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Power/Energy calc

Power/Energy calc

Power/Energy calc

I have a process running with the following thermal cooling needs:

Presently they're using city water thru a garden hose which is where they got the temp in and out and flow.

Does this look correct?

Tons, aren't those a unit over 24hrs?

Do I recall correctly that 1 Ton is about 1 Horsepower?

This process runs at most 4 hours a day.

The facility is seriously power limited while the process is running. Knowing all the above how would you providing this cooling?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Power/Energy calc

1 Refrigeration Ton is 12000 BTU/hour, ~ 3.5 kW.

What is the limitation, exactly? Is it they need more cooling or they can't use a heat pump due to lack of electrical capacity or they don't want to spend more money on water?

RE: Power/Energy calc

One ton of refrigeration will freeze one ton of water in 24 hours = 1200 btu/hr. It does take about one horsepower to create one ton of refrigeration using a chiller.

Using municipal water for once-through cooling is illegal in many locales because of the burden it places on water and sewer. Small cooling towers are not very expensive, basically swamp coolers.

RE: Power/Energy calc

3DDave; Limitation is electrical power. They have to curtail some operations while running this process as it is. Adding a bunch of chiller or mechanical refrigeration would probably not be possible.

Comp; You're correct, they haven't allowed city water cooling around here for 20 years. These days they'd probably send a swat team if they found out, hence the reason I'm moving them to something better.

I'd think the best option might be a big tank of chilled water. They can chill it overnight using cheaper power and colder air over 12 hours which would mean smaller equipment.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Power/Energy calc

That big tank was going to be my suggestion as well unless money was the problem - perhaps use a swamp cooler setup to augment the temperature decrease if the air is dry enough. The disadvantage to the tank in the long term is keeping stuff from living there, such as Legionella bacteria.

RE: Power/Energy calc

Isn't a swamp cooler or little cooling tower more of a Legionella problem than a tank?

I still have to figure out what size tank this would be. A 100k gallon tank would probably be a problem... LOL

Keith Cress
kcress - http://www.flaminsystems.com

RE: Power/Energy calc

I think the "ton of refrigeration" is a remnant from the past practice of cooling a chamber using a block of ice, common in the USA prior to 1920. The ice was typically cut out of a frozen river during winter and stored in an underground ice house , insulated with sawdust. A teamster ( a man with a team of horses and a wagon) would visit the icehouse, load the block of ice onto the wagon, then drop off the ice at the customers. At that time it was also common for families to keep their recently deceased relative "on ice" in their parlor ( now called a living room) for 2 days to allow others to pay respects. That might require a 200 pound load of ice for 2 days internment. Since that earlier time we now have funeral "parlors" that use formaldehyde to keep the corpse from decaying ( and which pollutes the ground water at the cemetaries) and we now call the home parlors "living rooms" to avoid the past association with death.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

RE: Power/Energy calc

Would an absorption chiller (lithium chloride) payout quicker than mechanical refrigeration in this application in the long run? Electrical power demand is much less.

RE: Power/Energy calc

I think the unit tons of refrigeration originated from the fact that the first large scale use of refrigeration was to make ice for the ice market, competing ice houses that stored winter lake ice. Ah, the good old days!

RE: Power/Energy calc

And sold cold beer on the side.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

RE: Power/Energy calc

1HP per TR is too tight unless you are running a screw or centrifugal at full load. Evaporative coolers can be used with biocide dosing. Combination of direct indirect evaporative cooling is an option but not much cooling if the ambient is humid. Is this for process or space?

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