Chuck Spyropulos
Non-member
Yes, I agree...see my last post
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How does it work? Vol 3: Closed loop
- Thread starter Moe_K
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Chuck,
I posted before seeing your last post.
>Greg, I think the heat you are referring to is the heat that is dissipated in the process that brings the water back to calm, or that converts the kinetic energy of the moving water into heat. Of course this is all due to friction and yes the product of friction is heat. The water hits the side of the tank, scrapes across the tank surfaces, etc and the product is heat. However, the water is also cooling naturally during the evaporation process.<
Although I suppose if you had a Tunze mounted close to the water surface it might speed evaporation, but if it was mounted at depth I don't see how this would have much effect.
> This effect, plus the fact that you need much more energy to heat up the water than you do to move it, makes this effect negligible. If this were not the case then we would use pumps or water motion instead of resistive heaters to heat our water when required !<
IMO the effect is the same, you can heat your tank with pumps if you like. However, if you are using a non-submersible pump then some of the heat is lost to the air cooling on the pump, and therefore not the most efficient way if all you are doing is trying to heat the water.
>Also this effect occurs regardless of how you input the kinetic energy (powerheads, Streams, external pumps), and as such is not a discriminating factor when comparing the performance of these devices.<
I agree of course. The thing that people need to understand is that ANY submersible device that uses electricity converts ALL the electricity to heat. No two ways around it.
I posted before seeing your last post.
>Greg, I think the heat you are referring to is the heat that is dissipated in the process that brings the water back to calm, or that converts the kinetic energy of the moving water into heat. Of course this is all due to friction and yes the product of friction is heat. The water hits the side of the tank, scrapes across the tank surfaces, etc and the product is heat. However, the water is also cooling naturally during the evaporation process.<
Although I suppose if you had a Tunze mounted close to the water surface it might speed evaporation, but if it was mounted at depth I don't see how this would have much effect.
> This effect, plus the fact that you need much more energy to heat up the water than you do to move it, makes this effect negligible. If this were not the case then we would use pumps or water motion instead of resistive heaters to heat our water when required !<
IMO the effect is the same, you can heat your tank with pumps if you like. However, if you are using a non-submersible pump then some of the heat is lost to the air cooling on the pump, and therefore not the most efficient way if all you are doing is trying to heat the water.
>Also this effect occurs regardless of how you input the kinetic energy (powerheads, Streams, external pumps), and as such is not a discriminating factor when comparing the performance of these devices.<
I agree of course. The thing that people need to understand is that ANY submersible device that uses electricity converts ALL the electricity to heat. No two ways around it.
Chuck Spyropulos
Non-member
But, this is not directly produced by the pump and it does not depend on how you input the kinetic energy.
Plus you have to consider evaporative cooling of the water....the water does not boil right ? It takes a LOT of kinetic energy in a closed system (unlike our open top aquariums) over a long time to heat up water this way.
Plus you have to consider evaporative cooling of the water....the water does not boil right ? It takes a LOT of kinetic energy in a closed system (unlike our open top aquariums) over a long time to heat up water this way.
Chuck Spyropulos
Non-member
OK...I think I finally understand both of our points!
I think we beat the dead horse to death, as well!
I think we beat the dead horse to death, as well!
Chuck Spyropulos
Non-member
Hey Dennis....how's it going?
>Plus you have to consider evaporative cooling of the water....the water does not boil right ?<
Actually, if you put a such a device into a perfectly insulated container full of water, assuming the device could continue to operate at high temperature...yes...the water would boil.
I agree that evaporative cooling is one of the most efficient ways of cooling a tank.
Keep in mind, I'm not saying that the Tunze's over heat the average tank...I think they are fine, that's why I'm planning on using them.
What happens to the heat created by any device in the tank.....it accumulates (your tank heats up) until the rate of cooling of the tank is equivalent to the rate of input of energy (heat in heat out, NO accumulation). Recall that the rate of cooling of a tank is equal to the heat removed by evaporation (which will be higher/faster as the water temp is higher), and the overall losses of heat from radiation (small, but dependent on temp diffs raised to the fourth as I recall), and convection and conduction to the surrounding air and solid 'things' in contact with the tank. For conduction (and convection I think, but it's been a long time) the rate of heat transfer out will be equal to some heat transfer coefficient (which will depend upon a LOT of factors, but which will can be considered to be largely constant if the temps are not changing too much) and the difference in the temperatures of the two objects (your tank and the surroundings, air or other surroundings). So...as your tank heats up and the difference in the temperatures is higher the heat transfer will increase. No difference in temperature...no transfer of heat. If your tank is at 80 and the room is at 80 no cooling due to conduction at all. If your tank is at 82 and the room at 80 then 2 times the heat transfer coefficient. If 84 and the room at 80, then twice as much conductive heat transfer as with 80 and 82.
Actually, if you put a such a device into a perfectly insulated container full of water, assuming the device could continue to operate at high temperature...yes...the water would boil.
I agree that evaporative cooling is one of the most efficient ways of cooling a tank.
Keep in mind, I'm not saying that the Tunze's over heat the average tank...I think they are fine, that's why I'm planning on using them.
What happens to the heat created by any device in the tank.....it accumulates (your tank heats up) until the rate of cooling of the tank is equivalent to the rate of input of energy (heat in heat out, NO accumulation). Recall that the rate of cooling of a tank is equal to the heat removed by evaporation (which will be higher/faster as the water temp is higher), and the overall losses of heat from radiation (small, but dependent on temp diffs raised to the fourth as I recall), and convection and conduction to the surrounding air and solid 'things' in contact with the tank. For conduction (and convection I think, but it's been a long time) the rate of heat transfer out will be equal to some heat transfer coefficient (which will depend upon a LOT of factors, but which will can be considered to be largely constant if the temps are not changing too much) and the difference in the temperatures of the two objects (your tank and the surroundings, air or other surroundings). So...as your tank heats up and the difference in the temperatures is higher the heat transfer will increase. No difference in temperature...no transfer of heat. If your tank is at 80 and the room is at 80 no cooling due to conduction at all. If your tank is at 82 and the room at 80 then 2 times the heat transfer coefficient. If 84 and the room at 80, then twice as much conductive heat transfer as with 80 and 82.
>I think we beat the dead horse to death, as well<
It's not dead yet, put I do have to sleep.
Have a good night.
It's not dead yet, put I do have to sleep.
Have a good night.NateHanson
Non-member
Yikes, this is worse than the MACNA discussions! 
What were we talking about?
What were we talking about?
Chuck Spyropulos
Non-member
Summary
Just to be clear:
External pumps generate radiant heat that is lost to the surrounding air and thus does not heat the water up as much as a TOTALLY submerged pump.
Powerheads radiate heat and DO heat your water up since they are submerged and any radiated heat will heat the water.
Tunze Streams are sort of a different class since the part that is submerged is a DC motor and a propeller that radiate much less heat than an AC motor. The transformer and electronic controller for each Stream is located outside the tank and thus they also radiate heat to the surrounding air. Incidentally this means that not all of the energy is converted to kinetic energy so watt for watt we can never completely transfer the total power supplied to the Tunze to water motion....and yes, in the end, to heating the water.
ALL of these pumps move water since they convert electrical energy into water motion. Of course, the kinetic energy in the moving water has to go somewhere and it will heat up the water in the end AND create sound waves AND cause splashing AND result in loss of water AND do any other kind of work (like break your tank....just kidding). So technically, since heating may not be the ONLY work that is performed, not all of the electical energy may converted to heat. But this effect is common to all of these devices, or any water movement device, and can not be eliminated. While an interesting observation of a fundamental law of thermodynamics (conservation of energy).....it is useless in deciding what kind of water motion system (closed or open loop) to use.
My point is that the Tunze Streams will tend to not heat up your water (by radiating heat) as much as a powerhead and that they are much more efficient at generating water motion than either a powerhead or an extenal pump for the reasons explained in my previous posts.....THAT'S IT.....that is all I was trying to say in the beginning of this thread. What happens to the kinetic energy present in the water motion is irrelevant, when comparing the various devices discussed above, since it is ever-present regardless of the water motion device and it can never be eliminated. Therefore it has nothing do do with the point I was trying to make earlier regarding the Tunze Stream's efficiency when compared to the other pumps/devices.
Just to be clear:
External pumps generate radiant heat that is lost to the surrounding air and thus does not heat the water up as much as a TOTALLY submerged pump.
Powerheads radiate heat and DO heat your water up since they are submerged and any radiated heat will heat the water.
Tunze Streams are sort of a different class since the part that is submerged is a DC motor and a propeller that radiate much less heat than an AC motor. The transformer and electronic controller for each Stream is located outside the tank and thus they also radiate heat to the surrounding air. Incidentally this means that not all of the energy is converted to kinetic energy so watt for watt we can never completely transfer the total power supplied to the Tunze to water motion....and yes, in the end, to heating the water.
ALL of these pumps move water since they convert electrical energy into water motion. Of course, the kinetic energy in the moving water has to go somewhere and it will heat up the water in the end AND create sound waves AND cause splashing AND result in loss of water AND do any other kind of work (like break your tank....just kidding). So technically, since heating may not be the ONLY work that is performed, not all of the electical energy may converted to heat. But this effect is common to all of these devices, or any water movement device, and can not be eliminated. While an interesting observation of a fundamental law of thermodynamics (conservation of energy).....it is useless in deciding what kind of water motion system (closed or open loop) to use.
My point is that the Tunze Streams will tend to not heat up your water (by radiating heat) as much as a powerhead and that they are much more efficient at generating water motion than either a powerhead or an extenal pump for the reasons explained in my previous posts.....THAT'S IT.....that is all I was trying to say in the beginning of this thread. What happens to the kinetic energy present in the water motion is irrelevant, when comparing the various devices discussed above, since it is ever-present regardless of the water motion device and it can never be eliminated. Therefore it has nothing do do with the point I was trying to make earlier regarding the Tunze Stream's efficiency when compared to the other pumps/devices.
NateHanson
Non-member
jimmyj7090 said:
In Layman's Reef terms, it's a pump that sucks water from the display tank, and blows it back into the same tank, utilizing no other tank or open reservoir in the system, other than the display tank.
Thanks guys,
I was really just trying to coax the thread back to topic.
How about the "Calfo Loop"? I saw a drawing of one the other day in another thread that did not look like a closed loop if I understood the diagram right (looked like it pulled water from the sump and returned it to the display).
I was really just trying to coax the thread back to topic.
How about the "Calfo Loop"? I saw a drawing of one the other day in another thread that did not look like a closed loop if I understood the diagram right (looked like it pulled water from the sump and returned it to the display).
Jimmy,
Nothing wrong with that type of loop, but you lose the energy that the water had when it was at the height of the tank, so for the same flow generated you generate more heat. The pump has to be stronger to compensate for the head loss.
Nothing wrong with that type of loop, but you lose the energy that the water had when it was at the height of the tank, so for the same flow generated you generate more heat. The pump has to be stronger to compensate for the head loss.
Matt L.
Non-member
Jimmy, sorry for any confusion. I gave you the true hydraulic definition of a closed loop, which differs from the reef definition of a closed loop.jimmyj7090 said:
Look to Nate's post for the reefing definition of a closed loop and disregard what I said.
The only reason I responded as I did was because I thought you were referring to a past line in this thread where I discuss with Chuck past arguments over the term "closed loop"
The "Calfo" closed loop is just another form of closed loop (or not, if you go by the actual definition!) where the discharge is above the water surface and creates a water jetting action on the surface. Greg is right. This form of a loop is less hydraulically efficient but has other benefits,jimmyj7090 said:
Matt
