System and method for pre-cooling of buildings

• US 20070227721A1
• Filed: 05/29/2007
• Published: 10/04/2007
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: NightBreeze Corp.
• Original Assignee: Davis Energy Group, Inc.
• Inventors: Rainer, Leo, Springer, David
• Granted Patent: US 7,992,630 B2
• Time in Patent Office: Days
• US Class Current: 165/291
• 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 11/56 Remote control
• 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 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 2013/1473 with cams or levers
• CPC Class Codes: F24F 2130/00 Control inputs relating to environmental factors not covered by group F24F2110/00
• CPC Class Codes: F24F 2130/10 Weather information or forecasts
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A method is provided for nighttime pre-cooling of a building comprising inputting one or more user settings, lowering the indoor temperature reading of the building during nighttime by operating an outside air ventilation system followed, if necessary, by a vapor compression cooling system. The method provides for nighttime pre-cooling of a building that maintains indoor temperatures within a comfort range based on the user input settings, calculated operational settings, and predictions of indoor and outdoor temperature trends for a future period of time such as the next day. The method reduces energy costs and minimizes energy consumption during periods of peak electric demand.

Claims

1. A method of pre-cooling a building comprising,

ventilating and cooling with outside air if a current outside temperature is lower than a current inside temperature by a set amount, and if the current indoor air temperature is greater than a calculated ventilation cooling low limit temperature;

operating a vapor compression air conditioner, if a current time of day is between an air conditioner pre-cooling start time setting and an air conditioner pre-cooling stop time setting, and if the current indoor air temperature is greater than a calculated air conditioner pre-cooling low limit temperature that is greater than the calculated ventilation cooling low limit temperature;

measuring and storing outdoor and indoor temperatures and temperature trends; and

calculating and resetting operational settings based on user settings and indoor and outdoor temperatures and temperature trends, the calculated operational settings including at least fan speed, ventilation cooling low limit temperature and air conditioner pre-cooling low limit temperature.

2. A method of pre-cooling as described in claim 1, wherein the calculated operational settings further comprise a predicted minimum indoor temperature for the current day and a predicted maximum indoor temperature for the current day, and the method further comprises displaying the predicted minimum and maximum indoor temperatures for the current day.

3. A method of pre-cooling as described in claim 2, further comprising determining whether to change user inputs based on the displayed predicted minimum and maximum indoor temperatures for the current day.

4. A method as described in claim 1, wherein the user settings include a minimum indoor temperature setting, a maximum indoor temperature setting, the air conditioner pre-cooling start time setting, and the air conditioner pre-cooling stop time setting.

5. A method as described in claim 1, further including calculating and resetting the operational settings each day at a predetermined time of day.

6. A method as described in claim 1, wherein the step of ventilating with outside air includes the steps of opening an outside air damper and operating a ventilation cooling fan at a calculated fan speed setting.

7. A method as described in claim 1 wherein the calculated air conditioner pre-cooling low limit temperature is higher than the calculated ventilation cooling low limit temperature by an offset amount.

8. A method as described in claim 1, further including inputting user-selected settings.

9. A method as described in claim 1, further including selecting the air conditioner pre-cooling start time setting and the air conditioner pre-cooling stop time setting so that the air conditioning pre-cooling is enabled during a utility off-peak period and disabled during a utility on-peak period.

10. A method as described in claim 1, further comprising operating a vapor compression air conditioner at any time if the current indoor air temperature is greater than the maximum indoor temperature setting.

11. A system for pre-cooling a building, comprising a controller that:

receives an outdoor temperature signal from an outdoor temperature sensor;

receives an indoor temperature signal from an indoor temperature sensor;

receives a current time of day signal from a clock device;

receives one or more user-selected setting signals from an input device;

opens an outside air damper and operates a fan at a calculated fan speed to ventilate and cool the building with outside air if a current outside temperature is lower than a current inside temperature by a set amount, and if the current indoor air temperature is greater than a calculated ventilation cooling low limit temperature;

operates a vapor compression air conditioner, if a current time of day is within an air conditioner pre-cooling start time setting and an air conditioner pre-cooling stop time setting, and if the current indoor air temperature is greater than a calculated air conditioner pre-cooling low limit temperature;

measures and stores outdoor and indoor temperatures and temperature trends; and

calculates and resets operational settings based on user settings and indoor and outdoor temperatures and temperature trends, the calculated operational settings comprising at least fan speed, ventilation cooling low limit temperature and air conditioner pre-cooling low limit temperature.

12. A system for pre-cooling as described in claim 11, wherein the operational settings further comprise a predicted minimum indoor temperature for the current day and a predicted maximum indoor temperature for the current day, and the input device has a display that displays the predicted minimum and maximum indoor temperatures for the current day.

13. A system as described in claim 11, wherein the user settings include a minimum indoor temperature setting, a maximum indoor temperature setting, an air conditioner pre-cooling start time setting, and an air conditioner pre-cooling stop time setting.

14. A system as described in claim 11, wherein the controller calculates and resets the operational settings each day at a predetermined time of day.