Control system

Abstract

A pull-down control process for a chiller system is provided. The pull-down control process can override the capacity control process for the chiller system to pull-down the leaving chilled liquid temperature faster than the capacity control process. The pull-down control process can maintain pre-rotation vanes in a fully open position to pull-down the leaving chilled liquid temperature as quickly as possible to a predetermined setpoint.

Description

[0001] Cross References to Related Applications [0002] This application claims priority and benefit to U.S. Provisional Application No. 60 / 950,205, filed July 17, 2007, entitled "Pull-down control for chiller systems," which The provisional application is incorporated into this application by reference. technical field [0003] The present application relates generally to control systems for refrigeration liquid systems. More specifically, the present application relates to a control process for pulling down the leaving chilled liquid temperature of a chilled liquid system to a predetermined set point. Background technique [0004] In a refrigerated liquid system, a refrigerated liquid, such as water, is circulated through a building to remove heat from the building. The liquid in a refrigerated liquid system is cooled in an evaporator (or refrigerator) using a heat exchanger, where the liquid is cooled by a refrigerant that absorbs heat from the liquid. Refrigerated li...

AI Technical Summary

Problems solved by technology

However, when operating at the current limit of the motor, the refrigerant liquid system cannot physically work harder to pull down the LCHLT

Since the refrigerant liquid system cannot work more powerfully, the LCHLT cannot be pulled down faster and the pulldown rate is reduced

When the capacity controller closes the pre-rotation vane when the motor is at or close to its corresponding current limit, the closure of the pre-rotation vane can cause the pull-down time to be prolonged

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