Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers
Online ISSN : 2185-789X
Print ISSN : 1344-4905
ISSN-L : 1344-4905
Volume 5, Issue 2
Displaying 1-15 of 15 articles from this issue
Review Article
  • Hitoshi OBATA
    1988 Volume 5 Issue 2 Pages 143-152
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Since the discovery of ice-nucleating bacteria in 1974 by Maki et al., a large number of studies on the biological characteristics, ice-nucleating substance, ice nucleation gene and frost damage etc. of the bacteria have been carried out. Ice-nucleating bacteria can cause the freezing of water at relatively warm temperature (-2.3°C). Tween 20 was good substrates for ice-nucleating activity of Pseudomonas fluorescens KUIN-1. Major fatty acids of Isolate (Pseudomonas fluorescens) W-11 grown at 30°C were palmitic, cis-9-hexadecenoic and cis-11-octadecenoic which amounted to 90% of the total fatty acids. Sequence analysis shows that an ice nucleation gene from Pseudomonas fluorescens is related to the gene of Pseudomonas syringae.
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Paper
  • Experimental Investigation of Heat Transfer in an Evaporator and Condenser
    Hideaki IMURA, Yuji SAITO
    1988 Volume 5 Issue 2 Pages 153-162
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    A two-phase closed-loop thermosyphon is a device which transports heat energy from a heat source to a sink under the body force field and has many practical applications. The critical heat flux of this thermosyphon is larger than that of a non-loop thermosyphon, because the flooding phenomenon occurring in the no-loop one does not occur. In addition, there is another merit that the evaporator and the condencer can be installed in comparatively arbitrary position because these are interconnected by piping. In most previous investigations of the two-phase closed-loop thermosyphons, overall heat resistances were measured. The overall heat resistance, however, consists of three heat resistances; the heat resistances in the evaporator and the condenser, and the transport resistance in the interconnecting pipe. Therefore, we should consider these heat resistances separately. In the present study, we took note of the heat resistances (or heat transfer coefficients) of the evaporator and the condenser. The experiment was performed using two experimental setups and three kinds of test liquid. And, the effects of rotation angle, heat flux, inside temperature (or inside pressure) and liquid charge on the heat transfer coefficients were investigated.
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  • Yutaka OGAWA
    1988 Volume 5 Issue 2 Pages 163-174
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    The present experiments were carried out on freezing of ham/sausage to measure the internal pressure which causes gape and heave of frozen body during the CaCl2 or ethanol brine immersion/spray freezing and to forestall these undue defects of frozen foodstuffs by the internal pressure. Both of the temperature and the internal pressure of ham/sausage were measured and recorded continuously by a temperature sensor and a pressure sensor during the freezing.
    The results were that frozen body could supported to resist against considerable pressure during the freezing of ham/sausage and that gape of frozen body was created by the internal pressure during the freezing when the dody had been partially injuried or could not be expanded during the freezing. The empirical result that the thick cylindrical body like ham/sausage always caused gape only during freezing was theoretically supported. The internal pressure or stress of frozen bodies was released by a thermal equalizing process during freezing.
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  • Hiromichi UMEMIYA, Hiroshi KOIKE
    1988 Volume 5 Issue 2 Pages 175-182
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    The exhaust gas ejected from engine heat pump contain the injurious materials, SOx, NOx and dust. And it also has a good deal of thermal energy, so thermal recovery from the exhaust gas increases the total C.O.P. of the heat pump system. The experimental study for the purpose of the purification of the exhaust gas and the thermal recovery from exhaust gas has been conducted with the wet-type electrostatic precipitator, which has the advantage of high collection efficiency and the gas-liquid direct heat-exchanism. The experimental results showed that:
    1. For the dust, the collection efficiency of 96 % was achieved, when applied voltage was 19,000V.
    2. The effect of the alkali absorption of Nox and SOx gases was made sure by the experiment.
    3. The fundamental equation which is useful for design method was resolved by kinetic model of charged particle.
    4. In the phenomenon of coagulation the velocity constant was decided with "Chemical Kinetics" and so that the density of coagulant, Ca(OH)2 was decided.
    5. It is shown that mixing coagulant, Ca(OH)2, was a very effective way to remove the dust particles from the waste water.
    6. Thermal energy of 5.3 kW was recovered from exhaust gas, so that total C.O.P. of heat pump system increases from 1.83 to 1.97.
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  • Mathematical Modelling and System Simulation
    Kuan-Hsiung Yang
    1988 Volume 5 Issue 2 Pages 183-188
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    In this paper, the mathematical modelling and simulation of a desiccant added air-conditioning hybrid system is studied.
    The system is composed of a chemical dehumidifier, often named the silica gel honeycomb machine, to dehumidify the incoming air and then followed by a conventional air-conditioner to lower the temperature so that room environment can be controlled as needed.
    The analysis starts with modelling the chemical dehumidifier with a thermodynamic adiabatic-regeneration process. While output conditions of the dehumidified air are generated and inputed spontaneously to the conventional air-conditioner model, the whole system is simulated.
    Simulation results of the hybrid system indicated huge energy saving potential over the conventional system in an industrial drying applications.
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  • Experimental Investigation and Application
    Kuan-Hsiung Yang
    1988 Volume 5 Issue 2 Pages 189-194
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    During the first phase of study, the mathematical modelling and the performance of the hybrid cooling system using solid desiccants were analyzed numerically. During this phase of study, the experimental investigation was conducted which yielded successful results with 5 % deviation as compared with the operational data of available commerical dehumidifiers.
    Furthmore, a prototype hybrid cooling system was actually constructed in the Refrigeration & Air-Conditioning Lab of National Sun Yat-Sen University (NSYSU), which generated good correlations with 7% deviation only, as compared with the analytical results. In other words, the good correlations obtained among the math modeling, the commercial unit operational data, and the NSYSU prototype system warrant the potential applications of this system for many industrial dehumidification and drying processes.
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  • Masao SHIIBAYASHI, Kenji TOJO, Tetsuya ARATA, Naoshi UCHIKAWA
    1988 Volume 5 Issue 2 Pages 195-206
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    The forces acting on the orbiting scroll under the actual operating conditions have not yet been studied sufficiently, while theoretical analysis about forces acting on the orbiting scroll and fixed scroll wraps have been made. In this study, first the acting forces on the orbiting scroll are calculated from the indicator diagram and compared with the theoretical prediction results where no internal leakage between scroll wraps is assumed. It is found that the magnitude of the force from the indicator diagram agrees with the theoretical one within several percent error, although the crank angle position of the maximum force obtained from the indicator diagram lies several ten degrees behind the theoretical discharge starting position. Second, axial displacement of the orbiting scroll is calculated based on the forces from the indicator diagram, and compared with the measured data. The comparison results are found to be acceptable.
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  • Investigation of an effect of characteristics of Surface and Cooling Rate on a Freezing Temperature of supercooled Water
    Akio SAITO, Yoshio UTAKA, Seiji OKAWA, Kazuyuki MATSUZAWA, Atsushi TAM ...
    1988 Volume 5 Issue 2 Pages 207-218
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Relating to the problem of supercooling for ice storage devices, basic investigation was carried out by performing numerous experiments and statistical analysis. In the experiment, freezing temperature of supercooled water was measured. It was observed that the property of heat-transfer surface and the cooling rate affect the ice appearance process. The freezing temperature seems to be a statistical phenomenon, and the frequency distribution differs from one kind of surface to the other. The type of surface used for the experiment were copper disks, which were electrolytically polished, buffed, gold-plated, nickel-plated and porous. The results indicate that supercooled water can be frozen at higher temperature on coarser surface than on smoother one and at slower cooling rate than faster one. The probability of getting ice within the unit surface area in unit time interval is introduced as a function of surface temperature and surface property including roughness. Finally, the method to predict the most probable freezing temperature of supercooled water for a given cooling condition and surface property is proposed
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  • 2nd Report : Local Pressure Drop
    Jong-soo KIM, Katsuya NAGATA, Masafumi KATSUTA, Toshikazu SAKUMA, Koui ...
    1988 Volume 5 Issue 2 Pages 219-226
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Experimental measurements of pressure drop have been made for forced convection evaporation of refrigerant(R12)-oil(SUNISO 5GS) mixtures inside a horizontal tube. Parameters were changed in mass velocity range(110-290 kg/(m2·s))and wall heat flux(5-30 kW/m2), oil weight concentration(0-11 %), quality(0.1-1.2).
    In general, at low oil concentration region up to 3%, the average pressure drop was, increased sharply with increasing oil concentration, and beyond 3% increment rate of pressure drop was gradually decreased. Average pressure drop at 10% was almost twice as this of oil free case.
    The experimental data were compared with the various existing frictional pressure drop expressions.
    Gronnerud's correlation and Chisholm's correlation presenting the best representations for oil free data were modified to ensure the more accurate prediction and to extend the application for oil mixture case.
    The local pressure drop was predicted within ±30% by modified correlations.
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  • Yukinori NOZAKI, Koichi FUKUDA, Shigeaki YADA, Yasuaki TAKAKI, Hisao K ...
    1988 Volume 5 Issue 2 Pages 227-234
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Redwing gurnard was stored at a low temperature, and studied for its characteristics as the raw material of fish jelly products. The following results were obtained.
    Gel-forming ability of the fish decreased rapidly to about 50% of original value after 5 days of iced storage. The allowable iced storage period of the fish as the material for fish jelly products was about one week.
    Gel-forming abilities of the fish by three kinds of storage conditions were arrenged in the following order: quick freezing, storage at -50°C> slow freezing, storage at -50°C> quick freezing, storage at -25°C> slow freezing, storage at -25°C. The allowable storage periods of the fish as the raw material for fish jelly products were about 5, 4 , 4 , and 1 month, respectively, in above order.
    The gel-forming ability correlated significantly with total myofibrillar Ca-ATPase activity and the solubility of myofibrils both in iced and frozen stored fish.
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  • Masashi OKADA, Susumu NAKAMURA
    1988 Volume 5 Issue 2 Pages 235-246
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Water in a vertical annulus is frozen from the inner cylinder wall. The outer cylinder wall is insulated. The water is initially kept at a uniform temperature. Experiments and numerical analysis of this freezing process were carried out under the various temperature conditions. In the experiments, the water was 150 mm high and the diameters of the inner and outer cylinders were 20 mm and 100 mm, respectively. In the present analysis, a boundary fixing method was used and the two-dimensional unsteady natural convection in the liquid phase with density inversion was calculated. The analytical results of the time-wise changes of the freezing front and the temperature distribution agreed well with the experimental results. The effects of the density inversion on the temperature distribution in the liquid phase were shown clearly by the analytical results. Furthermore a one-dimensional approximate analysis was carried out, where the appropriate heat-transfer coefficient on the freezing front was given. It was shown that the approximate analysis as well as the present analysis was able to obtain the time-wise changes of the frozen volume and the total thermal energy storage.
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  • Masatoshi NAKAMURA, Yasuyuki IKEGAMI, Haruo UEHARA
    1988 Volume 5 Issue 2 Pages 247-254
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    The purpose of ocean thermal energy conversion (OTEC) is to extract power from temperature differences existing in the oceans. The OTEC system design mainly comprises an OTEC plant design and an OTEC control design. The main purpose of this paper is to demonstrate the importance of a computer simulator for the OTEC system design. The computer simulator, constructed by a computer with A/D and D/A converters, produces analogue input and output signals which are equivalent to those of an actual OTEC plant. By using the computer simulator of an OTEC plant, we can estimate properties of any OTEC plant easily, economically and safely. The computer simulator also plays an important role in detecting difficulties in designing the OTEC controller. We furthermore described the procedure for designing the OTEC controller as follows: (i) statement of the control objective, (ii) modeling of the controlled object, (iii) application of control theory to the model, (iv) characterization of the detector and the input signal part, and (v) construction of the controller. We constructed the computer simulator and the controller for pump flow rate as part of the OTEC plant. We then obtained satisfactory control performance for flow rate control of experiments.
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  • Hiroshi HONDA, Shigeru NOZU, Youichi MATSUOKA, Tohru AOYAMA, Haruo NAK ...
    1988 Volume 5 Issue 2 Pages 255-266
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    Experiments were performed to study the flow characteristics and heat transfer during condensation of R11 and R113 in horizontal annuli with an enhanced inner tube. The inner tube was a 19.1 mm o.d. corrugated tube with soldered wire fins on the outer surface. The outer tubes were 24.8, 27.2 and 29.9mm i.d. smooth tubes. The mass velocity of the test fluids ranged from 50 to 300 kg/m2s, and the condensation temperature difference from 0.7 to 20 K. The frictional pressure gradient was correlated fairly well by using the Lockhart and Martinelli parameters. The local heat transfer coefficient was 2 to 18 times as large as those for horizontal annuli with smooth and corrugated inner tubes. An empirical equation for the local heat transfer coefficient was developed, where the dimensionless parameters based on the surface tension drained flow and the vapor shear drained flow models were introduced for the low and high vapor velocity regimes, respectively.
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  • Masashi OKADA
    1988 Volume 5 Issue 2 Pages 267-274
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    In the present paper, a plate-fin heat exchanger with a phase change material (PCM) was studied. The heat exchanger was a singlepass cross-flow type, where both fluids (air) were unmixed. N-octadecane, of which the fusion temperature is 28.0°C, was used as the PCM. Three kinds of experiments were carried out and the inlet and outlet temperatures and the temperatures in the PCM were measured. In the first experiments, the effectiveness and the overall heat-transfer coefficient were obtained at steady states. By the calculations of steady three-dimensional heat conduction, the effects of the parameters, ---, dimensions, thermal properties, and heat transfer coefficients of air ---, on the overall heat-transfer coefficients were obtaiend clearly. In the second experiments, after the higher-temperature air-flow was stopped, the outlet temperatures of the lower-temperature air were maintained at the constant temperatures for 90-150 minutes. In the third experiments, the higher temperature air was flowed intermittently with an equal interval. The fluctuation of the outlet temperature of the lower-temperature air was within ±2.5°C. The above transient and periodical experiments showed that the present heat exchanger with PCM had useful characters of latent heat storage.
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  • Yu SESHIMO
    1988 Volume 5 Issue 2 Pages 275-284
    Published: 1988
    Released on J-STAGE: October 11, 2011
    JOURNAL FREE ACCESS
    This paper presents a method for the determination of effectiveness on plate-fin and tube heat exchangers as a function of the parameters, viz. the thermal capacity ratio, the number of transfer unit and the flow arrangement. The analytical model of the heat exchanger which is adopted that of a multi-pass crossflow heat exchanger with one fluid mixed and another unmixed. For three kinds of flow arrangements of plate-fin and tube heat exchangers, equations on the effectiveness were obtained and the experimental verification of these equations was also performed.
    In addition, this paper is concerned with method which obtains the fin efficiency of the plate-fin and tube heat exchangers. It is usual practice to evaluate the fin efficiency by assuming that the uniform heat transfer and other suppositions. In this paper, a more realistic determination of fin efficiency is reported, which take into account the heat transfer distribution over the fin surface. It was confirmed that the results of fin efficiency by usual manner were almost equal to that of the realistic estimation in this study.
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