Many common software questions are answered in the categories below. If you can’t find a response for yours, try checking our User Forum, or, contact HelpDesk for direct assistance

MarketManager » Cooling Equipment
Q: Should I attach heating and cooling equipment to Zones or Plants?


This is how the MarketManager simulation algorithm works:

  1. calculate zone loads

  2. if there is zonal equipment, apply that to the zonal loads

  3. if the zonal equipment satisfies zonal loads, then stop. If the zonal equipment does not satisfy zonal loads, then goto step 4

  4. collect all remaining child zone loads and apply them to the parent system. During this step, apply system parameters such as outside air, economizers, preheat coil. Ventilation loads are added at this step. (The scheduling in the system item works on zonal equipment regardless of the outcome of step 3, unless otherwise scheduled.)

  5. system turns on any attached fans

  6. collect all child system loads and apply them to parent plant.

  7. the plant looks to child heating, air-cooling and chiller items to meet loads.

If the zonal loads are met in step 3, then the ventilation loads as configured in the system | outside air data form are not applied. For this reason, we advise you to attach equipment to zones whenever possible.


  1. water-air heat pumps can only be attached to zones

  2. if one or some (but not all) zones in a system have their own dedicated heating or cooling equipment, then you should attach the dedicated equipment to the zone. An example of this might be the CEO's office which has its own dedicated "window shaker" air conditioning unit.

  3. if zones are conditioned by what should be two systems. For example, if your zone is conditioned by steam radiators and package units, you can choose to model this as a hydronic system and add the Air-Cooling items to the zones themselves.

I can’t find the answer to your question ? Try checking our User Forums.

Otherwise feel free to contact our Tech Support staff at (805) 329-6565, or via email at helpdesk@abraxasenergy.com.

MetrixMarketManagerReportMakerOption C