Use of Low-Temperature Geothermal Energy for Desalination in the Western United States

Turchi, Craig S.¹  Akar, Sertac¹  Cath, Tzahi²  Vanneste, Johan²  Geza, Mengistu² 

[1] National Renewable Energy Lab. (NREL), Golden, CO (United States);Colorado School of Mines, Golden, CO (United States)

关键词: geothermal;    desalination;    multi-effect distillation;   

DOI  :  10.2172/1227955
RP-ID  :  NREL/TP--5500-65277
PID  :  OSTI ID: 1227955

学科分类：再生能源与代替技术

美国|英语

来源: SciTech Connect

【 摘 要 】

This joint project between the National Renewable Energy Laboratory and the Colorado School of Mines has examined the potential of using low-temperature geothermal resources for desalination. The temperature range in question is not well suited for electricity generation, but can be used for direct heating. Accordingly, the best integration approaches use thermal desalination technologies such as multi-effect distillation (MED) or membrane distillation (MD), rather than electric-driven technologies such as reverse osmosis (RO). The examination of different desalination technologies led to the selection of MD for pairing with geothermal energy. MD operates at near-ambient pressure and temperatures less than 100?��C with hydrophobic membranes. The technology is modular like RO, but the equipment costs are lower. The thermal energy demands of MD are higher than MED, but this is offset by an ability to run at lower temperatures and a low capital cost. Consequently, a geothermal-MD system could offer a low capital cost and, if paired with low-cost geothermal energy, a low operating cost. The target product water cost is $1.0 to $1.5 per cubic meter depending on system capacity and the cost of thermal energy.