Discussion of “a comparison of several heat and mass transfer networks of interest in water conservation”

The use of electrical networks to describe heat‐ and mass‐transfer problems is an interesting concept and undoubtedly will be of considerable value in future water‐loss investigations, provided the processes involved can be represented, electrically, with sufficient accuracy.

Although it is true that errors in measurement of water‐surface temperature may arise when there are steep gradients in the fluid, such a temperature profile will not be associated with high evaporation rates, as implied by Poppendiek and Tribus. High evaporation is associated with appreciable wind and a resultant stirring or mixing of the upper part of the fluid. Hence the possibility of making large errors in water‐surface temperature measurements during periods of high evaporation rates are minimized. The results of the first three months of operation at Lake Hefner, Oklahoma City, Okla. [Anderson, Anderson, and Marciano, 1950] indicate that any error in evaporation computed from either the mass‐transfer or the energy‐budget equations due to errors in the measurement of the water‐surface temperature are insignificant when total evaporation over a 24‐hour period is considered.