Energy from the Ocean Whenever two objects are at different temperatures, therma
ID: 2218219 • Letter: E
Question
Energy from the Ocean Whenever two objects are at different temperatures, thermal energy can be extracted with a heat engine. A case in point is the ocean, where one "object" is the warm water near the surface, and the other is the cold water at considerable depth. Tropical seas, in particular, can have significant temperature differences between the sun-warmed surface waters, and the cold, dark water 1000 { m m} or more below the surface. A typical oceanic "temperature profile" is shown in the figure(Figure 1) , where we see a rapid change in temperature-a thermocline-between depths of approximately 400 { m m} and 900 { m m}. The idea of tapping this potential source of energy has been around for a long time. In 1870, for example, Captain Nemo in Jules Verne's Twenty Thousand Leagues Under the Sea, said, "I owe all to the ocean; it produces electricity, and electricity gives heat, light, motion, and, in a word, life to the Nautilus." Just 11 years later, the French physicist Jacques Arsene d'Arsonval proposed a practical system referred to as Ocean Thermal Energy Conversion (OTEC), and in 1930 Georges Claude, one of d'Arsonval's students, built and operated the first experimental OTEC system off the coast of Cuba. OTEC systems, which are potentially low-cost and carbon neutral, can provide not only electricity, but also desalinated water as part of the process. In fact, an OTEC plant generating 2 { m MW} of electricity is expected to produce over 14,000 cubic feet of desalinated water a day. Today, the governments of Hawaii, Japan, and Australia are actively pursuing plans for OTEC systems. The National Energy Laboratory of Hawaii Authority (NELHA), for example, operated a test facility near Kona, Hawaii, from 1992 to 1998, and plans further tests in the future. Suppose an OTEC system operates with surface water at 22 ^circ { m C} and deep water at 4.0 ^circ { m C}. What is the maximum efficiency this system could have? 6.10% 8.20% 9.40% 18.0%Explanation / Answer
6.10%
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.