Yuriy I. Aristov

Effect of Residual Gas on Water Adsorption Dynamics Under Typical Conditions of an Adsorption Chiller

In this article the effect of a non-adsorbable gas (air) on kinetics of water adsorption on loose grains was studied for three adsorbents promising for adsorption chilling: SWS-1L (silica KSK modified by calcium chloride), silica Fuji type RD, and FAM-Z02. The experimental conditions were fixed similar to real operating conditions during an isobaric adsorption stage of the basic cycle of an adsorption chiller (AC). Reduction of the adsorption rate was revealed even at a partial pressure of residual air as low as 0.06 mbar. Dependence of the characteristic adsorption time on air partial pressure was found to be linear for partial pressures greater than 0.4 mbar, with the slope depending on the adsorbent nature. Desorption stage was less affected by the residual air. Specific power released in an AC evaporator during the adsorption process was estimated as a function of the partial pressure of residual air, and recommendations how to improve cooling performance are made.

Adsorption Dynamics in Adsorptive Heat Transformers: Review of New Trends

This review addresses recent advances in understanding and trends in studying dynamics in adsorptive heat transformers (AHTs), which are considered as an alternative to common compression and absorption machines. Experimental data have been obtained mainly by a new large temperature jump method (LTJM) specifically developed to imitate the conditions of isobaric stages of AHTs. Here we consider merely a simple but quite realistic configuration of an “adsorbent–heat exchanger” (Ad-HEx) with n-layers of loose adsorbent grains (n = 1–8). Water, methanol, and ammonia are used as adsorbates. Several recommendations following from this experimental study have been checked with prototypes of adsorptive chiller in ITAE-CNR (Italy) and the University of Warwick (UK). These tests clearly demonstrated that the dynamic performance of AHT can be significantly improved by a proper management of AHT cycle and Ad-HEx geometry. The most important findings and general regularities that have been revealed by systematic studying of the adsorption dynamics of water, methanol, and ammonia in AHT systems are summarized, illustrated, and discussed in this review.

ARTIC-1: A New Humidity Buffer for Showcases

Abstract This paper considers an efficient approach to passive humidity control for art objects in exhibition cases, picture frames and transporting containers. This approach is based on a gas–solid chemical reaction between an inorganic salt and water vapor. Requirements for hydration/dehydration reactions and salt hydrates, which are optimal for hydrostats for safe display, conservation and transportation of various works of art, ancient manuscripts, books, archival documents, etc., have been formulated. New materials for maintaining the relative humidity between 40 and 70% have been synthesized and studied. Tests on a novel material (the so-called ARTIC-1) for maintaining the relative humidity between 50 and 60% at the Museum of the History and Culture of Siberian Nations (Novosibirsk, Russia) and the State Scientific Library of the Siberian branch of the Russian Academy of Sciences showed its feasibility for the efficient smoothing of daily and seasonal variations of the relative humidity. These trials confirmed that ARTIC-1 is an effective adsorbent for use in sufficiently airtight showcases and containers.