Energy plus: Different heating,and cooling loads only by changing the HVAC systems

asked 2020-01-14 01:13:11 -0500

rezaei2 gravatar image

updated 2020-01-14 13:56:29 -0500

I have a question. I asked my question in other websites but nobody answered that. I'll be appreciate if anybody could answer my question. I made a geothermal system ( horizontal) with a' VAV' systems in Energyplus and I follow the same steps of examples of Energyplus 'Example files'. It seems I did well and the results show that in each zone the temperature is the same value with the value that I considered in thermostat and schedule. But there are something wrong, I already simulated this building with 2 different HVAC systems. The heating ,and cooling loads have a big difference between geothermal system with VAV ,and other systems. In geothermal system with VAV were found 37kw/h heating load in peak but in other systems heating load in peak are around 75kw/h,and 73kw/h. I thought it should be change the value of some parameters in VAV system like maximum air flow rate,and design water flow rate in heating and cooling, finally the heating changed but maximum to 44 kw/h(in peak),and there is still a big difference to 78kw/h that I already found in other systems. I don't know what is the problem, the results,and errors show everything are ok, but it is not correct. Thank you for your helping .

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How are you obtaining the heating and cooling loads for the different systems?

shorowit gravatar image shorowit  ( 2020-01-14 08:23:50 -0500 )edit

It's a same building, material,and schedule. Only HVAC systems are different. I obtained them in"output Meter:Heating and cooling energy transfer" I also checked them in HTML results (in Zone Sensible Cooling, and Zone Sensible Heating) for each zone.Do you have any idea?

rezaei2 gravatar image rezaei2  ( 2020-01-14 10:45:22 -0500 )edit

Have the zone temperatures or amount of outdoor air changed?

rraustad gravatar image rraustad  ( 2020-01-14 14:03:38 -0500 )edit

Differences in Zone Sensible Cooling/Heating means the supply air condition to the zone has changed.

rraustad gravatar image rraustad  ( 2020-01-14 14:04:50 -0500 )edit

The location,zone temperatures, and air condition(in outdoor,and inside) are the same,and didn't change. I think it should be changed some amounts in VAV system. As I mentioned, changed some amounts in VAV system but there is still a big difference in heating ,and cooling loads between systems.I can share the EP-Lunch file,if my explanation is not clear.

rezaei2 gravatar image rezaei2  ( 2020-01-14 14:14:18 -0500 )edit