A holistic microclimate model

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apps:biomet_pet [2017/11/11 08:39]
enviadmin
apps:biomet_pet [2019/01/12 21:15] (current)
enviadmin
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-Despite its popularity, PET lacks a proper and comprehensive documentation. Basically, one needs to read the 2 papers Gagge et al. (1971) and Höppe (1984) -in german- plus the computer source code provided by VDI 3787. \\ +Despite its popularity, PET long time lacked ​a proper and comprehensive documentation. Basically, one needed ​to read the 2 papers Gagge et al. (1971) and Höppe (1984) -in german- plus the computer source code provided by VDI 3787. \\
-It has to be noted, that there are some unlogical assumptions and errors in the original set of equations. In the ENVI-met implementation,​ these errors have been corrected. As a consequence,​ PET values calculated by ENVI-met may differ from values calculated by other programs, but we see no sense in copying wrong code or unlogical assumptions. Fundamental changes from the original are marked in the description. ​+
  
--The description still needs to be compiled ​and written, please hold on-+In 2018, this gap has been closed by the paper "//The P.E.T. comfort index: Questioning the model//"​ by E. Walther and Q. Goestchel ([[https://​www.sciencedirect.com/​science/​article/​pii/​S0360132318301896?​via%3Dihub|Link ​to Paper]] who take the effort to summarize all the equations ​and assumptions. ​
  
-Main changes to original PET in short :+It has to be noted, that there are some non-logical assumptions and errors in the original set of equations plus coding errors in the code published in VDI 3787. In addition, there have been better parametrisations for the Mean Radiant Temperature (TMRT) which is is not directly a part of PET but widely influences the results. 
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 +In the ENVI-met implementation in BioMet 1.x, many of these errors have been corrected. As a consequence,​ PET values calculated by ENVI-met may differ from values calculated by other programs, but we see no sense in copying wrong code or non-logical assumptions. Fundamental changes from the original are marked in the description.  
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 +Main changes ​in ENVI-met BioMet compared ​to original PET in short are:
   * For the indoor setting, the turbulent exchange coefficients for heat and vapour are calculated using the indoor air velocity instead of keeping them at the outdoor value   * For the indoor setting, the turbulent exchange coefficients for heat and vapour are calculated using the indoor air velocity instead of keeping them at the outdoor value
   * The sweat rate and the amount of sweat on the skin is set to zero when starting calculating the indoor environment   * The sweat rate and the amount of sweat on the skin is set to zero when starting calculating the indoor environment
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 +The suggestions form Walther and Goestchel (2018) ​ plus several other improvements will be added to BioMet in upcoming versions.
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 ===== General Idea ===== ===== General Idea =====