| In view of the industry problems of domestic and foreign cold storage,such as the long construction period,high construction costs,idle standing for a long time and unable moving for the whole and so on,this project broke six core technical bottlenecks through fiber cotton insulation,structural optimization,heat and mass transfer,shape coefficient,temperature and humidity-phase flow field and inflatable molding,which developed the first inflatable mini-cold storage at home and abroad with the advantage of simple,practical,easy construction and reliable performance.simple and practical,easy to build and reliable performance.Comprehensive index which envelope barrier properties and the effect of fruit and vegetable preservation are better than traditional assembled mini-cold storage,and the total cost difference was not significant.(1)The optimization of insulation fiber insulation materials.The composite insulation cotton(80%polyester +20%acrylic)owns well fire resistance,smooth fiber surface,thermal conductivity 0.0330 W/(m·K),moisture content 0.29%,moisture regain 0.22%,tensile strength 0.23MPa,elongation at break 138.96%,the unit price of thermal resistance 8.71 yuan/(m 2·m 2·K/W),which is 10 kinds of fiber material most suitable inflatable materials for the inflatable mini-cold storage,followed by hollow cotton insulation.(2)The optimization of the envelope."Double-sided silver coated fabric +foamed polyurethane + PE film + the composite insulation cotton + PE film + foamed polyurethane + sided silver coated fabric " is the most suitable wall composite materials for the inflatable mini-cold storage.Its thermal conductivity is 0.0295 W/(m·K),water absorption is 2.14%,breaking strength is 469.2 N/cm,tensile strength is 33.4%,breaking strength is 459.4 N/cm and tensile strength is 32.6%after artificial aging.At the same time,the mechanical strength of the aluminum foil is relatively low,is not suitable for the inflatable mini-cold storage wall materials.The double-sided silver coated fabric has good mechanical properties,water resistance,resistance to aging,and to some extent,can play an aluminum foil effect,so The double-sided silver coated fabric is the ideal inflatable outer material for wall composite material of the inflatable mini-cold storage.(3)Study on the thermal performance of the inflatable mini-cold storage.The result indicating that it has good insulation properties with the thermal insulation of the palisade structure of 11.5 W/m~2·K,the overall heat transfer coefficient of 0.089 m~2·K/W,empty storage cooling time of 25 min,and outside temperature almost no impact on its internal temperature.(4)Study on the supporting technology.Pressure pre-cooling is an effective way to remove field heat of fruits and vegetables.The experiment developed a new type of pressure pre-cooling device,which consists mainly of a plenum matching axial fan and a simple vertical or horizontal tunnel.Potatoes do not cover air pre-cooling PE bags of potatoes cooling effect of the cooling jacket potato PE bags little effect,and forced pre-cooling need such large sets of accounts under the same conditions as the pre-cooling effect is not as large accounts drilling not perforated pre-cooling effect.It is recommended sets of accounts are not reconciled punch pre-cooling;large fans(air volume 504 m3/min)of the pre-cooling effect is significantly better than small wind turbines(air volume 150 m/min).(5)The preservation effect of the Red Globe Grape.The result indicating that the preservation effect of the Red Globe Grape in the inflatable mini-cold storage was better than the assembled mini-cold storage,and the comparison of two different pre-cooling processed the Red Globe Grape in 90d which the shattering rate,water loss rate,hardness,total acid content,vitamin C content and soluble solids content shows were better the ordinary pre-cooling.There were not significant difference of the overall cost between the inflatable mini-cold storage and the assembled mini-cold storage. |
PDF Full Text Request