Cooline ASQ Series, Руководство пользователя

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A. Single or multiple chillers with constant water flow through chillers and load system:
In this type of arrangement, constant water flow through the chillers and load distribution piping circuit is maintained.
Before proceeding further, a brief explanation on the operation of a typical chilled water system / valves which is funda-
mental to the design or analysis of a system.
Where multiple zones of control are required, the various load devices are controlled first; then the source (chillers)
system capacity is controlled to follow the capacity requirement of the loads. Control valves are commonly used to control
loads. These valves control the capacity of each load by varying the amount of water flow through the load device.
Control valves for these applications are two-way (straight-through) and three-way valves. The effect of either valve is to
vary the amount of water flowing through the load device. With a two-way valve, as the valve strokes from full-open to full-
closed, the quantity of water flowing through the load gradually decreases from design flow to no flow. The three-way
mixing valve has the same effect on the load as the two way valve - as the load reduces, the quantity of water flowing
through the load decreases in proportion to the load and the difference amount is directed through a bypass.
In terms of load control, a two-way valve and a three-way valve perform identical functions—they both vary the flow
through the load as the load changes. The fundamental difference between the two-way valve and the three-way valve is
that as the source or distribution system sees the load, the two-way valve provides a variable flow load response and the
three-way valve provides a constant flow load response.
Referring to the foregoing schematic layout, this is a conventional system and is not as energy efficient as the two-way
valve systems especially on the pumping side due to constant water circulation in the system. On multiple chiller instal-
lations, pumps are required to operate continuously and the sequencing of chillers is dependent on water temperatures.
CHWS
CHWR
Load Load
3-Way
Valve
3-Way
Valve
Constant Speed Pump
Chiller