HVAC control system and method

• US 9,429,923 B2
• Filed: 12/15/2010
• Issued: 08/30/2016
• Est. Priority Date: 12/16/2009
• Status: Active Grant

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Ward, John, Wall, Joshua, Platt, Glenn
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): Laughlin, Nathan L
• Application Number:
  US13/515,644
• Publication Number:
  US 20120259469A1
• Time in Patent Office: 2,085 Days
• US Class Current: 1/1
• 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 11/47 Responding to energy costs
• CPC Class Codes: F24F 11/52 Indication arrangements, e.g. displays
• 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 11/63 Electronic processing
• CPC Class Codes: F24F 2120/00 Control inputs relating to users or occupants
• CPC Class Codes: F24F 2120/20 Feedback from users
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• CPC Class Codes: G05B 2219/2642 Domotique, domestic, home control, automation, smart house
• CPC Class Codes: G05D 23/1917 using digital means

Abstract

A method of controlling the heating, ventilation and air conditioning (HVAC) system of a building, the method comprising the steps of: (a) developing an initial thermal model of the building, and continuously updating the thermal model over time; (b) utilising the thermal model to continuously develop a daily HVAC operating plan for the building; and (c) continuously examining a current HVAC operating plan and optimising the alignment of the current HVAC operation with the current HVAC operating plan.

Claims

1. A method of controlling the heating, ventilation and air conditioning (HVAC) system of a building, the method comprising the steps of:

(a) developing an initial thermal model of the building, and continuously updating this thermal model substantially daily;

(b) utilising the thermal model to continuously develop a daily HVAC operating plan for the building wherein the daily HVAC operating plan includes the aggregate impact of multiple heating/cooling sources on a series of zone temperatures in said building, with the daily HVAC operating plan being recalculated substantially every 5 minutes; and

(c) continuously examining a current HVAC operating plan and optimising the alignment of the current HVAC operation with the current HVAC operating plan substantially on the basis of seconds.

2. The method of claim 1, wherein said thermal model utilises a series of parameters, fitted to historical thermal data for the building.

3. The method of claim 1, wherein said thermal model is a piecewise polynomial model.

4. The method of claim 1, wherein said optimising the alignment of said current HVAC operation with the current HVAC operating plan is attempted substantially every 10 seconds.

5. The method of claim 1, wherein the thermal model has substantially the following form:

6. The method of claim 5, wherein the baseline function changes depending on the day of the week.

7. The method of claim 6, wherein the baseline function is formed of a combination of triangular basis functions that are estimated at specific fixed points throughout a day.

8. The method of claim 1, wherein said optimising the alignment of the current HVAC operation with the current HVAC operating plan is attempted substantially in increments of seconds.

9. The method of claim 1, wherein the thermal model has substantially the following form:

T_z=F_A(s)·

T_Amb+BaselineFcn−

F_T(s)·

Δ

T_SS

where;

T_z is a modelled aggregate zone temperature;

T_Amb is an outside ambient air temperature;

Δ

T_ss is a steady state difference in zone temperature that would result from the current HVAC cooling and heating powers;

BaselineFcn is a learnt function of time, accounting for at least one of people, equipment, or sun;

F_A(s) and F_T(s) are linear time invariant filters, accounting for system dynamics.

10. The method of claim 9, wherein Δ

T_ss has the form of an equation;

Δ

T_ss=∝

_c·

μ

_c·

max{0,P_cool−

P_cb}−

∝

_h·

μ

_h·

max{0,P_Heat−

P_hb}

where;

the first part of the equation is an effective cooling temperature (Δ

T_cool);

the second part of the equation is an effective heating temperature (Δ

T_Heat);

P_cool and P_Heat are estimates of actual cooling power and actual heating power, respectively;

P_cb and P_hb are baseline cooling power and actual heating power, respectively;

∝

_c, and ∝

_h are nominal scaling for HVAC power effectiveness; and

μ

_c and μ

_h are HVAC efficiency de-ratings as a function of external temperature.