HVAC control system and method

Patent metadata

Field	Value
Publication number	US-9429923-B2
Application number	US-201013515644-A
Country	US
Kind code	B2
Filing date	Dec 15, 2010
Priority date	Dec 16, 2009
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

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.

First claim

We claim:

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:

T
int

⁡

(
z
)

=

F
amb

⁡

(
z
)

⁢

T
amb

⁡

(
z
)

-

10

P
coolTyp

⁢

F
Pcool

⁡

(
z
)

⁢

P
cool

⁡

(
z
)

+

1

P
heatTyp

⁢

F
Pheat

⁡

(
z
)

⁢

P
heat

⁡

(
z
)

+

B
⁡

(
z
)

Where:
T int (z) is an average internal building temperature;
T amb (z) is an ambient temperature;
P cool (z) is a HVAC cooling power consumption;
P coolTyp is a typical HVAC cooling power consumption;
P heat (z) is a HVAC heating power consumption;
P heatTyp is a typical HVAC heating power consumption;
F amb (z) captures an internal building temperature response to the ambient temperature;
F Pcool (z) captures an internal building temperature response to the HVAC cooling power consumption;
F Pheat (z) captures an internal building temperature response to HVAC heating power consumption;
B(z) is a baseline fucntion and captures factors other than those captured by F amb (z), F Pcool (z) and F Pheat (z); and
10 is a scaling factor.

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 +Baseline Fcn−F T ( s )·Δ T SS

where:
T z is a modelled aggregate zone temperature;
T Amb is an outside ambient air temperature;
ΔT 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 ΔT 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 (ΔT cool );
the second part of the equation is an effective heating temperature (ΔT 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.

Assignees

• Ward John
• Wall Joshua
• Platt Glenn
• Commw Scient Ind Res Org

Inventors

• Ward John
• Wall Joshua
• Platt Glenn

Classifications

• G05B2219/2642

  Domotique, domestic, home control, automation, smart house · CPC title

• F24F11/46

  Improving electric energy efficiency or saving · CPC title

• G05D23/1917

  using digital means · CPC title

• G05B17/02

  electric · CPC title

• G05B15/02 Primary

  electric · CPC title