Spectral and Total Transmittances of Magnesium Chloride-Water Solution

We report measurements of the spectral transmittance and calculations of the total transmittance of magnesium chloride-water solution to be used as the working fluid for a solar pond. The spectral transmittance of MgCl2-water solution in the visible, infrared and nearby regions decreases with increasing salt concentration. The total transmittance of MgCl2-water solution can be calculated using an exact integration method and a simple 5-band partition method over a 3 m depth of pond water. The simple method is useful in practice to calculate the total transmittance for a conventional solar pond, because the rate of difference between the results calculated by the two methods is less than 10% at shallow depths and then it decreases rapidly being followed by 0% at a depth of 3 m. Furthermore, the absorption coefficient calculated from the spectral transmittance of the present work is compared with that from Usmanov's data as shown in references (6) and (7).