Chiller Efficiency Improvements hvac chillers
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Date: 2023-11-17
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Comments and reviews: 11
Elliot
Some great videos Paul. One thing that is not mentioned here is regarding the size of the heat exchanger - because it is sized for the peak load, when running at part loads the flow still goes through the same heat exchanger but at lower velocities. Reduced velocities equate to lower Reynold's numbers (a measure of how turbulent the flow is) - the higher the Reynold's number the better the heat transfer and hence efficiency. If the Reynold's number is low enough the flow is laminar and there is a significant reduction in performance. Hence operating at part loads causes a loss in efficiency as the heat exchanger is essentially oversized. This can also cause the heat exchanger to foul up more quickly as the particles that cause fouling can drop out more easily and stick to the surface of the heat exchanger. The only way to improve this is to have multiple heat exchangers that can be brought online as the load increases - however this is not always an option with space restrictions so the design of the heat exchanger is fundamentally important in that respect.
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Some great videos Paul. One thing that is not mentioned here is regarding the size of the heat exchanger - because it is sized for the peak load, when running at part loads the flow still goes through the same heat exchanger but at lower velocities. Reduced velocities equate to lower Reynold's numbers (a measure of how turbulent the flow is) - the higher the Reynold's number the better the heat transfer and hence efficiency. If the Reynold's number is low enough the flow is laminar and there is a significant reduction in performance. Hence operating at part loads causes a loss in efficiency as the heat exchanger is essentially oversized. This can also cause the heat exchanger to foul up more quickly as the particles that cause fouling can drop out more easily and stick to the surface of the heat exchanger. The only way to improve this is to have multiple heat exchangers that can be brought online as the load increases - however this is not always an option with space restrictions so the design of the heat exchanger is fundamentally important in that respect.
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Big
Cooling tower fans do not consume a lot of power compared to the chiller compressor(s. I don't like a single condenser water set point (i. e. 80F/27C, because it often makes the chillers work harder unnecessarily, killing your COP. I prefer targeting 5F(3C) above the outside air wet bulb temperature with a 55F(13C) low limit. This strategy works in every climate, dry or humid.
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Cooling tower fans do not consume a lot of power compared to the chiller compressor(s. I don't like a single condenser water set point (i. e. 80F/27C, because it often makes the chillers work harder unnecessarily, killing your COP. I prefer targeting 5F(3C) above the outside air wet bulb temperature with a 55F(13C) low limit. This strategy works in every climate, dry or humid.
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Austin
Thanks for your videos! Do you have any extra information or videos on how to go about utilizing a chiller sequencer? Is this similar to lead/lag, or can I program the chillers to run at specific loads instead of just on/off.
We have two chillers of different capacities, so each has different efficiencies at different loads.
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Thanks for your videos! Do you have any extra information or videos on how to go about utilizing a chiller sequencer? Is this similar to lead/lag, or can I program the chillers to run at specific loads instead of just on/off.
We have two chillers of different capacities, so each has different efficiencies at different loads.
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Amir
These standard manufacturers of chillers are not efficient. We have a new carrier unit chiller and the power consumption is horrible. We purchased an chiller from a refrigeration company that designed it from scratch, and its consuming half the electricity of the carrier unit. Plus it was about 30%cheaper than the carrier unit
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These standard manufacturers of chillers are not efficient. We have a new carrier unit chiller and the power consumption is horrible. We purchased an chiller from a refrigeration company that designed it from scratch, and its consuming half the electricity of the carrier unit. Plus it was about 30%cheaper than the carrier unit
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maboto6969
hello,
big thanks on all the great videos you post. they are a huge help.
is there an option that you will do a video or a series of videos about
humidifiers and how they work?
reply
hello,
big thanks on all the great videos you post. they are a huge help.
is there an option that you will do a video or a series of videos about
humidifiers and how they work?
reply
education
is there a video out for setting up danfoss hvac drives especially one that goes into all the settings and software settings? ive seen some but not all of them are that helpful.
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is there a video out for setting up danfoss hvac drives especially one that goes into all the settings and software settings? ive seen some but not all of them are that helpful.
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Abhishek
Does EC (air-cooled chiller) fans retrofit at condenser improve the efficiency significantly where the normal non-EC fans used have staging feature?
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Does EC (air-cooled chiller) fans retrofit at condenser improve the efficiency significantly where the normal non-EC fans used have staging feature?
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DecimalZero
You do amazing videos, thank you! The animation in your videos, showing the moving lines representing flow, what program are you using?
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You do amazing videos, thank you! The animation in your videos, showing the moving lines representing flow, what program are you using?
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MD
Your video are really amazing. Can you please a video on chemical dosing for Condenser water & chilled water. your work is highly appreciated.
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Your video are really amazing. Can you please a video on chemical dosing for Condenser water & chilled water. your work is highly appreciated.
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Suhaila
What are the pros and cons of increasing the chiller's flow rate? by increasing the chiller flow rate, it'll produce more cooling water.
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What are the pros and cons of increasing the chiller's flow rate? by increasing the chiller flow rate, it'll produce more cooling water.
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DaleDozer
i work for Johnson Controls, i love the videos i tell my guys to check out alot of your vids it helps train alot of these younger guys
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i work for Johnson Controls, i love the videos i tell my guys to check out alot of your vids it helps train alot of these younger guys
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