operating parameters (fan speed, capacity, and damper positions)

Patent Status

Patent Pending

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Inventors

  • Modera, Mark P.

Other Information

Keywords

control, variable-capacity, duct system, variable-speed, air conditioner, heat pump, A/C

Categorized As