Re: [EnergyPlus_Support] Calculation of Zone Air system Sensible Cooling Rate Manually

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The answer to your first question is that you could manually calculate one itteration of an algorithm used to solve the heat balance of the air node of a zone. It would require you to download the source code, find the relevant section and have a good grasp of mass and heat transfer modelling.

What I propose is doing very simplified calculations to get rough estimates of what you expect and then compare those to what the program calculates.

Essentially, the zone air node only exchanges heat via convection to bounding surfaces (including windows) + mass energy via air from infiltration, air supply and idealHVAC or other equipment directly transferring energy to the air (like the convective and latent fraction of lighting, or persons).

The capacitor nature of the masses associated with the bounding surfaces dictate the speed of the heat transfer or heat flux which is where things get tricky for non-steady state calculations.

On 31 Jan 2018 9:06 am, "srk.iitm@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

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Please answer to my queries ....Any one?

How to calculate manually Zone Air system Sensible cooling rate manually?

Summing up of Zone air heat balance inernal convective heat gain rate, Zone air heat balance Surface convective heat gain rate, infiltration heat gain rate, interzone heat gain rate will serve the purpose??

Any thing else is to be done?Â

where is the window component appearing here? I guess it should be inÂ Zone air heat balance Surface convective heat gain rate.

The above formula looks alright till the zone air temperature is meeting the setpoint.Â

But once it crosses the set point, there is a huge difference between the summation and reporting value.
How to calculate these values when the room temperature is not meeting the set point.

tell me how to calculate these components manually?

I observed that theÂ Zone Air Heat Balance System Air Transfer Rate and Zone air system sensible cooling rate are reporting values that are different from the component Zone predicted sensible cooling load to the thermostat. the number is huge. why is this difference?

I observed from the reports that Zone Air Heat Balance System Air Transfer Rate and Zone air system sensible cooling rate are reporting same values. Does it mean the definition is same for both these terms?

at times, Zone air heat balance system air transfer rate becomes Zero even though it is scheduled to run and even though the temperature inside the zone do not meet the setpoint. Why is this happening?