US Patent 10458672 Optimized energy usage in an air handling unit

Rather than complex modeling or time consuming repetitive measuring for optimizing an HVAC system, a slope or change in energy use as a function of a change in a variable (e.g., temperature or humidity) is used to adjust the variable. In an HVAC system, the temperature or humidity of supplied air from the AHU is set based on the derived slope. The energy usage to heat and/or cool supplied air at the terminal units is balanced with the energy usage to heat and/or cool the air to be supplied by the AHU. The slope of the total energy usage may be indicated by a sum of flow rates.