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Dehumidification using Hvac Template:Zone:Ideal loads airsystem

asked 2018-01-07 03:22:04 -0500

Prinz Qwert gravatar image

updated 2018-01-07 09:22:10 -0500

Avi gravatar image

Hi! I am using HVACTEMPLATE:ZONE:IDEALLOADSAIRSYSTEM and I want to limit the temperature to 26°C and the humidity to 60%. I set the Dehumidification Control Type to constant sensible heat ratio and the Dehumidification Setpoint to 0.6. However it seems to have no effect on the humidity. Is there any way I can limit the relative humidity to a constant value ?? Thank you in advance!

HVACTemplate:Zone:IdealLoadsAirSystem,
    exhibition,              !- Zone Name
    thermostat,              !- Template Thermostat Name
    Assembly HVAC on,        !- System Availability Schedule Name
    50,                      !- Maximum Heating Supply Air Temperature {C}
    13,                      !- Minimum Cooling Supply Air Temperature {C}
    0.0156,                  !- Maximum Heating Supply Air Humidity Ratio {kgWater/kgDryAir}
    0.0077,                  !- Minimum Cooling Supply Air Humidity Ratio {kgWater/kgDryAir}
    NoLimit,                 !- Heating Limit
    ,                        !- Maximum Heating Air Flow Rate {m3/s}
    ,                        !- Maximum Sensible Heating Capacity {W}
    NoLimit,                 !- Cooling Limit
    ,                        !- Maximum Cooling Air Flow Rate {m3/s}
    ,                        !- Maximum Total Cooling Capacity {W}
    ,                        !- Heating Availability Schedule Name
    ,                        !- Cooling Availability Schedule Name
    ConstantSensibleHeatRatio,  !- Dehumidification Control Type
    0.6,                     !- Cooling Sensible Heat Ratio {dimensionless}
    60,                      !- Dehumidification Setpoint {percent}
    None,                    !- Humidification Control Type
    30,                      !- Humidification Setpoint {percent}
    None,                    !- Outdoor Air Method
    0.00944,                 !- Outdoor Air Flow Rate per Person {m3/s}
    ,                        !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
    ,                        !- Outdoor Air Flow Rate per Zone {m3/s}
    ,                        !- Design Specification Outdoor Air Object Name
    None,                    !- Demand Controlled Ventilation Type
    NoEconomizer,            !- Outdoor Air Economizer Type
    None,                    !- Heat Recovery Type
    0.7,                     !- Sensible Heat Recovery Effectiveness {dimensionless}
    0.65;                    !- Latent Heat Recovery Effectiveness {dimensionless}
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@Prinz Qwert Are you Using OpenStudio with E+ measure?

Avi gravatar image Avi  ( 2018-01-07 10:18:37 -0500 )edit

No I just modeled it in E+

Prinz Qwert gravatar image Prinz Qwert  ( 2018-01-08 09:38:09 -0500 )edit

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answered 2018-01-07 10:20:24 -0500

Avi gravatar image

updated 2018-01-07 10:20:58 -0500

I think you must add ZoneControl:Humidistat object which references a humidity set point schedule with schedule type set to 'Percent'. Look at that Post though for OS.

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Thank you for your answer! i will try that!

Prinz Qwert gravatar image Prinz Qwert  ( 2018-01-08 07:50:28 -0500 )edit

Is it possible to use a humidity setpoint just to calculate the idel loads? I build my model now in OpenStudio and it seems to me that I need an HVAC system in order to use the setpoint magager. Is that correct?

Prinz Qwert gravatar image Prinz Qwert  ( 2018-01-10 07:15:32 -0500 )edit

@Prinz Qwert No you don't need any HVAC. But you will need to use E+ measure in order to get to all of the Ideal loads setting. You can try the one I wrote which works for me in OS 2.3.0.

Avi gravatar image Avi  ( 2018-01-10 07:49:55 -0500 )edit

Works like a charm!! Thank you soo much!! you saved my day :)

Prinz Qwert gravatar image Prinz Qwert  ( 2018-01-13 13:22:35 -0500 )edit

@Avi Hi, I would like to use this measure since I am working with high humidity spaces. I uploaded it from the BCL and as someone said in the comments overthere, it is not possible to assign a schedule to 'System avaibility', 'Heating avaibility' and 'Cooling avaibility'. I tried with 2.3.0. and 2.4.0. Do you have any suggestions to make it works? Thank you!

mhtalb gravatar image mhtalb  ( 2018-09-23 19:34:25 -0500 )edit

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Asked: 2018-01-07 03:22:04 -0500

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Last updated: Jan 07 '18