DW's profile - activity

Tracking HPWH Performance I am trying to model a Heat Pump Water Heater in OS 2.9.1 I keep seeing high peak electrical

Tracking HPWH Performance I am trying to model a Heat Pump Water Heater in OS 2.9.1 I keep seeing high peak electrical

Tracking HPWH Performance I am trying to model a Heat Pump Water Heater in OS 2.9.1 I keep seeing high peak electrical

I would like to use the autosizing feature for a boiler and chiller in a building I am testing. I would like to add an oversize factor so the plant equipment is at 110% of the peak load. I do not want to hard-code the numbers as I will be using this model in a range of weather climates using PAT. Is there a way to add or customize an oversize factor in OpenStudio or PAT?

I have a functioning EnergyPlus model in version 8.2 that runs without any severe errors. I would like to be able to utilize some of the PAT functionality of OpenStudio and have been working to import the EnergyPlus IDF into OpenStudio 1.5. Unfortunately, whenever I do, I receive the following error:

"File is not valid to draft strictness"

The two errors mentioned are: Field level data error of type DataType Error is in an object of type 'Sizing:System', named '', in field 20. correct type. Field level data error of type DataType Error is in an object of type 'PlantLoop', named 'Water_Loop Mixed Water Loop', in field 18.

This error occurs when both directly importing through OpenStudio application, and when importing the IDF using the SketchUp Plugin.

I am trying to understand what objects need to be altered so that I can import the EnergyPlus model into OpenStudio. Any help would be appreciated

It looks like it was an issue with referencing old BCL folders. I solved my issue by renaming the BCL folder on the C dr

I'm having this same issue as well. I've used this measure in the past and it was finicky but would work. Now it won't w

How to Locate EPW Error I am creating my own EPW files, but occasionally, the simulation crashes. When the error report

@rkbest The dual duct split is available under "Add HVAC System" The green "+" on the HVAC tab. Instead of adding an em

Joe, you are correct. EnergyPlus CAN work with shorter weather files as long as the run period falls within the time per

Thank you! That helps a lot.

I am working to run my EnergyPlus (v8.7) model with a custom weather file. Sometimes this means that I want my simulation to start at 7:00 AM on 1/5 and finish at 7 AM on 1/22. Eventually, I would like to do this in OpenStudio as well.

Unfortunately, the simulation seems to fail unless it starts at hour 1 of the day and ends at hour 24 of the last day. Does anyone know a way around this?

For example, I can run starting at 1/5 1:00 - 1/22 24:00, but if I try to start the weather file at 07:00 on 1/5 or end at 07:00 on 1/22, then I get a fatal error from EnergyPlus.

Hey Aaron, Thank you for the answer. I have adjusted my run period in my .idf already so I am able to run it with less t

How to Start EnergyPlus Simulation at Custom Hour I am working to run my EnergyPlus (v8.7) model with a custom weather f

How to Start EnergyPlus Simulation at Custom Hour I am working to run my EnergyPlus model with a custom weather file. So

Update on OpenStudio Slab Integration? I am struggling to include any ground temperatures in my OpenStudio 2.2 model. I

I am struggling to reduce my unmet hours for my LEED baseline building in OpenStudio 2.2. The building is occupied M-F 7:00-17:00. However, when I set my HVAC Operation schedule to follow this, I end up with 500 unmet hours during unoccupied periods. When I set the HVAC Operation schedule to "Always On", I end up with 0 unmet hours.

The proposed building uses a VRV which states that: "The VRV shall enter an unoccupied mode - should the ambient space temperatures request conditioned air, the associated fan coil and condensing unit shall be started, and will operate to meet the unoccupied setpoint. The supply fan should be off during the unoccupied schedule." The proposed model has about 113 unmet hours whether or not the HVAC operation schedule is set to Always On or only on during occupied mode.

What are the correct settings to meet the 90.1 requirements for night cycling of the baseline system? If it is only supposed to be on during occupied periods, and if so, how do I reduce unmet hours?

Further notes on the model: The building is a medium office. I have modeled a Type 5 packaged VAV system. My tolerance is 2 F. The heating and cooling setpoints are 70 and 74 respectively with setbacks of 68 and 75. My design day setpoints are defined as constant 70/74 for heating and cooling. The air loop setpoint manager is of type "warmest" with a minimum of 54 and a maximum of 60. The zone sizing is based on "temperature difference" and that difference is set to 20 F. The unmet hours are for both cooling and heating, with twice as many cooling unmet hours. I am using the ddy file associated with this location that I downloaded from the energyPlus weather website.

Thank you. I found out that the unmet hours were coming as a result of not looking at my occupancy schedules closely eno

It's helpful knowing to set the operation schedule to be only occupied. However, that leaves me with many unmet hours. C

What is Proper HVAC Operation Schedule for LEED? I am struggling to reduce my unmet hours for my LEED baseline building

The latter two schedule fields still seem to be failing. I tried just using fractional schedules, and I could select the

I am running an experiment with one of the BEST-TEST models in EnergyPlus (case 900). It is simply a box with two 6m2 windows on the south wall. I want to see the response of this structure when I hold outdoor conditions constant. I have modified a TMY file to hold the Tdb to 0C for all hours with no wind and no solar gains at all.

I have a heater inside the model maintaining indoor temperature 25oC for a few days, and then I force it off. I was hoping to see the model drift down to ambient conditions where the internal temperature slowly drops to meet the outdoor air temperature. However, the model cools down to 0C and then keeps on cooling! The model settles on a steady-state condition of -5C. I don't understand why it would cool below 0. There are no internal gains and no cooling equipment - it is simply a box.

What feature of the EnergyPlus heat transfer calculations could account for why the building reaches a steady state colder than the ambient temperature?

I have started on an energy model and I've run into a conundrum given the usual method of modeling walls as 2D surfaces in Sketchup.

The building I am modeling has windows that are inset (see the revit and streetview images below). I have considered three options, and I don't know which is best.

The building is really interesting, I'm just not sure how to model it correctly. These are the three (admittedly bad) ideas I've come up with so far:

Option A: I model the walls as flat. Problem: I miss out on the shading that is provided by the inset.

Option B: I model shading devices around each window. Problem: the shading devices will cover much of the exterior wall thus affecting the solar heat gains through the opaque envelope

Option C: I model the windows as pushed-in from the flat wall. Problem: the solar gains now appear closer to the center of the zones, I have to re-classify each subsurface around the window when I push it in and these are subsurfaces so I cannot set them as adiabatic so I will have more envelope surface area inside each zone than I want - also it's really time consuming.

If you had this project, which option would you choose? Is there a better way that I'm not thinking of? Any advice would be appreciated.

How to Model Inset Windows I have started on an energy model and I've run into a conundrum given the usual method of mod

Right now, based on the order in your pictures, it looks like the model will use the ERV as the primary heating source. So, the radiant system may not even turn on if the model thinks it can handle the heating load with the ERV alone. If you want the radiant system to be the primary source, it must be placed first - or you can open the osm file in a text editor and change their priorities.

After that, you might want to make sure that you are getting some flow through your radiant floors by tracking some of the node flows and temperatures.

Lastly, the throttling range you have seems narrow, so your radiant system doesn't vary its flow much (It's on at full capacity below 17.5C and it's completely off above 18.5C). This means the radiant floor will not be on unless the control temperature starts dropping right down to 18. By the time this happens, there may be a large time delay before the radiant slab can raise the indoor temperature if that's what its control is based on. Consider widening the throttling range so that the radiant slab can begin combatting the heat loss from the space before the indoor temp drops below your setpoint.

Let me know if you're still having problems after trying the strategies above.

What is your control temperature type? (mean indoor air temp, outdoor air temp, operative temp, or mean radiant temperature?) What climate are you running this in, and what are the internal temperatures you are hoping for?

Also, you should be able to see which layers the radiant tubes are between by exporting to EnergyPlus and looking up "Construction:InternalSource" to see after which layer the source is present.

I recently created a model in OpenStudio 1.13 with a dual-duct HVAC system. I am confused because when I expanded the deadband for the zone temperatures, my EUI increases instead of decreases.

I started the model with very conservative zone heating and cooling setpoints: 72 Htg, 74 Clg

When I expanded the zone setpoints to a very liberal 65 Htg, 85 Clg as an experiment, my EUI increased!

Ideally, I should be saving lots of energy by expanding the setpoints so much. I checked to make sure I was using the same weather file and I've applied the schedules correctly. I concluded that I must have something wrong with the way I set up my dual-duct coil setpoints. I did my best to match what was written on the design documents, but now I suspect that I have not implemented them the right way.

Does anyone have any advice as to why this is occuring or how I should adjust the setpoints in the system below?