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2015-09-25 02:52:05 -0500 | received badge | ● Scholar (source) |
2015-09-21 02:34:14 -0500 | asked a question | Re-cooling zone air after mixing with return air I am modeling a mechanical VAC system in Energyplus similar to the image below where the system mixes fixed amount of conditioned and return air and cools it down again. But I am facing difficulties with the zone equipment side. So I was wondering if I am building the system correctly or not.
Thank you |
2015-06-18 01:30:08 -0500 | commented answer | Verifying energy balance of Energy+ simulations Thanks Neal for the suggestion. Changing the HeatBalance Algorithm does improve the ‘Zone Air Heat Balance Deviation Rate W ’ (it is basically zero…order of E-13) and there is no more warnings from Energyplus. So, the air heat energy balance is being fulfilled by Energyplus. But I wanted to calculate the energy balance manually as well and not just look at the deviation rate. During this exercise I came across another issue. I have edited my question above as I think it still falls under the topic of energy balance. |
2015-06-16 08:50:30 -0500 | received badge | ● Student (source) |
2015-06-16 08:50:01 -0500 | asked a question | Verifying energy balance of Energy+ simulations I am trying to verify the energy balance of Energy Plus models. As a reference I took the very simple ‘1ZoneUncontrolled.idf’ file for location CO and looked at the ‘Zone Air Heat Balance Deviation Rate [W]’ and also monitored Output:Diagnostics-> DisplayZoneAirHeatBalanceOffBalance. One segment from the output from the .errr file was
Suggestions on which variables to monitor to track would be appreciated. I have gone through the zone and surface outputs listed in 'input-output-reference' documentation but no luck in finding a balance of the heat transfers in the zone. Thanks. **Update of question with the next part following the answer from Neal Kruis Thanks Neal for the suggestion. Changing the HeatBalance Algorithm does improve the ‘Zone Air Heat Balance Deviation Rate [W](TimeStep)’ (it is basically zero…order of E-13) and there is no more warnings from Energyplus. So, the air heat energy balance is being fulfilled by Energyplus. But just to be sure I calculated the balance manually. Going back to the basis for the Zone and Air System Integration, I used the following variables as outputs in csv. Since the idf file has no HVAC or internal loads or infiltration, all other parameters in the balancing equation, like convective internal loads, heat transfer from infiltration, heat transfer due to interzone mixing, air systems output are all zero. Check 1: I looked at the difference between A) and B) and it is basically zero. So this check of energy balance is fulfilled. Check 2: Here I took the summation of C-H) and A) i.e. summation of the outputs from the six surfaces (convective heat transfer from the zone surfaces) and zone air heat balance (energy stored in zone air). From my understanding, this should ideally be zero. But that is not the case as the summation of the variables deviate largely from zero and is still in the order of hundreds of watts. Check2b) By following up on why this difference arises, I realized that if I take the So my questions/comments on this issue are:
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