Hi all-

Thanks for answering that good, albeit simple, question yesterday. I've got another one today, that is more obscure, and one that I've run into on a number of occasions in the last few weeks, as more and more projects are asking for advice on natural ventilation feasibility.

Conditioned spaces, semi-heated spaces, and unconditioned spaces seem pretty straightforward to determine. In my experience, conditioned spaces must simply meet the criteria set forth for cooling load and heating load (which is a Btu/hr.ft2 threshold, which is dependent upon the climate zone for heating load, at least). If a space has no heating or cooling system at all, or virtually no load, then the space is unconditioned. Semi heated kind of falls between the two.

But indirectly conditioned spaces, where do they really apply? This is made more complicated by the ASHRAE 90.1 stipulation that naturally ventilated spaces must be modeled with a cooling system (I guess this is sort of like a hybrid system) to meet the load should your space be poorly designed. We have some people scratching their heads now that nat vent is becoming more inviting.

Have I missed anything here?

Sincerely,
Chien Si