Modelling mechanical ventilation without heating or cooling

Hi all, how can I model a mechanical system that only supplies a certain air change rate of outdoor air, without actually providing heating or cooling?

So far, in these cases I have assigned an HVAC system and simply set the heating and cooling setpoints to impossible values (e.g. -99 and 99, respectively), but this seems like a hack and probably not best practice. I have also noticed that many HVAC systems will always have a bit of energy consumption going for the heating and cooling parts, even when they are not in use.

Hi @MaxMarschall,

Changing room’s setpoints should work exactly the same as when you create a HVAC system with only ventilation system.

The reason that you are still seeing a small amount of energy used in heating or cooling is mainly for ventilation system. Cooling is used for cooling air temperature to 12.5C (55F) and heat them back to neutral temperature 24C (75F). This is the dehumidification process for outdoor air. Unless you build a HVAC system without cooling and heating components on your own, I think these energy consumptions are always needed in the ventilation system when it is required in all HVAC templates.

Or you could just simply ignore those heating and cooling energy values.

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@MingboPeng would this also be true if the dehumidity/humidity setpoints were also maxed out (100% and 0% respectively)? I believe it would work for ideal loads, but not sure if it would also override a typical VAV (for example)…

I’ll try to check when I get the chance.