Question on Simulaiton

grasshopper dragonfly
1

I have discovered that the use of energy use intensity for the VAV system is much smaller than VAV district chilled water system after simulation, is it a normal situation?

2

I’m a beginner with EnergyPlus but that sounds likely. I believe the district VAV will have a cooling COP of 1 whereas the system will likely have a cooling COP of 4-6 (I’m not sure what the default system efficiency is).

Worth looking on Big Ladder to understand what’s happening in Energy Plus, or opening the HB model in OpenStudio to inspect the set up there.

1 Like
3

therefore, how to setup the grshopper command so as not to make the visualization result so weird, i.e. cooling energy consumption based on electrical-driven chiller should count as electricty-cooling consumption

4

Hi @yinlong, I’m not sure I follow what you mean, are you able to share more information?

5

i mean how to plot a chart for the electrical-driven chiller VAV strategy by enabling or disabling COP effect. When enable, it focused on the energy consumption of the chiller. While it is focused on how many cooling energy is consumed on evaporator when COP effect is disable

6

You could look at the room level cooling demand to understand what cooling energy is required to condition the room.

7

actually, my project is district scale simulation. therefore, would you mind teach me how to set the setting

8

I think I understand. For the district project are you just interested in how much cooling energy your district cooling network needs to supply?

Or are you interested in how much energy each connected building is using?

9

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actually yes. is the above figure already show how much cooling energy consumed for the zone.

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as i have mentioned before, when i apply the circled strategy, the value for cooling energy consumption is drop dramatically. may the problem same as your mentioned, it multiplies the COP behind

10

if the circled strategy is applyed, the result i want to know is how much electricty is used on the chiller, and the cooling energy used for the space, not just the COP multiplied cooling energy consumption, so that i can conduct reasonable carbon emission analysis

11

Hi @yinlong ,

I’m just noting that I responded to our question here:

If you know how efficient your district cooling system might be, this could allow you to compare electricity to electricity.