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  1. #14
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
    Posts
    1,595
    EFFICIENCY
    In the English l‑P system, chiller efficiency is measured
    in kW / ton:
    kW / ton = kW input
    tons refrigerant effect
    In the Sl Metric system, chiller efficiency is measured
    in Coefficient of Performance (COP).
    COP = kW refrigeration effect
    kW input
    kW / ton and COP are related as follows:
    kW/ton = 3.516
    COP
    COP = 3.516
    kW/ton
    Arguing with your Boss is like wrestling with a pig in
    mud.
    After a while you realize that while you are getting
    dirty, the pig is actually enjoying it.

    It is not exactly cheating, I prefer to consider it
    creative problem solving.

    25 years ago we had Bob Hope , Steve Jobs , and Johnny Cash today we have no Hope no Jobs and no Cash !
    I can fix broke but i can't fix stupid !

  2. #15
    Join Date
    Feb 2006
    Posts
    224
    EFFICIENCY
    In the English l‑P system, chiller efficiency is measured
    in kW / ton:
    kW / ton = kW input
    tons refrigerant effect
    In the Sl Metric system, chiller efficiency is measured
    in Coefficient of Performance (COP).
    COP = kW refrigeration effect
    kW input
    kW / ton and COP are related as follows:
    kW/ton = 3.516
    COP
    COP = 3.516
    kW/ton
    I think kw/ton and COP are two ways of describing the same thing only inverse of each other. kw/ton is" motor kw divided by tonnes of refrigeration."
    Where as COP is" kw refrigeration divided by motor kw."
    kw Refrigeration is tonnes x 12/3.41

    Jay, most 19XR's or YK with VSD will show power factors of 0.95-0.98.
    A power factor of 1.0 or greater will damage a motor windings. It wont matter much to the calculations.

  3. #16
    Join Date
    Aug 2000
    Location
    Austell, Ga.
    Posts
    1,294
    Power Factor can "Never" be greater than 1.
    A power factor of 1 indicates a purely resistive load.
    The power factor we always see would properly be stated as .95lag-.98lag ect.
    Going beyond a unity power factor of 1 results in the forbidden realm of "Leading power factor",(Capacitive load) again always less than 1, and would be stated as .95lead-.98 lead.(example)
    Please...No more references to "Greater than 1 power factor"...It just ain't there...
    Ain't "None" of us as smart as "All" of us..

  4. #17
    Join Date
    Sep 2004
    Location
    Kansas City, Kansas, United States
    Posts
    13,832
    GREAT!!!!!!!!!!!!!!!!!!!

    Great equipment room reading!!!!!!!!!


    Quote Originally Posted by jayguy View Post
    I WILL SELL WORK,GENERATE BUSINESS, GO GET NEW CUSTOMERS!
    YOU SHUT THE HELL UP AND QUIT RUNNING YOUR MOUTH!

  5. #18
    Join Date
    Jul 2012
    Posts
    25
    Are the power factors of these devices close enough to 1.0 that a capacitor is not needed on the secondary of the contactor? I would expect to find a power factor improvement capacitor on every device but I haven't seen a single one. Also, since it would only be active when the device was running and would be on the 240 VAC line with the rest of the branch circuits, I don't see any detriment to installing one at each chiller.

    Thoughts?

  6. #19
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,297
    Quote Originally Posted by jayguy View Post
    Damn Jay, you got me sidetracked and I forgot what this thread is about!!!

  7. #20
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,255
    Quote Originally Posted by R123 View Post
    Damn Jay, you got me sidetracked and I forgot what this thread is about!!!
    i forgot i did that too!
    my 1st time jumping out of a plane...http://youtu.be/Kv38G0MHsGo

  8. #21
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,255
    Quote Originally Posted by Priya1956 View Post
    Are the power factors of these devices close enough to 1.0 that a capacitor is not needed on the secondary of the contactor?...
    if you are talking about a vfd/vsd type of system, then you generally don't need or want a Power Factor Correction Capacitor between the line side of the drive and the utility. you definitely don't want any PFCC's between the drive and the motor.


    Quote Originally Posted by Priya1956 View Post
    ...I would expect to find a power factor improvement capacitor on every device but I haven't seen a single one....
    PFCC's have a lot of great things going for them, however, they are generally misunderstood and/or misapplied. PFCC's can cause a harmonic resonance in the power wiring of the system if they are not engineered properly...this generally doesn't happen, but it can.


    Quote Originally Posted by Priya1956 View Post
    ...Also, since it would only be active when the device was running and would be on the 240 VAC line with the rest of the branch circuits, I don't see any detriment to installing one at each chiller....
    i have seen many instances where they were sized for the chiller, installed AT the chiller but on the wrong side of the contactors (in a non-vfd chiller). this allowed for Power Factor Correction for the whole plant when the chiller wasn't running. every once in a while....BOOOOM.... and then every maintenance person running around like crazy. there are generally 2 different ways to install PFCC's and a 3rd hybrid which is what i like.

    1. install a big power factor bank at the utility entrance...the good: corrects for the whole building to 95% or so...the bad: only helps the utility, the building doesn't get any benefit except for a lower utility bill (which is nice, but there are other benefits that are missing)

    2. install a PFCC at every end device...the good: allows for better voltage regulation throughout the facility and a lower utility bill....the bad: high install cost and higher maintenance costs.

    3. install a PFCC at all of the non-vfd major loads (chillers, pumps, fans) and install a smaller PFCC bank at the enterance...the good: better voltage regulation throughout the facility, lower utility bills, lower overall costs, the PFCC bank can still be used to perform a final correction to 95% or better...the bad: still has a high cost per device but not as bad as Option #2.
    my 1st time jumping out of a plane...http://youtu.be/Kv38G0MHsGo

  9. #22
    Join Date
    Jul 2012
    Posts
    25
    The hybrid approach seems best especially as it improves power factor only on demand without the risk of overcompensation. Sounds like the big hurdle is quantifying the benefits beyond a reduction on the utility bill. How to put a $ value to better voltage regulation?

    Assuming that the capital cost of the PFCC is recovered only from a utility bill reduction, what is the typical payoff period for a device installed PFCC? Perhaps it is too long for owners to spend the capital up front??

  10. #23
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,255
    the benefits are difficult to quantify. like you said, you are helping them with 'savings' which is a negative cost and very difficult to prove. you are usually going to find the only customers who want this are large users, people who understand the benefits and those that are already having problems.
    my 1st time jumping out of a plane...http://youtu.be/Kv38G0MHsGo

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