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Volume 7 (1990)
- Issue 3 Pages 201-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 7, Issue 3
Displaying 1-8 of 8 articles from this issue
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Masataka MOCHIZUKI1990 Volume 7 Issue 3 Pages 201-211
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSRecently, there has been put into practical use of heat pipes as space application, electronics cooling, and waste heat recovery. Especially, the low temperature heat pipe which can be used in below atmospheric temperature are also actively developed and applied in terrestrial field. These are based on utilization of natural energy in cold region. This paper is described about application of snow melting and deicing system on a road and roof, snow damage prevention system for electric pole branch wire, artificial permafrost storage system as a reverse utilization of cold atmosphere, and cryo-anchor applied in Alaska and northern Canada.View full abstractDownload PDF (714K) -
Akio SAITO, Seiji OKAWA, Shinji KOGANEZAWA1990 Volume 7 Issue 3 Pages 213-224
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSIn relation to the supercooling problem of ice storage devices, experiments on freezing a relatively large volume of supercooled water was carried out. Existence of non-uniform temperature distribution is usually a problem in a case of heating or cooling a large size of material. However, supercooled water has a phenomenon that once ice appears on one spot in supercooled water, the whole supercooled region attached to it freeze rapidly. By making use of it, an experimental method to determine a probability of freezing a large volume of supercooled water with a uniform temperature distribution was introduced. It was accomplished by dividing the water into many smaller droplets. In the statistical analysis, a method to improve an accuracy in a case of having a limited number of experiments was introduced and the probability of freezing was calculated for each degree of supercooling. The average freezing temperature for this experiment was placed just at the extended region of the other researchers results worked on small droplets.
By relating the value with the probability of freezing on various kinds of heat transfer surfaces, which was shown in our former report, the probability of freezing which was independent of the surface was calculated. It was confirmed to be negligible compared with the one on the surface.View full abstractDownload PDF (513K) -
Yuji YOSHIDA, Kazuo NAKATANI, Koji ARITA, Mitsuhiro IKOMA1990 Volume 7 Issue 3 Pages 225-234
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSFour kinds of nonazeotropic mixtures R22/R134a, R22/R142b, R22/R152a and R22/R123, which contain some new halocarbons which are considered to be the alternatives for CFCs, were evaluated in order to realize higher condensing temperature than that using R22 at high temperature operation, and larger heating capacity than that using R22/R114 at normal temperature operation. Isothermal vapor-liquid equilibrium for some of these mixtures was measured by the static method. Selected mixtures were applied to a newly-developed composition changeable rectifying circuit in which the higher-boiling-point refrigerant was separated and stored. As a result, the composition changeable high-temperature heat pump indicated the most effective characteristics when using R22/R142b as the refrigerant.View full abstractDownload PDF (441K) -
Akira SASAKI, Shinya AIBA, Kozaburo NEGISHI1990 Volume 7 Issue 3 Pages 235-242
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSAn experimental study was performed to investigate the freezing characteristics of porous media wetted by water. For the experimental sample a sand was used, whose mean grain size was 208μm and specific weight 2.57. The experiments were carried out at the volumetric water content 0.10 and 0.25. The porosity was varied from 0.46 to 0.55and the cooling rates were -2 °C/h and -13°C/h. Freezing temperature of suppercooled water and thermal energy released from the wetted and unsaturated porous media were measured in the experiment. The effects of the porosity, the water content and the cooling rate for the degree of the supercooling and the released heat flux were clarified in the present study.View full abstractDownload PDF (336K) -
Masato FUKUSHIMA, Naohiro WATANABE, Toru KAMIMURA1990 Volume 7 Issue 3 Pages 243-256
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe vapor pressure and PVT properties in a superheated vapor and compressed liquid phase region of two environmentally acceptable hydrogen-containing halocarbons (HCFC123 and HFC134a) were determined experimentally. The measurements of vapor pressure and PVT properties were made using constant-volume method. Sixty-five vapor pressure points were obtained in the range of temperature of 314 K to critical temperature for HCFC123, and forty-one vapor pressure points were obtained in the range of temperature of 262K to critical temperature for HFC134a. Fifty-nine PVT data points were obtained in the range of temperature 352K to 484K, of pressure 0.5 to 5.2MPa and of density 29 to 1030 kg/m3. And sixty-three PVT data points, were obtained in the range of temperature 294K to 424K, of pressure 0.6 to 5.7MPa and of density 24 to 1101kg/m3. On the basis of these results, the critical pressure was determined to be 3.672MPa for HCFC123, and it was determined to be 4.055MPa for HFC134a. In addition, the equation of state and vapor pressure correlation were developed.View full abstractDownload PDF (674K) -
Isamu FUKUHARA, Katsuhiko TSUJI1990 Volume 7 Issue 3 Pages 257-264
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSCo-generation systems have many practical applications for energy-saving, utilization of various energy resources and energy recovery of waste gas. However, it is pointed out that heat exchangers of co-generation system involve some problems which are corrosion of heat surface, decrease of heat transfer rate due to accumulation of soot and NOx in waste gas.
Then. the heat exchange which contacts waste gas with liquid are studied to solve the above problems. The contacting state of gas and liquid has not been researched on the direct contact heat exchanger of gas and liquid. For it is considered that the contacting state has direct effects on a thermal efficiency and gas absorption. Then, we try to investigate the contacting state of gas and liquid by experiments of heating and image processing on the direct contact heat exchanger.
From the results, the contacting state of gas and liquid can be evaluate by a gas-liquid contacting area.View full abstractDownload PDF (438K) -
2nd Rep : Dynamic Thermal Performance and Its EvaluationNobuya NISHIMURA, Tomohiro NOMURA, Akihiro YABUSHITA, Takao KASHIWAGI1990 Volume 7 Issue 3 Pages 265-274
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSA computer simulation has been developed on transient drying process in order to predict the dynamic thermal performance of a new superheated steam drying system using an absorption type temperature amplifier as a steam superheater. A feature of this drying system is that one can reuse the exhausted superheated stream conventionally discharged from the dryer as a driving heat source for the generator in this heat pump. But in the transient drying process, the evaporation of moisture sharply decreases. Accordingly, it is hardly expected to reuse an exhausted superheated steam as heating source for the generator. 80 the effects of this exhausted superheated steam and of changes in hot water and the cooling water temperatures were mainly investigated checking whether this drying system can be driven directly by the low level energy of sun or waste heat. Furthermore, the system performances of this drying system were evaluated on a qualitative-basis by using the exergy efficiency. The results show that, under the transient drying conditions, the temperature boost of superheated steam is possible at a high temperature and thus the absorption type temperature amplifier can be an effective steam superheater system.View full abstractDownload PDF (561K) -
Eiji HIHARA, Isamu FUJITA, Takamoto SAITO1990 Volume 7 Issue 3 Pages 275-280
Published: 1990
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSA method for measuring liquid. surface temperature by a infrared radiation thermometer is described. When the temperature is measured through a glass plate, following corrections are required: (1) transmissivity of the glass plate, (2) Thermal radiation from the glass plate, and (3) thermal radiation from the room walls which reflects at the glass plate. In this study, a correction method of the above effects is presented, and is confirmed by the experiment. The surface temperature of water was measured through a BaF2 plate in the range of 40∼90°C. The accuracy of the measurements was within ±0.5°C.View full abstractDownload PDF (255K)
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