The experiment uses technology developed by Prof. Haruo Uehara and researchers at Saga University to generate electricity from ocean thermal energy. It is hoped that the test will produce 1,000 kilowatts of electricity. The ocean thermal energy conversion (OTEC) process uses ammonia, which evaporates at a lower temperature than water, making it more efficient. First, ammonia is heated to steam using warm surface water and used to generate electricity. Then it is cooled back to liquid using cold deep sea water. While less efficient than fossil fuel or nuclear plants, OTEC could provide cost-efficient, environmentally friendly energy.

1. Learner tasks with info mapping mapping text writing from maps summarizing controlling navigation

2. Learner tasks with info mapping mapping text writing from maps summarizing controlling navigation

3. Learner tasks with info mapping mapping text writing from maps summarizing controlling navigation in mapping tasks, limit the number of nodes this forces learners to identify main structures

4. Ocean thermal energy could be the wave of the future Noriyuki Yoshida The Daily Yomiuri 01 01 23 _____________________________________________________________________________ _____________________________________________________________________________ The experiment uses technology developed by Prof. Haruo Uehara and researchers at the science and engineering department of Saga University. It is hoped that the test will produce 1,000 kilowatts of electricity, and it is expected that the technology will provide cost-efficient, environmentally friendly energy in the 21st century. _____________________________________________________________________________ _____________________________________________________________________________ Thermal and nuclear power plants boil water into steam, which rotates turbines to generate electricity. The basic mechanism of the OTEC is the same, but instead of water, the OTEC process uses ammonia, which is more energy efficient because it evaporates at a much lower temperature than water. _____________________________________________________________________________ _____________________________________________________________________________ First, liquid ammonia is heated with water of 20 C to 30 C drawn from near the surface of the Indian Ocean and converted into steam. Then the ammonia steam rotates turbines and generates electricity. Finally the steam is cooled with 6 C deep-sea water and converted back to liquid. _____________________________________________________________________________ _____________________________________________________________________________ In thermal power generators, the temperature difference between water and steam is about 500 C, which means the steam is packed with energy. But the temperature difference in the OTEC system is only about 20 C, so the energy from the ammonia steam is relatively low. To overcome this, OTEC utilizes a process developed by Uehara to improve the heating and cooling of the ammonia and use water as a solvent. _____________________________________________________________________________ _____________________________________________________________________________ The OTEC system's heat efficiency rate (the percentage of generated power compared to the total energy poured into the system) has reached a high of 5.2 percent under the Uehara Cycle. This is much lower than 40-percent level in thermal power generation and the 50 to 60 percent efficiency of power generation using a combination of thermal systems and gas. _____________________________________________________________________________ _____________________________________________________________________________ Uehara said, "Because the source of heat is seawater, the energy cost is zero. The overall costs of the power generation processes are not much higher than those of thermal generation and other forms," he said. e.g. Take a tech article, remove topic and conclusion sentences from each paragraph, have learners map the article with 15 nodes or fewer.

5. Use the infomap links to map the text. Description Classification Degree comparison Attribute comparison Sequence Cause-effect Contrast ! < big

6. General process: boil NH3 Make steam Rotate turbines Generate electricity Boil a liquid older type plants OTEC plants boil H2O seawater heat fossil or N-heat steam 20C steam 500C low power high power zero energy cost high energy cost hunter systems ! ! ! Steam-based power generating systems

7. General process: boil NH3 Make steam Rotate turbines Generate electricity Boil a liquid older type plants OTEC plants boil H2O seawater heat fossil or N-heat steam 20C steam 500C low power high power zero energy cost high energy cost hunter systems ! ! ! Steam-based power generating systems

8. Steam-based power generating systems General process: hunter systems Make steam Rotate turbines Generate electricity Boil a liquid

9. boil H2O seawater heat fossil or N-heat steam 20C steam 500C low power high power zero energy cost high energy cost older type plants OTEC plants Steam plants boil NH3 Steam-based power generating systems

10. boil H2O seawater heat fossil or N-heat steam 20C steam 500C low power high power zero energy cost high energy cost older type plants OTEC plants Steam plants boil NH3 Steam-based power generating systems