small thermal zones

asked 2023-02-27 03:10:24 -0600

jferamo89
45 ●5

updated 2023-03-07 09:11:27 -0600

Neal Kruis

4745 ●10 ●17 http://bigladdersoftware.com/

Dear all,

I am currently developing an energy model for a mall building. In this mall there are hundreds of small retail units, each including a tiny service toilet for employee use (<5m2).

In such a large scale, I am seeing how my model thermal zones are x2 because of these small toilets, but I cannot find any standard of indication/recommendation on how to model these spaces or whether they should be merged with the zone they serve.

Does anyone have had a similar issue? do you know any standard that defines these spaces or how to deal with them? I believe since the size and the loads are not significant they should be merged along with the areas that provide service, which on the other hand is a conservative scenario energy-wise since these areas will have a larger load overall.

We are trying to simplify the model since the simulation time will increase considerably the more the number of zones, and thus the complexity of any consequent data post process.

I will be grateful to hear about previous experiences in this matter or similar.

Thanks

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Hi again,

Have you faced this issue before? Can anyone give me a hint?

Thank

jferamo89 ( 2023-03-07 01:39:37 -0600 )edit

Thank you very much for your reply. It is more clear now.

jferamo89 ( 2023-03-07 09:57:15 -0600 )edit

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answered 2023-03-07 07:35:20 -0600

Denis Bourgeois
2981 ●111 ●8 http://www.rd2.ca

updated 2023-03-08 08:47:22 -0600

which simulation engine?
new vs existing building? existing HVAC?
similar retail units, e.g. similar occupancy + setpoints + lighting? vs food court?
central vs individual RTUs? local WC exhaust?

... so it depends. Yet in general, it's usually fine to merge typical sales and backroom areas as a single thermal zone per retail unit. How return vs WC exhaust air is taken into account depends on available simulation engine options. And based on the simulation engine, one can also look into deleting interzone surfaces between units and/or relying on unit multipliers (fewer surfaces == faster runs).