碩士 / 國立臺北大學 / 自然資源與環境管理研究所 / 106 / In recent years, Taiwan has been affected by climate change, result in uneven rainfall distribution and increased demand for water, which cause the increasing water shortage risk in the future. In the face of the uncertainty of climate change, flexible water resources adaptation strategies should be established. But, traditional water sources such as reservoirs, weir and transbasin diversion in Taiwan have been difficult to develop. Therefore, development of emerging water source will become an important part of water resources management. Emerging water sources include reclaimed water, desalination and rainwater harvesting. Among others, emerging water sources, reclaimed water and seawater desalination are much more stable for that can be used as an auxiliary water source during the dry season to relieve the pressure of water resource allocation in Taiwan.
However, compare with traditional water sources, wastewater reuse treatment and seawater desalination must consume lots more energy in the process. In the future, if wastewater reuse treatment and seawater desalination are widely used, it may lead to problems such as increased electricity consumption, greenhouse gas emissions and air pollution. Therefore, this study develops four hypothetical scenarios, using solar thermal energy to provide the mechanical energy required for reverse osmosis high-pressure pumps by the organic Rankine cycle system to replace conventional energy consumption, and applying the concept of Life Cycle Sustainability Assessment to explore wastewater reuse treatment and seawater desalination in Taiwan.
The results indicate that the energy consumption per unit of water produced by wastewater reuse treatment and seawater desalination using conventional energy is about 1.25 kWh/m3 and 4.18 kWh/m3. In the hypothetical scenario, the hours of sunshine are 6.7 hours and 5.36 hours respectively, solar thermal energy-mechanical energy conversion efficiency is 19% and 23% respectively, and replaces two reverse osmosis high-pressure pumps with reclaimed water production capacity of 5,000 CMD, so that the energy consumption per unit of production water is reduced to 1.21-1.22 kWh/m3. The solar field setting area is about 2,804.51 m2 and 2,316.77 m2. In terms of unit water production cost, the reclaimed water using conventional energy is about 22.56 NT$/m3, and the seawater desalination is about 29 NT$/m3. Solar thermal reverse osmosis wastewater reuse treatment, neglecting the investment capital costs and operation and maintenance costs of recuperator, condenser and pump, is approximately 23.32-23.34 NT$/m3.
However, the energy replaced by solar thermal is affected by the weather, especially in the southwestern part of Taiwan, the water shortage period is mostly during winter, will increase the difficulty of using the solar thermal reverse osmosis system. In addition, Taiwan has limited land and it is difficult to build large solar field. But, if energy price rises and the efficiency of the solar organic Rankine cycle system increases, there is still potential for development.
| Identifer | oai:union.ndltd.org:TW/106NTPU0399004 |
| Date | January 2018 |
| Creators | ZHANG, CHUN-YI, 張淳毅 |
| Contributors | LEE, YUH-MING, 李育明 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 98 |
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