HVAC Control System

• US 20110238222A1
• Filed: 03/24/2010
• Published: 09/29/2011
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Microsoft Corporation, Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Laughman, Christopher, Nikovski, Daniel
• Granted Patent: US 8,412,381 B2
• Time in Patent Office: Days
• US Class Current: 700/276
• 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 11/56 Remote control
• CPC Class Codes: F24F 11/58 using Internet communication
• 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 2120/12 Position of occupants

Abstract

A method controls a heating, ventilation, air conditioning (HVAC) system by determining a travel time from a mobile site to a fixed site, and determining a conditioning time for a HVAC system at the fixed site. The HVAC is maintained in an ON state if the travel time is less than the conditioning time, and otherwise maintaining the HVAC in an OFF state, and wherein the conditioning time is determined using a building thermal model.

Claims

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

determining a travel time from a mobile site to a fixed site;

determining a conditioning time for a HVAC system at the fixed site; and

maintaining the HVAC in an ON state if the travel time is less than the conditioning time, and otherwise maintaining the HVAC in an OFF state, wherein the conditioning time is determined using a building thermal model, and wherein the steps are performed in a processor.

2. The method of claim 1, wherein the conditioning time includes a threshold time.

3. The method of claim 1, wherein the mobile site includes a mobile transceiver, a mobile locator;

and wherein the fixed site includes a mobile transceiver; and

wherein the processor includes a fixed processor at the fixed site and a mobile processor at the mobile site.

4. The method of claim 1, wherein the fixed site and the mobile site communicate via a network.

5. The method of claim 3, wherein the mobile locator is a global positioning system.

6. The method of claim 3, wherein the mobile locator is a BlueTooth device communicating with a fixed-location BlueTooth beacon.

7. The method of claim 3, wherein the mobile locator is a mobile telephone, and a location of the mobile site is provided by a mobile telephone service provider.

8. The method of claim 1, wherein the travel time is determined from locations of the mobile site.

9. The method of claim 1, wherein the travel time depends on traffic and weather conditions.

10. The method of claim 1, wherein the travel time is based on probabilistic information obtained from previous traveling patterns, and considers a mode of travel, time of day, date, and day of week.

11. The method of claim 1, wherein the travel time is determined based on schedules of public transportation.

12. The method of claim 1, wherein the travel time is determined at either the fixed site or the mobile site.

13. The method of claim 1, wherein the travel time is transmitted to the fixed site periodically.

14. The method of claim 1, wherein the travel time is transmitted at a request by either the fixed site or the mobile site.

15. The method of claim 1, wherein the conditioning time is constant.

16. The method of claim 1, wherein the conditioning time is adjusted for diurnal and annual variations, and according weather forecasts.

17. The method of claim 1, wherein the conditioning time is adjusted for internal environmental conditions at the fixed site.

18. The method of claim 1, wherein the conditioning time maximizes performance of the HVAC system.

19. The method of claim 1, wherein the mobile site and the fixed site communicate the travel time and the conditioning time only if any of the following constraints is true:

HVAC is OFF, site is fixed, and Θ

>

λ

;

HVAC is OFF, site is mobile, and λ

<

Θ

;

HVAC is ON, site is fixed, and Θ

<

λ

−

ε

;

HVAC is ON, site is mobile, and λ

>

Θ

+ε

;

where λ

is the travel time, Θ

is the conditioning time, and ε

is a threshold time.

20. The method of claim 1, where the conditioning time is approximately proportional to the travel time.

21. The method of claim 1, wherein there are N multiple mobile sites that each communicate travel times λ

to the fixed site and the HVAC system turns ON when any of the travel times λ

_N is less than the conditioning time Θ and

turns OFF when all of the travel times λ

_N are greater than the conditioning time Θ

plus a threshold time ε

.

22. The method of claim 21, in which the fixed site estimates a separate conditioning time Θ

_N for each of N multiple mobile sites.

23. The method of claim 1, wherein the conditioning time is slowly varying.

24. The method of claim 1, wherein the model considers thermal gain and transmission through windows, convection and conduction, shading and insulation.

25. The method of claim 24, wherein the conditioning time satisfies a thermal property constraint.

26. A method for controlling a heating, ventilation, air conditioning (HVAC) system, comprising the steps:

determining a travel time from a mobile site to a fixed site including a HVAC system; and

setting an operation of the HVAC system according to the travel time.