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Abstract: This two-part study proposes a dynamic model for the orbiting scroll based on the pressures in scroll chambers. Part II investigates scroll compressors by using the dynamic model developed in this work to predicate the dynamic characteristics of the scroll compressors and the dynamic model is validated by comparing the predicted results with the experimental results of the powers of two air scroll compressors. This study utilizes two air scroll compressors and ten virtual scroll compressors to investigate the pressure distribution on the wrap surfaces of orbiting scrolls, the component forces and moments of orbiting scrolls, the overturning moment of the scroll mechanism, and the theoretical driving power of scroll compressors. The effects of scroll type (such as modified-wrap scroll, truncated-wrap scroll, single-wrap scroll, multi-wrap scroll, odd-wrap scroll, and even-wrap scroll) on the dynamic performance of the scroll compressor based on the pressures in scroll chambers are also analyzed. [Copyright &y& Elsevier]

Abstract: Following a widespread trend in international research on R744 cooling applications, the authors have developed a test rig for investigating refrigerating cycles and equipment which operates with such refrigerant. The facility was designed aiming to a compact layout and to a high flexibility in terms of cycles and pieces of equipment to be tested. The test rig can operate stand-alone thanks to a passive load management system which works with water as secondary fluid. The paper gives some useful data, based on direct experience, for the realization and management of a multi-purpose test rig that allows the analysis of several cycle layouts over wide operating ranges. Some of the main critical issues related to proper plant and component design, a correct choice of the measurement equipment and a suitable system management are shown and discussed. The paper also includes experimental data obtained while testing a reciprocating compressor and a single-stage cycle layout both with and without using an internal heat exchanger. [Copyright &y& Elsevier]

Abstract: A combined double-way thermochemical sorption refrigeration thermodynamic cycle was proposed and tested. Both adsorption refrigeration and resorption refrigeration processes were combined in order to improve the system performance. Two different consolidated composite materials were used as the reactive sorbents and ammonia was used as the refrigerant. Experimental results showed that a system operating with such proposed cycle can have two useful cold productions during one cycle at the expense of only one heat input at high temperature. The average specific cooling power (SCP) during the adsorption refrigeration phase was 301Wkg−1. Analysis of the experimental data showed that the driving equilibrium drop during the resorption process was much lower than that during the adsorption process, when the cold production temperature was similar. The proposed combined double-way sorption cycle has a larger cooling capacity per unit of heat input and the maximum theoretical coefficient of performance (COP) is 1.24 when MnCl2 and BaCl2 are used as the reactive sorbents. [Copyright &y& Elsevier]

Abstract: The aim of this study was to assess the impact of mist-chilling on high-grade strawberry post-harvest quality (Cultivars “Gariguette” and “Mara des Bois”). Strawberries were chilled at 2°C using three processes: air blast chilling at 0.3ms−1 or 1ms−1 and mist-chilling at 1ms−1. After chilling, fruits were submitted to different distribution chains characterised by different handling conditions and storage temperatures (2°C or 7°C) and by a 12h retailing step at 20°C. Strawberry quality was assessed by measuring 7 parameters: weight loss, commercial loss, firmness, sugar content, acidity, colour and sensory quality. Compared to air-chilling, mist-chilling did not reduce chilling time but it reduced weight loss by 20–40%. Mist-chilling had no detrimental effect on commercial loss defined as the percentage of fruit more than 1/3 of surface affected. It did not induce any major changes on strawberry quality. Temperature fluctuations undergone during cold storage and retailing had a detrimental effect on weight loss. The beneficial effect of packaging on weight loss was confirmed. [Copyright &y& Elsevier]

Heat transformation with sorption systems has received increased attention in recent years. In this review it is intended to discuss current trends as well as forthcoming applications with the respective appropriate technology as it is deduced from activities in the field. Especially, we report about the papers and discussions of the International Sorption Heat Pump Conference (ISHPC''99) which was held in March 1999 in Munich, Germany. The review is grouped into a fundamentals part, a part about thermodynamic cycles, and an applications part. In the fundamentals part the discussion about working pairs and heat and mass transfer is reflected. Thermodynamic cycles which are being discussed are special solid sorption cycles, cycles fit for low-temperature driving heat, compression-sorption hybrids, and open cycles. In the applications part the classical cooling business is the main issue. The review comprises chillers and refrigerators which may be direct fired or waste heat driven. Interest is given to the improvement of efficiency on the one hand as well as to adaptation to low temperature waste heat use on the other hand — two very different developments. The use of solar energy as a heat source belongs to that area also. An additional important role — for decades — is played by automotive application. The area of heat pumping for heating purposes is less prominent but not negligible. Systems with a large capacity are being installed every once in a while, but the small scale domestic market still is not really covered with appropriate technology. Finally, industrial heat pumping involves the reverse cycle (heat transformer) also. Activity in this field is rather small. In summary, no unexpected developments can be reported on, but progress is steady and the market increases continuously, especially in the far east. [Copyright &y& Elsevier]