gc.198950
2008-11-03, 01:30 PM
I have tested ecotect with the base test case 600 of the ANSI/ASHRAE Standard 140-2004 and I have got the following results:
AnnualHeating(MWh)
Minimum: 4.298
Maximum: 5.709
Average: 5.080
Ecotect 6.578
Difference,% 29%
AnnualCooling(MWh)
Minimum 6.137
Maximum 7.964
Average 6.900
Ecotect 10.007
Difference,% 45%
PeakHeating(kW)
Minimum 3.437
Maximum 4.258
Average 3.943
Ecotect 4.795
Difference,% 22%
PeakCooling(kW)
Minimum 5.965
Maximum 6.827
Average 6.386
Ecotect 7.574
Difference,% 19%
The differences are quite significant (maybe they'll become smaller when the alternating solar gains problem I mention in another post is solved).
The minimum,maximum and average come from the calculation of well known simulation engines (Blast,DOE2,ESP-R,SERIRES,S3PAS, TASE and TRNSYS) and Case 600 is the most basic case in the ASHRAE standard.
I think it would be a good idea to test ecotect with these or other cases in order to verify the precision of its results. I know that, as Ecotect's documentation states:
"The upshot is that Ecotect was not meant as a final one-shot design validation tool. For maximum benefit, it should really be used right from the very start of a project. As the design nears completion it is possible to further capitalise on any work put in creating the model by exporting to more focussed validation tools such as EnergyPlus and RADIANCE, as used by lighting engineers and energy consultants."
But I also have the impression that this fact is not always taken into account (not Ecotet's fault) and many users give too much credibilty to absolute numbers in Ecotect. Maybe some tests on the validity of ecotect as an "absolute" or "comparative" tool will help designers to make the most of Ecotect's capabilities.
AnnualHeating(MWh)
Minimum: 4.298
Maximum: 5.709
Average: 5.080
Ecotect 6.578
Difference,% 29%
AnnualCooling(MWh)
Minimum 6.137
Maximum 7.964
Average 6.900
Ecotect 10.007
Difference,% 45%
PeakHeating(kW)
Minimum 3.437
Maximum 4.258
Average 3.943
Ecotect 4.795
Difference,% 22%
PeakCooling(kW)
Minimum 5.965
Maximum 6.827
Average 6.386
Ecotect 7.574
Difference,% 19%
The differences are quite significant (maybe they'll become smaller when the alternating solar gains problem I mention in another post is solved).
The minimum,maximum and average come from the calculation of well known simulation engines (Blast,DOE2,ESP-R,SERIRES,S3PAS, TASE and TRNSYS) and Case 600 is the most basic case in the ASHRAE standard.
I think it would be a good idea to test ecotect with these or other cases in order to verify the precision of its results. I know that, as Ecotect's documentation states:
"The upshot is that Ecotect was not meant as a final one-shot design validation tool. For maximum benefit, it should really be used right from the very start of a project. As the design nears completion it is possible to further capitalise on any work put in creating the model by exporting to more focussed validation tools such as EnergyPlus and RADIANCE, as used by lighting engineers and energy consultants."
But I also have the impression that this fact is not always taken into account (not Ecotet's fault) and many users give too much credibilty to absolute numbers in Ecotect. Maybe some tests on the validity of ecotect as an "absolute" or "comparative" tool will help designers to make the most of Ecotect's capabilities.