The arid northwest China is an undeveloped area in economy, being rich in mineral resources but shortage in water resources due to sparse rainfall and intense evaporation.
我国西北地区降水稀少，蒸发强烈，水资源贫乏，是矿产资源富饶的缺水贫困区。
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Contraposing the problem of evaporation section, technology transformation measures of evaporation section were introduced in process and equipment. The economy benefit was also analyzed.
It is noted that all these four schemes are economically feasible. The one based on a direct evaporation of refrigerant and low-temperature air supply system enjoys the best economy.