Please define \"delta-t\"

Joe_8

Does anyone have simple wording to define "delta-t" for my clients? Everytime I try, my brain and my mouth just can't work to keep it simple. Thanks.

Lurkin' Murkin'

Ask Joe Cocker...

"Delta T" is the difference between two temperatures. Usually for boiler talk, it's the temperature rise from the return water to the supply water - but other areas of the system can be discussed like this, too.

Mike T., Swampeast MO

Delta-t is nothing more than "change in temperature". When a hydronic systems gives off heat to the structure the temperature of the water drops. If the temperature did not drop then the system would not be giving transferring any of its energy to the structure.

Delta signifies "change in" and "t" stands for temperature. Delta-p is simlar. It stand for "change in pressure".

hot_rod

or as I like to say Delta tea

hand them a cup of hot tea. When their hand wraps around the warm cup they will understand delta T.

The tempersature difference between their skin, and the outside of the cup

hot rod

Darin(in Michigan)_3

Delta T

A triangle is the engineers symbol for delta and delta means change so if you were looking in a text book and you see a triangle it means "change". The "T" represents temperature so delta t means change in temperature as was stated earlier

Brad White_9

Similar to Delta-P

Which is the difference in pressure between two measurement points.

Delta-Pee also refers to urological issues associated with older males compared to when they were younger. Wait 'til you see the gauges used to measure that...

Unknown

Please Brad...

Don't remind me,,,

It didn't help at ALL that the urologist looked like Lurch.

Can "difference in temp" and "change in temp" both be used interchangeably to describe "delta T" ?

Lurkin' Murkin'

You rang?

If there is only one medium being measured, then the Delta T would mean "change" in temperature - but couldn't it also refer to different mediums, where it would mean "difference" in temperature?

And having a Urologist that looks like Lurch is not half as bad as having a Proctologist that sounds like Lurch - "Uuuuhhhhuuuhhhuuuhhhhhhhhhhhh..."

scott markle_2

delt t

I was wondering under what type of circumstances you would be discussing this with your clients?

My own current interest in heating design is mostly about maximizing condensing boiler efficiency. Delta t plays into this in a big way. The wider this delta the more energy that can be transfered. This is why solar coils are at the bottom of duel coil indirects were the colder water will stratify. Or why colder return water will create more condensation: Here the delta is between the Hx and the flame, (the higher the better) . Even room temps factor into this the delta between the emitter and the air temp will determine rate of energy transfer. Delt t is a big part of understanding how ground source heat pumps work. Pump chilled 32deg. water into a (huge) 45deg. heat sink and your return water comes back 10 or 12 degrees warmer. (It's the refrigerant phase change part I have a hard time explaining, or fully understanding)

When I first got into this stuff I thought wide delt-t was the enemy, because of uneven distribution issues. I now see that the real challenge in progressive heating design is about maximizing delt t while maintaining comfortable even distribution.

Explaining these concepts to potential clients is a challenge, One of my biggest problems is TMI (to much information). I love to talk about this stuff. but if I get to specific I risk loosing my audience, or worse yet giving the impression that I'm trying to snow them with a lot of technical BS. Try explaining net vs. gross caloric fuel values and the theoretical potential for
+100% efficiency from condensing boilers. I'v gotten some very suspicious looks trying to explain this!

Brad White_9

MPF:

Yes, exactly on Delta-T.

The old joke regarding the phone greeting at a urologists office:

"Urology. Can you hold?"