Study On Energy Saving Of Water Cooling System Of Jiangshui DC Cooling System In Low Temperature Storage

Low temperature grain storage is one of the most promising green grain storage technologies in the21st century. To implement the national energy strategy, reducing energy consumption of the low temperature grain storage is inevitable. In recent years, the research focuses of grain low-temperature storage are the applications of shallow geothermal energy and solar cooling technology. As the cold source, the surface water source has many advantages such as clean, environmentally friendly and broad. Therefore, although this technology is not yet mature, it is still an exploring-worthwhile technology. This paper presents an air conditioning system which using the river cooling directly and a new mechanical ventilation to carry out basic researches of the low-temperature grain storage.In this paper, the relationship between water temperature and air temperature is analyzed, and three kinds of commonly used temperature prediction model that is a first-order linear, cubic model and logistic curve model are introduced, then the different water temperature deviation calculated by the different models are compared. The results indicate that the river temperature error is the minimum, which is fitted by the logistic curve model.In this study, the energy saving and environmental benefits of the river direct cooling air conditioning system relative to the three other forms of air conditioning is analyzed, which is from the perspective of the primary energy efficiency and the pollutant emissions. The calculate results show that the primary energy efficiency of this air conditioning system is maximum and the pollutant emissions is second. Therefore, this way of low temperature grain storage has a strong advantage in every aspect.A three-dimensional mathematical model of the temperature field of the granary developed by the CFD software, and the temperature changes of the grain bulk were simulated respectively under conditions of natural and mechanical ventilation. Under natural conditions, the external conditions are the main factors which affect the temperature distribution of the granary. The temperature in the area around the wall is affected very obvious, while the central region is less affected which retain constant state. As the ambient temperature rises, the grain temperature in the area around the granary wall also elevate, then the high temperature concentrated area is gradually formed. Thereby the key of low temperature grain storage is to inhibit the rise of the grain temperature in this area. On the condition of mechanical ventilation, the high temperature radius is narrowed, but there is still a relatively high temperature gathering area. The temperature difference will cause the condensation phenomenon during the actual storage, and the high-temperature region will mildew, so the cooling of the area around the walls should be the focus of the optimization design of the mechanical ventilation system.According to the defect that the prior ventilation modes have blind spot in varying degrees, a new ventilation mode by air insulation layer circulation ventilation and vertical circulation ventilation in the zone around the walls is proposed, and the temperature field and the velocity field are simulated. Simulation results indicate that the hot area radius of this mechanical ventilation mode is reduced and the temperature gradient is smaller, which is conducive to the food storage.