On summary, the OTECs process would make deep water warmer and surface water cooler. Since the heat exchange process on the deep water areas formation keep going, we still have water masses getting denser, and so sinking. Due the continuity the surface water must move to fill that gap. Since the OTECs is making the surface water cooler, the formation area would start with lower temeperature and so the final temperature, after loss heat to atmosphere, should be lesser, so higher density and keep sinking. On this sense you might be right, this circulation shouldn't stop. But thinking on the energy flux, since the tropical waters would be colder, the heat advection to north Atlantic should be lesser, and so the available energy there (N. Atlantic). This is because OTECs process should improve the vertical heat exchange, which now is slow and spread around the world. The conclusion is that the winter on north Atlantic should be more intense.
About the scale, you're right again! They might not be able to develop a complex big enough to make significant difference on energy involved on the Thermohaline Circulation (TC), but conceptualy, more energy took from there, colder winter, higher demand of energy to warm homes. Considering the possible eficiency of the process, this can't has a positive balance (for us).
The most interesting point that you're question bring is, actually the OTECs system should tend to reduce the TC area. What was suposed to run around almost all the world would be confined to the Atlantic, or at least part of the energy. This is interesting! The first thing I can imagine is the movement downard of the thermocline around the world, outside the new reduced TC. Since you close the cicle, why deep water should keep cold? Thermohaline deeper means more energy available on surface oceans, the same energy used by hurricanes. Maybe lesser sazonality due the higher specific heat of the water. But in oposite direction higher evaporation and heat loss from ocean to atmosphere by latent and sensible heat, plus the long wave. All due a higher sea surface temperature. I don't know what would be the new balance!?! I would need to think more about it.
There is a global circulation system called thermohaline. Basically in three relative small areas of the oceans the water sinks until the bottom, and then spread around the world. This water slowly go up again and the system is closed with surface warmer waters flowing in direction of the areas of generation.
I'm not even considering the energetic balance of the proposed structure, but if it works it might reduce the vertical thermal gradient and make the thermohaline circulation weaker. Maybe stop it. The movie "The Day After Tomorrow" is a fantasy about it, but be sure at least that the surface temperature on the North Atlantic would reduce since is one of those areas of generation of deep waters. You can imagine how would be the winter on Europe and North America? Would need a lot of energy to keep people warm there!
There is a global circulation system called "Thermohaline Circulation". Basically some amount of water, North Atlantic Deep Water (NADW), sink around Labrador Sea, due high salinity and low temperature, until sea bottom (or almost there) and then spread around the world following the Stommel-Arons model.
Due mass continuity, some amount of water must source that water and this is made by surface water, which is much warmer than that cold deep water. So, North Atlantic export cold water and import warm one, which means a positive heat balance. Without that, North America and Europe should be colder than they are now. Some people would call that "Climate Changes"!;)
P.S.: This is only part of the story, where I neglect some "details".
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Good question!
On summary, the OTECs process would make deep water warmer and surface water cooler. Since the heat exchange process on the deep water areas formation keep going, we still have water masses getting denser, and so sinking. Due the continuity the surface water must move to fill that gap. Since the OTECs is making the surface water cooler, the formation area would start with lower temeperature and so the final temperature, after loss heat to atmosphere, should be lesser, so higher density and keep sinking. On this sense you might be right, this circulation shouldn't stop. But thinking on the energy flux, since the tropical waters would be colder, the heat advection to north Atlantic should be lesser, and so the available energy there (N. Atlantic). This is because OTECs process should improve the vertical heat exchange, which now is slow and spread around the world. The conclusion is that the winter on north Atlantic should be more intense.
About the scale, you're right again! They might not be able to develop a complex big enough to make significant difference on energy involved on the Thermohaline Circulation (TC), but conceptualy, more energy took from there, colder winter, higher demand of energy to warm homes. Considering the possible eficiency of the process, this can't has a positive balance (for us).
The most interesting point that you're question bring is, actually the OTECs system should tend to reduce the TC area. What was suposed to run around almost all the world would be confined to the Atlantic, or at least part of the energy. This is interesting! The first thing I can imagine is the movement downard of the thermocline around the world, outside the new reduced TC. Since you close the cicle, why deep water should keep cold? Thermohaline deeper means more energy available on surface oceans, the same energy used by hurricanes. Maybe lesser sazonality due the higher specific heat of the water. But in oposite direction higher evaporation and heat loss from ocean to atmosphere by latent and sensible heat, plus the long wave. All due a higher sea surface temperature. I don't know what would be the new balance!?! I would need to think more about it.
Deja vu!?!
There is a global circulation system called thermohaline. Basically in three relative small areas of the oceans the water sinks until the bottom, and then spread around the world. This water slowly go up again and the system is closed with surface warmer waters flowing in direction of the areas of generation.
I'm not even considering the energetic balance of the proposed structure, but if it works it might reduce the vertical thermal gradient and make the thermohaline circulation weaker. Maybe stop it. The movie "The Day After Tomorrow" is a fantasy about it, but be sure at least that the surface temperature on the North Atlantic would reduce since is one of those areas of generation of deep waters. You can imagine how would be the winter on Europe and North America? Would need a lot of energy to keep people warm there!
There is a global circulation system called "Thermohaline Circulation". Basically some amount of water, North Atlantic Deep Water (NADW), sink around Labrador Sea, due high salinity and low temperature, until sea bottom (or almost there) and then spread around the world following the Stommel-Arons model.
Due mass continuity, some amount of water must source that water and this is made by surface water, which is much warmer than that cold deep water. So, North Atlantic export cold water and import warm one, which means a positive heat balance. Without that, North America and Europe should be colder than they are now. Some people would call that "Climate Changes"! ;)
P.S.: This is only part of the story, where I neglect some "details".