摘要
Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice is transported to the central cooling plant of the DCS.In scheme Ⅱ,return water from the DCS is directly chilled by LNG cold energy,and the chilled water is then sent back to the central plant.The heat transportation loss is the main negative impact in the DCS and is emphatically analyzed when evaluating the efficiency of each scheme.The results show that the DCS utilizing LNG cold energy is feasible and valuable.The cooling supply distance of scheme Ⅱ is limited within 13 km while scheme Ⅰ has no distance limit.When the distance is between 6 and 13 km,scheme Ⅱ is more practical and effective.Contrarily,scheme Ⅰ has a better economic performance when the distance is shorter than 6 km or longer than 13 km.
针对利用液化天然气冷能作为冷源的区域供冷系统,设计了2种方案.方案1使用冰作为蓄冷介质,先用液化天然气的冷能制冰,然后将冰运送至区域供冷系统的中心冷站.方案2则直接利用液化天然气冷能冷却回水,并通过管道运输冷冻水至需冷终端.冷能运输过程中的冷量损失是影响系统效率的主要因素,在评估2种方案的效率时对其进行了重点分析.分析结果显示,利用液化天然气冷能进行区域供冷在经济上是现实可行的.方案2的供冷距离限于13km以内,方案1则没有供冷距离的限制.当供冷距离在6～13km之间时,方案2的效率更高;当供冷距离小于6km或大于13km时,采用方案1在经济上更为合理.
