chiller btu testing

[freeze22]

just wanted to know if this was a proper way to do a basic btu test? thanks
Wes,

I have attached the BTU test sheet for a 1-ton chiller. Please note the bottom right corner for a place to keep the temperature for each minute. The instructions for the test are as follows:

1) You must have the exact volume of water contained within the chiller and system. It would be easiest to calculate this volume if you can tie the input and output lines together that run to the air handler. Or, you must empty the system and measure the amount of water exactly to the gallon that you add to fill the system completely.
2) Allow the water to heat up and stabilize to around 90-95 degrees F either by allowing the pump to run without the compressor kicking on or cut the thermostat of the chiller up to 90-95 degrees to allow the water to get that hot and once it reaches 90-95 then set the chiller thermostat down to 45 degrees and when the compressor kicks on allow a few moments for the refrigerant to flow and the unit to begin working. When the temperature begins to drop start timing and start recording the temperature.
3) Measure and record the temperature of the water each minute for 10-15 minutes. After the 10 or 15 minutes stop the refrigerated part of the chiller but leave the pump on and write the temperature down. Monitor the temperature and if it drops any further then use this as a final temperature.
4) Take the total volume of water(in gallons) and multiply it by 8.34 to give you the total weight of water in lbs.
5) Take the total weight of water in lbs. and multiply it by the total difference(starting temp vs final temp) in temperature measured on the water from step #3.
6) Take the number you get from the calculation in step #5 and multiply it by 6(if you measured water temp for 10 mins) or by 4(if you measured the water temp for 15 mins) to give you the total BTUs.

[klove]

GPM times delta T divided by 24 = evaporator tons

You're goin' around the world to get next door with that nutroll of calculations you're talkin' about........

[freeze22]

so basically the formula i have is in-correct? what is delta T?

[klove]

1 ton or 1000 tons, if you're working with a chiller and you don't know what delta T means, you're way behind the power curve. It's temperature differential between inlet and outlet water. For any more info than that, you'll have to put some history in your profile so we'll know who we're speaking with and what your level of experience is.

[freeze22]

i bought a 10 ton chiller and installed it myself. It doesnt seem to be working at any were near 10 tons using two separate williams air handlers for cooling. I have a hvac contractor servicing the unit, and i want him, or me, to do a btu test after i spent alot of $$. I'm mechanically inclined, but i only have general ac knowledge. The manufacturer is the one who gave me the btu test which i posted on this link. temperature differential can easily be done, sounds like the gpm flow will be the harder measurement.

[klove]

"Chillers Use this forum to discuss all about chillers. Remember, no DIY."


This is the heading at the top of the thread listing. Pay special attention to the last sentence. It's time to let your contractor do his job, or find someone that is familiar with what you need and get them to do it.

[9675]

What is the Brand and Model # of your chiller

[freeze22]

it is a 10 chill king chiller. They are a mom and pop shop. I always try to let contractors do there jobs, and chill king gave me the formula to test the unit. The contractor said he had never heard of this method, but it was a simple test without a precise flow meter to test gpm so we did it. The unit only tested at 83,591 btu. I honestly think that is correct. The reason for the test and calling the private contractor, was because the unit wasn't keeping up with the demand of any were near what a 10 ton should perform. I am extremely disappointed in the unit, and the customer service from chill king in Texas.

[freeze22]

I appreciate any help.

[Southern Mech]

have you checked evap flow to chart, to make sure your not moving water to fast?

[freeze22]

No i have not checked that, it uses a 1.5 hp flotec jet pump. I will look into that.

[Southern Mech]

what a 1.5 hp jet pump, thats what I use on my irrigation system. holly cow.

[freeze22]

I brought this to chill kings attention, and they said that typically they use a 1 hp, and did not think that it was a issue. The contractor believes the problem could be the homemade coil in tank they installed on the chiller, for a heat exchanger. He is recommending a plate heat exchanger. I'm just not sure if i want to spend a few thousand more into the unit for parts and labor, without a guarantee it will perform at the 120,000 btu of cooling or close too.

[Southern Mech]

I can gaurantee this homemade heat exchanger is a culprit, to get what the mfg specs, one must use what mfg suggests. who designed this apparatis?

[Southern Mech]

is this gonna get any better or should I stay seated?

[milkyway]

yep., bad idea., cant just go out designing new things to work with ones brand of equipment.,

[freeze22]

Chill king made the heat exchanger, i just don't see it being very efficient. It seems it would only pull heat out of the water that comes in direct contact with it. I understand that companies have used these in the past, but a plate heat exchanger would probably work better. Chill King designed everything on the unit, and so far nothing has been altered. I'm debating on just switching to a dx system or spending thousands to fix this one.

[Southern Mech]

You posted this is a new chiller, therefore the proper xchager would be dime on the dollar to ripping all this out and putting in a 10 ton DX.


Now, I am seeing bit's and pieces of a story am I not. You just told us this was a home made xchanger that the contractor made, now you say its from Chillking.

[jayguy]

i bought a 10 ton chiller and installed it myself...

...He is recommending a plate heat exchanger. I'm just not sure if i want to spend a few thousand more into the unit for parts and labor, without a guarantee it will perform at the 120,000 btu of cooling or close too.

who engineered this thing?

i probably would recommend replacing the evaporator heat exchanger too (although this is on your comments of what may/may not be working well and you have provided 0 technical details of how the chiller is working). yet you want the contractor to guarantee something that they did not engineer, provide or install?

i, too, am possibly recommending the evap be changed...do you want me to guarantee it too? and i have about as much responsibility for this thing as your contractor!

...The reason for the test and calling the private contractor, was because the unit wasn't keeping up with the demand of any were near what a 10 ton should perform...

maybe the demand is greater than 10 tons. got water or glycol? temperatures in/out? gpm? lots going on here. and 10 tons of process work is much different that 10 tons of regular ol' air conditioning.


i am not trying to bust your balls, but it is now time to give someone the keys to this car and let them drive it. you said that you are not a a chiller tech. you may have gotten away cheap on the install, but it does not seem cheap now...and it won't be cheap to fix either (i hope that it is something simple and cheap, but experience and your posts say otherwise). maybe you are right. maybe there is a design flaw or the compressor(s) may be faulty. without any numbers...you only can get speculation on the cause of your issues.

[freeze22]

i should never have posted "homemade",(MISLEADING) that's what the contractor said when he saw it, upon inspecting the unit, and was concerned. Chill king made everything except the air handlers i purchased separately. I called and asked about the design and they stated that the heat exchanger is made in house at chill king.I will try and have the contractor chime in or at least give me the specs you guys are asking for. I understand my lack of knowledge can be frustrating, (i have been on the other end as well designing off road suspension) but it's hard to ask a contractor in the beginning to post in a forum. I was simply asking if the Formula i posted from Chill king was a semi- accurate way of testing btu. I do appreciate everyone's help, and responses