Experimental Testing of the Water Distillation System with Regard to Heat and Cooling Generation by Means of Reversible Thermochemical Reactions

The paper presents the results of an experimental study on the exothermal heat and endothermal cooling generation under vacuum conditions using a water distillation system of special design. The heat and cooling are generated when KOH and NH4NO3 crystals are dissolved as a result of natural mixing in the water, distilled from NH4NO3 and KOH liquid solutions, respectively. The time evolutions of the temperatures measured in KOH→H2O→NH4NO3 and NH4NO3→H2O→KOH experiments are presented and discussed. It has been shown that under vacuum conditions, the endothermal effect of NH4NO3 dissolution in water is stronger than that observed at atmospheric pressure, while the exothermal effect of KOH dissolution in water is weaker. The experimental results obtained will be used to develop the dual thermochemical heat storage and cooling generating system in order to utilize solar heat in the summer.

THERMAL DECOMPOSITION OF MOLECULAR COMPLEXES: II. β-QUINOL CLATHRATES

The β-quinol clathrates of nitrogen, carbon dioxide, methanol, and methyl cyanide decompose at temperatures well below the melting point of the host quinol lattice. The accompanying endothermal effect is broad, indicating that the decomposition occurs gradually over a considerable temperature range. The clathrate decomposition was verified by measurement of the gas evolved. The enthalpy change accompanying decomposition correlates closely with the energy of interaction of the guest molecule with the β-quinol lattice, and the decomposition of the clathrate is suggested to occur by a lattice distortion mechanism in which the size and shape of the guest molecule are important.

A dickite with an elongated crystal habit and its dehydroxylation

SummaryDickite from a new occurrence at Barkly East, Cape Province, is described and compared with a previously unreported dickite from Postmasburg and a dickite from Ouray, Colorado. The Barkly East dickite crystals are elongated in the direction of the a-axis; the ratio of length to width of crystals varies from 3:1 to 16:1. Optical, electron microscopic, X-ray, and thermal data and a chemical analysis are given. The thermogram of the fraction smaller than 2 µ e.s.d.1 is characterized by a single peak at 600°C., while that of fractions larger than 2 µ e.s.d. shows a double endothermal effect. This two-stage dehydroxylation of dickite on heating is attributed to a particle size effect.