Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

OpenStudio/EnergyPlus - Design Cooling and Heating Loads = 0

asked 2014-12-23 09:31:10 -0500

pursuit's avatar

updated 2015-07-11 10:45:46 -0500


I'm trying to modelling a simple house, with only one space (and one thermal zone). But every time I run my model I get these warnings:

* Warning * SetUpZoneSizingArrays: Requested Sizing for Zone="THERMAL ZONE 1", Zone has no thermostat (ref: ZoneControl:Thermostat, et al) * Warning * Calculated design cooling load for zone=THERMAL ZONE 1 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs. * Warning * Calculated design heating load for zone=THERMAL ZONE 1 is zero. * ~~~ * Check Sizing:Zone and ZoneControl:Thermostat inputs.

I'm using IDEAL AIR LOADS for my thermal zone (only).

What can I do to get my heating and cooling loads?

Thank you very much!

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2014-12-23 11:09:59 -0500

@pursuit, it looks like your zone does not have a thermostat so the ideal air loads system does not know what temperature to condition the zone to. The Space Types and Thermal Zones video on this page should help you out.


edit flag offensive delete link more


Thank you! I made it :)

Now I have another question: the energy I'm getting is the District Heating (and Cooling) Consumption in Millions Btu. Is this energy the final building needs? Or do I have to convert it with a factor?

Thank you!

pursuit's avatar pursuit  ( 2014-12-29 12:40:08 -0500 )edit

Good to hear @pursuit. The energy numbers you are getting would be the energy used to condition your building if you had a perfectly efficient HVAC system (which you won't have). To account for the energy your actual system will use you do need to apply some conversion factors to account for cooling COP, fan efficiencies, etc. These may help you IO Ref, Engineering Ref

macumber's avatar macumber  ( 2014-12-29 12:57:09 -0500 )edit

Ideal air systems also do not include outdoor air requirements which may significantly impact your results.

macumber's avatar macumber  ( 2014-12-29 12:57:41 -0500 )edit

Ideal air systems in EnergyPlus may include outdoor air requirements if specified, but I believe the default in OpenStudio is to model ideal loads without outdoor air.

MJWitte's avatar MJWitte  ( 2014-12-31 08:42:13 -0500 )edit

Thanks @michael-j-witte, that may be something we want to look into

@kyle-benne, @david-goldwasser FYI

macumber's avatar macumber  ( 2014-12-31 13:35:22 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Training Workshops


Question Tools

1 follower


Asked: 2014-12-23 09:31:10 -0500

Seen: 2,660 times

Last updated: Dec 23 '14