[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[EnergyPlus_Support] Re: Ideal Loads Latent Cooling Rate
Youâ??re right, I totally forgot to consider this point... Setting the inlet temperature to a higher value decreases the latent part.
Thank you very much for the answer.
Florian
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Santiago Velez <santiagogvelez@...> wrote:
>
> Dear Florian, if I'm not missing something, according
> to psychometrics theory, since you are injecting air at 12 �C, even if
> supply air is set to its maximum possible humidity (100% relative), the
> absolute humidity will probably be less than the return air mixed with
> outside air. This means that you will necessary have to loose humidity to
> get to 12�C, this loss of energy is the latent load, even when there is no
> humidity control.
> You will see no latent load when you have no outside air and *no latent
> load in the room*, or when you have outside air dry
> enough to compensate for moisture created in the room. I don't think you
> should see latent load in winter with no humidity control.
> Very good source of info about this subject is ASHRAE Fundamentals Chapter
> one.
>
> Best,
> Santiago.
>
>
>
>
> 2013/2/25 simonflorian2002 <f.simon.mail@...>
>
> > **
> >
> >
> > With an Ideal Loads System, you will specify the temperature (°C) and the
> > Maximum Heating Supply Air Humidity Ratio and the Minimum Cooling Supply
> > Air Humidity Ratio.
> >
> > If you set correctly these values you should find a situation where you
> > donâ??t need to humidify or dehumidify, furthermore if you set the Fields
> > â??Dehumidification Control Type� and â??Humidification Control Type� to
> > none.
> > Thus the latent load for the room should be to zeroâ?¦
> >
> > Why canâ??t I have this result ?
> >
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "jeannieboef@" wrote:
> > >
> > > With an Ideal Loads simulation, you will specify the air (deg C) and
> > > absolute humidity (g water/g dry)
> > > This means that the simulation will compare these two properties to
> > those of the outdoor air conditions so as to deturmine how much the air
> > needs to be heated or cooled, humidified or dehumidified to reach the
> > delivery air conditions that you specified.
> > >
> > > Latent load = energy of the water if the zone were at perfect design
> > setpoint conditions (which you specify or which the program may assume) -
> > >
> > > the energy of the current water amount at the current timestep zone
> > temperature.
> > >
> > > As people and other things can add or subtract water to the zone, the
> > Latent Load may fluctuate.
> > >
> > > Right?
> > >
> > > Sent from my iPhone
> > >
> > > On 22.02.2013, at 16:35, "simonflorian2002" wrote:
> > > > Dear E+ User,
> > > >
> > > > I have some difficulties to understand how is calculated the latent
> > Energy/Rate for Ideal Loads air System. I'm using such a system, with
> > humidification and deshumidification set to none, and yet, I found a "Ideal
> > Loads Latent Cooling Rate". I thought that, with this setting, the sensible
> > and latent cooling rates are the same, why are they different ?
> > > >
> > > > Thank you.
> > > > Florian
> > > >
> > > > ZoneHVAC:IdealLoadsAirSystem, Bloc1:Zone1 Ideal Loads Air, !- Ideal
> > Loads Air Name
> > > > , !- Availability Schedule Name
> > > > Node Bloc1:Zone1 In, !- Zone Supply Air Node Name
> > > > , !- Zone Exhaust Air Node Name
> > > > 35, !- Heating Supply Air Temp {C}
> > > > 12, !- Cooling Supply Air Temp {C}
> > > > 0.01, !- Heating Supply Air Humidity Ratio {kg-H2O/kg-air}
> > > > 0.01, !- Cooling Supply Air Humidity Ratio {kg-H2O/kg-air}
> > > > NoLimit, !- Heating Limit
> > > > , !- Maximum Heating Air Flow Rate {m3/s}
> > > > , !- Maximum Sensible Heating Capacity
> > > > NoLimit, !- Cooling Limit
> > > > , !- Maximum Cooling Air Flow Rate {m3/s}
> > > > , !- Maximum Total Cooling Capacity
> > > > Bloc1:Zone1 Heating Availability Sch, !- Heating Availability Schedule
> > > > Bloc1:Zone1 Cooling Availability Sch, !- Cooling availability schedule
> > > > None, !- Dehumidification Control Type
> > > > , !- Cooling Sensible Heat Ratio
> > > > None, !- Humidification Control Type
> > > > , !- Design Specification Outdoor Air Object Name
> > > > , !- Outdoor Air Inlet Node Name
> > > > , !- Demand Controlled Ventilation Type
> > > > NoEconomizer, !- Outdoor Air Economizer Type
> > > > None, !- Heat Recovery Type
> > > > , !- Sensible Heat Recovery Effectiveness
> > > > ; !- Latent Heat Recovery Effectiveness
> > > >
> > > >
> > >
> >
> >
> >
>
------------------------------------
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/