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Volume 4 (1987)
- Issue 3 Pages 163-
- Issue 2 Pages 71-
- Issue 1 Pages 1-
Volume 4, Issue 1
Displaying 1-7 of 7 articles from this issue
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Kimitoshi RYOKAI, Masami FUKUDA1987 Volume 4 Issue 1 Pages 1-10
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSIn the cold regions like Hokkaido and Tohoku Districts, they have been advocating snow-overcoming, advantages of snow and effective utilization of cold climate. In fact, they have been positively trying to make use of snow and coldness as water resources, energy sources, structural materials and so on.
One of energy utilization is for low temperature storage of foods. Since the potatoes have properties of adapting themselves to cold temperature when they are stored under cold environment, they have the tendency of growing in their sugar contents. As the results, all those foods which are stored under these cold environments will be the products of higher additional value.
Here we will introduce the present situation of low temperature storage of foods by artificial permafrost, not only as the construction materials for cold storage house itself but also utilizing its own cold temperature.View full abstractDownload PDF (502K) -
Seizo FUJIKAWA1987 Volume 4 Issue 1 Pages 11-26
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe mechanisms of freezing injury in living cells were reviewed. The freezing injury takes place by at least two different factors depending upon cooling rate, those are intracellular freezing and extracellular freezing. The freezing injury caused by extracellular freezing also takes place by two different factors, those are direct and indirect effects by the formation of extracellular ice. These different stresses by freezing cause different damages on the plasma membranes in the same cell. Furthermore, freezing of different cell results in different form of membrane damage. Thus, the occurrence of freezing injury takes place by diverse mechanisms depending upon not only different freezing stresses but also difference of cell type.View full abstractDownload PDF (1085K) -
Tetsu FUJII, Shigeru KOYAMA, Akio MIYARA1987 Volume 4 Issue 1 Pages 27-34
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe present paper treats a possibility of performance improvement and its evaluation method for a heat pump cycle of non-azeotropic refrigerant mixtures. Calculation is made for R22 + R114 and R22 + R11 mixtures under the conditions that the inlet temperature and flow rates of heat source fluids through a condenser and an evaporator of counter flow type, heat pump thermal output and FK-value (heat transfer area times average overall heat transfer coefficient) are given. It is graphically shown that the coefficient of performance (COP)h, pressures and volumetric flow rates at suction and discharge ports of a compressor depend on the FK-value and on the flow rate of heat source fluid as well as mixture composition. The characteristics of the heat pump cycle thus obtained are markedly different from those, in which the state points of the refrigerant mixture are fixed.View full abstractDownload PDF (406K) -
Akio SAITO, Nobuyuki MIYAZAWA1987 Volume 4 Issue 1 Pages 35-44
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSEffects on the heat transfer characteristics of a vacuum type solar collector system by connecting piping sections were discussed experimentally and analytically. Experiments were carried out under various solar radiation intensities, water flow rates, inlet water temperatures, periods of the solar intensity fluctuations and the insulating specifications for the piping section. Simulations were also performed by the finite difference calculations which were proved to agree well with the experimental results. As the results, it was found that the slight water temperature decrease at the entrance of the collector, by connecting the piping section, did not affect the collector efficiency seriously, although the whole collector plate temperature was lowered. It was also found that the heat loss from the collector plate to the pipe was negligible, if the piping section was insulated properly, and the effects appeared only in the limited edge sections of the collector plate, lowering the plate temperature.View full abstractDownload PDF (396K) -
Yukio OHASHI, Kenichi HASHIZUME1987 Volume 4 Issue 1 Pages 45-54
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSExperimental studies on heat transfer augmentation in water-flowing shell sides of counter flow multitube exchangers are presented. Various kinds of augmented tube bundles have been examined to obtain the characteristics of pressure drop and heat transfer. Data for a smooth tube bundle were a little different from those for the tube side. The pressure drop in the shell side depended on Re-0.4 and deviated from the tube side pressure drop to within +30%, while the shell side heat transfer coefficient depended on Re0.8 but about 35%. larger than that of the tube side. Furthermore the augmented tube bundles have been evaluated and compared using 21 evaluation criteria. Enhanced tube bundles, low-finned tube bundles and those with twisted tapes inserted had especially good performances. The ratios of increase in heat transfer were larger than those in pressure drop. In case of low-finned tube bundles, there seem to exist an optimum fin-pitch and an optimum relation between the fin-pitch and the pitch of twisted tapes inserted.View full abstractDownload PDF (434K) -
Norimitsu ABE, Kenichi HASHIZUME1987 Volume 4 Issue 1 Pages 55-62
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSAn experimental investigation was performed to obtain local heat transfer coefficients of evaporating two-phase flow in horizontal tube bundles. Each test bundle consisted of 7 tubes, and tested tubes were 9 kinds of smooth and enhanced tubes. Refrigerant R113 was used as a test fluid. Flow pattern observation and a pool boiling experiment were also conducted. Obtained results were summarized as follows: 1) Corresponding flow patterns to in-tube flow were observed, but the boundaries on a flow pattern map were considerably different from those of in-tube flow. 2) Degradation in heat transfer coefficient with increasing vapor quality was observed also in a small vapor quality region, this could be explained by the flow pattern transition from stratified to wavy flow. 3) Heat transfer coefficient became smaller with increasing heat flux, excluding the nucleate boiling dominant region. 4) The vapor quality showing the maximum heat transfer coefficient at a constant mass flux was about 0.5 for all tested bundles. 5) The enhanced evaporation tube bunble showed the maximum local heat transfer coefficient throughout the experiment, however, the enhanced condenser tube bundle surpassed it in some specifc conditions of heat and mass fluxes.View full abstractDownload PDF (398K) -
Tomohiro NOMURA, Yuji MURAKAMI, Motoyuki UCHIKAWA1987 Volume 4 Issue 1 Pages 63-69
Published: 1987
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe time variation of temperature in the reinforced concrete frame with an internal insulation or with an external insulation and the unsteady stored heat behavior, which results from the thermal mass of the concrete frame, have been investigated. The experiments with the concrete models and the measurements of the heat flux through the practical cold storage were performed. The experimental results under the unsteady condition showed great difference of the stored heat behavior between the internal insulation type and the external type. In addition, it was shown that the external insulation frame was useful for heat storage. The simulation method with two dimentional unsteady FEM was introduced for easily analyzing the stored heat behavior problems of the practical cold storages, which had various specifications in design. The calculated results of the heat flux and temperature in the concrete frame agreed with the experiments approximately. From these results, the suggestions for the design of the insulation wall under the unsteady condition were given.View full abstractDownload PDF (395K)
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