A novel thermodynamic model has been proposed so as to calculate the thermodynamic properties at the vapor-liquid coexistence of HFC (hydrofluorocarbon) refrigerants and their binary mixtures. This model has been developed by modifying the Patel-Teja equation, well-known cubic equation of state, for HFC refrigerants, R- 32, R-125, R-134a, and their binary mixtures for temperatures from 220 K to their critical temperatures. The developed model has features in calculating various thermodynamic properties with ease but accurately.
The calculated results on the vapor-liquid equilibrium (VLE) properties by the present model illustrate its superiority to the conventional cubic equations of state. A comparison of the proposed model with the so-called modified Benedict-Webb-Rubin (MBWR) model and the multi-term Helmholtz function model confirms equivalent effectiveness and accuracy by the present model and, therefore, it would be concluded that the proposed model is very powerful in various practical application in refrigeration industry.

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In conventional natural gas combustion power plants, vaporization heat of liquefied natural gas(LNG) has been supplied from sea water and/or air. In the plants, cold and liquefaction energy have been lost without any effective utilization. An advanced technology in which carbon dioxide in the flue gas is solidified and separated as dry-ice has been developed. Carbon dioxide in the flue gas from a LNG combined cycle is cooled and solidified by the evaporation of LNG.
Fundamental studies using a cooling box were carried out to measure the solidification rate of carbon dioxide in the flue gas on a cooling plate. The solidified particles had a rectangular prism-shaped non-crystallographic structure.

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From the point of view of utilization of shells as a waste product of fishery industry, the cryoprotective effect of chitin made from shell of crustaceans (Japanese fan lobster and Japanese swimming crab) and cartilage of cephalopods (spear squid) are studied. Chitin from the shells and cartilage were added to lizard fish myofibrils, and the changes of unfrozen water in myofibrils and ATPase activity of myofibrillar protein were observed during frozen storage at -250°C for 120days.
The amount of unfrozen water were increased by addition of three kinds of chitin, and decreased moderately during forzen storage. Whereas, in the chitin free sample, the amount of unfrozen water were decreased rapidly during frozen storage. Changes of ATPase activity of samples showed similar tendency to that of the amount of unfrozen water.
The present moderate cryoprotective effect of chitin and data of unfrozen water and ATPase activity of myofibrillar protein suggest the importance of the amount of unfrozen water in frozen matrix.

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The objectives of this paper are to develop an advanced GAX cycle (WGAX) to reduce the generator exit temperature as low as possible using waste heat sources, and to compare it with the standard GAX cycle (SGAX). This paper performed parametric analysis to study the effects of the waste heat source temperature(Tw=135°~200°C) and the outlet temperature(Tg =170°C ~200°C) of the gas fired desorber (GFD) on the cycle performance. Two different WGAX cycles, Type A and Type B were introduced, and compared from the viewpoint of cycle performance. It was found that the effect of the waste heat source temperature on COPs was negligible for a given GFD outlet temperature. The GFD outlet temperature could be reduced down to 170°C with a higher COP of WGAX cycle than that of SGAX. The corrosion problem which may occur at high temperature in GFD of the SGAX cycle would be solved by adopting the WGAX cycles with a comparable COP. In the WGAX cycle, Type A has a merit from the viewpoint of larger absorber/generator (GAX) heat exchange while Type B has a merit from the viewpoint of smaller exergy loss. In the current cycle modeling, the effect of the GAX heat exchange was dominant for a lower temperature than 181°C while the effect of the exergy loss was dominant for a higher temperature than 181°C. It is strongly recommended that there should be a subcooling effect to improve the cycle COP in the WGAX systems.

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A numerical analysis on simultaneous heat and mass transfer for ammonia-water air-conditioning with a vertical falling-film type of absorber and generator was performed by the one-dimensional difference method which takes into account only the change of flow direction. In the calculation, the geometries of absorber/generator and the temperature conditions were taken like as those in our previous works for water-lithium bromide system. Therefore, the liquid and vapor concentrations ranged 53-55 and 99-l00mass%NH₃, respectively. The ratio of the liquid mass flow rate to the vapor mass flow rate, L/V, ranged up to 18000.
For these thermal conditions, it was found that the vapor-phase mass transfer resistance is negligibly small, and the absorption/generation rates are almost constant regardless of the vapor flow rate, but increase with increasing liquid flow rate. It was also found that the calculated values of heat fluxes in the absorber/generator for ammonia-water system are equivalent or superior to those for water-lithium bromide system.

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The object of this study is to research the possibility of in-line measurement of the thermal diffusivity on composite materials, such as suspension and emulsion, by previously developed apparatus for the dynamic viscosity.
The calibration curve between the thermal diffusivity and any physical quantity that can be measured by this apparatus is proposed by the numerical analysis. The experimental results were obtained by using the dispersed materials composed agargel cooking oil (as matrix) and Ti0₂ particle.
Nondimensional effective thermal diffusivity that is the ratio of the effective thermal diffusivity of dispersed materials to the one of the matrix are compared with previous results obtained by periodic heating method. These data of nondimensional values show good agreement with each other. From these results, this measurement apparatus may be applicable for the thermal diffusivity measurement of dispersed materals.

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An experimental study is carried out for natural-convection heat transfer to air from upward-facing and downward-facing heated circular plates under the condition that the amount of heat dissipating through the side wall of the plates is sufficiently negligible.
For the case of upward-facing plate, it is shown that in laminar flow region, the temperature distributions in air near the plate are similar when the Rayleigh numbers of the experimental runs are equal to each other. A correlation equation is proposed for the average heat transfer coefficient, with the discussion on the applicability of previously proposed equations.
Another heat transfer correlation is proposed for downward-facing plate and compared with previousily proposed experimental and theoretical correlations. Moreover, a profile method is applied to investigate the functional forms of the velocity and temperature profiles in boundary layer.

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Expenmentswere conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134 a on a staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a m ass fraction at the tube bundle inlet were maintained at about 50°C and 14% respectively. The refrigerant mass velocity ranged from 9 to 33 kg/m²s, and the condensation temperature difference from 2 to 12K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for HCFC-123. However, the effect of fin geometry was much smaller for the mixture than for HCFC-123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. On the other hand, the mass transfer coefficient increased with condensation temperature difference. This was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube.

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