Browse Prior Art Database

Method of Starting an Additional Chiller in Chiller Group Control System

IP.com Disclosure Number: IPCOM000104440D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Harasono, Y: AUTHOR [+4]

Abstract

Disclosed is a method of increasing the number of chillers in chiller group control system to utilize maximum chiller capacity in operation and to stabilize system outlet temperature.

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This is the abbreviated version, containing approximately 67% of the total text.

Method of Starting an Additional Chiller in Chiller Group Control System

      Disclosed is a method of increasing the number of chillers in
chiller group control system to utilize maximum chiller capacity in
operation and to stabilize system outlet temperature.

      In conventional chiller group control system, start/stop
operations are basically controlled by the comparison of cooling load
with chiller capacity in terms of calorie through controller 1.  An
additional chiller starts when cooling load increases larger than the
preset value, which is normally smaller than chiller rated capacity
to allow chiller deterioration.  If cooling load is nearly equal to
chiller rated capacity exceeding the preset value, an unnecessary
chiller starts, which is a waste of energy.  Besides, system outlet
temperature is not stable because it is not considered in the control
method (Figs. 1 and 2).

      Figs. 3 and 4 show the new control system.  The remote set
point of chiller outlet temperature (Trsp) is controlled by the
master controller 2 for the system outlet temperature.  On the other
hand, chiller outlet temperature (Tmax) at maximum chiller capacity
has a linear functional relation of system inlet temperature (Ti) as
follows:

      Tmax = aTi + b     a, b: constant

Relations between Trsp and Tmax are as follows:

      Trsp > Tmax   :   Chiller Capacity > Cooling Load

      Trsp = Tmax   :   Chiller Capacity = Cooling Load

     ...