US 12,687,314 B2Granted

Method and system for controlling a fresh air intake of an air handling unit of an HVAC system

AssigneeHoneywell International Inc.

InventorsVishwanath Gupta, Kanchan Aggarwal, Deepika Sandeep, Rohil Pal, Madhav Kamath, Bhavesh S. Gupta, Prabhat Ranjan

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Abstract

Controlling a fresh air intake includes determining a fresh air intake damper position based on the supply air flowrate, a measure of energy delivered to the supply air flow, or a measure of humidity of the supply air flow. Determining the fresh air intake damper position is subject to a constraint that the AHU maintains one or more comfort conditions in the building space and one or more of a constraint regarding maintaining one or more Indoor Air Quality (IAQ) contaminants in the building space below one or more IAQ thresholds, minimizing energy consumption of the AHU, and maximizing the fresh air ventilation air flow into the building space. Various parameters used to determine the fresh air intake damper position may be derived from available sensed conditions so as to reduce the number of physical sensors that are required.

Claims20

Dependent claims

A method for controlling a fresh air intake of an Air Handling Unit (AHU) of an HVAC (Heating, Ventilating and Air Conditioning) system servicing a building space, the AHU including a fresh air intake damper for admitting a fresh air ventilation air flow, a return air duct for receiving return air from the building space, a mixed air duct for mixing the fresh air ventilation air flow from the fresh air intake damper and return air from the return air duct and providing a mixed air flow to a heating and/or cooling unit of the AHU which supplies a supply air flow to the building space, the AHU including a fan for providing a motive force to move the return air, the fresh air ventilation air flow, the mixed air flow and the supply air flow through the AHU, the method comprising:

determining a fresh air intake damper position for the fresh air intake damper based at least in part on each of a measure of flow rate of the supply air flow, a measure of energy delivered by the heating and/or cooling unit to the supply air flow, and a measure of humidity of the supply air flow;
wherein determining the fresh air intake damper position is subject to two or more constraints including a constraint that the AHU maintains one or more comfort conditions in the building space and one or more of:
a constraint that the AHU maintains one or more Indoor Air Quality (IAQ) contaminants in the building space below one or more IAQ thresholds;
a constraint that the AHU minimizes energy consumption of the AHU;
and
a constraint that the AHU maximizes the fresh air ventilation air flow into the building space;
wherein determining the fresh air intake damper position includes one or more of:
determining the measure of flow rate of the supply air flow based on:
a signal representing a current fan speed of the fan of the AHU;
and
a predetermined flow rate of the fan at each of one or more predetermined fan speeds;
determining the measure of humidity of the supply air flow based on:
a signal representing a relative humidity of the fresh air ventilation air flow;
a signal representing a flow rate of the fresh air ventilation air flow;
a signal representing a relative humidity of the return air;
and
a signal representing a flow rate of the return air;
setting the fresh air intake damper to the determined fresh air intake damper position during a subsequent operation of the AHU.

15 more elements

An Air Handling Unit (AHU) of an HVAC (Heating, Ventilating and Air Conditioning) system for servicing a building space, the AHU including:

a fresh air intake damper for admitting a fresh air ventilation air flow;
a return air duct for receiving return air from the building space;
a heating and/or cooling unit;
a mixed air duct for mixing the fresh air ventilation air flow from the fresh air intake damper and return air from the return air duct and providing a mixed air flow to the heating and/or cooling unit of the AHU which supplies a supply air flow to the building space;
a fan for providing a motive force to move the return air, the fresh air ventilation air flow, the mixed air flow and the supply air flow through the AHU;
a controller operatively coupled to the fresh air intake damper, the heating and/or cooling unit and the fan, the controller configured to:
determine a fresh air intake damper position for the fresh air intake damper based at least in part on each of a measure of flow rate of the supply air flow, a measure of energy delivered by the heating and/or cooling unit to the supply air flow, and a measure of humidity of the supply air flow;
wherein the fresh air intake damper position is subject to two or more constraints including a constraint that the AHU maintains one or more comfort conditions in the building space and of:
a constraint that the AHU maintains one or more Indoor Air Quality (IAQ) contaminants in the building space below one or more IAQ thresholds;
a constraint that the AHU minimizes energy consumption of the AHU;
and
a constraint that the AHU maximizes the fresh air ventilation air flow into the building space;
wherein the controller, when determining the fresh air intake damper position, includes of:
determine the measure of flow rate of the supply air flow based on:
a signal representing a current fan speed of the fan of the AHU;
and
a predetermined flow rate of the fan at each of one or more predetermined fan speeds;
determine the measure of humidity of the supply air flow based on:
a signal representing a relative humidity of the fresh air ventilation air flow;
a signal representing a flow rate of the fresh air ventilation air flow;
a signal representing a relative humidity of the return air;
a signal representing a flow rate of the return air;
and
set the fresh air intake damper to the determined fresh air intake damper position.

21 more elements

A non-transitory computer readable medium storing instructions thereon that when executed by one or more processors cause the one or more processors to:

control a fresh air intake damper of an Air Handling Unit (AHU) of an HVAC (Heating, Ventilating and Air Conditioning) system servicing a building space, wherein the AHU includes:
a fresh air intake damper for admitting a fresh air ventilation air flow;
a return air duct for receiving return air from the building space;
a heating and/or cooling unit;
a mixed air duct for mixing the fresh air ventilation air flow from the fresh air intake damper and return air from the return air duct and providing a mixed air flow to the heating and/or cooling unit of the AHU which supplies a supply air flow to the building space;
a fan for providing a motive force to move the return air, the fresh air ventilation air flow, the mixed air flow and the supply air flow through the AHU;
wherein the instructions cause the one or more processors to:
determine a fresh air intake damper position for the fresh air intake damper based at least in part on each of a measure of flow rate of the supply air flow, a measure of energy delivered by the heating and/or cooling unit to the supply air flow, and a measure of humidity of the supply air flow;
wherein the fresh air intake damper position is subject to two or more constraints including a constraint that the AHU maintains one or more comfort conditions in the building space and of:
a constraint that the AHU maintains one or more Indoor Air Quality (IAQ) contaminants in the building space below one or more IAQ thresholds;
a constraint that the AHU minimizes energy consumption of the AHU;
and
a constraint that the AHU maximizes the fresh air ventilation air flow into the building space;
wherein, when determining the fresh air intake damper position, the instructions cause the one or more processor to perform of:
determine the measure of flow rate of the supply air flow based on:
a signal representing a current fan speed of the fan of the AHU;
and
a predetermined flow rate of the fan at each of one or more predetermined fan speeds;
determine the measure of humidity of the supply air flow based on:
a signal representing a relative humidity of the fresh air ventilation air flow;
a signal representing a flow rate of the fresh air ventilation air flow;
a signal representing a relative humidity of the return air;
a signal representing a flow rate of the return air;
and
set the fresh air intake damper to the determined fresh air intake damper position.

22 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/319,447Filed 17 May 2023
Published: US 2024/0384887 A121 Nov 2024
Granted: 21 Jul 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

F24F 11/63
Characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values: electronic…
F24F 11/77
For controlling air flow rate or air velocity: by controlling the speed of ventilators
F24F 11/72
Control systems characterised by their outputs; Constructional details thereof: for controlling the supply of treated air, e.g. its pressure
F24F 11/74
For controlling the supply of treated air, e.g. its pressure: for controlling air flow rate or air velocity