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rankoromane
Posts: 66
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 Posted: Wed Feb 01, 2006 5:59 am Post subject: weather data for cooling / heating design |
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I have modelled a simple house using the Johannesburg weather file.
When I do a 'cooling design' simulation and look at the weather data, the altitude data for the sun is way out; similar to what it should be in mid winter.
The 'heating design' weather data appears to be limited to a DB temp, no other weather data at all.
The weather output for a 'simulation' looks correct.
Am I missing something?
regards,
Agas. |
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Andy Tindale
Posts: 1149
Location: Stroud |
| Posted: Wed Feb 01, 2006 4:57 pm Post subject: |
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Thanks for pointing out the problem with solar altitude display in Cooling Design output - it was displaying July solar altitude instead of data for January.
This problem does not affect the Cooling Design results generated by EnergyPlus, just the display of site weather data.
There will be a new release of DesignBuilder in the next few days containing a fix for this.
Regarding Heating Design site data, you should only see winter design external dry-bulb air temperature. Ideally the wind speed would also be displayed but this is not possible in version 1. The other site weather data is not relevant for Heating Design.
Andy
Last edited by Andy Tindale on Thu Feb 02, 2006 8:10 pm; edited 1 time in total |
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rankoromane
Posts: 66
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| Posted: Thu Feb 02, 2006 6:22 am Post subject: weather data for heating / cooling design |
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Thanks for the reply, which raises some further questions.
If the weather data in the report is not the weather data used in the simulation, then how can we confirm what this data is and that it is correct?
How can the heating design calculations be carried out using only a single DB air temp? Do these not need to respond to a full range of envelope heating loads which will be determined by the daily temperature profile, the solar radiation parameters, wind speed and wind direction? |
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Andy Tindale
Posts: 1149
Location: Stroud |
| Posted: Thu Feb 02, 2006 8:04 pm Post subject: |
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Agas,
| Quote: | | If the weather data in the report is not the weather data used in the simulation, then how can we confirm what this data is and that it is correct? |
The only way to verify the weather data for Cooling Design calculations carried out in the southern hemisphere in version 1.0.1 is to look at the EnergyPlus IDF data used to carry out the calculation.
You can see this by clicking on the 'View the input data' link in the info panel on the right of the screen. If you have EnergyPlus installed on your computer this will load the IDF data used to generate the Cooling Design calculations into the IDF editor. If you do not have EnergyPlus installed then you must associate the extension IDF with a text editor to allow this option to work.
To associate the IDF extension with your text editor, start Windows Explorer and open up the Folder Options dialog from the Tools menu. You can associate the extension on the File Types tab.
| Quote: | | How can the heating design calculations be carried out using only a single DB air temp? Do these not need to respond to a full range of envelope heating loads which will be determined by the daily temperature profile, the solar radiation parameters, wind speed and wind direction? |
Heating design calculations are traditionally carried out using worst-case winter design external conditions applied in the steady state. Solar (and other) gains are usually ignored when sizing heating equipment because they cannot be relied upon at night. Wind speed and direction are used in the calculations because they affect the external convective heat transfer coefficients, but are currently not available for viewing because of an oversight.
The next version of the software will allow viewing of all appropriate Design weather data input.
Regards
Andy |
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