Junaid Bin Masood - The Petroleum Institute's profile - activity

@Julien Marrec @adhilton

In design builder, when we want to connect more than 2 components to a single Fresh Air Handling Unit there is a need to connect all components to FAHU through same mixer / splitter. Multiple mixers / splitters cause severe errors in simulation. Whenever a component is added the mixer / splitter branch automatically updates to increase in number of connections making more connectors available. See following images.

https://1drv.ms/f/s!Ase9DtM9ZxGyjFqFs...

The final results after annual simulation give me monthly energy consumption for different parameters. Now all the energy is in positive while cooling is with negative sign. Plus, there are three parameters Zone Sensible Cooling, Total Cooling and Sensible Cooling reported. Shall I just mathematically add all kWh energy consumption irrespective of the signs and would that be my monthly energy consumption? Or Do I remove one of the cooling results?

Results Shown : https://1drv.ms/i/s!Ase9DtM9ZxGyjB9ek...

When Using the Detailed HVAC do we need to add a humidifier to the Air Handling Unit? Does the software not automatically take the humidity set points from the Activity set?

Problem is when I am changing the RH Humdification and Dehumidification set points the results are not giving any changes in energy.

@Julien Marrec . Yes I have assigned them by adding several splitters to the FAHUs. Here are the images: https://1drv.ms/f/s!Ase9DtM9ZxGyjAu47... . What do you think should be the solution?

@Julien Marrec I checked in the IDF file. Yes there are more than one mixers. But one FAHU is serving more than one zones. So won't it definitely have more than one mixers too?

Here's the link to the IDF file of my simulation.

https://1drv.ms/u/s!Ase9DtM9ZxGyjAruk...

@adhilton

Where is it in FAHU visually?

What do you mean by mixers? You mean the exhaust air fan?

After assigning 32 Fan Coil Units and 3 Fresh Air Handling Units with COPs, simulation is giving error for FAHUs. It says:

1. Too many zone mixers in Return Air Path=FAHU1 DEMAND SIDE RETURN PATH
2. Too many zone mixers in Return Air Path=FAHU2 DEMAND SIDE RETURN PATH
3. Too many zone mixers in Return Air Path=FAHU3 DEMAND SIDE RETURN PATH
4. Return air Path(s) did not pass integrity testing

What is the solution to this? Because 8 zones are assigned to FAHU1, 8 to FAHU2 and 12 to FAHU3.

Ok. I got your point. I will follow the forum guidelines, as I was unaware up till now.

But none has been answered yet.

I am using detailed HVAC and have assigned 32 Fan Coil Units (PTAC) to 32 zones of the building I am simulating. Now all the zones are also connected to 3 Fresh Air Handling Units.

Problem is when I assign the FCUs and select the zones in zone groups then how do I assign FAHUs to all zones, as they disappear from zone group options because they already are assigned the FCUs?

Dear fellows,

I have 32 Fan Coil Units serving 32 zones and 3 Fresh Air Handling Units serving the whole building. I understand adding 32 FCUs (PTACs) with COPs and performance curves to 32 zones. After adding 32 FCUs how will I assign 3 FAHUs to all the zones, as in DB once the zone is in zone group it disappears from the selection option.

Waiting for a reply.

Yes I agree with you. Visit this site: https://designbuilder.co.uk/tutorials/ I am sure this will give you a clear idea of the detailed HVAC systems in Design Builder.

Yes I just fixed it. Thank you for your reply.

Ok. Thanks for your suggestion

Both softwares can be used for your purpose, but I would prefer Design Builder. It is less time consuming. In OpenStudio default settings are much more complex than design builder which is more user friendly. Plus OpenStudio model visualization is not possible. In Designbuilder majority settings are already set by default to help simulate multiple times and then make changes according to your needs. Chances of errors are less so it saves your time. As for HVAC system I would suggest using Simple HVAC first, after it completes without errors you can then add the detailed HVAC. To complete a model with standard systems (for building your size) can take me 7-10 days while detailed might take a more than 2 weeks (for complete detailed HVAC). But again it depends how much time you are spending on it. Hope this helps.

I am entering the detailed HVAC in Design Builder. After entering it is giving the following errors:

Can you kindly help me guide why am I having this error?

Dear Dave,

Thank you for your response. I am trying to run any template for right now as the simulation is giving errors (something regarding the zone matching...). However your reply has given me a good direction. I am grateful for your support.

Regards, Junaid

Dear Banicu,

Thank you for your reply. I will look into this. Thanks again for the help.

Regards, Junaid

Dear Fellows,

I am working on an institutional building model. The building has 5 types of Fan Coil Units serving 32 different zones. It has 3 Fresh Air Handling Units for all zones. The outdoor air enters the FCU whose coils are not connected to any water system rather the heating and cooling coils work with electric power to provide set point temperatures. Refrigerant is circulating in the cooling coil. The air is then supplied to the zone. I don't know how to model this template? Shall I use only a Fan Coil Unit with air inlet and outlet connecting to zone only? Kindly help.

Hello fellows,

I have the readings for the flow rate(air coming out of vents) for each defined zone. I want to enter this to Design Builder model. Where do I enter this?

Kindly reply.

Regards.

Great. Your reply was of great help and very useful. Thanks a bundle.

Dear Fellows,

The building that I am auditting has 3 separate Fresh Air Handling Units for entire building and Fan Coil Units for each room. I figured out how to assign the FCUs in DB but the problem is i need to assign FAHUs also along with the FCUs. Is it possible? Which tab can I use to assign separately the FAHUs with the FCUs. Please reply.

Tonnes of thanks.

Hello. I have entered the coefficients also. I did not face any problem. But all my temperatures were positive. I guess may be due to negative low temperature you are facing this problem.

Thanks a lot. Solved my problem.

Hi fellows,

I am doing energy analysis of one of the buildings in my institute. I want to enter the calculated coefficients of performance curves. Where do I access the tab in design builder from?

Regards

Dear Fellows,

I am doing energy analysis of one of the buildings at my institute. How do I access the editable coefficients for the performance curves? Kindly reply as I have tried but I am not finding any options.

Regards.