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Volume 22 (1991 - 199･･･
- Issue 3 Pages 145-
- Issue 2 Pages 69-
- Issue 1 Pages 5-
Volume 22, Issue 1
Displaying 1-5 of 5 articles from this issue
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Yukoh OGURA, Nobuaki FUJISHIGE, Ryuji ARAI, Torayoshi KAWAMATA1991 Volume 22 Issue 1 Pages 5-8
Published: July 26, 1991
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThis research was undertaken to investigate how some improvement of internal side curtain films and the well-water spraying system in a twin-span greenhouse affects the thermal insulation characteristics during the coldest season.
The twin-span greenhouse was covered with PVC, and had an internal movable roof curtain with the well-water spraying system of 4m-interval nozzles, two movable curtains, and a single fixed side curtain. The overall heat transfer coefficient of this greenhouse was calculated at 1.81W·m-2·°C-1.
In the above-mentioned greenhouse, the overall heat transfer coefficient changed into 1.36W·m-2·°C-1, when the internal side curtain with a single-layered film was replaced with the one with double-layered film.
When the well-water spraying system was changed by replacing the hard plastic pipe with 4m-interval nozzles with the plastic film tube with 3cm-interval pores, and was applied to the first greenhouse, the overall heat transfer coefficient became 1.77W·m-2·°C-1.
When this system was applied to the side curtain as well as to the internal movable curtain, the overall heat transfer coefficient was calculated at 1.25W·m-2·°C-1.View full abstractDownload PDF (452K) -
Modeling and Mathematical AnalysisC. M. LIAO, T. S. WANG, C. M. LIU1991 Volume 22 Issue 1 Pages 9-16
Published: July 26, 1991
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSMathematical analysis of a model for describing the dynamic behavior of carbon dioxide concentration at any location within a slot-ventilated airspace is presented from the standpoint of a lumped-parameter approximation. The system equation can be represented by a first-order time-invariant vector-matrix differential equation. The key point of the model structure is the system state matrix [A] contains the essential dynamic characters of the system. The inverse transport matrix [Q]-1 is the product of the inverse local airflow matrix and the transition probability matrix. This product can be used to evaluate the local transport phenomena of carbon dioxide concentration. From the physical and mathematical properties of the model, the overall mixing factor of the ventilation system can be estimated. An analysis of the stability properties of the system equation is presented.View full abstractDownload PDF (933K) -
Model VerificationC. M. LIAO, T. S. WANG, C. M. LIU1991 Volume 22 Issue 1 Pages 17-24
Published: July 26, 1991
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThis paper describes a laboratory project to assess the accuracy of a lumped-parameter model used in predicting carbon dioxide concentrations in a slot-ventilated airspace. The carbon dioxide concentration was characterized in an environmental chamber by measuring its equilibrium concentrations over a range of ventilation rates. The transient behavior response of carbon dioxide concentrations was evaluated at three points and monitored as a function of ventilation rate. The model calculation solved as a three-dimensional lumped form of control volumes representing conservation of airflow rate. The results show that measured carbon dioxide concentrations are compared very favorably with those predicted by a lumped-parameter model (deviations were 8%-14%). The results also suggest that the range of ventilation rate when this model can be suitably applied is between 1000m3/h and 370m3/h.View full abstractDownload PDF (898K) -
For BarleySatoshi MURATA, Toshio KAWANO, Yoshiaki HORI, Kiyoshi MIYAUCHI, Masahi ...1991 Volume 22 Issue 1 Pages 25-31
Published: July 26, 1991
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThe mix storage pilot plant with three storage tanks, a grain mixer and some conveyers was trial constructed and some tests were carried out to assure the practical use of the mix storage method and natural air drying in storage tank.
The method means that high moisture cereal grains mix to dried grains and storage for a week or shorter period in order to deal with excess intensive reception of harvested grains to the drying facilities.
The tests for barley were continued for a week and the results were as follows:
1) The moisture of the grains were converged rapidly to mean moisture content as predicted our diffusion theory.
2) The values of quality factors, the viability by TTC, fatty acid, gas composition in the air among the grains by gas chromatography and dry matter loss were in the safety degree.
3) The natural air drying test showed satisfactory results though very low air flow rate.View full abstractDownload PDF (2659K) -
Kazuhiko ABE, Makoto NARA1991 Volume 22 Issue 1 Pages 35-39
Published: July 26, 1991
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSBased on the thermal characteristics of the solar greenhouse which have been previously reported (Vol. 20, No. 2, pp. 177-184, 195-201, 1989), various equations have been developed. Using these equations, the various effects (degrees of contribution by each function, supplementing relationships between each function, etc.) related to the functions (heat collection, heat storage, incidence, heat preservation and other functions) of the solar greenhouse have been clarified. In addition, the method of space required for heat collection based on the foregoing have been indicated.View full abstractDownload PDF (455K)
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