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Volume 38, Issue 4
Displaying 1-14 of 14 articles from this issue
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Toyoki KOZAI, Hideo TAKEUCHI, Seiji OKAZAKI, Ichiro WATANABE, Makio HA ...1983 Volume 38 Issue 4 Pages 361-369
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSEnvironmental measurements were made on a solar greenhouse (Floor area 856m2) with inhouse heat storage and heat exchange water tanks for nighttime heating. The greenhouse was installed with double layer movable thermal screen. The heat exchange fans were operated, in principle, when the inside air temperature was above 22-23°C or below 13°C. The oil heater for auxiliary heating was switched on when the inside air temperature was below 11°C. Thermal properties of the greenhouse were analyzed as follows:
1) Average solar energy collection factor, η, was 0.11.
2) Average oil reduction factor, r, was 0.93.
3) The coefficient of performance of the greenhouse system, C.O.P., was 2.4, on average.
C.O.P. of the system was considered to be much improved if the friction loss of spiral air ducts in the heat storage and heat exchange tank (1.2mmAq/m at an air speed of 5m/s) was reduced to that of a normal rigid PVC pipe with a diameter of 90mm (0.4mmAq/m at an air speed of 5m/s).
Average solar energy collection factor could probably be improved as high as 0.15 if the setpoint inside air temperature for ventilation was raised from 23-24°C to 27-28°C, while the setpoints for heat exchange fans were remained the same.
As for the solar greenhouse, the split-night air temperature control was considered to be essential to improve the oil reduction factor. Much more work will be needed for making clear the effects of that on crop growth, as well as on the thermal properties of the greenhouse.View full abstractDownload PDF (1080K) -
1983 Volume 38 Issue 4 Pages 370-370,388
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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(V) Changes of Plant Status by Long-term Exposure to MistKazuyoshi KIMURA, Michiyo ARIYOSHI1983 Volume 38 Issue 4 Pages 371-378
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe effect of long-term exposure to mist on elongation, fresh weight, dry weight and water content of kidney bean grown in growth chamber (20°C, 6, 000lx) was investigated.
1) Water-mist treatment increased the elongation and fresh weight of the primary leaves during the first 24 hours, but the rate of increase decreased from the second day on. The leaves of the misted plants did not grow thicker, although those of the non-misted plants did. Mist treatment increased the dry weight and chlorophyll content of the leaves, but the rates of increase were smaller than those of the non-misted plants.
2) The stem of the misted and non-misted plants elongated almost similarly. Mist treatment greatly increased the fresh weight and water content of the stems, but greatly decreased dry weight.
3) Length, fresh weight and water content of root of the misted and the non-misted plants seemed to be similar, but the roots of the plants misted for 6 days were somewhat longer than those of the non-misted plants. Dry weight of the roots during the first 2 days of mist treatment increased similarly as the control plants, but from the fourth to sixth day of mist treatment it was smaller than that of the non-misted plants.
4) T-R ratios in fresh weight of the misted plants were higher than those of the non-misted plants, but the T-R ratios in dry weight were lower.
5) In general, the elongation, fresh weight and dry weight of the three organs and chlorophyll content of the leaf of the plants exposed to mist for 6 days were smaller than those of the non-misted plants, except for root length and fresh weight of stem.
6) Wetting of only the shoot by the exposure to mist had a similar effect as that when the vermiculite in the pot as well as the shoot was allowed to be wetted by the mist. The use of deionized water had a similar effect. Therefore, the effect of mist is probably caused by wetting of the shoot (mainly, leaf), and not by the high moisture in the rhizosphere or by any substance contained in the tap water.View full abstractDownload PDF (916K) -
(1) Heating SystemMakio HAYASHI, Toyoki KOZAI, Jun NAKAMURA, Ichiro WATANABE1983 Volume 38 Issue 4 Pages 379-387
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA solar heating system of the greenhouse, using a heat pump, was developed and its thermal performances were tested. The whole system consists of a water-to-air heat pump, air-to-water heat exchanger, a heat storage water tank, and a plastic greenhouse with the double layer movable thermal screen (Fig. 1). In this system the surplus solar heat in the greenhouse, when inside air temperature was above 22-25°C, was collected by the air-to-water heat exchanger and was stored in the heat storage water tank. The heat stored was used for heating with the water-to-air heat pump when the inside air temperature was below 11-13°C. Measurements were carried out during the period from January 13 to February 28 in 1982.
Results are as follows:
1) Collection efficiency, defined as in equation (3), of the greenhouse with a clear polyethylene thermal screen open was 0.07 on the average, with a minimum of 0.0 under overcast conditions and a maximum of 0.19 under clear sky conditions. Collection efficiency of the greenhouse with the thermal screen closed was 0.12 on the average, with a minimum of 0.07 and a maximum of 0.17.
2) The heat released from the storage tank accounted for about 45% of the total nighttime heating load.
3) The C.O.P. of the heat pump was increased from 2 to 5 with increasing the water temperature in the storage tank from 5 to 20°C (Fig. 3).
4) The C.O.P. of the system was as low as 1.9 on the average (Table 2). It would be improved as high as 2.5 if the system was operated at a water temperature of around 15°C of the heat storage water tank.View full abstractDownload PDF (1178K) -
(2)The Characteristics of Meteorological Conditions in the year of Cool Summer Damage (1980) at Yufutsu and Ishikari PlainsIkuo HORIGUCHI, Shinji MATSUMURA, Hiroshi TANI1983 Volume 38 Issue 4 Pages 389-394
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe relationships between wind directions and meteorological conditions in Yufutsu and Ishikari plains were reported in the previous paper. Among the four years (1978-1981) that have been analyzed in the former study, the rice yields on Hokkaido were good in 1978 and 1979, but poor in 1980 and 1981. Especially in 1980, it was poor crop caused by the cool summer wind blown from Okhotsk High, and the crop situation index was 81.
The meteorological conditions in 1980 for Yufutsu and Ishikari plains were compared with those in 1978, 1979 and 1981 in this study. The methods of analysis are the same as those in the previous paper; the wind types were defined by wind directions and were classified three airflow patterns using AMeDAS data from May to August.
The monthly frequency of Pacific Ocean airflow for each year and the comparison of main wind types in Pacific Ocean airflow during August were shown in Figs. 1 and 2, and also, the monthly mean temperature and mean time of sunshine for an hour were shown in Table 1.
The following results were summarized;
1) The total occurrence of Pacific Ocean airflow (SSS*) in 1980 was the maximum but the difference among four years was not so large.
2) The occurrence of Pacific Ocean airflow during August of 1980 is less than those of 1979 and 1981, nevertheless the summer damage in 1980 was caused by low temperature of August.
3) The SSSN wind type in Pacific Ocean airflow has the highest frequency in August of 1980, on the other hand, the SSSS wind type is the fewest.
4) The monthly mean temperature and mean time of sunshine for an hour in August of 1980, while Pacific Ocean airflow flew through Yufutsu and Ishikari plains, were the lowest among four years, but in the other months of 1980 they were not.
Items 1) and 2) are different from the results reported for Tohoku Area that the year of cool summer damage has many frequencies of North-East wind, and also different from the present analysis for Tohoku Area shown in Table 2. The reason is that there are many frequency of Pacific Ocean airflow in Yufutsu and Ishikari plains every year because of topographical features, so that the frequency do not increase specially in cool summer year. It is recognized that few sunshine hour by low temperature causes a frequent occurrence of SSSN wind type instead of SSSS wind type.View full abstractDownload PDF (662K) -
K. O. KESSEY, P. G. GLOCKNER1983 Volume 38 Issue 4 Pages 395-402
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA transparent plastic-covered model greenhouse built without vegetation was tested under various operating conditions to determine the relative magnitude of its energy fluxes, namely, hot air heat and solar energy inputs, surface and ground losses as well as its efficiency.
It is established that surface or membrane losses are quite comparable to the energy inputs and even larger than either input under certain operating conditions. The efficiency is found to be generally below 50% and is particularly low at high solar intensities, dropping to a low of 10% under such conditions.
The Reynolds Number and a new Solar Parameter characterizing the mass flow rate of hot air injection and the rate of solar energy transmission into the greenhouse, respectively, are found to have a very significant influence on greenhouse performance. Notably, membrane losses are observed to increase remarkably with either increasing Reynolds Number or rising Solar Parameter.View full abstractDownload PDF (857K) -
K. O. KESSEY, P. G. GLOCKNER1983 Volume 38 Issue 4 Pages 403-408
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA model greenhouse, covered with a transparent plastic material, ‘Fabrene’, was built without vegetation and tested in Calgary, Canada, with the primary objective of determining the effect of environmental temperatures on its performance characteristics.
It is found that when the temperature of the intake hot air (Ji) and the Reynolds Number (RN) for air flow through the intake duct are kept constant, the performance of the greenhouse, characterized by surface membrane heat losses, overall heat transfer coefficient, and efficiency, does not depend a great deal on changes in environmental temperature (Ja) under conditions of zero Solar Parameter (K). This finding is clearly confirmed by the fact that the Supply Air Temperature Drop (Ji-Je) between the inlet and outlet of the greenhouse varied only slightly in spite of the large variations in ambient temperatures under conditions of zero Solar Parameter and constant intake hot air temperature and Reynolds Number.View full abstractDownload PDF (535K) -
Takeharu BOKURA, Hiroshi YAMASHITA1983 Volume 38 Issue 4 Pages 409-414
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Keiichi NAKAYAMA, Juro HANYU, Hisashi KON1983 Volume 38 Issue 4 Pages 415-418
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Masumi Okada1983 Volume 38 Issue 4 Pages 419-421
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Kensei Muramatsu1983 Volume 38 Issue 4 Pages 423-424
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Masatoshi Aoki1983 Volume 38 Issue 4 Pages 425-427
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Commission for Protected Cultivation1983 Volume 38 Issue 4 Pages 429-434
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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Kenji KURATA, Hideo MINAGAWA, Tadashi TAKAKURA1983 Volume 38 Issue 4 Pages 435-440
Published: March 10, 1983
Released on J-STAGE: February 25, 2010
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