Archive - Abstract
Vol.49 No.1 (March, 2018)
- Technical Paper (Japanese)
Stationary-type Drying for Cutting Chip of Japanese Cedar
- Kazuhiro TAKEKURA and Kenichi YAKUSHIDO
- Stationary-type drying for cutting chip of Japanese cedar was developed and examined. The wood chip is expected as alternative fuel to heavy oil for boiler heating greenhouse. It is desirable to assume that the heat source for chip dryer is the exhausted heat of a biogas power plant. Therefore, we conducted a subscale and full-scale experiments of drying live-cut Japanese cedar wood chip through ventilation.
- For the subscale (0.1 m3 scale) experiment, the chip was dried for 210 min under the following conditions: an accumulated height of 30 cm; a ventilation flow of 14.2 L/s; and a ventilation temperature of 95 ℃. At constant ventilation flow and temperature, it was shown that the drying time was proportional to the accumulated height. For the full-scale (1 m3 scale) experiment, the chip was dried for 580 min with a ventilation temperature of 100 ℃. Over the course of these experiments, it became clear that the chip could be dried using the experimental dryer and a simple composting container. Therefore, we developed a new heatproof flexible container for ventilated drying. We estimate a drying time of 14.5 h with a ventilation temperature of 100 ℃ using the heatproof flexible container.
Keywords: biomass, solid fuel, energy conversion, cutting wood chips, stationary-type drying
- Technical Paper (Japanese)
Development of Greenhouse Heating System using Biomass Boiler
- Kazuhiro TAKEKURA, Yoshimichi YAMASHITA, Genta KANAI, Kenichi YAKUSHIDO and Dong-Hyuk AHN
- We substituted fossil fuel with woody biomass during greenhouse heating for horticulture, which promoted the utilization of woody biomass as local resources. Field tests were performed by heating greenhouses with warm air converted from combustion heated hot water using a biomass boiler system with a rotary kiln-type burner as a main component.
- The air temperature of the rotary kiln-type burner was around 700 ℃, and did not cause the common problem of fusion in the kiln. For 5 hours and 15 minutes, 65.6 kg of pellets was burned. The calories exchanged from combustion by a heat exchanger produced water of temperature about 80 ℃ in 5.5 hours from a 50 % rated fuel supply. The total calorie content was 935 MJ, and the heat efficiency was 84 %. The greenhouse was able to be heated from 17:30 to 09:30 the next morning. The temperature control accuracy in the greenhouse was ± 1 ℃, and the total heat produced from calorie radiated heat was 840 MJ. This biomass boiler system has a heat storage tank, therefore even a small burner can heat the greenhouse. The unit cost of the system is around 70 thousand yen per kilowatt of burner capacity. Establishing more appropriate methods of burning and circulating hot water is necessary to improve the efficiency of calories produced from the burning of woody biomass.
Keywords: wood chip, wood pellet, greenhouse heating, warm air heating, biomass boiler, rotary kiln-type burner, radiator, heat exchange
Vol.49 No.2 (June, 2018)
- Research Paper (Japanese)
Collapse Process and Reinforcement Effects of Pipe-framed Greenhouses under Wind Loading Based on a 3-D Analysis
- Kazuya TAKAHASHI and Yasushi UEMATSU
- The present paper investigates the collapse process of pipe-framed greenhouses under static wind loading based on a finite element analysis in order to establish more reasonable wind resistant design of these structures. The wind direction is limited to that normal to the ridge. In the analyses, both geometric and material non-linearity are taken into account. The flow-structural interaction is also considered, because the wind-induced deformation of the structure affects the external pressure coefficient distribution on it significantly. Both 2-D and 3-D analyses are carried out. The effects of 3-D pressure distribution and reinforcement by adding members on the collapse process are made clear. The result on the collapse process is consistent with the practical damage caused by strong winds such as typhoons. The effects of various reinforcements made on the frame are discussed based on the similar analyses up to the allowable deformation limit specified in the current design guideline. The results show most effective reinforcement from the viewpoint of wind resistant design.
Keywords: pipe-framed greenhouse, enclosed structure, collapse process, wind load, three-dimensional analysis, elastic-plastic analysis, fluid-structure interaction
- Technical Paper (Japanese)
Drying Test of Corn Grain with Circulation Dryer and Comparison of Moisture Meters on the Market
- Genta KANAI, Yoshiya SHINOTO and Yoshimichi YAMASHITA
- Some rice farmers have recently started to grow and harvest corn grain for feed. For rice farmers who intend to grow corn under conditions given little information of postharvest processes of corn in Japan, corn grain drying tests were conducted. We also checked moisture meters that the farmers can readily purchase.
- Corn grain drying tests were conducted using a conventional circulation dryer designed for rice, wheat, barley, and soy beans. The soybean moisture meter of the dryer can accommodate the corn grain physically. However, because the anti-wrinkling system in soybean mode prevents drying with heat, wheat-mode drying is more practical with a soybean moisture meter dismounted. The drying speed was found to be higher at higher drying temperatures. It was 1 – 2 %/h with wheat mode. Energy for water removal was 5.5 – 6.0 MJ/kg, which agrees with previously reported results of the relevant literature.
- Moisture meters were compared with the oven method, which uses 135 ℃ for 10 g grain during 24 h. Two models of moisture meters for corn based on electrostatic capacity were examined: one domestic and one imported. Both showed good moisture content measuring results. Results for the domestic moisture meter showed less fluctuation than the imported one.
- Moisture meters of two types for soybean were examined: one based on electrostatic capacity and another based on electric conductivity between a pair of kernel-crushing wheels. The latter is a part of the grain dryer for soybean drying. Because both were designed for soybeans, the indicated values differed from the moisture contents. The values must be converted to corn moisture contents with the regression equation between the oven method and the examined methods. The moisture meter based on electric conductivity showed less fluctuation than the other based on the electrostatic capacity.
Keywords: corn, corn grain, circulation dryer, moisture content, moisture meter
Vol.49 No.3 (September, 2018)
- Research Paper (Japanese)
Optimizing the Opening/Closing Times of a Multi-Layered Thermal Curtain for a Greenhouse with Water Heat Storage
- Shuh MATSUDA, Hisashi YOSHIKOSHI, Hiroki KAWASHIMA, Ayaka CHIBA, Osamu YAMADA, Yuuki OHTA, Tomoyo SUZUKI, Hiroshi ARIMA, Daisuke YASUTAKE and Masaharu KITANO
- Greenhouses with multi-layered thermal curtains have been widely disseminated. However, the optimization of the timing of opening/closing operation of such curtains deserves additional study. First, the heat dynamics in the greenhouse with multi-layered thermal curtains was modeled by combining steady and unsteady processes of heat transfer, and the model was verified to have a reliable validity. Next, based on the model, the timing thresholds for the opening/closing operation were examined with reference to the room temperature, time of day, and amount of solar radiation. The relationships between the respective timing thresholds and the fuel consumption were investigated at a set room temperature of 12 ℃. In the case of the curtain operation based on the room temperature threshold, fuel consumption was the lowest at the threshold of 13 ℃ (the standard control operation). In the case of the threshold of time of day, the minimum fuel consumption was calculated at the respective thresholds of 08:40 and 15:10 for opening and closing, and the fuel consumption was 46.1 L lower than that in the standard control operation. In the case of the threshold of amount of solar radiation, the minimum fuel consumption was calculated at the threshold of 180 W m-2, and the fuel consumption was 52.1 L lower than that in the standard control operation. Furthermore, it was found that the threshold for the opening operation is more important for energy saving than that for its counterpart closing operation. Resultantly, a method to optimize the thresholds for the opening/closing operation of the greenhouse curtain was proposed in consideration for the fuel consumption and the solar radiation.
Keywords: multi-layered thermal curtain, heat dynamics, timing of opening/closing, fuel consumption
- Technical Paper (Japanese)
Effects of Recycled Compost on Composting Reaction, Quality of Compost and Facilities Management in Swine Manure
- Fumihito MIYATAKE, Natsumi TOKIHISA and Takehito ONO
- To clarify the effects of recycled compost on composting reaction, quality of compost and facilities management in swine manure composting, temperature profile, fertilizer components, microbial flora and management estimate was investigated with a real composting facility of swine manure. Compost material mixed with swine manure, sawdust and recycled compost at 1:1:1 (volume ratio) maintained a temperature of 55 ℃ or higher for 238 hours continuously, showing that it is possible to produce safe compost in which coliform bacteria were killed. In addition, this duration of high temperature promoted moisture evaporation, leading to high drying efficiency. On the other hand, the compost temperature of material regulated the moisture content with only sawdust had only 36 hours for a duration of 55 ℃ or higher. Therefore, the number of coliform bacteria in the compost was detected at 3.2 x 105 cfu g-ds-1. For the fertilizer components, the concentration of phosphoric acid, potassium, zinc, copper and EC in the product compost increased by 1.4 to 2.4 times as the amount of recycled compost increased. According to management analysis, composting with material mixed at 1:0.5:2 had major economic effect. Meanwhile, it showed that composting of 1:1:1 leads to and labor saving of facility management.
Keywords: composting, recycled compost, compost temperature, fertilizer component, facilities management, swine manure
Vol.49 No.4 (December, 2018)
- Research Paper (Japanese)
Viscosity Measurement Method Using Central-mode Piezoelectric Resonator Embedded in Bottom of Plastic Vessel
- Takahiro ADACHI, Koichi MIZUTANI, Naoto WAKATSUKI and Tadashi EBIHARA
- In this paper, a viscometor suitable for food-processing process is proposed. This viscometer can measure a small amount of liquid, be easy to care, and embed in pipe. This viscometer has disk-shaped piezoelectric resonator embedded in bottom or wall of vessel and pipe. Viscosity is obtained by estimating equivalent circuit parameters of piezoelectric resonator at resonance. To measure viscosity in the case of gluing the circumference of the resonator to the vessel, center of the piezoelectric resonator is vibrated by proposed electrode arrangement. To verify effectiveness of proposed viscometer, the viscometer was made and relationship between resistance Rs obtained by equivalent circuit of piezoelectric resonator and viscosity η of standard liquid of calibrating viscometor was confirmed. In this confirming, standard liquid of calibrating viscometor as measurement sample was 10 mL. As a result, radial-mode vibration did not give one-to-one correspondence η and Rs. However, central-mode vibration gave one-to-one correspondence η and Rs, and η was proportional to Rs2 in the range of 9.1 - 478 (mPa∙s). Therefore, proposed viscometor can be embedded bottom of vessel, and measure a small amount of sample. Thus, it was shown that proposed viscometor is suitable for food-processing process.
Keywords: viscosity measurement, vibrational viscometer, piezoelectric resonator, equivalent circuit
- Research Paper (Japanese)
Collapse Process and Reinforcement Effects of Pipe-framed Greenhouses under Snow Loading based on a 3-D Analysis
- Kazuya TAKAHASHI and Yasushi UEMATSU
- The present paper investigates the collapse process of pipe-framed greenhouses under snow loading based on a finite element analysis in order to establish more reasonable snow resistant design of these structures. Three snow load distribution patterns under the effects of wind and/or solar radiation are considered. In the analyses, both geometric and material non-linearity are taken into account. Furthermore, the effects of buckling and initial geometric imperfection similar to the buckling mode are also considered. Both 2-D and 3-D analyses are carried out. The effect of reinforcement by adding members on the collapse process is made clear. The result on the collapse process is consistent with the practical damage caused by heavy snowfall. The effects of various reinforcements made on the frame are discussed based on the similar analyses up to the ultimate state. The results show the effective reinforcement methods from the viewpoint of snow resistant design.
Keywords: pipe-framed greenhouse, collapse process, snow load, three-dimensional analysis, geometric non-linearity, elastic-plastic analysis, uneven load, initial geometric imperfection, reinforcement
- Note (Japanese)
Trends and Functional Analysis of ICT Energy-Environment Monitoring Systems of Greenhouses
- Ryota TSUCHIYA, Kazuhiro MOCHIDZUKI, Limi OKUSHIMA, Masahisa ISHII and Tomoharu YAMAGUCHI
- Numerous types of ICT (Information and Communication Technology) monitoring systems have been developed to help farmers of greenhouse horticulture easily understand the environmental condition within their greenhouses. In addition, these monitoring systems are also effective to optimize the amount of energy required to control its environment. In this paper, the function trends of ICT greenhouse monitoring systems, already commercialized in Japan, are reviewed with respect to monitoring items, functions, installability, and ICT ability and the recently developed ICT energy-environment monitoring system is characterized based on the review. These trends were analyzed using information from websites and catalogues of existing products. The properties of each product were then visually summarized in radar charts using five scores. The radar charts for the new system suggest the need to improve its installability and expand its support functions for farmers.
Keywords: environmental monitoring, ICT, energy-saving, greenhouse
