Different results in simulation

rahmiandarini · Posts: 43

Dear Sir,

I have just installed the newest version of DB, v.1.5.0.076, and simulated three different building models, then compare the results with previous version, v.1.4.0.056.
1. Case 600 ASHRAE
There is no significant difference between these 2 versions (les than 0.1%).

2. A three storey building, and each storey has 1 zone, there is no stairs (no hole between 2 storeys).
The difference of Zone Sensible Cooling is about 0.14%, so, I think that this is also not a significant different.

3. A two storey building, and there is hole between this building (I assume as stair). The difference on the Zone Sensible Cooling is 8%, and this is significant. According to this result, then I tried to compare (from CSV file) what made this differece.
I found that site data are exactly the same.
But then the heat gain from glazing, door, floor, occupancy are difference, lead to the difference on the Zone Sensible Cooling.

My question is, is this significant difference due to the new 'equations behind' in calculation air flow between two floors? or the is other reason which cause the difference result.

Thanks
rahmi

Andy Tindale · Posts: 1111 Location: Stroud

Rahmi,

It's hard to say what causes the difference in case 3 but you could try selecting the previous version of EnergyPlus (version 2.1 DOE) in the current version of DB to see if the difference lies with the calculation engine or with the interface. You can change the version of EnergyPlus on the program options dialog on the EnergyPlus tab.

Andy

rahmiandarini · Posts: 43

Andy,

Thanks for the suggestion.
I have tried to change the EP version for the new DB, and it gave the same result which means that when I do simulation using DB V.5.0.74, and using EP version 2.1 and EP Version 2.2, both the results are the same.

Is there any other suggestion about my 3rd question (from my previous posting)?

Thanks,
Rahmi

Andy Tindale · Posts: 1111 Location: Stroud

If you post the dsb model in v.1.4 format I will take a quick look to see if I can pin point the reason for the differences.

Andy

rahmiandarini · Posts: 43

OK Andy,

I attached the model.

Thanks,
Rahmi

rahmiandarini · Posts: 43

Dear Sir,

I have just tried to simulate this building using DesignBuilder version v.1.4.0.056, just have a look what happens if I put insulation on the roof. The result shows that the zone sensible cooling decreases (compare to the model without roof insulation), and this makes sense.

Then when I simulated using the newest version of DesignBuilder, I found that with additional roof insulation caused the zone sensible cooling increase. How come?

Please advice me about this.

Thanks,
Rahmi

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