ETF and Thermal Comfort Statements

Y. Kurazumi et al. 616 and baby tears. Thermal comfort statements with benjamin are coolwarm sen- sation statements, which fall in the middle of the readings from the foliage plant groups described above. As described for the relationship between ETF and thermal sensation state- ments, moss ball and baby tears have a dense shape of very small leaves; people look at a point on the green crown architecture, a shape which makes people think of wetness. Benjamin has a crown architecture that spreads in the desktop space near the body, which gives a sense of being closed in, which may weaken the relief of warm feelings [14] . At 25˚ thermal environment conditions with statements that are approx- imately “−1”, and at 31˚ thermal environment conditions with statements that are approximately “1”, there may be tiny differences in benefits of visual stimu- lation by foliage plants. However, second-order regression coefficients of the re- gression equation are negative for pothos, oxycardium, moss ball, and baby tears, but they are positive for cacti, benjamin, and the condition of no plants. Therefore, under thermal environment conditions of approximately 27˚C to 29˚C ETF, which has neutral coolwarm sensation statements—neither cool nor warm—visual stimulation of foliage plants may have benefits. We used a non-linear second-order regression model to check for homogene- ity between the condition with no foliage plants in visual stimulation and condi- tions with foliage plants added. In all conditions with plants, compared to the condition without plants, p 0.20 for intercept and slope, showing no significant differences. In research by Matsubara et al. [6] and Shimada et al. [31] mainly on psycho- logical evaluation, and by Kurazumi et al. [14] based on a comprehensive envi- ronment index for heat exchange, they found that benefits that improve non- specific sensations according to independent heat exchange of coolwarm sensa- tions are greater than those in thermal sensation, as measured by specific sensa- tion-dependent heat exchange. But our research produced different results. Spe- cific response can be defined as a response that depends on evaluating each type of environmental factor. Non-specific response is a response where combina- tions of all types of environmental factors are being evaluated. That is, non-spe- cific response is the evaluation of impression of the space. The effects of visual stimulation in this research may have been affected by fondness for foliage plants. We found that high-level brain processes cause differences to occur in comprehensive thermal senses; this can be conjectured from the range of results in this research, but there is a need for further study.

4.4. ETF and Thermal Comfort Statements

Figure 6 shows the relationship between ETF and thermal comfort statements. As in the relationships between ETF and thermal sensation statements and coolwarm sensation statements, thermal comfort statements have a large dis- tribution. Thermal comfort statements are measured on a discrete grade scale, so some thermal comfort statements are at the same level; many thermal comfort Y. Kurazumi et al. 617 Figure 6. Relation between ETF and thermal comfort. statements are concentrated at “−1” or “0” for a 25˚C thermal environment con- dition setting, “0” or “1” for 28˚C, and “−1” for 31˚C. The tendency of thermal comfort statements indicates that the 26˚C to 29˚C ETF range may be the most comfortable thermal environment. Focusing on the regression line in the range of 26˚C to 29˚C ETF, thermal comfort statements tend to be low with cacti or the condition with no foliage plants in visual stimulation. Thermal comfort statements tend to be high with pothos, oxycardium, or benjamin. Thermal comfort statements with baby tears or moss ball are in the middle of the foliage plant groups described above. Compared to other visual stimulation conditions, the second-order coeffi- cients of the regression coefficient for moss ball tend to differ from all of the others. Moss balls do not spread in a tree architecture, so even if we try to give them a high green coverage ratio, their psychological green coverage ratio may be recognized as relatively low. We used a non-linear second-order regression model to verify homogeneity between conditions with no visual stimulation by foliage plants against condi- tions with foliage plants added. Comparing moss ball to the condition with no foliage plants in visual stimulation, we found that intercept, slope, and second order coefficient all have p 0.20, showing significant differences. Fondness for foliage plants may have effects, but it is possible that, if foliage plants with a coverage ratio approximately 0.75 or higher are placed on the side of the desk, then the thermal environment of an inorganic office working space may be organically improved to be more pleasant.

4.5. Visual Stimulation and Human Responses