Mitsubishi Electric CMB-WP-V-GA1 Data Book page 145

3. SYSTEM DESIGN GUIDE
Example-2 Combination of closed type cooling tower and hot water heat storage tank
T1 : Proportional type, insertion system thermostat
T2 : Proportional type, insertion system thermostat
T3 : Proportional type, insertion system thermostat
V1 : Proportional type, motor-driven 3-way valve
V2 : Proportional type, motor-driven 3-way valve
XS : Auxiliary switch (Duplex switch type)
SC : Step controller
R : Relay
MG : Magnetic
source
In the summer, as the circulation water temperature rises exceeding the set temperature of T1, the bypass port of V1
will open to lower the circulation water temperature. In the winter, if the circulation water temperature stays below
25°C [77°F], V2 will open/close by the command of T2 to keep the circulation water temperature constant.
The temperature of the hot water inside the heat storage tank will be controlled through the step control of the electric
heater by step controller operation following the command of T3.
During the stopping of the heat source water pump, the bypass port of V2 will be closed fully by interlocking thus
preventing the high temperature water from entering into the system at the starting of the pump.
The start/stop control of the fan and pump of the closed type cooling tower is applied with the step control of the fan
and pump following the command of the auxiliary switch XS of V1, that operates only the fan at the light load while the
fan and pump at the maximum load thus controlling water temperature and saving motor power.
MEE15K052
Closed type
cooling tower
V1
XS
Heat
unit
SC MG
T3
CV
V2
R T2
Heat source
water pump
Pump interlock
Hot water heat
storage tank
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