季节蓄热太阳能区域供热的规模化优势

欧洲地区太阳能区域供热运用已积累丰富的理论和实践经验。经验表明,集热场规模越大,单位面积集热器成本和单位体积蓄热体成本就越低。集热器铺设规模由2,000m^2增加到50,000m^2,单位面积集热器屋顶安装成本下降906元/m^2,降幅达35.0%,地面铺设成本下降560元/m^2,降幅达32.4%,制热成本则由180元/MWh下降到128元/MWh。采用水罐蓄热,蓄热体规模由300m^3扩大到12,000m^3时,单位体积蓄热成本降低355元/m^3,降低75%;采用水池蓄热,蓄热体规模由700m^3扩大到75,000m^3时,单位体积蓄热成本由250元/m^3降至30元/m^3,单位体积蓄热成本降低了220元/m^3,降低88%,制热成本则由35元/MWh下降到23元/MWh。因此,太阳能区域供热规模越大,经济效应越显著,最终热价也相对较低。

Prospect of the Seawater Desalination Technology

This article classifies the seawater desalination technology into four types of hot method, membrane method, electric field method and solvent method. Electric field method and solvent method still remain experimental stage, while hot method and membrane method have been realized in commercialization but are difficult to be promoted. The problem lies in high water-producing cost. It is difficult for membrane method seawater desalination technology to reduce the water-producing cost. The heat utilization efficiency is not high for the current hot method seawater desalination technology and there is large amount of heat lost with the emission of concentrated seawater. The new hot method seawater desalination technology and new solar-powered seawater desalination technology can divide the seawater into fresh water and solid salt without any emission of concentrated seawater so that the heat utilization efficiency can reach theoretical limit to multiply reduce the water-producing cost. They will become the mainstream technology for seawater desalination and can totally eliminate the global water crisis.