Cooking exhaust hood ventilation system and related methods

• US 9,702,566 B2
• Filed: 01/28/2014
• Issued: 07/11/2017
• Est. Priority Date: 01/28/2014
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Robison, Russell, Lukens, Bruce, Borntrager, Michael
• Primary Examiner(s): Marini, Matthew G
• Application Number:
  US14/166,529
• Publication Number:
  US 20150211749A1
• Time in Patent Office: 1,260 Days
• CPC Class Codes: F24C 15/2021 Arrangement or mounting of control or safety systems
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 11/755 for cyclical variation of air flow rate or air velocity
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

Controlling an exhaust hood system having multiple hood sections each with an exhaust output having an associated damper, each exhaust output feeding to a common downstream fan, where damper position and fan speed control an exhaust flow rate through each hood section, involves monitoring at least one condition of each hood section and, based upon the monitoring, establishing a target flow rate for each hood section; based upon a sum of the target flow rates, establishing a fan speed; and monitoring an actual flow rate through each hood section and responsively controlling damper position to achieve the target flow rate for the hood section. Adjusting fan speed and damper position until damper position for at least one hood section achieves a predetermined open position, while at the same time each hood section satisfies its associated target flow rate, can reduce energy costs associated with system operation.

Claims

1. A method of automatically adjusting a commercial kitchen exhaust hood arrangement over time, the method comprising:

utilizing a commercial kitchen exhaust hood arrangement installed in a commercial kitchen above one or more cooking appliances, the exhaust hood arrangement having at least one hood section, a controller operable to control exhaust operations in accordance with a set of stored operating parameters, and one or more of (a) a manual override trigger input that enables a user to manually trigger a maximum exhaust mode for the hood section, (b) a thermal load monitoring system that adjusts exhaust flow based upon monitored thermal load, the thermal load monitoring system including at least one temperature sensor for detecting temperature within the hood section or (c) a VOC monitoring system with at least one VOC sensor, wherein the VOC monitoring system is configured to trigger a maximum exhaust mode for the hood section when sensed VOCs exceed a VOC limit;

establishing an initial set of stored operating parameters for the exhaust hood arrangement, the initial set of stored operating parameters affecting control of exhaust operations under varying conditions;

during an established adjustment time period, operating the exhaust hood arrangement as needed for cooking operations in the commercial kitchen;

during the established adjustment time period the controller automatically monitors operation of the exhaust hood arrangement and thereafter adjusts the set of stored operating parameters for use on a going forward basis, wherein the automatic monitoring and adjusting involves;

(a1) tracking a number of manually triggered overrides, determining whether the number of manually triggered overrides exceeds a set number and, if so, adjusting one or more of the stored operating parameters in a manner that will produce increased exhaust flow for a given thermal load condition experienced going forward; and

/or

(b1) tracking a number of sensed temperature conditions in excess of an upper temperature limit defined in accordance with the initial set of stored operating parameters, determining whether the number of sensed temperature conditions exceeds a threshold number and, if so, adjusting one or more of the stored operating parameters in a manner that will increase the upper temperature limit going forward; and

/or

(c1) tracking a number of sensed VOC conditions in excess of the VOC limit, determining whether the number of sensed VOC conditions exceeds a specific number and, if so, adjusting one or more of the stored operating parameters in a manner that will produce increased exhaust flow for a given thermal load condition experienced going forward.

2. The method of claim 1 wherein the automatic monitoring and adjusting includes:

determining whether the number of manually triggered overrides exceeds one or both of the set number and a higher number, and,

if the number of manually triggered overrides exceeds the set number but not the higher number, adjusting the set of stored operating parameters in a manner that will produce a first level of increased exhaust flow for the given thermal load condition;

if the number of manually triggered overrides exceeds the higher number, adjusting the set of stored operating parameters in a manner that will produce a second level of increased exhaust flow for the given thermal load condition, where the second level is higher than the first level.

3. The method of claim 2 wherein:

the adjustment time period is a specified number of weeks, the initial set of stored operating parameters includes operating parameters for different time segments during each day of the week;

the determining step is carried out on a weekly basis for each different time segment, and the number of manually triggered overrides that is evaluated relative to the set number and the higher number is a calculated average number of manually triggered overrides for each different time segment.

4. The method of claim 1 including:

establishing multiple flow rate curves, where each flow rate curve defines a relationship of how changes in thermal load condition affect target flow rate that will be achieved through the hood section, and each flow rate curve has a common start point and a common end point;

wherein the adjusting of the set of stored operating parameters involves changing the flow rate curve that is used to define exhaust flow based upon monitored thermal load.

5. The method of claim 4 wherein the commercial kitchen exhaust hood arrangement includes multiple temperature sensors, and each temperature sensor includes an associated flow rate curve that in part defines the stored operating parameters of the exhaust hood arrangement.

6. The method of claim 1 wherein the automatic monitoring and adjusting includes:

determining whether the number of temperature conditions in excess of the upper temperature limit exceeds one or both of the threshold number and a higher number, and,

if the number of temperature conditions in excess of the upper temperature limit exceeds the threshold number but not the higher number, adjusting the set of stored operating parameters so as to increase the upper temperature limit by a first amount,

if the number of temperature conditions in excess of the upper temperature limit exceeds the higher number, adjusting the set of stored operating parameters so as to increase the upper temperature limit by a second amount, where the second amount is greater than the first amount.

7. The method of claim 6 wherein:

the adjustment time period is a specified number of weeks, the initial set of stored operating parameters includes operating parameters for different time segments during each day of the week;

the determining step is carried out on a weekly basis for each different time segment, and the number of temperature conditions that is evaluated relative to the threshold number and the higher number is a calculated average number of temperature conditions for each different time segment.

8. The method of claim 1, wherein the automatic monitoring and adjusting includes:

determining whether the number of VOC conditions in excess of the VOC limit exceeds one or both of the specific number and a higher number, and,

if the number of VOC conditions in excess of the VOC limit exceeds the specific number but not the higher number, adjusting the set of stored operating parameters in a manner that will produce a first level of increased exhaust flow for the given thermal load condition;

if the number of VOC conditions in excess of the VOC limit exceeds the higher number, adjusting the set of stored operating parameters in a manner that will produce a second level of increased exhaust flow for the given thermal load condition, where the second level is higher than the first level.

9. The method of claim 8 including:

establishing multiple flow rate curves, where each flow rate curve defines a relationship of how changes in thermal load condition affect target flow rate that will be achieved through the hood section, and each flow rate curve has a common start point and a common end point;

wherein the adjusting of the set of stored operating parameters involves changing the flow rate curve that is used to define exhaust flow based upon monitored thermal load.

10. A method of automatically controlling a commercial kitchen exhaust hood arrangement, the method comprising:

utilizing a commercial kitchen exhaust hood arrangement installed in a commercial kitchen above one or more cooking appliances, the commercial kitchen exhaust hood arrangement having at least one hood section, a controller operable to control exhaust operations in accordance with a set of stored operating parameters, a thermal load monitoring system that adjusts exhaust flow based upon monitored thermal load, and a manual override trigger input that enables a user to manually trigger a maximum exhaust mode for the hood section;

establishing an initial set of stored operating parameters for the exhaust hood arrangement, the initial set of stored operating parameters affecting control of exhaust operations under varying conditions;

during an adjustment time period, operating the exhaust hood arrangement as needed for cooking operations in the commercial kitchen, wherein such operating involves responding to a particular thermal load condition by establishing a first flow rate through the hood section;

during the adjustment time period the controller automatically monitors operation of the exhaust hood arrangement and thereafter adjusts one or more of the stored operating parameters for use on a going forward basis, wherein the automatic monitoring and adjusting involves;

tracking a number of manually triggered overrides, determining whether the number of manually triggered overrides exceeds an override threshold and, if so, adjusting one or more of the stored operating parameters in a manner that will produce a second flow rate through the hood section for the particular thermal load condition going forward, where the second flow rate is different than the first flow rate.

11. The method of claim 10, wherein the thermal load monitoring system includes at least one temperature sensor for detecting temperature within the hood section,

during the adjustment time period, the operating of the exhaust hood arrangement involves responding to a temperature in excess of an upper temperature limit by establishing a maximum flow rate through the hood section, where the upper temperature limit is defined in accordance with the initial set of stored operating parameters,

and the automatic monitoring and adjusting further involves:

tracking a number of sensed temperature conditions in excess of the upper temperature limit, determining whether the number of sensed temperature conditions exceeds a temperature condition threshold and, if so, adjusting one or more of the stored operating parameters in a manner that will increase the upper temperature limit going forward.

12. The method of claim 11, wherein the exhaust hood arrangement further includes a VOC monitoring system with at least one VOC sensor, wherein the VOC monitoring system is configured to trigger a maximum exhaust mode for the hood section,

during the adjustment time period, the operating of the exhaust hood arrangement involves responding to a specific thermal load condition by establishing a third flow rate through the hood section,

and the automatic monitoring and adjusting further involves:

tracking a number of sensed VOC conditions in excess of a VOC limit, determining whether the number of sensed VOC conditions exceeds a VOC condition threshold and, if so, adjusting one or more of the stored operating parameters in a manner that will produce a fourth flow rate through the hood section for the specific thermal load condition going forward, where the fourth flow rate is different than the third flow rate.