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Doron Bracha

Jun 11, 2014
08:38

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Interesting proposal and good thinking. Water Source Cooling has been studied and done in different locations around the world. http://energyandsustainability.fs.cornell.edu/util/cooling/production/lsc/works.cfm The idea is great, but the set-up of a system is expensive and labor-intensive. The system also requires a great amount of source material for its construction and placement. http://en.wikipedia.org/wiki/Deep_water_source_cooling A thorough analysis is required in order to determine economic viability, and overall advantage. If we're consuming a lot of materials and energy in setting up and running the system, as well as maintenance and repair, and if the payback takes too many years, it may not be a good option. Yet this is certainly interesting and has great potential. Here's an interesting case study: http://crcresearch.org/case-studies/case-studies-sustainable-infrastructure/energy/deep-water-cooling Cheers !..

Patrick Mcnulty

Jun 16, 2014
09:37

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Thanks Doron you may consider clicking the support proposal icon to the right on this link : https://www.climatecolab.org/web/guest/plans/-/plans/contestId/1300203/planId/1306820

Maryette Haggerty Perrault

Jun 19, 2014
10:31

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Quite the idea cyclonebuster! Just as Doron_Bracha has said the system will require considerable capital and a heavy infrastructure cost, even just to build the district cooling system which does not presently exist in all coastal cities. However my biggest concern is the increase temperature of the sea water discharged back to the oceans. Many ecosystems along the eastern US seaboard are already at a critical state because of human development. I'm not sure that raising the sea temperature is an acceptable cost for reducing green house gas emissions from power plants. I did find a few resources discussing this issue (http://www.rivercenter.uga.edu/education/watershed/thermal.htm), but I am sure there are more out there. Increased water temperatures have been linked to algae blooms, invasive/non-native species, lower oxygen content of water, and more. I think this ocean water heat exchanger could have potential but I worry that the proposed scale could have negative impacts on the ecosystems even in the great, big ocean. I'm interested to hear if you have encountered this argument before and what comments you might have in response!

Maryette Haggerty Perrault

Jun 19, 2014
10:43

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Also, another thing to think about - just because a buildings cooling system is drawing its chilled water from a GHG-free source (cold ocean water), does not mean that the building is operating efficiently. In theory this GHG-free energy source could just be being wasted by an inefficient building. This is along the same lines as installing a solar PV array on an inefficient building - just because you're offsetting the GHG emissions, doesn't mean you should be able to waste energy. Best of luck!

Patrick Mcnulty

Jun 20, 2014
08:49

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Hello Maryette thanks for your concern I actually thought of that. Correct the water that is discharged back to the ocean is a little warmer but it is still cooler than the upper layers where the coral reefs are perhaps a couple hundred feet below the surface and all the way up to the surface in some locations... I didn't mention this in my proposal but should have.. I want to use that water upstream of the coral reefs to stop the coral bleaching that is occurring to them since our oceans are to hot from anthropogenic warming.. This can be done at various locations along the reefs. Computer modeling of the currents would tell us the optimum locations to place them. On the subject of discharging warm water to the ocean. A single 900MW nuke plant discharges about 1.5 million gallons PER MINUTE of hot 100 to 110 degree F water from the condensers right into the ocean. My idea is much cooler than that and also removes the fossil and nuke plants from the grid.. The Gulfstream has enough heat energy in it to power the industrialized world over 100 times. We just need ~.5% to 1% of that heat energy to power our country.

Patrick Mcnulty

Jun 20, 2014
04:21

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As you can see according to NOAA the 0-700 Meter layer needs some cooling off anyways. This idea has similar effects of upwelling on the oceanic ecosystem. http://www1.ncdc.noaa.gov/pub/data/cmb/images/indicators/ocean-heat-content.gif

Saravanan Dhalavoi Pandian

Jun 25, 2014
02:21

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Great idea!! and thank you for proposing this concept!! I guess everyone knows the adv. and dis adv. of this technology but it would be good if you can add some clarity on the following: 1. Basic cost economics numbers like (a) Levelised Cost of Electricity produced using OTEC (b) $ investment per MW (c) expected IRR 2. Cost of chilled water produced from OTEC vs. Conventional cooling system 3. List the challenges to OTEC (like the efficiency limit between 6 and 7%, effects on biodiversity, massive heat exchanger and its operational challenges) and any ideas from you to address them 4. List down some operational pilot plants and case studies around the world All the best, Saravanan.

Patrick Mcnulty

Jun 25, 2014
04:31

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Thanks Saravan, Lockheed Martin is building a 10MW prototype plant in Hawaii now with plans of a 100mw plant or greater. http://www.lockheedmartin.com/us/100years/stories/otec.html Effects of biodiversity is great because they drive fossil fuels off the market which will lower sea surface temperatures, restore Arctic Ice and drive Co2 back down to 300pppm in the atmosphere. So the effects are wanted. They can send the cold deep chilled water to the buildings for air conditioner purposes as well as supply base load to to the grid at the same time. Placed in the Gulfstream they have the potential to power the industrialized world over 100 times as mentioned in this NASA award winning video. Scroll to 2:35 seconds. https://www.youtube.com/watch?v=6hD52H7rQak . For us here in the USA we only need .5% of that energy to do the job. So if you like my proposal don't forget to click the support proposal icon near the top right of the page.

Patrick Mcnulty

Jun 25, 2014
04:29

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Basically we don't have a choice. We must build them or face 5,000 years of A warming planet with climate change projections to us 60 TRILLION dollars by 2050. That will bankrupt all societies on Earth. So we better get busy NOW. http://www.cnn.com/2013/07/24/world/climate-arctic-methane/

Patrick Mcnulty

Jun 25, 2014
04:18

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Basically we don't have a choice. We must build them or face 5,000 years of a warming planet with climate change projections to cost us 60 TRILLION dollars by 2050. That will bankrupt all societies on Earth. So we better get busy NOW. http://www.cnn.com/2013/07/24/world/climate-arctic-methane/

George Hawirko

Jun 30, 2014
07:17

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Maryette, heat could be extracted for hot water need's before the seawater returns to the ocean. This alone has a large monetary value.

Maryette Haggerty Perrault

Jul 7, 2014
05:33

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Thank you for addressing my concerns in such a concise way cyclonebuster! I personally feel that your proposal would greatly benefit from statistics such as those which you shared here in the comments section. Contrasting the proposed OTEC's precise outflow temperatures and rates with those of a coal or nuclear plant offers great context, particularly when you estimate how many coal/nuke plants could be decommissioned based on OTEC offsets. Your comments on the health of reefs being improved by lower water temperatures, and the fact that the discharge temperature proposed in your system is actually below that of surface ocean temperature is also quite intriguing to me. I'd love to see this incorporated into the proposal with the hard facts to back it up. Another useful analysis which could be included in your proposal could be how many square feet of buildings are in an area where OTEC could be used as a cooling source relative to the whole building stock. ergodesk - are you suggesting that preheating of domestic hot water could be done using the discharge water from OTEC? I was under the impression that discharge temperatures would be lower than what would be beneficial for DHW preheating, but I could be wrong. cyclonebuster, this would be a great reason to include specific discharge temperature examples! Thanks again for the great discussion that's happening here!

Patrick Mcnulty

Jul 7, 2014
07:51

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Maryette, Again thanks for for your interest.. OTEC systems typically use warm ocean surface water 90 to 95 degrees F. the warmer the better and more efficient they become as the temperature differential increases between the deep cool water and warm surface water... So the OTEC discharge water would still be well below the discharge temperature than that of nuclear or fossil fuel plants... If OTEC were to use 40 degree water as their cooling medium for their condensers then the exit temperatures for the condenser would be near 70 degrees F. much cooler than the condenser outlet of nuclear and fossil fuel plants. Mixing that 70 degree F water with the warm sea surface water at 90 degrees F with a 1:1 would give us 80 degree water to direct over the heat stressed reefs... You could also regulate the flow of that 70 degree F water to raise or lower the temperature over any time period so as to not shock the sea life in the area while cooling the reef... Computer modeling would give us the information we need.. This could easily cool every building on the East coast from Key West to North Carolina... Perhaps, further North too... The cubic footage is so large I wouldn't know how to begin to calculate it.