Control algorithm for backup power system

• US 7,389,159 B2
• Filed: 03/09/2006
• Issued: 06/17/2008
• Est. Priority Date: 03/09/2006
• Status: Active Grant

• Current Assignee: Lennox Manufacturing Inc. (Lennox International Incorporated)
• Original Assignee: Lennox Manufacturing Inc. (Lennox International Incorporated)
• Inventors: Warren, Donald, Smith, John
• Primary Examiner(s): Masinick; Michael D.
• Application Number:
  US11/371,751
• Publication Number:
  US 20070213876A1
• Time in Patent Office: 831 Days
• Field of Search: 700/295, 700/300, 700/291, 700/296, 700/299, 713/300, 713/320
• US Class Current: 700/295
• CPC Class Codes: G05D 23/1924 using thermal energy, the availability of which is aleatory

Abstract

A method for controlling fossil fuel fired heating systems according to an improved adaptive cyclical control method when operating on backup (auxiliary DC) electrical power. Battery life is prolonged when used in conjunction with such improved method. Operating characteristics of the heating equipment and home or building being heated are monitored and stored in electronic memory during normal periods of operation when grid power is available. These characteristics are used to create control algorithms that are in turn specific to the system, as defined by the heating equipment and conditioned space. When the grid power is lost the control algorithms select the optimal heating mode, determine optimal cycle duration, and estimate the time to exhaustion of the remaining backup power.

Operation is divided into sequential modes. When a prolonged low voltage period is detected, the backup power control initiates a short-term preliminary energy conservation mode. As the outage persists, the control transitions to intermediate and long-term energy conservation modes until the backup power is exhausted or grid power is restored.

Claims

1. A method for controlling a heating unit in a dwelling operating on backup electrical power comprising the steps of:

(a) operating the heating unit according to at least one comfort mode when an estimate of remaining backup electrical power is above a threshold value; and

,

(b) operating the heating unit according to a long-term electrical power protection mode when said estimate of remaining backup electrical power is below a threshold value;

wherein said threshold value and estimate are based upon an analysis of a database of heat loss characteristics of said heating unit in said dwelling.

2. The method of claim 1 further comprising the steps of:

(c) operating the heating unit according to a short-term comfort mode when said estimate of remaining backup electrical power is above said threshold value and when a heating cycle count is below a pre-determined short-term limit;

(d) operating the heating unit according to a long-term comfort mode when said estimate of remaining backup electrical power is above said threshold value, when said heating cycle count is above said pre-determined short-term limit, and when a cycle count is below a pre-determined long-term limit; and

(e) operating the heating unit according to said long-term electrical power protection mode when said heating cycle count is above said pre-determined long-term limit.

3. The method of claim 2 wherein the heating unit is operated according to said long-term electrical power protection mode if a comfort mode override switch is set.

4. The method of claim 2 wherein steps (a) through (e) are performed only after said heating unit is operating on backup electrical power for a pre-determined amount of time.

5. The method of claim 2 where said short-term and long-term limits are based upon a secondary analysis of said database of heat loss characteristics of said heating unit in said dwelling.

6. The method of claim 2 where said short-term and long-term limits are manually pre-set.

7. The method of claim 2 wherein step (d)'"'"'s long-term comfort mode comprises relaxing a differential temperature band and reducing the number of heating cycles per time period from that of said short-term comfort mode.

8. The method of claim 7 wherein step (e)'"'"'s long-term protection mode comprises reducing an indoor temperature set point, further relaxing said differential temperature band and further reducing the number of heating cycles per time period from that of said long-term comfort mode.

9. The method of claim 1 wherein said database of heat loss characteristics include weather data, time of day, and an operational characteristic of said heating unit during normal power consumption in said dwelling.

10. The method of claim 9 wherein said database of heat loss characteristics include outdoor temperature, indoor temperature set point, heating unit operation time per hour, and heating unit shutoff time per hour in said dwelling.

11. The method of claim 10 wherein said database of heat loss characteristics further includes operation mode and electrical power usage.

12. The method of claim 9 wherein said weather data includes supplementary data from public recording agencies.

13. The method of claim 1 further comprising sending a notification of remaining operational time to a party prior to remaining backup electrical power drops below an operable voltage limit.

14. The Method of claim 1 further comprising remotely accessing said database of heat loss characteristics of said heating unit in said dwelling.