Method for controlling a multi-zone forced air HVAC system to reduce energy use

• US 7,967,218 B2
• Filed: 10/23/2008
• Issued: 06/28/2011
• Est. Priority Date: 10/23/2008
• Status: Active Grant

• Current Assignee: Emme E2MS, LLC
• Original Assignee: Home Comfort Zones Incorporated
• Inventors: Alles, Harold Gene
• Primary Examiner(s): Norman; Marc E
• Application Number:
  US12/257,181
• Publication Number:
  US 20100102135A1
• Time in Patent Office: 978 Days
• Field of Search: 236/1.B, 236/49.3, 165/208, 165/209, 165/212, 165/237, 700/277
• US Class Current: 236/1.00B
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 2120/10 Occupancy
• CPC Class Codes: F24F 3/044 Systems in which all treatment is given in the central station, i.e. all-air systems

Abstract

In a multi-zone control system for central forced air HVAC systems where the minimum conditioned airflow produced by the HVAC equipment significantly exceeds the airflow capacity to many of the zones, the invention is an energy saving method for choosing non-calling zones to receive excess airflow in. When satisfying calls for conditioning from one or a few zones, excess conditioned airflow is directed to non-calling zones. The method chooses occupied non-calling zones using a priority that provides comfort, and chooses unoccupied non-calling zones using a different priority that provides energy savings. Limits are provided for each zone to prevent excessive over conditioning in non-calling zones.

Claims

1. In a control system for forced air HVAC systems, said HVAC system having a source of conditioned airflow of certain amount, said control system controlling said source, said control system having a plurality of control zones, each said zone capable of receiving a portion of said source under control of said control system, each said zone capable of calling for conditioning, said control system sending said portion to each calling zone while said calling continues, said control system capable of selecting non-calling zones to receive excess of said conditioned airflow not sent to said calling zones such that the sum of said portions sent to said calling zones and said portions sent to said non-calling zones is equal to or greater than said certain amount, an energy efficient method for selecting said non-calling zones to receive said excess comprising:

a. providing a conditioning limit for each said zone;

b. determining the occupancy each said zone;

c. providing a comfort method for selecting a non-calling unconditioned and occupied said zone within said conditioning limit for receiving said excess;

d. providing an energy efficient method for selecting a non-calling unconditioned and unoccupied said zone within said conditioning limit for receiving said excess.

2. The method of claim 1 where said energy efficient method selects the said non-calling unconditioned and unoccupied said zone that has the largest heat exchange with occupied said zones.

3. The method of claim 1 where said energy efficient method selects the said non-calling unconditioned and unoccupied said zone that has the largest heat exchange with occupied said zones, and if none are found, selects the said non-calling unconditioned and unoccupied said zone that has the largest said heat exchange with said zones receiving said conditioning.

4. The method of claim 1 where said comfort method selects the said non-calling unconditioned and occupied zone that is nearest the condition for making said call.

5. In a control system for forced air HVAC systems, said HVAC system having a source of conditioned airflow of certain amount, said control system controlling said source, said control system having a plurality of control zones, each said zone capable of receiving a portion of said source under control of said control system, each said zone capable of calling for conditioning, said control system sending said portion to each calling zone while said calling continues, said control system capable of selecting non-calling zones to receive excess of said conditioned airflow not sent to said calling zones such that the sum of said portions sent to said calling zones and said portions sent to said non-calling zones is equal to or greater than said certain amount, an energy efficient method for selecting said non-calling zones to receive said excess comprising:

a. providing a conditioning limit for each said zone;

b. determining the occupancy each said zone;

c. providing a heat flow coefficient between an occupied said zone and an unoccupied said zone;

d. providing a comfort method for selecting a non-calling unconditioned and occupied said zone within said conditioning limit for receiving said excess;

e. providing an energy efficient method for selecting a non-calling unconditioned and unoccupied said zone within said conditioning limit for receiving said excess.

6. The method of claim 5 where said energy efficient method selects the said non-calling unconditioned and unoccupied said zone that has the largest heat exchange with occupied said zones.

7. The method of claim 5 where said energy efficient method selects the said non-calling unconditioned and unoccupied said zone that has the largest heat exchange with occupied said zones, and if none are found, selects the said non-calling unconditioned and unoccupied said zone that has the largest said heat exchange with said zones receiving said conditioning.

8. The method of claim 5 where said comfort method selects the said non-calling unconditioned and occupied zone that is nearest the condition for making said call.