Tapping Thermal-Gradient Cold: Free Power or Planetary Suicide?

Advocates of tapping ocean depths for “stored cold” promise a clean future of indoor comfort at low cost. But is this practice really environmentally friendly, or is it a slippery slope into unrecoverable catastrophe?

by Mary-Sue Haliburton
Pure Energy Systems News
Copyright © 2005

TORONTO, ONTARIO, CANADA -- The Enwave Company, noted for its steam heating services, is now getting into air conditioning by tapping Lake Ontario, which is deep enough to have a substantial supply of water in its densest and coldest state. They promote their new air-conditioning service by claiming that it has reduced electricity usage by 59 megawatts in Toronto. (ref)

Source: http://www.enwave.com/enwave/dlwc/
Deep Lake Water Cooling System

The company says that they are not pumping water out of the lake into buildings, but merely sending it through heat exchangers. The idea is to replace the many small electrically-powered units that use refrigeration technology by pre-cooling in a central plant, then feeding the coolant to the surrounding buildings. The company also says that deep-lake air-conditioning uses no CFCs, and that it will continue to work during blackouts. This technology and similar concepts are endorsed by Robert F. Kennedy and by various “Green” organizations and individuals.

So, what’s the problem?

Transferring heat into the depths of the lake is the problem, though it’s being touted as a solution to urban heat buildup. Eventually the added heat circulated back into the lake from the heat exchangers will push the deep water above four degree Celsius, the "anomaly point" that allows cold water to sink but ice to rise.

John Piña Craven
Source: Wired.com

Others are on this bandwagon, including John Piña Craven, who is planning large-scale developments in coastal areas that so that he can easily and cheaply tap the ocean’s cold depths. He says that what the world needs is more cold, not more heat. While that is true in one sense, it is stated in a backwards manner, and therein lies a misconception and a deeper issue.

John Piña Craven's concept:
Clockwise from top left: Power generation, desalination, irrigation, refrigeration.  Image by Bryan Christie

Clockwise from top left: Power generation, desalination, irrigation, refrigeration.
Source: Wired.com June '05

An article in Wired Magazine refers to this cold water as an “inexhaustible supply” for direct cooling, and for pulling fresh water out of the atmosphere as condensation. “Running the frigid pipes through heat exchangers produces unlimited air-conditioning that costs almost nothing,” the magazine gushes.

In the minds of “boomers” and older readers, such blanket statements may rouse uncomfortable echoes of 1950s promotional films, when we were being taught as children that fish in the ocean were an inexhaustible supply of food that could be harvested indefinitely. Now we are grown up, and aware of the Newfoundland fishery that had to be closed due to depletion of the northern cod, and that other fish species are under threat. Anyone remember the “tiny turbot” incident? An illegally-modified net captured from a deep-sea turbot-fishing vessel showed that this species was being taken while too immature to have reproduced even once! No species can withstand that type of pressure.

By now we are – or should be – suspicious of that word “inexhaustible” when it is being applied to any natural resource.

At its “anomaly point” of four degrees Celsius, fresh non-saline water is highly resistant to temperature change. It is also at its greatest density. At four degrees Celsius, it sinks below lighter layers of water that are warmer by even fractions of degrees. At the anomaly point, super-cooled but liquid water remains below ice due to the rapid expansion of H2O during freezing. And salt water may be even colder than that.

Such cold but not frozen water has other unusual properties, as discovered and elucidated by Viktor Schauberger. In his landmark book Living Energies, Callum Coats explains those theories, original inventions and patents, emphasizing particularly the critical nature of positive and negative temperature gradients to the biosphere. When the temperature rises on land due to deforestation and solar heating of manmade surfaces, rivers and other bodies of water become too warm due to this ambient heat and removal of shade from the shoreline. In this way, human landscape engineering based on ignorance of nature’s temperature gradients disrupts the climate and leads to desertification.

There is, therefore, a serious risk to unrestrained tapping of deep lakes or oceans to obtain and use this cold water. In moderation, and especially as an interim measure to reduce reliance on combustion and nuclear methods of electricity generation, it is tempting to feel that so-called deep-ocean cold extraction may give us more time to move toward a sustainable-energy future in which all life can flourish. However, to talk about transferring cold is a backward expression that should set off warning bells.

Cold is not “given off” – in any concept of physics. Heat, which is our perception of a higher energy state, is transferred into the area of lower energy, which feels “cooler” to our bodies. This process only feels – to our bodily perceptions – as if cold is “radiating” which is of course nonsense. Cold is not an energy that can be tapped. It is a lower-energy-state area into which we want to dump heat.

We must not wear rose-colored glasses. Expecting the great lakes and oceans to stay cold indefinitely while we pump heat into them flies into the teeth of logic. Just because deep-ocean warming may take a couple of decades, that delay doesn’t mean it’s not happening. It takes a while to boil water after you put the pot on the stove too.

As long as we thoughtlessly continue to build cities full of heat-absorbing pavement and black tarred flat roofs that heat up to fifty or sixty degrees Celsius, we are passively raising the temperature of significant areas of the planet. To transfer this passive heat buildup into large bodies of water would be slow suicide for the human race and all other creatures.

The better solution is to prevent the passive heat buildup in the first place, by redesigning our cities and by retrofitting as many black roofs, paved and bricked areas as possible with living green roofs, shade trees, and arbors which, in giving back the oxygen from the carbon dioxide, utilize the sun’s energy for photosynthesis instead of merely absorbing it. Studies show that living green surfaces of leaves do not build up heat. On the contrary, the slow evaporation of moisture from billions of leaves is nature’s refrigerator. This actually helps to cool both the plants and the surface of the ground below them. But I digress.

In the short term, there are profits to be made by exploiting this allegedly “free” resource. One might argue that regulating how much heat can be transferred into the lake or ocean, perhaps according to some formula related to its size and depth, would mean this practice is acceptable. As long as we continue to monitor the temperature of the deeper ocean layers and are prepared to cease operations when the deep-water temperature shows signs of beginning to rise in response to this activity, we might think that we’re not on thin ice.

But who would do, and pay for, this monitoring? Once a business infrastructure has been built and is bringing in profits, it is sustained by sheer psychological and financial inertia, and by political manipulation. Free enterprise hates regulation. Corporations resist paying taxes, especially to support monitoring of their activities. Should we let the plans to transfer heat into deep water go ahead and trust business to regulate itself?

We’ve all seen examples of “self-regulating” industries pushing the financial envelope and covering up environmental abuses. Think “Enron”. (ref: The recent film, ENRON: The Smartest Guys in the Room, shows the complete disregard for any principle other than maximizing profit. The attitude driving this energy company led to criminal fraud on a massive scale.)

And, evidence is already in that deeper ocean temperatures are not permanently colder. But spokesmen for profitable combustion-energy businesses (including their minions in the current U.S. Administration) dismiss the implications of the U.S. National Oceanic and Atmospheric Administration report. Based on worldwide data and adjusting for all possible regional variation, this report shows there has already been an increase half of one degree Celsius overall in average ocean temperature worldwide over the past forty years. (ref)

This report indicates that this temperature change affects deeper levels in the Atlantic Ocean as opposed to the Pacific, probably due to the smaller size. (It takes longer to boil a big pot of water than a small one on a burner of the same size.)

This change has been tracked over past decades and has occurred due to factors already present before the use of extracting deep cold. And we are about to turn up the heat under our global water-pot.

We can confidently predict that ocean warming will speed up once mining of cold – i.e. transferring of heat into the ocean depths – is in full swing. Even before large-scale ocean-sourced air conditioning is implemented, this oceanic temperature increase will result in faster melting of Arctic ice, which in turn is likely to contribute to increased warming due to loss of the white heat-reflective ice sheets. And the severity and frequency of hurricanes, which are generated over warm ocean surfaces, is likely to increase as well.

This is why we should regard this glowing advocacy of tapping the ocean temperature gradient with a great deal of caution and skepticism. Cold, deep water is a resource which is vital to survival of life on earth. And it is not infinite.

In the light of this, then, I read with dismay the proposal of John Craven and his investors to build developments based on tapping ocean cold. The ideal location is an island with no continental shelf, so that it’s even cheaper and easier to exploit that natural resource. “Sink a big pipe, crank a pump, and - voilà! - you've entered a world powered by ocean water. Once primed, the pipe acts like a giant siphon, requiring relatively little energy to keep an inexhaustible supply of cold at hand.” Craven’s Natural Energy Lab is already using a fifty-five-inch diameter pipe which puts 27,000 gallons a minute at their disposal, twenty-four/seven.

There are those rose-colored glasses again. Inexhaustible supply feeds a giant siphon and it doesn’t even need to be pumped up – that is, until the temperature gradient becomes compromised and we end up in more serious trouble than we are in now. Since the purpose of that plan is profit, not saving the environment, we are free to critique both the concept and the outcome. The planned development on Saipan will feature townhouses, a golf course, soccer fields, and athletic complex, with the intention of attracting athletes who have a healthy training budget.

The idea of making multiple uses of this same seawater is at least less wasteful than merely mining for cold. For example, the Craven complex includes applying cooler condensate water to plant roots to stimulate growth in greenhouses, at least in species that like their roots to be cooler than their crowns.

And the contrasting temperature from surface and deep water is used to generate electricity without combustion. The Wired article is rather vague about this process, stating only that the warmer water enters a vacuum chamber and evaporates into steam that drives a turbine to generate electricity. One is also wondering where the energy comes from to drive the suction machine that creates the vacuum. Is that how the solar energy is used?

Then the colder water condenses the steam back into drinking water, thus efficiently combining desalination with power generation. However, that colder water, now much less cold, is returned to the ocean, where it will not sink back down to the deepest layers, but find its level according to the laws of temperature gradient and laminar flow. Eventually the deepest cold layer will become thinner as the warmer layers above it deepen and continue to get warmer. Have climate-change researchers added this new variable to their predictions yet? If not, it’s time to do so!

It may be a long time before the ocean’s reserve of anomaly-point cold water is depleted, but it can happen given enough time and enough developments like those of Mr. Craven. A rise of between eight and twelve degrees Celsius worldwide is all that is required to make the planet uninhabitable. Therefore, we should question this resource exploitation and challenge those who conduct it for profit to prove their restraint.

To make environmentally-responsible use of this deep-water-cold, the power company must not be permitted to regard it as a bottomless heat-dump. After transferring heat into this water, the business exploiting the resource must re-cool it back down to four degrees Celsius, before it goes back into to the ocean or deep lake. This may perhaps be achieved cheaply by means of a night-time cooling pond, and/or an additional expansion-coil in the outlet pipe. (ref)

Otherwise we, or our descendants, may all come to a slow boil.

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Living Energies: The Schauberger's Work With Trees, Light, Air, and Water
  • How Air Conditioners Work - (HowStuffWorks.com)
    [In the diagram at this site, both high- and low-pressure coils are shown the same size, and the expansion valve is shown as a narrowing of the tube! This could create confusion. Unfortunately search engines turn up many diagrams purporting to explain refrigeration principles but which are similarly oversimplified, failing to display pictorially the difference of coil diameter between the high-pressure thin segment and the larger-diameter, low-pressure, cooled segment. Would simple gravity pulling water down through an expansion valve cool it sufficiently without further application of pumping power?]

  • Ocean temperature increase more proof of Global Warming! (18.02.2005) (found at Profindpages.com)


From: Mary-Sue
Sent: Thursday, July 21, 2005 10:55 AM
Subject: [pes_news] Lake Ontario heating up, blackout threat - news report

The Canadian Weather Channel reported today (July 21) that Lake Ontario is five degrees warmer than it was last summer, and is therefore less effective at cooling the nuclear plants. This increases the threat of rolling blackouts. Both the direct heating from the sun, and using cold water from (i.e. transferring heat into) the lake from industrial cooling are combining to produce this heating up of a major body of water.

The above note should be appended to the article about cold-water air conditioning, in which I questioned the assumption that this resource is "free" and "unlimited".