Pepsi, let me try to answer your question.
The quick and dirty answer is "No". Submersible or otherwise does not matter when talking about "pump heat".
A pump simply transfers the mechanical energy from the rotating shaft to the fluid being pumped. It does not matter what form the pump takes (submersible, centrifigal, positive displacement, etc.) as energy must be conserved.
If you are driving the pump with an electric motor, the electrical energy the motor uses ends up somewhere and it must all be accounted for. The Ehiem, 1048, for example, is rated at 10 watts. Since the pump is not operating at runout (max possible flow rate), somewhat less than 10 watts is actually being consumed by the motor. Let's assume the motor uses only 8 watts. A very small percentage of this 8 watts is dissapated as heat from the motor itself. The rest ends up as mechanical energy in the rotating shaft. All this energy (assume 7.5 watts - this is a guess) ends up in the water and it appears in the form of an elevated temperature. Again, I must emphasize, that the type or form of the pump does not matter. The energy still is transfered into the water.
As an aside, once this energy is in the water, almost all of it appears in the form of a higher water temperature. The pump does increase the mass flow rate and therefore the Kinetic Energy of the water. However, surprising to many, the increase in Kinetic Energy of the water only reperesents an insignificant amount of the energy contained in the water. Something called the "General Energy Equation" explains this but this is well beyond anything that should be discussed here.
More flow means better cooling in the heat exchangers. However, we have a double edged sword here because increasing flow via pump capacity means we are putting more energy into the system that must also be removed. You will find a balance, or sweet spot as some others have called it, where temperatures will be the lowest. Assuming your pumps are centrifugal pumps, I would suggest controlling your flow by throttling the discharge (certainly not the suction) of your pump. Even though it is still a big pump, the amount of energy a centrifigal pump uses is proportional to the flow. Therefore, if you throttle the flow, you will be putting less pump heat into the system. The big motor may be operating a little less efficiently but this will be a very minor effect.
If it is not a centrifigal pump, do not even think of trying to throttle the discharge. For example positive displacement pumps (piston, gear, etc) are going to pump at a flow rate determined by the speed of the motor. Attempting to throttle the discharge of PD pumps will only result in an ever increasing discharge pressure until something bursts. Also, if you try to throttle the suction of any pump, you seriously risk cavitating the pump.
I hope this answers your question.
The quick and dirty answer is "No". Submersible or otherwise does not matter when talking about "pump heat".
A pump simply transfers the mechanical energy from the rotating shaft to the fluid being pumped. It does not matter what form the pump takes (submersible, centrifigal, positive displacement, etc.) as energy must be conserved.
If you are driving the pump with an electric motor, the electrical energy the motor uses ends up somewhere and it must all be accounted for. The Ehiem, 1048, for example, is rated at 10 watts. Since the pump is not operating at runout (max possible flow rate), somewhat less than 10 watts is actually being consumed by the motor. Let's assume the motor uses only 8 watts. A very small percentage of this 8 watts is dissapated as heat from the motor itself. The rest ends up as mechanical energy in the rotating shaft. All this energy (assume 7.5 watts - this is a guess) ends up in the water and it appears in the form of an elevated temperature. Again, I must emphasize, that the type or form of the pump does not matter. The energy still is transfered into the water.
As an aside, once this energy is in the water, almost all of it appears in the form of a higher water temperature. The pump does increase the mass flow rate and therefore the Kinetic Energy of the water. However, surprising to many, the increase in Kinetic Energy of the water only reperesents an insignificant amount of the energy contained in the water. Something called the "General Energy Equation" explains this but this is well beyond anything that should be discussed here.
More flow means better cooling in the heat exchangers. However, we have a double edged sword here because increasing flow via pump capacity means we are putting more energy into the system that must also be removed. You will find a balance, or sweet spot as some others have called it, where temperatures will be the lowest. Assuming your pumps are centrifugal pumps, I would suggest controlling your flow by throttling the discharge (certainly not the suction) of your pump. Even though it is still a big pump, the amount of energy a centrifigal pump uses is proportional to the flow. Therefore, if you throttle the flow, you will be putting less pump heat into the system. The big motor may be operating a little less efficiently but this will be a very minor effect.
If it is not a centrifigal pump, do not even think of trying to throttle the discharge. For example positive displacement pumps (piston, gear, etc) are going to pump at a flow rate determined by the speed of the motor. Attempting to throttle the discharge of PD pumps will only result in an ever increasing discharge pressure until something bursts. Also, if you try to throttle the suction of any pump, you seriously risk cavitating the pump.
I hope this answers your question.
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