ConstantsOcean thermal energy conversion is a process that usesthe temperature difference between the warm surfacewater of tropical oceans and the cold deepocean water torun a heat engine. (Figure 1) shows a typical decrease oftemperature with depth below the surface in tropicaloceans. In the heat engine, the warmer surface watervaporizes a low-boiling-point fluid, such as ammonia. Theheat of vaporization of ammonia is 260 cal/g at 27°C,the surface-water temperature. The vapor is used to turna turbine and is then condensed back into a liquid bymeans of cold water brought from deep below thesurface through a large intake pipe. A power plantproducing 10 MW of useful power would require a coldseawater flow rate of about 30,000 kg/s.Part ACompare the entropy change of the warmer water to that of the colder water during one cycle of the heat engine,assuming an ideal Carnot cycle.The entropy does not change during one cycle in either case.The entropy of the warmer water decreases by more than the entropy of the colder water increases,because some of the heat removed from the warmer water goes to the work done by the engine.The entropy of the warmer water decreases by the same amount that the entropy of the colder waterincreases.Figure1 of 1The entropy of both increases, but the entropy of the colder water increases by more because its initialtemperature is lower.5 10 15 20 25 30°C100SubmitRequest Answer200300400Provide FeedbackNext >5006007008009001000Depth (m)

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Constants Ocean thermal energy conversion is a process that uses the temperature difference between the warm surface water of tropical oceans and the cold deepocean water to run a heat engine. (Figure 1) shows a typical decrease of temperature with depth below the surface in tropical oceans. In the heat engine, the warmer surface water Part A vaporizes a low-boiling-point fluid, such as ammonia. The of amr Compare the entropy change of the warmer water to that of the colder water during one cycle of the heat engine, assuming an ideal Carnot cycle. heat of vaporization of ammonia is 260 cal/g at 27° C, the surface-water temperature. The vapor is used to turn turbine and is then condensed back into a liquid by means of cold water brought from deep below the surface through a large intake pipe. A power plant producing 10 MW of useful power would require a cold seawater flow rate of about 30,000 kg/s. O The entropy does not change during one cycle in either case. The entropy of the warmer water decreases by more than the entropy of the colder water increases, because some of the heat removed from the warmer water goes to the work done by the engine. The entropy of the warmer water decreases by the same amount that the entropy of the colder water increases. Figure 1 of 1 The entropy of both increases, but the entropy of the colder water increases by more because its initial temperature is lower. 5 10 15 20 25 30 °C 100 Submit Request Answer 200 300 400 Provide Feedback Next > 500 600 700 800 900 1000 Depth (m)

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter1: Temperature And Heat

Section: Chapter Questions

Problem 100P: One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a...