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  1. #14
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    Feb 2016
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    Louisburg Kansas
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    For the evaporative cooling tower guys we should add when it comes to cooling tower fan airflow everything matters.

  2. #15
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    Apr 2017
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    Houston, Tx
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    absolutly. i imagine cooling tower calcs would be very tight?

    lol... there is a small manufacturing place on my way to work. they have this adorable little little hyperbolic fiberglass tower thing ontop of what looks like a tubaxial fan box. i always wonder about that thing. maby its just an evaporative cooler? idk... this is houston, i dont imagine an evaporative cooler that small would do very much.

    literally like 7 feet tall including the fan box.

  3. #16
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    Tower calcs are a pain that is why I mentioned them because miniscule differences in the saturated air tables makes a difference. Funny how that tower has got your attention and funnier I'm the same way. What is your design tower wet bulb 79 F?

  4. #17
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    Apr 2017
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    Houston, Tx
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    oh man i have never even considered designing a cooling tower if thats what you are asking.

    but i just pulled out the ASHRAE houston station and our 1% cooling day is 93.3 and 77.5 dry bulb and wet bulb average at 93.3

    our evap. 1% day is 80f wet bulb and 88.3 dry bulb average at 80f wet bulb.

    edit:

    btw, have you ever seen a similar teensy cooling tower like that before? im curious if its some sort of wierd retrofit job to gain some more efficiency... but its jsut so tiny.

    i have heard of some company in colerado that makes condensing units with evaporative cooling pads built in that it draws air through... but this thing looks nothing like that particular unit.

  5. #18
    Join Date
    Sep 2015
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    Many T&B companies use Shortridge instruments, but they are very costly and I understand only Shortridge sells them.

    A Dwyer 0-0.25" wg magnehelic with their stainless steel pitot tube will do the job. I have a 36" and 12". This is an all manual approach and IMHO a PITA.

    The best for my purpose is an Amprobe unit. More accurate than the above gauge, much more user friendly and at this price you won't lose your shirt if it goes clattering down a duct shaft. Mine captures temperature and humidity, makes all the corrections, stores individual readings, provides flow based on inputted duct size and downloads to a laptop.
    https://www.amazon.com/Amprobe-TMA-2...probe+air+flow

  6. #19
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    Feb 2016
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    queequeg,
    The smallest HVAC evap cooling tower I tested was 25 ton. It was bigger than the tower you described. I did some dry coolers that were about that size but most of them were for equipment cooling. I did test the cooling tower at that theater just outside Dallas but couldn't remember the design wet bulb. That is the only tower I ever tested that overflowed with design GPM.
    throrope,
    True most TAB companies use Shortridge or Alnor equipment. The main reason is not many manufacturers equipment meets all the certifying agencies requirements because the market isn't big enough. Most balancers prefer Shortridge equipment which is a little more expensive than Alnor. I have some equipment from both companies but it is all really expensive and calibration check is also expensive and has to be done yearly. Unless you have a lot of use for the equipment you are better served going cheaper except for maybe the flow hood.
    It is a good idea to have an inclined manometer in the event you have doubt about the accuracy of a traverse.

  7. Likes queequeg152 liked this post
  8. #20
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    Apr 2017
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    Houston, Tx
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    Quote Originally Posted by WAYNE3298 View Post
    queequeg,
    The smallest HVAC evap cooling tower I tested was 25 ton. It was bigger than the tower you described. I did some dry coolers that were about that size but most of them were for equipment cooling. I did test the cooling tower at that theater just outside Dallas but couldn't remember the design wet bulb. That is the only tower I ever tested that overflowed with design GPM.
    throrope,
    True most TAB companies use Shortridge or Alnor equipment. The main reason is not many manufacturers equipment meets all the certifying agencies requirements because the market isn't big enough. Most balancers prefer Shortridge equipment which is a little more expensive than Alnor. I have some equipment from both companies but it is all really expensive and calibration check is also expensive and has to be done yearly. Unless you have a lot of use for the equipment you are better served going cheaper except for maybe the flow hood.
    It is a good idea to have an inclined manometer in the event you have doubt about the accuracy of a traverse.
    oooh just an air/liquid heat exchanger... id not thought of that. thats probably what it is now that i think about it.

    what do they typically cool? like milling machine or lathe cutting fluid? alot of small machine shops are set up around here making parts for the oil and gas industry... one place i worked on had a little 50,000 building with like 20 CNC mills just cutting blanks all day long.... people swarming all around the place. i wonder if they had something similar to cool the lubricant.

    regarding old school inclined manometers... i have a pair of dwyer 100 series... 125v's? 0-1" with 20 increments per .1", supposedly good for .005" accuracy, but i suspect you would need to level it out with a machinist level to approach that. big chunky beasts like 20" long. the nice thing though is the case that carries them is the perfect size for a pitot tube as well.

    also, an old school inclined manometer is pretty good for adjusting and field calibrating filter gauges or pressure transducers. not as good as a lab calibration, but you cant beat it for a good field calibration. you just need one of those vernier piston calibration pumps or even one of those blood pressure bulb hand pumps things.

  9. #21
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    The dry coolers typically cool small loads in plants where they want to operate equipment on a part time basis.
    You are good with the inclines you have. Yes they do need to be level but the trick some people miss is it is best to leave them in the space you are going to use them in long enough for the liquid temperature to stabilize. If not get the pitot run as quickly as possible and keep an eye on the zero. Oil or water doesn't expand much but it doesn't take much on that instrument. I got burned on that once and luckily noticed it after the traverse was done and redid it. If the inclined is calibrated it really is as good as lab calibration but you can't certify anything calibrated with it as NIST traceable.
    My inclines are the go to guys in case of problems and since retired they are used to calibrate some of my equipment. Saves a lot of money and time.

  10. #22
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    Apr 2017
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    Houston, Tx
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    Quote Originally Posted by WAYNE3298 View Post
    The dry coolers typically cool small loads in plants where they want to operate equipment on a part time basis.
    You are good with the inclines you have. Yes they do need to be level but the trick some people miss is it is best to leave them in the space you are going to use them in long enough for the liquid temperature to stabilize. If not get the pitot run as quickly as possible and keep an eye on the zero. Oil or water doesn't expand much but it doesn't take much on that instrument. I got burned on that once and luckily noticed it after the traverse was done and redid it. If the inclined is calibrated it really is as good as lab calibration but you can't certify anything calibrated with it as NIST traceable.
    My inclines are the go to guys in case of problems and since retired they are used to calibrate some of my equipment. Saves a lot of money and time.
    excellent point regarding the oil. i assumed the expansion would be negligible in what ever oil they formulated, but i guess not. im going to have to stalk your older posts man, you give out tons of good information.

    on an unrelated note, i love my acrylic manometers, so pretty an elegant. i have like... 5 now? including a dwyer microtector model 1430 that i have yet to tinker with(fluid spilled during shipping). its too bad they are discontinuing so many of them.

  11. #23
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    I use red oil in my incline and it's not fun when you spill it. Most folks like digital now days and that's OK but nothing beats the accuracy of water. You are correct the expansion of water in the incline is not much of a problem and none at all in the standard vertical manometer.

  12. #24
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    Apr 2017
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    Houston, Tx
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    the microtector uses a water based fluid with some flourescent dye, and a surfactant to eliminate some of the meniscus. i think some of the vertical manometers still use the same fluid luckily.

    the thing uses the depth micrometer as an electrode basically, so the fluid needs to be conductive to some extent.

    its still available on their site somewhere, i just have not had a chance to look it up.

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