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Air Cavity Calculator Tomasz Kornicki Presents
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Unit Price:   USD 25.91 
Total:   USD 25.91
 Info plus 4.3% sales tax/VAT to USD 25.91: USD 1.11
USD 27.02
Delivery:   Download
Platform:   .NET Windows, Windows 2000, Windows XP x32, XP Tablet PC, Windows Vista x32, Windows XP x64, MS.NET 1.1 required
Language:   English, German
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File Size:   Full version: 1.3 MB
Download Time:   Full version
  • 56k: ~3 min.
  • DSL/Cable (1/8/16Mbit): <1 / <1 / <1 min.

 
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The Air Cavity Calculator is used as a tool for rapid calculation of equivalent heat conductivity of small air cavities and air gaps based on the input of their dimensions and heat stream direction.

To calculate equivalent heat conductivity (lambda) the application uses formulas defining calculation of heat transfer resistance of air spaces described in EN ISO 6946:2005 Appendix B - please be aware of limitations related to its application (e.g. small, closed air cavities).
Calculation regulation are geared to European norms EN ISO 6946 and EN ISO 10077-2 and cover two dimensional calculations.

Heat Stream direction Definition of heat stream direction:
  • Horizontal (default)
  • Upwards
  • Downwards
Thickness (stream dir.) The thickness of the cavity measured in the heat stream direction.
Remark: Thickness and width can be swapped via a context menu.
Width The width of the cavity (perpendicular to the thickness)
Remark: Thickness and width can be swapped via a context menu.
Temperature difference dT The difference of temperature between cavity boundaries in the heat stream direction.
Equiv. Resistance Equivalent heat transfer resistance of particular air cavity
Equiv. Lambda Equivalent heat conductivity of particular air cavity
Result Calculation result is replaced by the actual value.

Remark: According to normative regulations one shall set the temperature difference, if exact value is not known, accordingly. Buttons "5K (EN 6946)" and "10K (EN 10077) set this value to one of magnitudes required in these respective regulations.

For the very usual case of non rectangular air cavities normative regulations define following procedure to account for:

An equivalent conductivity is to be calculated for a fictive rectangular cavity. Such fictive cavity shall be constructed as follows:

  1. create a rectangle surrounding the cavity of interest.
  2. the area of a fictive cavity rectangle shall be equal to the area original (non rectangular) cavity.
  3. the ratio of width to the height of the fictive rectangle cavity shall be the same as of the rectangle surrounding the original.

The conductivity calculated for such fictive rectangular cavity is the used instead for the (non rectangular) original air cavity.

Heat Stream direction Definition of heat stream direction:
  • Horizontal (default)
  • Upwards
  • Downwards
Thickness (stream dir.) The thickness of the rectangle surrounding the cavity measured in the heat stream direction.
Remark: Thickness and width can be swapped via a context menu.
Width The width of the rectangle surrounding the cavity (perpendicular to the thickness)
Remark: Thickness and width can be swapped via a context menu.
Area The actual are of the real (non rectangular) air cavity
Temperature difference dT The difference of temperature between cavity boundaries in the heat stream direction.
Equiv. Lambda Equivalent heat conductivity of particular air cavity
Result Calculation result is replaced by the actual value.

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