Methods and systems for controlling an HVAC system to identify energy usage under different control strategies

A Heating, Ventilating and/or Air Conditioning (HVAC) system of a facility, wherein the HVAC system includes a Variable Air Volume (VAV) box receiving a supply air from an Air Handler Unit (AHU) of the HVAC system and providing a VAV discharge air flow to a space of the facility, the HVAC system comprising:

• an AHU supply air temperature sensor for providing an AHU supply air temperature (TAHUSAT) that is representative of the temperature of the supply air that is received from the AHU by the VAV box;
• a VAV discharge air temperature sensor for providing a VAV discharge air temperature (TDAT) that is representative of the temperature of the VAV discharge air flow provided to the space by the VAV box;
• a space air temperature sensor for providing a space air temperature (TSPACE) that is representative of the temperature of the air in the space;
• a VAV discharge flow rate sensor for providing a VAV discharge flow rate (VAVFLOWRATE) that is representative of a flow rate of the VAV discharge air flow provided to the space by the VAV box;
• a controller operatively coupled to the AHU supply air temperature sensor, the VAV discharge air temperature sensor, the space air temperature sensor and the VAV discharge flow rate sensor, the controller configured to:
• control the HVAC system of the facility using first control parameters over a first period of time;
• determine a measure of thermal energy delivered by the VAV box to the space based at least in part on three or more of the VAV discharge flow rate (VAVFLOWRATE), the VAV discharge air temperature (TDAT), the space air temperature (TSPACE) and the AHU supply air temperature (TAHUSAT);
• aggregate the determined measure of thermal energy delivered by the VAV box and a determined measure of thermal energy delivered by each of a plurality of other VAV boxes of the facility over the first period of time, resulting in a first aggregated measure of thermal energy;
• control the HVAC system of the facility using second control parameters over a second period of time;
• determine a measure of thermal energy delivered by the VAV box to the space based at least in part on three or more of the VAV discharge flow rate (VAVFLOWRATE), the VAV discharge air temperature (TDAT), the space air temperature (TSPACE) and the AHU supply air temperature (TAHUSAT);
• aggregate the determined measure of thermal energy delivered by the VAV box and the determined measure of thermal energy delivered by each of the plurality of other VAV boxes of the facility over the second period of time, resulting in a second aggregated measure of thermal energy;
• and
• display the first aggregated measure of thermal energy and the second aggregated measure of thermal energy on a display to help identify the effectiveness in controlling the HVAC system using the first control parameters relative to the second control parameters.

A Heating, Ventilating and/or Air Conditioning (HVAC) system of a facility, wherein the HVAC system includes a Variable Air Volume (VAV) box receiving a supply air from an Air Handler Unit (AHU) of the HVAC system and providing a VAV discharge air flow to a space of the facility, the HVAC system comprising:

• an AHU supply air temperature sensor for providing an AHU supply air temperature (TAHUSAT) that is representative of the temperature of the supply air that is received from the AHU by the VAV box;
• a VAV discharge air temperature sensor for providing a VAV discharge air temperature (TDAT) that is representative of the temperature of the VAV discharge air flow provided to the space by the VAV box;
• a space air temperature sensor for providing a space air temperature (TSPACE) that is representative of the temperature of the air in the space;
• a VAV discharge flow rate sensor for providing a VAV discharge flow rate (VAVFLOWRATE) that is representative of a flow rate of the VAV discharge air flow provided to the space by the VAV box;
• a controller operatively coupled to the AHU supply air temperature sensor, the VAV discharge air temperature sensor, the space air temperature sensor and the VAV discharge flow rate sensor, the controller configured to:
• control the HVAC system of the facility using first control parameters over each of a plurality of operating conditions;
• determine a measure of thermal energy delivered by the VAV box to the space under each of the plurality of operating conditions based at least in part on three or more of the VAV discharge flow rate (VAVFLOWRATE), the VAV discharge air temperature (TDAT), the space air temperature (TSPACE) and the AHU supply air temperature (TAHUSAT);
• refine a baseline thermal energy consumption model of the facility based at least in part on the determined measure of thermal energy delivered by the VAV box to the space under each of the plurality of operating conditions;
• control the HVAC system of the facility using second control parameters under a particular operating condition;
• determine a measure of thermal energy delivered by the VAV box to the space under the particular operating condition based at least in part on three or more of the VAV discharge flow rate (VAVFLOWRATE), the VAV discharge air temperature (TDAT), the space air temperature (TSPACE) and the AHU supply air temperature (TAHUSAT);
• comparing the measure of thermal energy delivered by the VAV box while controlling the HVAC system of the facility using the second control parameters under the particular operating condition with a baseline measure of thermal energy generated using the baseline thermal energy consumption model;
• and
• based at least in part on the comparison, determining a relative performance of controlling the HVAC system of the facility using the second control parameters versus controlling the HVAC system of the facility using the first control parameters.