Delta T on radiator spec sheet

circadian

Hi all,

Just a quick one. I'm looking for new rads and the majority of spec sheets show the Delta T with degrees C, but I've found a minority with K in place of C (I'm assuming this might be Kelvins?) For example ∆t=50K, is this something I need to factor in or is it just a quirk between manufacturers?

Cheers,

C

MrMusician18

Just a quirk. Kelvin's and Celsius are the same size unit but have a different starting point

circadian

https://www.boards.ie/discussion/comment/119393029#Comment_119393029

Thanks. I understand that Kelvins start from absolute zero, which means ∆t=50K means the radiator runs at -223.15 Celsius? That doesn't add up.

MrMusician18

A delta T is the difference between two temperatures. So the difference between the temp of the radiator and the ambient air is a delta T, or the difference between the radiator inlet and outlet temperature is also a delta t.

cruizer101

Delta T just refers to the temperature difference, so it doesn't matter if it is K or C its just the difference between two temperatures.

20C = 293K

100C = 373K

373-293 = 80 = 100 - 20

MrMusician18

In terms of radiators delta T is used to differentiate between high temperature systems and low temperature ones, delta t = 50 is standard system, like a gas boiler. Radiators have a rated output for a given delta T.

If you had a low temperature system you might use a delta 30, say for example a heat pump.

circadian

https://www.boards.ie/discussion/comment/119393120#Comment_119393120

Yep exactly what I'm trying to calculate for.

John.G

A 50C Rad (European standard) is the mean (flow+return temps)/2 minus the required room temperature, the calculation for any other deg rad is the (degrad/50)^1.3. Ie a 25deg rad does NOT output 50% of a 50deg rad but a lot less, havnt got my laptop to do the power to calculation.

It's 40.6% output of its 50deg rating.