4656 (RP-1041) -- Survey of Available Data on Secondary Properties of the Ammonia-Water Solution and Sensors for Their Measurement PDF

The ammonia concentration in water varies from near zero to 100% by mass over a temperature range from 0°C to 230°C in ammonia absorption refrigeration cycles. An accurate local measurement of ammonia concentration would assist the control and development of absorption refrigeration systems. In this project, the secondary property data available in the literature for the ammonia-water solution were reviewed along with an assessment of the currently available ammonia concentration detectors suitable for use with ammonia-water solutions. From information found, a calculation procedure for the speed of sound was developed over the entire concentration and temperature ranges. For portions of the concentration and temperature ranges, secondary property information was found for index of refraction, electric resistivity and conductivity, intensities of Raman line, ionization constant, chemical dissociation, viscosity, surface tension, ammonia solubility in water, thermal conductivity, diffusive coefficient, and thermal volume expansion. Surveying the current sensors for the detection of ammonia concentration yielded eight promising methods. These include refractive index, speed of sound, harmonic oscillation, wet chemistry ion-selective detection, electrodeless conductivity, straight acid/base titration, wet chemistry colorimetry, and spectrometry.

Units: SI