Dependencies of Some Shades such as Cloud, Wisteria Trellis, Camphor Tree, Sunshade and Parasol on WBGT in Heat Environment

Abstract

  Effects of shades afforded with cloud, wisteria trellis, camphor tree, parasol and sunshade on WBGT in the summer heat were discussed.

(1) WBGT rises gradually to take the maximum value at 14:00 and falls after this time. This maximum value of WBGT come up to more over 30.8℃ in the mid of July.

(2) At the time 14:00 when WBGT shows maximum in a day, the shade of wisteria trellis (2030×830cm²×250cm in size) bring decrease of 8.77% of WBGT, 4.22% of camphor tree (1200cm in height), and 2.0-3.5% of parasol and sunshade. Thus, the decrease effect of WBGT under the shade of trees in the summer heat is above all larger.

(3) The depth of shade S_d was defined as follow,

    S_d＝ (1－L_m/L₀) ×100

where, L₀ : illumination on the ground when nothing to shut out the sun's rays. L_m : illumination of the shade when something to shut out the sun's rays.

  But, although S_d becomes a useful factor in order to consider WBGT relating to the environment when L₀ is able to be regarded as same in setting one environment against another, it's nouseful when L₀ deffers each other. It's possible to consider WBGT in the different environments of L₀, if L_m was used as the factor to discuss WBG T instead of S_d.

(4) The correlation coefficient between WBGT and L_m is 0.759, even if in different environment of L₀. The variation of WBGT due to L_m depend upon largely both T_g and T_d as the factors of WBGT. In special measure, between L_m and T_g exists 0.870 of correlation coefficient.