|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1991 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1990 : ¥1,800,000 (Direct Cost : ¥1,800,000)
We had developed a mo del plant for the artificial permafrost storage at Obihiro University in December, 1987. Since then, the fluctuation of the temperatures and humidity in cold room and the changes of temperatures in frozen ground has been investigated, measuring the soil temperature and the situation of the created frozen ground layer. The qualitative changes of the stored vegetables(mainly, potatoes, Chinese yam, burdock)were investigated and examined. Although this storage system was prove possible to stock the vegetables, a few problems were left. As the cooling effect of heat pipes became too great, the room temperature dropped below the freezing point during the severe winter(from January to May). In order to settle this problem, the fins of the condensative section on 108 pieces of heat pipes was covered with cloth sheets and consequently this operation proved that the cooling effect was reduced. The worldng of heat pipe was stopped automatically owing to the thermal diode ef
fect since April.
The automatic water pouring system was applied on the room wall and if the room temperature became below the freezing point, this system was operated to prevent the vegetables from killing. And the poured water turned ice sheet in the room and much ice on the floor kept cool in the stocked vegetables. Then room temperature in this year was kept colder to 2.5ﾟC in the warmest month, August than 4.0ﾟC in last year.
The most important thing is to keep the freshness of the stored vegetables for the food storage system, we proved the ability for store potatoes Chinese yam, burdock and carrot, and they have well worth commercial. In this year, the new stored matter, flesh flower was stocked in the artificial permafrost storage and it was found that chrysanthemum, lily, carnation and statice were keep fresh during one month. Also roses, tulips and haze grass were found to keep fresh to tree weeks.
Thus, we concluded that this artificial permafrost storage was profitable system to keep the vegetables an flowers fresh during a long period. Less