OPTIMIZING MULTIPLE BOILER PLANT SYSTEMS WITH MIXED CONDENSING AND NON-CONDENSING BOILERS

• US 20100006042A1
• Filed: 06/29/2009
• Published: 01/14/2010
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Heat-Timer Corporation
• Original Assignee: Heat-Timer Corporation
• Inventors: Pitonyak, Michael T., Pan, Pengpeng, Clerico, Vincent S.
• Granted Patent: US 8,479,689 B2
• Time in Patent Office: Days
• US Class Current: 122/448.300
• CPC Class Codes: F22B 33/00 Steam-generation plants, e.g. comprising steam boilers of different types in mutual association arrangements or dispositions of steam-generation plants in marine vessels B63H21/00
• CPC Class Codes: F22B 35/008 Control systems for two or more steam generators F22D5/36 takes precedence
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A system is provided to optimize multiple boiler plant systems having mixed condensing and non-condensing boiler groups. The system advantageously employs the independent groups of boilers depending on preset conditions under control of a system control unit. The preset conditions are checked against operating conditions of the boiler plant, and a system control unit controls which of the groups of boilers is the lead and which is secondary. In some instances, both groups of boilers may be utilized under heavy load. Further, effective switching between groups and within groups is also provided to minimize unnecessary repetitive boiler operation.

Claims

1. A control system for a multiple boiler plant with mixed condensing and non-condensing boilers comprising:

separating a plurality of boilers into condensing and non-condensing groups,

setting a system threshold to select which of said groups shall serve as lead boiler group for a selected boiler operating condition,

said system threshold comprising settable parameters relating to the operation of said boiler plant,

said settable parameters being entered into a system control unit to be stored therein,

operating condition sensors to provide sensed operating condition data derived from the operating conditions of said boiler plant,

said system control unit comprising comparator means to compare said settable parameters with said operating condition data, and

said system control unit selecting from said groups of boilers to control which group shall be the lead group in response to a control signal provided by said comparator means.

2. A control system as set forth in claim 1, wherein said sensed operating condition comprises the boiler plant system water temperature.

3. A control system as set forth in claim 1, wherein said operating condition is comprised of a proxy for the boiler plant system water temperature.

4. A control system as set forth in claim 3, wherein said proxy is selected from a group consisting of supply system water temperature, system water return temperature, boiler header temperature, outdoor ambient temperature and boiler stack temperature.

5. A control system as set forth in claim 1, wherein said system control unit comprises means to delay switching between said groups of boilers after a preset operating condition is reached.

6. A control system as set forth in claim 5, wherein said means to delay switching comprises a dynamic delay signal related to boiler operating conditions.

7. A control system as set forth in claim 1, wherein said comparator includes minor offset means such that said control signal is not provided until said threshold level plus said minor offset is reached.

8. A control system as set forth in claim 1, wherein said preset parameters include non-system operating conditions comprising the date.

9. A control system as set forth in claim 8, wherein said non-system operating conditions comprise the time of day.

10. A control system as set forth in claim 1, wherein said control system comprises override means to prevent operation of respective ones of said groups of boilers when said operating conditions do not permit operation of respective ones of said groups of boilers.

11. A control system as set forth in claim 1, wherein said control system prevents said non-condensing boilers from operating below condensing boiler plant system temperatures.

12. A control system as set forth in claim 11, wherein said control system prevents said condensing boilers from operating at high boiler plant system temperatures.

13. A control system as set forth in claim 1, further comprising transition parameters minimizing unnecessary switching between boiler groups.

14. A control system as set forth in claim 1, wherein the system control unit comprises means to enable concurrent running of both groups of boilers.

15. A control system as set forth in claim 1, wherein each of said groups comprises at least two of said condensing or non-condensing boilers.

16. A control system for a multiple boiler plant with mixed condensing and non-condensing boilers comprising:

separating a plurality of boilers into condensing and non-condensing groups,

setting a system threshold to select which of said groups shall serve as lead boiler group for a selected boiler operating condition,

said system threshold comprising settable parameters relating to the operation of said condensing and non-condensing boilers within said groups of said condensing and non-condensing boilers,

said settable parameters being entered into a system control unit to be stored therein,

boiler operating condition sensors to provide the operating conditions of said boilers,

said system control unit comprising comparator means to compare said settable parameters with said operating boiler conditions, and

said system control unit selecting from said groups of boilers to control which group shall be the lead group in response to a control signal provided by said comparator means.

17. A control system as set forth in claim 16, wherein said preset and sensed boiler operating conditions comprise the boiler outputs of each of said groups.

18. A control system as set forth in claim 17, wherein said operating conditions comprise firing rate control signals emanating from said system control unit.