Capacity control for HVAC system

Patent metadata

Field	Value
Publication number	US-11892188-B2
Application number	US-202117453984-A
Country	US
Kind code	B2
Filing date	Nov 8, 2021
Priority date	May 30, 2021
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

A method is provided for controlling an HVAC system. The method includes receiving zone priority levels and zone temperature setpoints, where at least one of the zones haves a higher priority level than others of the zones, receiving an indication of zone ambient temperature values, determining requested zone capacity values to maintain the zone ambient temperature values within a threshold deviation of respective ones of the zone temperature setpoints, determining target zone capacity values from the requested zone capacity values and zone size values, and from the zone priority levels where the target zone capacity values may be responsive to a total of the requested zone capacity values that is less than a minimum capacity or greater than a maximum capacity of the HVAC system, and causing the HVAC system to provide the conditioned air to the zones according to respective ones of the target zone capacity values.

First claim

What is claimed is:

1. A heating, ventilation, and air conditioning (HVAC) system comprising:
HVAC equipment configured to provide conditioned air to a conditioned space that is divided into zones; and
control circuitry operably coupled to the HVAC equipment and configured to at least:
receive zone priority levels and zone temperature setpoints, at least one of the zones having a higher priority level than others of the zones;
receive an indication of zone ambient temperature values;
determine requested zone capacity values to maintain the zone ambient temperature values within a threshold deviation of respective ones of the zone temperature setpoints;
determine target zone capacity values from the requested zone capacity values and zone size values, and from the zone priority levels responsive to a total of the requested zone capacity values that is less than a minimum capacity of the HVAC system or greater than a maximum capacity of the HVAC system, wherein
the control circuitry determines the target zone capacity values corresponding to the requested zone capacity values scaled by respective ones of the zone size values, responsive to the total of the requested zone capacity values between the minimum capacity and the maximum capacity;

cause the HVAC system to provide the conditioned air to the zones according to respective ones of the target zone capacity values, wherein
the HVAC equipment is set up in an installation with zone dampers controllable to regulate airflow of the conditioned air to respective ones of the zones;

convert the target zone capacity values to target zone airflow values for the zones of the conditioned space;
determine a damper position set from the target zone airflow values; and
actuate the zone dampers to respective damper positions of the damper position set.

2. The HVAC system of claim 1 , wherein the control circuitry is configured to receive the zone priority levels through a user interface, using zone proximity sensor measurements and associated logic, or from a schedule of time intervals over which the zone priority levels for one or more of the zones are set.

3. The HVAC system of claim 1 , wherein the control circuitry configured to determine the target zone capacity values includes the control circuitry configured to scale down the target zone capacity values based on the maximum capacity and the zone priority levels, responsive to the total of the requested zone capacity values that is greater than the maximum capacity.

4. The HVAC system of claim 3 , wherein the control circuitry configured to scale down the target zone capacity values includes the control circuitry configured to at least:
determine redistributed zone capacity values based on the maximum capacity, the target zone capacity values, and zone cost values that represent loss of comfort and are a function of zone ambient temperature error values and the zone priority levels;
determine zone capacity excess or deficit values between respective ones of the target zone capacity values and the redistributed zone capacity values; and
redetermine the target zone capacity values based on respective ones of the redistributed zone capacity values and the zone capacity excess or deficit values.

5. The HVAC system of claim 4 , wherein the control circuitry is further configured to at least:
apply the zone ambient temperature error values and the zone priority levels to a cost function to determine the zone cost values that represent a zone loss of comfort, the zone ambient temperature error values indicating deviation of the zone ambient temperature values from respective ones of the zone temperature setpoints.

6. The HVAC system of claim 1 , wherein the control circuitry configured to determine the target zone capacity values includes the control circuitry configured to scale up the target zone capacity values based on the minimum capacity and respective proportions of a total of the target zone capacity values, responsive to the total of the requested zone capacity values that is less than the minimum capacity.

7. The HVAC system of claim 6 , wherein the control circuitry configured to determine the target zone capacity values further includes the control circuitry configured to at least:
determine that one or more of the target zone capacity values as scaled up for one or more of the zones are greater than a respective maximum zone capacity, thereby indicating excess capacity for the one or more of the zones; and
redetermine the target zone capacity values to distribute the excess capacity for the one or more of the zones to one or more other of the zones, the target zone capacity values redetermined based on the target zone capacity values as scaled up, and the zone priority levels.

8. The HVAC system of claim 7 , wherein the control circuitry configured to redetermine the target zone capacity values includes the control circuitry configured to at least:
determine that the one or more other of the zones are calling for the conditioned air, have a lower priority level in the zone priority levels, and have an available zone relief capacity; and
redetermine the target zone capacity values to distribute the excess capacity to the one or more other of the zones proportional to zone cost values that are a function of the target zone capacity values as scaled up, and the available zone relief capacity.

9. The HVAC system of claim 1 , wherein the control circuitry configured to determine the requested zone capacity values includes the control circuitry configured to at least:
determine a weighted average relative humidity value from the zone ambient temperature values, zone dew point values, and the zone priority levels; and
determine a weighted average temperature setpoint from the zone ambient temperature values, the zone temperature setpoints, and the zone priority levels, wherein
the control circuitry is configured to determine the requested zone capacity values from the weighted average relative humidity value and the weighted average temperature setpoint.

10. The HVAC system of claim 1 , wherein the HVAC system has a system operating mode and zone operating modes each of which is selectable between modes including a heating mode and a cooling mode, and the control circuitry is further configured to at least:
determine a weighted average heating mode error value and a weighted average cooling mode error value for those of the zones in respectively the heating mode and the cooling mode, based on the zone ambient temperature values and the zone temperature setpoints;
determine a switch mode error value from the weighted average heating mode error value and the weighted average cooling mode error value; and
switch or maintain the system operating mode based on the switch mode error value and a switchover error limit.

11. The HVAC system of claim 10 , wherein the control circuitry configured to switch or maintain the system operating mode includes the control circuitry configured to at least:
switch the system operating mode to the heating mode when the weighted average heating mode error value is greater than the weighted average cooling mode error, and the switch mode error value is greater than the switchover error limit;
switch the system operating mode to the cooling mode when the weighted average cooling mode error value is greater than the weighted average heating mode error, and the switch mode error value is greater than the switchover error limit; and
maintain the system operating mode when the switch mode error value is less than the switchover error limit.

12. The HVAC system of claim 1 , wherein
the HVAC system has multiple stages of operat

Assignees

• Trane Int Inc

Inventors

• Jaber Youssef A
• Kraft Wayne N
• Mylsamy Ragunanthanan
• Thiruvengadam Satish Mukundan
• Dharmar Satheesh
• Kaliyaperumal Arulkumar
• Kolloju Shivakumar
• Agrawal Sunit

Classifications

• F24F11/67 Primary

  Switching between heating and cooling modes · CPC title

• F24F11/41 Primary

  Defrosting; Preventing freezing · CPC title

• F24F11/74

  for controlling air flow rate or air velocity · CPC title

• F24F2110/10

  Temperature · CPC title

• F24F2110/20

  Humidity · CPC title