- 日本建築学会計画系論文集 (ISSN:13404210)
- vol.63, no.505, pp.51-58, 1998
This paper describes a method to calculate exergy and entropy balances of a leaf with an emphasis on photosynthesis and secretion. The purpose of investigating such balances is to have a better understanding of the exergy-entropy process of a leaf, which is a fundamental member of trees as a shading device with evaporative cooling capability for passive cooling of a building, together with the exergy-entropy process of various building environmental control systems such as lighting, cooling, and heating systems. We have derived the exergy balance equations for a leaf, taking into consideration not only the dispersion of energy due to the absorption of solar radiation and heat transfer, but also the dispersion of carbon dioxides, water vapor, and oxygen. Example calculation showed the following: exergy consumption within the leaf is 94% of the supplied exergy, which is the sum of the exergies of solar radiation, effective sky longwave radiation, and water; a half of the rest, namely 3%, is stored within the glucose, and the other is discharged with water vapor into the environment of the leaf and then consumed totally until the water vapor reaches the environment.