| China is a big country of fruits and vegetables and a country with very tight energy supply.The fresh supply and storage of fruits and vegetables is an important issue related to people’s livelihood and social development.Because of its high energy consumption,the high storage cost of some fruits and vegetables with lower prices has greatly affected people’s enthusiasm for planting and storage.Research and development of a low-cost,low-energy natural cooling source and mechanical refrigeration two-way switching energy-saving fresh-keeping equipment store in the eyebrow.This paper studies the feasibility of natural cold source and mechanical refrigeration two-way switching storage for fruit and vegetable preservation and the energy saving of natural cold source and mechanical refrigeration two-way switching storage.Based on the Comsol simulation,the optimal velocity and inlet size of natural cold source are simulated.The results showed that:(1)Compared with the common cellar,the natural cold source and mechanical refrigeration two-way switching storehouse play a significant role in the preservation of sweet potato.When stored to 100 d,the water content of sweet potato in the two-way storehouse is 7.69% higher than that in the common cellar,the hardness is 268.37 N/cm2,the content of soluble solids is 5.94% higher,the MDA content is less than 4.65%,and the starch content is 3.89% higher.During the period of storage to 40-50 d,the content of soluble solids reached a peak in the two groups of sweet potatoes,20.34% in the two-way switching storehouse and 17.22% in the control group.The appearance and color of sweet potato in the switching storehouse are better than those in the common cellar;(2)Through the observation and observation of the temperature and humidity of the sweet potato storehouse during the storage experiment,it was found that compared with the ordinary cellar storehouse at the same time,the natural cold source and the mechanical refrigeration bidirectional switching storehouse can better maintain the temperature and humidity environment in the storehouse,avoiding the temperature and humidity environment in the storehouse.The phenomenon of cold damage or dry consumption of sweet potatoes caused by excessive humidity fluctuations has a significant effect on the preservation of sweet potatoes;and compared with a single mechanical refrigeration cold storage with the same storage time,the natural cold source and mechanical refrigeration bidirectional switching storage have significant energy saving effects,and the energy saving efficiency is 76.34%;(3)Using Comsol software to simulate the physical field in the reservoir,it is found that the velocity field and temperature field in the reservoir have great influence on the stability of the velocity field and the temperature field in the reservoir with different velocity of air supply m/s.Taking into account that the time required to reach the steady state of mm 400 is less than that of mm 300,which avoids the cold of the storehouse caused by the excessive size,the opening size of the 400 mm and the wind speed of the 7 m/s are the best for the modified reservoir;The conclusions can provide theoretical basis and reference cases for the introduction of natural cold sources into storage of fruits and vegetables in the following northern areas,and promote the transformation of abandoned cellars in Northwest and North China and the combination of natural cold sources introduction technology,which is conducive to the introduction of natural cold sources according to local conditions,the development of fresh-keeping of fruit and vegetable producing areas according to the optimum storage temperature of fruits and vegetables,and the study of two-way switching energy-saving refrigeration devices between natural cold sources and mechanical refrigeration. |
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