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Volume 18 (1987 - 198･･･
- Issue 3 Pages 4-
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Volume 18, Issue 1
Displaying 1-5 of 5 articles from this issue
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Evaluations of Effective Ventilation Rate and Mixing Factor by Using the Water Vapor Balance Method in a Dairy BarnShin-ichi URANO1987 Volume 18 Issue 1 Pages 4-14
Published: July 31, 1987
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThe effective ventilation rates and the mixing factors in a mechanical ventilated dairy barn were measured and evaluated by using a water vapor balance method. Farther, the methods of estimating these parameters were discussed. The results were summarized as follows;
(1) The effective ventilation rates were approximately equal to the exhaust air volumes of fans at the time of low ventilation rate when the only two fans were moved. They showed two patterns of values, higher and lower than the exhaust air volumes of fans, at the time of high ventilation rate when the five fans were moved simultaneously. During the grazing time, the effective ventilation rates were lower than the exhaust air volumes of fans. From these results, it was suggested that the short-circuiting air ways occurred in the air space of the dairy barn at the time of high ventilation rate and at the grazing time.
(2) The mixing factors obtained from the effective ventilation rates and the exhaust air volumes of fans were from 0.6 to 1.3 in time and from 0.5 to 1.8 in space. The range of these values was wider than that of the values which Barber et al. (1984) obtained in the scale model experiments.
(3) The mixing factors based on the water vapor balance agreed approximately with those based on the sensible heat balance.
(4) Through these results and discussions, it was confirmed that the effective ventilation rates and mixing factor in livestock barns could be evaluated by the water vapor balance method.View full abstractDownload PDF (1446K) -
Evaluations of Structures Based on Ventilation and Sensible Heat Utilization in Dairy and Beef Cattle BarnsShin-ichi URANO1987 Volume 18 Issue 1 Pages 15-27
Published: July 31, 1987
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThe ventilation rates and the heat utility ratios based on the heat and moisture balances were compared in three types of livestock barns: the insulated and mechanical ventilated dairy barn and the naturally ventilated livestock barns of the ridge-vent beef barn and the monitor-roof dairy barn. The results were summarized as follows;
(1) In the insulated and mechanical ventilated dairy barn, the sensible heat utility ratios for ventilation and inside storage were higher than that of the other in winter observation. The phenomenon of that the heat which was stored into the building materials discharged to the inside air was observed at the time of high ventilation rate and low inside air temperature. In summer observation, the ventilation rates were relatively less than the other.
(2) In the naturally ventilated beef and dairy barns, it was observed in summer that the differences of inside and outside air temperatures were less than that of the insulated and mechanical ventilated dairy barn in spite of getting a large amount of heat through the structur. It was became clear that these barns had the characteristic of excellent ventilation.
(3) It was proved from these results that the insulated livestock barns with mechanical ventilation system were fit for cold climate regions, and the ridge-vent and monitor-roof livestock barns with naturally ventilation system were fit for warm climate regions or for species of animal which did not need warming in winter season.View full abstractDownload PDF (1790K) -
Effect of the Condensation on Heat Transmission CoefficientQingyun CHEN, Yoshiyasu AIHARA, Tomoharu YAMAGUCHI, Sadanori SASE, Mak ...1987 Volume 18 Issue 1 Pages 28-37
Published: July 31, 1987
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSIn order to evaluate the effects of condensation on heat transmission coefficient of a greenhouse, the amount of condensation on the greenhouse claddings, the radiant heat transmission coefficient, the convective heat transmission coefficient and the overall heat transmission coefficient were measured by utilizing four model greenhouses covered by polyethylene (PE) (anti-drop type and droplet making type) film, polyvinylchloride (PVC) (anti-drop type and droplet making type) film set in an environmental control room.
The main results obtained are the followings:
1) The maximum amount of condensation on the cladding is 155-180g/m2 on the PE droplet making type film; 50-85g/m2 on the PE anti-drop type film; 100-110g/m2 on the PVC droplet making type film and 50-55g/m2 on the PVC anti-drop type film. The constant amount of condensation in a steady state situation on the cladding is about 80g/m2 on the PE droplet making type film; 25-30g/m2 on the PE anti-drop type film; 30-50g/m2 on the PVC droplet making the film and 20-25g/m2 on the PVC anti-drop type film.
2) The radiant heat transmission coefficient when condensation occurs on the cladding decreased by 24-38% in the PE film, 7-15% in the PVC film as compared with that when condensation dose not occur. On the other hand, the convective heat transmission coefficient showed the opposite trend, that is, it increased 35-67% in the PE film, 22-52% in the PVC film. As a consequence the overall heat transmission coefficient when condensation occurs on the claddings decreased by 3-12% in the PE film, but it increased by 7-16% in the PVC film as compared with that when condensation dose not occur.View full abstractDownload PDF (1370K) -
Ken SASAKI, Toshihide KIDANI, Yoshiaki EMOTO, Takashi HAMAOKA1987 Volume 18 Issue 1 Pages 38-46
Published: July 31, 1987
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSMethane fermentation and working of biogas engine were carried out to develop the local efficacy utilization of livestock waste. During batch fermentation at 35°C, maximum gas production rate was 950ml/l/d (370mg/g-vs) and CH4 concentration was 58-76%. In continuous fermentation, the maximum values of gas production rate (840-1, 150ml/l/d), CH4 concentration (64-72%) and CODcr removal (61-63%) could be observed when loading of volatile solid was in the range 2.8 to 7.1g-vs/l/d. Using the mixed gas fuel consist of CH44 and CO2 (CH4, 60 and 80%), a 4 cycle spark ignition engine (550cc) was worked by means of controlling air-fuel ratio. The maximum power performance of 15 PS could be obtained, while the most efficient working was observed at 2, 500rpm (10 PS). It was estimated that 13hr (per day) continuous working might be possible using biogas from 500 pigs.View full abstractDownload PDF (1279K) -
Their Effectiveness on Heat Collection and the Shading of Non-visible Ray in a GreenhouseKazuhiko ABE, Makoto NARA1987 Volume 18 Issue 1 Pages 47-60
Published: July 31, 1987
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThis paper describes the effects of the transparent and thermally insulated walls on solar heat collection as well as the shading of infrared radiation in a greenhouse.
Three types of film were provided to construct a greenhouse wall; S: transparent polyester film, R: light transmissive and thermally reflective film and, A: reflective alminum foil, we constructed single to triple layered model greenhouses and examined their performance.
From the viewpoints of light transmission and thermal insulation, the following combination proved to obtain the best performance; S+S+S on the south wall, S+R+S on the roofs and S+A+S on the north wall.View full abstractDownload PDF (1303K)
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