Study Of Ice Storage System Based On L-CNG Fueling Station Cold Energy Utilization

With the increase of people's environmental protection consciousness,more and more clean energy comes into view of a lot of country.Natural Gas(NG)as one kind of clean and efficient energy resource draw people's attention.The nature gas vehicles also popular in China.As one of the CNG vehicles fueling station,the L-CNG fueling station has the advantages of small floor stage,low construction price and low operation cost.In the LCNG fueling station,approximately 830 KJ kg-1 cold energy will be released in the gasification process and the cold energy usually be dispersed into environment which is a kind of waste.An ice storage system was designed in the L-CNG fueling station,which can solve the problem of the cold energy discontinuous and can realize the rational realization of the resources.In this paper,we use the method of experiment and simulation,and find the optimum operating point for the cold energy utilization system and put forward the proposal for the design of the ice storage tank.First of all,through the literature research,the internal-melt ice storage tank was chosen as the main experimental model.And comparing with the different secondary refrigerant in the factors of freezing point temperature,viscosity,safety and economics,we choice the Ethylene glycol solution(EGS)with mass concentration 50% as the secondary refrigerant.Based on the analysis of freezing process,the method of calculating ice thickness based on energy balance equation and finite element method is proposed.Secondly,in the paper,the model of Solidification &Melting model in the software Fluent was used to build up a casing model,and the software ICEM was used to mesh generation.In the simulation result,we analyzed the different factors to the icing process and we can draw the conclusion that the EGS temperature have the important influence to the icing process.Then,a small-size ice storage system has been proposed based on the characteristic of the L-CNG fueling station.Sensors have been arranged reasonably and the visualization system can help us watch the ice thickness directly.Meanwhile the influence factors such as the temperature,flow rate and gravity and so on were also studied via the experiment.We can know that the gravity also has the important influence to the icing process,which cannot be observed in the simulation process.Finally,the paper summarized the results and puts forward the optimal working conditions and design suggestions for ice storage system based on the L-CNG fueling station cold energy utilization.