Notations and Units
Symbol |
Quantity |
Unit |
\(c_{\mathrm{m}}\) |
specific heat capacity of dry material |
\(\mathrm{J} /(\mathrm{kg} \cdot \mathrm{K})\) |
\(c_{\mathrm{w}}\) |
specific heat capacity of liquid water |
\(\mathrm{J} /(\mathrm{kg} \cdot \mathrm{K})\) |
\(D_{\mathrm{w}}\) |
moisture diffusivity |
\(\mathrm{m}^{2} / \mathrm{s}\) |
\(E_{\mathrm{sol}}\) |
total flux density of incident solar radiation |
\(\mathrm{W} / \mathrm{m}^{2}\) |
\(g\) |
density of moisture flow rate |
\(\mathrm{kg} /\left(\mathrm{m}^{2} \cdot \mathrm{s}\right)\) |
\(g_{\mathrm{p}}\) |
density of moisture flow rate of available water from precipitation |
\(\mathrm{kg} /\left(\mathrm{m}^{2} \cdot \mathrm{s}\right)\) |
\(g_{\mathrm{v}}\) |
density of water vapour flow rate |
\(\mathrm{kg} /\left(\mathrm{m}^{2} \cdot \mathrm{s}\right) \) |
\(g_{\mathrm{w}}\) |
density of liquid water flow rate |
\(\mathrm{kg} /\left(\mathrm{m}^{2} \cdot \mathrm{s}\right) \) |
\(g_{\mathrm{w}, \max }\) |
density of water flow rate which can be absorbed at the surface of a material |
\(\mathrm {kg} /\left(\mathrm{m}^{2} \cdot \mathrm{s}\right)\) |
\(h\) |
surface heat transfer coefficient |
\(\mathrm{W} /\left(\mathrm{m}^{2} \cdot \mathrm{K}\right)\) |
\(h_{\mathrm{c}}\) |
convective heat transfer coefficient |
\(\mathrm{W} /\left(\mathrm{m}^{2} \cdot \mathrm{K}\right)\) |
\(h_{\mathrm{e}}\) |
specific latent enthalpy of evaporation or condensation |
\(\mathrm{J} / \mathrm{kg}\) |
\(h_{\mathrm{r}}\) |
radiative heat transfer coefficient |
\(\mathrm{W} /\left(\mathrm{m}^{2} \cdot \mathrm{K}\right)\) |
\(K\) |
liquid conductivity |
\(\mathrm{s} / \mathrm{m}\) |
\(p_{\mathrm{a}}\) |
ambient atmospheric pressure |
\(\mathrm{Pa}\) |
\(p_{\text {suc }}\) |
suction pressure |
\(\mathrm{Pa}\) |
\(p_{\mathrm{v}}\) |
partial water vapour pressure |
\(\mathrm{Pa}\) |
\(p_{\mathrm{v}, \mathrm{a}}\) |
partial water vapour pressure in the air |
\(\mathrm{Pa}\) |
\(p_{\mathrm{v}, \mathrm{s}}\) |
partial water vapour pressure at a surface |
\(\mathrm{Pa}\) |
\(p_{\mathrm{v}, \mathrm{sat}}\) |
saturated water vapour pressure |
\(\mathrm{Pa}\) |
\(p_{\mathrm{w}}\) |
water pressure inside pores |
\(\mathrm{Pa}\) |
\(q\) |
density of heat flow rate |
\(\mathrm{W} / \mathrm{m}^{2}\) |
\(q_{\text {lat }}\) |
density of latent heat flow rate |
\(\mathrm{W} / \mathrm{m}^{2}\) |
\(q_{\text {sens }}\) |
density of sensible heat flow rate |
\(\mathrm{W} / \mathrm{m}^{2}\) |
\(R_{\mathrm{w}}\) |
liquid moisture flow resistance of interface |
\(\mathrm{m} / \mathrm{s}\) |
\(R_{\mathrm{H} 2 \mathrm{O}}\) |
gas constant of water vapour |
\(\mathrm{J} /(\mathrm{kg} \cdot \mathrm{K})\) |
\(s_{\mathrm{d}, \mathrm{s}}\) |
equivalent vapour diffusion thickness of a surface layer |
\(\mathrm{m}\) |
\(T\) |
thermodynamic temperature |
\(\mathrm{K}\) |
\(T_{\mathrm{a}}\) |
air temperature of the surrounding environment |
\(\mathrm{K}\) |
\(T_{\mathrm{eq}}\) |
equivalent temperature of the surrounding environment |
\(\mathrm{K}\) |
\(T_{\mathrm{r}}\) |
mean radiant temperature of the surrounding environment |
\(\mathrm{K}\) |
\(T_{\text {surf }}\) |
surface temperature |
\(\mathrm{K}\) |
\(t\) |
time |
\(\mathrm{s}\) |
\(v\) |
wind speed |
\(\mathrm{m} / \mathrm{s}\) |
\(w\) |
moisture content |
\(\mathrm{kg} / \mathrm{m}^{3}\) |
\(\alpha_{\mathrm{sol}}\) |
distance |
\(\mathrm{m}\) |
\(\delta_{0}\) |
solar absorptance |
\(\mathrm{kg} /(\mathrm{m} \cdot \mathrm{s} \cdot \mathrm{Pa})\) |
\(\delta_{\mathrm{p}}\) |
vapour permeability of still air |
\(\mathrm{kg} /(\mathrm{m} \cdot \mathrm{s} \cdot \mathrm{Pa})\) |
\(\varepsilon\) |
vapour permeability of material |
\(-\) |
\(\lambda\) |
longwave emissivity of the external surface |
\(\mathrm{W} / \mathrm{m} \cdot \mathrm{K})\) |
\(\varphi\) |
thermal conductivity |
\(-\) |
\(\mu\) |
relative humidity |
\(\mathrm{kg} / \mathrm{m}^{3}\) |
\(\rho_{\mathrm{a}}\) |
diffusion resistance factor |
\(\mathrm{kg} / \mathrm{m}^{3}\) |
\(\rho_{\mathrm{m}}\) |
density of air |
\(\mathrm{kg} / \mathrm{m}^{3}\) |
\(\sigma_{\mathrm{w}}\) |
density of solid matrix |
\(\mathrm{density}\) of liquid water |
\(\rho_{\mathrm{w}}\) |
density of liquid water |
\(\mathrm{kg} / \mathrm{m}^{3}\) |
\(\sigma_{\mathrm{s}}\) |
Stefan-Boltzmann constant |
\(\mathrm{W} /\left(\mathrm{m}^{2} \cdot \mathrm{K}^{4}\right)\) |