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[EnergyPlus_Support] Problems with coil:water:cooling in a unit ventilator
Dear all,
currently I'm modelling a server-room with high electric load (up to
700W/m2). For zone cooling I'm using a UnitVentilator. Actually there
are 4 cooling elements in the room.
One element is specified as:
Air-Temperature-in: 24 °C
Air-Temperature-out: 14.2 °C
Air-volumn flow rate: 6.11 m3/s
Water-Temperature-in: 12 °C
Water-Temperature-out:18 °C
Water-volumn flow rate: 0.0029 m3/s
Total cooling power: 73kW
The electric load in the zone is about 130kW. The 4 cooling elements
have a total cooling power of ~292kW which is more then twice the
internal load. So if the unit ventilator works correctly the zone
should be exact on the zone setpoint temperature.
When I use a coil:water:cooling in the unit ventilator and specify the
input values as mentioned above (except the flow-rates have been
multiplied with 4) the zone setpoint temperatures cannot be achieved!
Everything else seems to be OK: no errors, no warnings, correct air
flow rate, correct water flow rate, correct water inlet temperature,.
.. (same result in E+ v1.2.2 and v1.2.3).
I've now manually calculated the UA value for my cooling element,
changed the cooling coil to a coil:water:simplecooling object, used
this UA value (93870 W/K for 4 elements) and the model will give the
expected result.
Are there any know issues using the UnitVentilator with a coil:water:
cooling?
Christian
PS: I will upload the idf file: unitVentilatorCoolingCoilProblem.zip
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