olivier's profile - activity

Thanks I'll try it out. Comfort was what I was going for.

I wanted to know the quickest and most effective way to model a ceiling fan in Openstudio. The fan only displaces air in the zone and does not bring it from outdoors. If possible I would like a fan for which you can choose the air displacement (linked to the size of the blades).

Making a copy of the corrupted file in the file location (not through Openstudios) and re-naming that copy also works.

Hi I added a heating thermostat schedule set it to 0 C and a cooling thermostat schedule and set it to 25 and got a cooling load.

Hi,

I am currently designing the HVAC system of an existing building in Thailand. I've had diffuclty trying to get a cooling load out of my PTAC (still haven't managed) and after reducing the cooling and heating setpoint schedules to 0 degrees C to try and force a cooling load, the simuation failed (worked before I did this) with this error message:

Severe UpdateZoneSizing: Cooling supply air temperature (calculated) within 2C of zone temperature

~~~ ...check zone thermostat set point and design supply air temperatures

~~~ ...zone name = THERMAL ZONE OFFICE 1ST 5

~~~ ...design sensible cooling load = 32828.84 W

~~~ ...thermostat set point temp = 0.000 C

~~~ ...zone temperature = 14.100 C

~~~ ...supply air temperature = 14.000 C

~~~ ...temperature difference = -0.10013 C

~~~ ...calculated volume flow rate = 246279.71616 m3/s

~~~ ...calculated mass flow rate = 296175.07751 kg/s

So my zones are not hot at all, I had actually previously put in a default PTAC with an elec heating and got a heating load.... even though the outdoor temperature is 35C and there are internal loads. My building is however elevated off the floor with no Ground Surface Contact, I don't know if that's what affects it.

Any help on how to have my zone temperatures look like the real deal would be great!

Hi, thanks for your answer. I have added design days to my model, the .ddy file from the openstudio website. I have made a Cooling Setpoint Schedule for my thermal zone (20 C all year round). I have created a space type with internal loads (only lighting, elec eq), is there an internal load for the AC? I have also re-run the simulation with new PTACs that are all autosized. I have heating loads... Which is not very logical because I only need cooling loads...

Hi,

Being still a novice in Openstudio I do not know how to properly design HVAC systems. therefore I need help to correctly design one.

For the moment I am using PTAC DX Clg Elec Htg, in reality my AC has no heating. I have hard sized most of the parameters, namely:

OS:ZOneHVAC:PackagedTerminalAirConditioner

• Supply Air Flow Rate During Cooling Operation: 0.431 m^3/s
• Supply Air Flow Rate During Heating Operation: ~ 0 (because no heating)
• Supply Air Flow Rate When No Cooling or heating is Needed: 0 (because in reality the coils are always on when the fan is on, it's in Thailand so it is very hot and humid --> AC is working hard)
• Outdoor Air Flow Rate During Cooling Operation: 0.431 m^3/s
• Outdoor Air Flow Rate During Heating Operation: 0 (because no heating)
• Outdoor Air Flow Rate When No Cooling or heating is Needed: 0 (because in reality the coils are always on when the fan is on, it's in Thailand so it is very hot and humid --> AC is working hard)

OS:Coil:Heating:Electric

• Nominal Capacity: 0 (because no heating)

OS:Fan:ConstantVolume

• Maximum Flow Rate: 0.431 m^3/s (I had to hard size this because every time I ran the simulation it couldn't autosize because there was No "Zone:Sizing" objects even though I had set the Do Zone Sizing Calculation and Do System Sizing Calculation to on in Simulation Control, it works when hard sized)

OS:Coil:Cooling:DX:Single:Speed

• Rated Total Cooling Capacity: 10550 W
• Rated Sensible Heat Ratio: 0.7 (had to hard size, same reason explaine in OS:Fan:ConstantVolume)
• Rated COP 2.8

The rest was left alone.

When I run the simulation with the above parameters it is able to complete, however when I look at HVAC load I have this (0 cooling load).

I've left the Cooling Sizing Parameters and Heating Sizing Parameters to their default values and have not done any design days, I have only used the weather file from the NREL website. I have however made my own Availability Schedule For OS:ZOneHVAC:PackagedTerminalAirConditioner, it is an OnOff Schedule type and looks like this:

However the other Schedules have been left as there default schedule namely:

• Supply Air Fan Operating Mode Schedule for OS:ZOneHVAC:PackagedTerminalAirConditioner: Always On Discrete 17
• Availability Schdule for OS:Coil:Heating:Electric: Always On Discrete 19
• Availability Schdule for OS:Fan:ConstantVolume: Always On Discrete 18

And therefore there isn't any electrical consumption from the PTAC

Any help on how to correctly design this type of HVAC system to get cooling loads and electrical consumption would be greatly appreciated.

Thanks for your help :)

Thank you for your answer :)

Hi,

Is it possible to make spaces inherit default Construction Sets, Schedule sets and Design Specification Outdoor air through the Openstudio interface even though prior to creating these space types I had assigned different Construction Sets, Schedule sets and Design Specification Outdoor air for each Space through the Openstudio inspector in SketchUp?

Now If I assign a space type to an os space in sketchup it does not inherit the Construction Sets, Schedule sets and Design Specification Outdoor air I assigned to it in the os interface; it keeps the ones I had previously assigned. I imagine this would a question of inheritance priority.

Any help would be appreciated.

@PBrain Would you use a high DesinSpecification:OutdoorAir or a high SpaceInfiltration:DesignFlowRate? From my understanding DesinSpecification:OutdoorAir is usable by other objects whereas SpaceInfiltration:DesignFlowRate is unwanted outdoor air infiltration. I would think either would be good because no other object would use this outdoor air. Is this correct? Also If both are high do they double up?

@David Goldwasser Thanks for the answer. So why would we use thermostat setpoint schedules?

Hahaha, thanks Julien! It's a great answer, lots of details and different methods. I'll try one of these for sure!

Just to answer the question: from @ljbrackney: manually navigate to the html file in your model's run\7-UserScript0\mergedjob-0 and open it.

Hi,

I wanted to know how cooling setpoint schedules worked with a 'Temperature' variable. Do the limits mean that indoor temperatures will always be between those limits regardless of the outdoor temperature?

For my example I need to have schedule for the air conditioners (split unit) in a office room, on - off, when they are on the room temperature goes down to approximately 20 C but when it is off I have no idea, i.e. it depends on how hot it is outside. Would this type of schedule suit or should I use something else such as an HVAC system representing a split system AC with a on/off schedule?

Any help would be very much appreciated!

@Julien Marrec, Ok thanks. To give you a bit of context: - The building is in Thailand - It is a three story buidling with a steel I beam skeleton

I've edited my question to show a picture of one of the walls of the building.

My question still remains, how would I model this in Openstudio?

Hi,

I am confused as to how I can model a wall that is surrounded by steel I beams in Openstudio. I have found the correct components for the wall itself.

My questions is: Is it possible to integrate the steel I beams in the wall construction or do I have to draw the steel beams in my model and assign them to 'steel' component? Also is it actually worth it? (the building has a I Beam steel structure) Here's a rough sketch of my wall

Thank you for your help!

Here's a photo of one of the walls of the building

I'm using Windows 8.1

Yes that worked! Thanks a lot.

Hi,

When I try to access the View Data (once the view_data measure has run) in the results summary Openstudio 1.10.0 crashes. Here's a snippet of the error message.

Does anybody know how to counter this problem?

The warnings still appear but the simulation finishes.

Updated openstudios to 1.10.0 and sketchup to 2016 and it resolved my problems!

@aparker I'm using Openstudio 1.9.0 on OS Windows 8.1. I deleted all punctuation in my names, ran the simulation and it still fails... It indeed fails when generating the standard report. The eplusout.err is identical to the previous one. I didn't even choose the variable names the eplusout.err report is complaining about and I don't know where to find them to change them... Do you have anymore tricks I could try? Thank you for your help!

Hello!

Being still a novice with OS I am having trouble understanding why my simulation isn't completing. I have eliminated all severe and fatal errors... I still however have 130 warnings most of which I do not know how to attend... A great majority of these warnings are " * Warning * Processing Monthly Tabular Reports: BUILDING ENERGY PERFORMANCE - [text] ", most of which I don't need the results.

Also I have unused schedules and constructions even though I used the 'purge' button in the OS interface.

How can I get rid of these unused schedules and constructions?

How can get rid of the warnings related to "Processing Monthly Tabular Reports".

Any help would be greatly appreciated!

Here's a snippet of the eplusout.err file

file

Hi there!

I am quite new to Openstudios. I am currently modelling an existing building that is surrounded by dense trees in certain areas and less dense trees in others which creates good shade for the building. I wanted to use shading surfaces to model the trees, is this the best way to do it? Is it possible to adjust the transparency of the shading surfaces so it better resembles the actual situation? Any help is welcome.

Great thank you!