Space Heat Demand [closed]

asked 2016-02-24 08:23:36 -0500

samks123's avatar

updated 2016-02-25 06:44:07 -0500

I have a model named EZEBH_SAHP , another model named GHZEBH_SABLR and a last model named CHZEBH_SC. The EZEBH_SAHP and GHZEBH_SABLR have the same U-values, but the CHZEBH has lower U-values than the other two models.

That means that EZEBH_SAHP and GHZEBH_SABLR should have the same space heating demand, and lower space heating demand than CZEBH_SC, however, when I run the simulations and compare the three models, GHZEBH_SABRLR has higher space heating demand than CHZEBH_SC.

I have done the following in order to obtain the space heating demand (according to energyplus helpserve):

That can be tricky depending on the type of equipment you are modeling. "Zone Air System Predicted Sensible Load to Heating" is not a good choice if you plan to sum the value over time, because it represents the load required to reach the setpoint at the current timestep. If the load is not met, then any remaining load may be included again in the next time step.

For forced air systems, Zone Air System Sensible Heating Energy reflects the amount of heat that the system actually delivered to the space. This can be summed over time and will reflect the heating requirement as long as the system meets the load. The purest approach is to use the ideal loads air system which will always meet the load exactly.

For other system types, such as baseboard and radiant heat, you need to report the specific equipment output, such as Baseboard Total Heating.

To determine the heating demand without internal gains, you need to run a second simulation with all of the gains scheduled off.

See files attached in this link:



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Closed for the following reason the question is answered, right answer was accepted by samks123
close date 2016-04-10 18:18:28.985831


@samks123 please always include the software tag.

MatthewSteen's avatar MatthewSteen  ( 2016-02-24 08:28:12 -0500 )edit

The file link is not working.

rraustad's avatar rraustad  ( 2016-04-09 15:36:37 -0500 )edit

@rraustad. Thanks very much for your kind intention of assisting, but this case is now solved. Regards,

samks123's avatar samks123  ( 2016-04-10 18:18:17 -0500 )edit