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HVAC and Daylight error in Designbuilder

I have 3 questions related to Designbuilder, I'm working on my thesis which is the renovation of a public building. I had the baseline model which works fine and I created the proposed model out of it, when I run the simulation I don't understand some thing, I'm still learning DB so please correct me.

  1. Why the fan energy consumption is high? I used a VRF HVAC system will before I used a normal system with law fan energy consumption. https://cdn.discordapp.com/attachment...
  2. I did daylighting calculation, and only one side of the building got sun light, even that I have all the building with windows, especially south part. https://cdn.discordapp.com/attachment...
  3. For the simulation output, the cooling results are negative in the graph, is that okay?

Thank you

ilyass.hlioua@gmail.com's avatar
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ilyass.hlioua@gmail.com
asked 2024-04-15 07:39:08 -0500
Aaron Boranian's avatar
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Aaron Boranian
updated 2024-04-16 09:18:54 -0500
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1 Answer

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  1. My suggestion will be to identify which fan is producing the high-values and confirm that the inputs are correct. This can be done by looking at the simulation results eplusout.eso file and open it in DesignBuilder Results Viewer. The Summary tab also provides a report with the fan input values. Perhaps the Pressure rise entered for a particular fan is very high or the operation schedule selected was not set as expected (eg. 24/7 on).

  2. Based on the screenshot, it seems like you're running a point-in-time calculation with one of the sky options that takes into account the sun's position. The results are as expected.

  3. Yes that sounds correct.

Luís Filipe S.'s avatar
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Luís Filipe S.
answered 2024-04-17 09:20:15 -0500
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Thanks for your answer.

  1. I checked the schedule and it was 24/7, I changed it to the operation system I have in the zones. Also, in the Air loop, I had to calculate the right value for the outdoor air flow rate, I used a night cycle and recirculation. that helps to take 75% of the fan's consumption.

  2. True, I couldn't get any good results on Designbuilder, so I did it on Revit and it works fine for me.

ilyass.hlioua@gmail.com's avatar ilyass.hlioua@gmail.com (2024-04-18 17:46:54 -0500) edit
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