Hi folks,

We are modeling a large facility operating with multiple VAV AHUs with central heating and cooling coils, but no re-heat at the zones. There are high heat loads in the spaces and therefore higher return air temperatures than the norm.

When I remove the re-heat from the systems I have excessive unmet load hours (heating). I have specified "HEAT-SET-T" to activate the central heating coil. I also have cooling control set to "warmest" and heat control set to "coldest". If I do not set the coil capacity it is still not meeting the loads. The only way I have been able to eliminate these unmet hours is by adding the re-heat back in or changing it to a multi-zone (MZS) system with all the same parameters.

If I model this scenario using the multi-zone system in eQuest to get around this would that be vastly different than VAV with no re-heat? Has anyone had this issue before? Any insight is appreciated. Thanks!

-Dana

Mr. Dana Etherington, E.I.T., LEED AP BD+C | CRB