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Type: Posts; User: coolcoil

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  1. Replies
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    Assuming that your filter will be 24" X 24"...

    Assuming that your filter will be 24" X 24" nominal, you will probably have a clean filter pressure drop of at least 0.2 in. wg at 425 FPM air velocity if all 1700 cfm came though the louver. Of...
  2. Thread: Condo Humidty

    by coolcoil
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    414

    Do you have the fan set to run constantly? When...

    Do you have the fan set to run constantly? When you do that condensate left of the fins at the end of the cycle re-evaporates. A good article on the topic here:
    ...
  3. Thread: Condo Humidty

    by coolcoil
    Replies
    13
    Views
    414

    Do you have the fan set to run constantly? When...

    Do you have the fan set to run constantly? When you do that condensate left of the fins at the end of the cycle re-evaporates. A good article on the topic here:
    ...
  4. Just curious - what is the reason for running...

    Just curious - what is the reason for running such dry air?
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    The only advantage is that if you have poor air...

    The only advantage is that if you have poor air distribution continuing to run the fan will even out the temperatures in the house, at least to some degree. The disadvantage is that fan motors use a...
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    First, the answer to your question about...

    First, the answer to your question about ton-hours is that it is 12,000 Btu's of cooling provided for a period of one hour. It is measured with a btu meter, which is a device that measures...
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    It is not always true that most of the kW input...

    It is not always true that most of the kW input of a fan is converted to mechanical energy. Wire-to-air efficiency of a small motor and fan is very low - 25% is not unusual (eg. a fan coil with a 75%...
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    In your original example of lifting a weight, it...

    In your original example of lifting a weight, it is true that some of the energy is converted to potential energy because the height relative to the center of the Earth increased - the increase is...
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    EER is the Energy Efficiency Ratio at a defined...

    EER is the Energy Efficiency Ratio at a defined condition. This is the definition of EER from AHRI 340/360: Energy Efficiency Ratio (EER).A ratio of the Cooling Capacity in Btu/h to the power input...
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    A very good answer. I was going to write...

    A very good answer. I was going to write something similar.

    The Law of Conservation of Energy https://en.wikipedia.org/wiki/Conservation_of_energy always applies, at least in the physical world in...
  11. Fair enough, as you have already-existing hotels...

    Fair enough, as you have already-existing hotels that have a history as you describe. Your plans do make sense in this case.
  12. I should have mentioned this at the same time...

    I should have mentioned this at the same time that I gave you the DOE link:

    If your goal is to determine if your client can buy a smaller chiller plant, then you need to rethink that. For offices...
  13. If this unit uses a high percentage of outdoor...

    If this unit uses a high percentage of outdoor air, then you want a DX-DOAS unit. Essentially it looks like an RTU but is designed to cool air and reheat as you describe. Some of the brands listed...
  14. The DOE website has all of the prototype...

    The DOE website has all of the prototype buildings used to calculate energy savings of both ASHRAE 90.1 and IECC codes when they are updated. There is both a small and large hotel model. The...
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    Is it AHRI certified?

    Is it AHRI certified?
  16. Do you mean that the water is not going into the...

    Do you mean that the water is not going into the drainpan and blowing downstream? Is the fan still running when the unit shuts off? That is, when you say, 'the unit shuts down,' do you mean the...
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    Assuming that the point where the water is...

    Assuming that the point where the water is forming is after the metering device, it's condensation. When the liquid goes through the metering device the pressure drop causes some of the liquid to...
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    Again, without detailed knowledge of the coil and...

    Again, without detailed knowledge of the coil and access to a coil program that handles parallel-flow (few, if any, commercially available programs do) its hard to say. But I can say that if it is a...
  19. Thread: Solx energy

    by coolcoil
    Replies
    28
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    5,922

    These guys are full of it. Their latest claim,...

    These guys are full of it. Their latest claim, that the Mpemba Effect drives the savings is pure bull. The Mpemba Effect, which not all scientists agree even exists, is about the water that was hot...
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    I was responsible for the engineering of large...

    I was responsible for the engineering of large coils for a large air handler company for many years. There is no simple formula. It depends on your entering water temperature, entering air...
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    Do an internet search for "thermal coffee...

    Do an internet search for "thermal coffee carafe." Amazon has a large selection. I have a stainless steel one that keeps my coffee hot at least 8 hours. I do use it only indoors - you might not get...
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    I believe, but am not 100% sure that mini-split...

    I believe, but am not 100% sure that mini-split EEVís are in the outdoor unit. Though I think they still measure superheat st the coil.

    If you do this with a TXV, unless you have perfect...
  23. Replies
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    The purpose of dumping hot gas into the...

    The purpose of dumping hot gas into the evaporator is to put a false load on the compressor to allow the unit to run at very low loads. Normally a unit with a single speed compressor must run at full...
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    This is not a hot gas bypass coil. It is called a...

    This is not a hot gas bypass coil. It is called a hot gas reheat coil. It is very common to have one in humid climates to do just as BBeerme described. The air is cooled to get the dew point you...
  25. I would be surprised if it not circuited...

    I would be surprised if it not circuited inside/outside. You want the all of the water to touch the tubes in each circuit so that when only one circuit is running all of the water has a chance to...
  26. Assuming that the water is on the outside, I will...

    Assuming that the water is on the outside, I will put in my $0.02. This could be entirely wrong - I am just basing this on what we know.

    First, a perfect vacuum would add less than 15 psia to the...
  27. deleted.

    deleted.
  28. Replies
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    I would have to think about it, but off the top...

    I would have to think about it, but off the top of my head I don't think the TXV would see a difference. The same net total amount of heat is being transferred into the refrigerant. The only...
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    That would have some positive effect on both...

    That would have some positive effect on both capacity and efficiency. Assuming you were getting some flashing at the TXV you would now get less flashing so more liquid to evaporate in the condenser....
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    I agree that is not what they are intended to do,...

    I agree that is not what they are intended to do, but putting the false load on the compressor does just that. The compressor works just as hard, but you get less cold out of the coil. That's how...
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    Here is the page with the DOE certification...

    Here is the page with the DOE certification process for all appliances.

    https://www.ecfr.gov/cgi-bin/text-idx?SID=bbd32a0a465a70e9fcfc389962ee463b&mc=true&node=pt10.3.429&rgn=div5

    Scroll down...
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    I work on the regulatory side of the HVAC...

    I work on the regulatory side of the HVAC business and was curious to see what is going on. Though my job usually puts me on the opposite side of the table from manufacturers, I have a pretty high...
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    Just a couple of thoughts off the top of my head...

    Just a couple of thoughts off the top of my head -

    If you have enough cooling now, you may want to consider a Rawal valve as a temporary measure. They put a false load on the compressor by...
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    Agreed. Lower discharge temp causes lower SHR....

    Agreed. Lower discharge temp causes lower SHR. That’s assuming, of course, that your initial conditions had an SHR <1.0. If that was not the case, then you would have to know the entering air...
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    All of the technologies shown in the video are...

    All of the technologies shown in the video are well-understood in the industry and implemented where appropriate. Inducing airflow by converting velocity pressure to entrain air in the room is...
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    I will take a stab that this. First, I am...

    I will take a stab that this.

    First, I am going to assume that when you say that you will keep the 3-ton TXV that means that I will have the same refrigerant mass flow. If I adjust airflow to get...
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    Running a window air conditioner in the fan-only...

    Running a window air conditioner in the fan-only mode is a waste of energy unless you are sitting directly in front of the discharge and gaining some comfort due to the velocity of the air. The...
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    It's not cut-and-dried. The section of the law on...

    It's not cut-and-dried. The section of the law on which DOE based its regulation of furnace fan efficiency - 42 USC 6295(4) - only applies to furnaces, so that's why DOE has not created efficiency...
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    Here is the service manual. The sequence of...

    Here is the service manual. The sequence of operations that tells you how it is supposed to be running starts on page 24:

    https://dms.hvacpartners.com/docs/1009/public/05/38-40maq-01sm.pdf
    ...
  40. Functionally, the tape is fine, except for the...

    Functionally, the tape is fine, except for the fact that it blocks access to the breakers. And no, your unit should not leak like that. Either there is a flaw from the factory or the installers...
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    The regulation does not explicitly require the...

    The regulation does not explicitly require the use of any particular style of motor or that it be variable speed. It merely requires that the furnace be tested for a certain number of hours running...
  42. 220 psig would give you an evaporation...

    220 psig would give you an evaporation temperature of 75.5 degrees, so you would have no air conditioning at all. Maybe that measurement should be retaken.

    Wooshing sound in the evaporator could...
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    Just a thought - many years ago when I was the...

    Just a thought - many years ago when I was the product manager for a line of VRF my company private-labeled, the ducted fan coil units had a built-in condensate pump and the discharge was high - much...
  44. The Energy Plus building simulation program has...

    The Energy Plus building simulation program has excellent documentation for performance equations for all kinds of DX equipment, including chillers. There is a lot of information here.
    ...
  45. Replies
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    When you say tempered air, is it cooled but fully...

    When you say tempered air, is it cooled but fully saturated (i.e. 100% RH). If that is the case could adiabatic cooling from the pressure drop as it's going through the closet be the issue?
  46. Thread: Solx energy

    by coolcoil
    Replies
    28
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    5,922

    Just go back to selling the 100 mile-per-gallon...

    Just go back to selling the 100 mile-per-gallon carburetor that Big Oil is paying billions to the auto companies to suppress or the patches that you stick on your circuit panel to cut electricity...
  47. Your suspicions are correct. There is no problem...

    Your suspicions are correct. There is no problem using condensing gas in cold climates. First, most units are indoors in a heated or at least semi-heated space. If the unit must be outdoors, there...
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    If you must have air with an absolute humidity of...

    If you must have air with an absolute humidity of 9.2 g/kg, then you must cool it to 12.8 degrees. If the dry bulb temperature must be 22 degrees, then you have no choice but to supply enough heat to...
  49. Replies
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    I will try to be more clear: 1. You need to...

    I will try to be more clear:

    1. You need to cool the air to 12.8 degrees C to get the absolute humidity that you want.

    2. Therefore, in order to get the cooler air you need to do one or more of...
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    Because you are only cooling the air to 16...

    Because you are only cooling the air to 16 degrees C, which, when saturated has an absolute humidity of 11.3 g/kg. You need to cool the air to 12.8 degC to have an absolute humidity of 9.2 g/kg.
    ...
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