Search found 44 matches

by designbuilderbig
Tue May 03, 2016 1:37 pm
Forum: CFD
Topic: constant effective viscosity
Replies: 2
Views: 49442

I hope this has been asked before...how does one guess a good value for the constant effective viscosity. Can the model output me the results of this variable using the effective aggrigate average using the k-e turbulence model and then if the values don't "range" widely (due to only a few cells wit...
by designbuilderbig
Wed Dec 23, 2015 6:22 am
Forum: EnergyPlus General
Topic: window thermal transmittance - Uw
Replies: 15
Views: 192405

Your suspision is correct. As I understand it, e+ does not apply frames to glazing that is not rectangular. So if you have non-rectangular glazing, you will have to accomidate for heatlosses due to framing in some other way. Drawing lots of triangular windows in DesignBuilder may look really good, b...
by designbuilderbig
Wed Jul 08, 2015 12:50 pm
Forum: EnergyPlus HVAC
Topic: Desiccant Dehumidifiers
Replies: 8
Views: 35207

Stand-alone Dehumidifier: Is this achievable with a VRF or heatpump unit? Dehumidifier:Desiccant:NoFans is an e+ object. http://bigladdersoftware.com/epx/docs/8-0/input-output-reference/page-045.html Desiccant cooling/dehum systems. have been on the development list since 25/10/2012. As most of the ...
by designbuilderbig
Tue May 05, 2015 6:53 am
Forum: EnergyPlus General
Topic: Roof not included in simulations
Replies: 1
Views: 51627

There is a simulation option to exclude unoccupied zones from the results. It still gets simulated.
by designbuilderbig
Tue May 05, 2015 6:44 am
Forum: EnergyPlus General
Topic: is energy simulation in DesignBuilder done via IDF actually?
Replies: 1
Views: 49112

Yes. But some of the displayed results may differ or have differed in the past with DB specific post processing. However, in the energyplus folder, all the files are there including the eso.
by designbuilderbig
Tue May 05, 2015 6:42 am
Forum: EnergyPlus General
Topic: VRF simulation
Replies: 3
Views: 54389

by designbuilderbig
Mon Apr 13, 2015 3:20 pm
Forum: EnergyPlus HVAC
Topic: Simple HVAC in the Proposed building for Leed Certification
Replies: 2
Views: 21315

I don't think you can create a credible work around with simple hvac for your proposed design. simple hvac just won't capture the efficiencies of the componants in your design. I would recommend setting up what you can and then exporting the idf and working in e+ idfs from that point on to incorpora...
by designbuilderbig
Mon Apr 13, 2015 1:08 pm
Forum: EnergyPlus HVAC
Topic: Natural ventilation simulation test
Replies: 2
Views: 28563

For infiltration you're okay. For open skylight ventilation, not quite. As the documentation states, large horizontal openings are not well modelled with the program. The effect of wind should be well accounted for as long as DB is assigning the correct WPC to the opening. Wind is the main driver fo...
by designbuilderbig
Mon Apr 13, 2015 10:20 am
Forum: EnergyPlus General
Topic: Calculated natural ventilation in V4
Replies: 1
Views: 47732

Hi Geert, I believe there has been a fix in the latest BETAs. Furthermore, e+ 8.3 has released a new feature called AirflowNetwork:OccupantVentilationControl which Dr Gu has created for us based on a publication from myself and my boss. We're refining it a bit regarding the probability checks, but t...
by designbuilderbig
Mon Apr 13, 2015 10:12 am
Forum: EnergyPlus General
Topic: Earth-Sheltered Buildings
Replies: 1
Views: 40470

Yes and yes. you should use the slab & basement pre-processors for this effect, especially in naturally ventilated and or naturally conditioned building. Please note: e+ v8.3 has been released and has incorporated the slab and basement pre-processors into the program as a user-friendly object. I...
by designbuilderbig
Mon Apr 13, 2015 9:33 am
Forum: EnergyPlus General
Topic: Converting weather data files for climate change
Replies: 6
Views: 104241

I'm not aware of any automatic tool to do this. I only know a hand full of people that can do it. Dru Crawley and Linda Lawrie at http://www.climate.onebuilding.org/WMO_Region_6_Europe/default.html are converting TRY2010 to epw. There are TRY sets for future weather 2030 and 2050, but the conversion...
by designbuilderbig
Thu Aug 14, 2014 6:17 am
Forum: EnergyPlus HVAC
Topic: No chilled ceiling possible in a basement?
Replies: 1
Views: 10373

Have you tried drawing a sub-surface and embedding the internal source in the sub-surface?
by designbuilderbig
Thu May 15, 2014 9:13 am
Forum: CFD
Topic: Radiant Floor CFD
Replies: 1
Views: 56962

I would go with the temperature version. The strength of CFD is that it can very accurately calculate the local velocities at the point on a surface and thereby very well calculate the film convection heat transfer coefficients. If you have good temperature boundry conditions on all the other surfac...
by designbuilderbig
Thu May 15, 2014 8:59 am
Forum: EnergyPlus General
Topic: Adiabatic component, Heating and Cooling loads
Replies: 2
Views: 12341

1) set the floor construction as "adiabatic"
2) WWR can also be set at wall level
3) there are many ways. I like the values listed in the summary tables (html). the calculated design load and the peak sensible loads are interesting.
by designbuilderbig
Thu May 15, 2014 8:17 am
Forum: CFD
Topic: natural ventilation problems
Replies: 2
Views: 62430

1) velocity vectors appear to go through the floor/wall/roof/ect. so the middle of the velocity vector arrow is in the middle of the cell. the length of the arrow is graphically scaled to match the velocity as you specify. the arrow can be longer than the cell, so for cells adjacent to walls/etc., i...

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