the effect of timestep on peak cooling(heating) load

asked 2020-03-29 11:38:08 -0500

Wjkkkkkk gravatar image

updated 2020-03-30 09:05:17 -0500

Hi everybody!

I am doing the simulation work for a conference center to get the information of cooling and heating load in openstudio, the following is the problem i met:

in my report, there were several tags about load, such as designed load and caculated load of which the results were relatively normal. However, the peak cooling(heating)demand of the whole building were just too much(twice as much as the sum of disigned load of each zone), which might represented refrigerators with gigantic capacity. This was far beyond my estimated value of the peak load, so i checked the "sensible heat gain summury", and the "Opaque Surface Conduction and Other Heat Addition" was the contributor of such a high peak load demand.

Then I attempted to change the time step from 6/hr to 1/hr, the peak cooling(heating) load demand was only 1/6 of previous value, and so was the "Opaque Surface Conduction and Other Heat Addition" ,which seemed normal this time.

So, my question is why the timestep has such big effects on the peak cooling(heating) demand and "Opaque Surface Conduction and Other Heat Addition", and which value of peak load demand by different timestep should i accept?

Thanks a lot!!!

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