Calculating radiator output at different Temps

[Miek]

Hi folks

 

How do I calculate the actual heat output of a radiator at different temperature differences?

 

As far as I can work out a 2kW radiator is rated when it's running at 70 degrees in a 20 degree room, so 50 degrees difference, is that about right?

 

If for example I wanted to run the same radiator at 45 degrees (on a heat pump potentially) what would the output to room be if the rooms at 20? 

 

My mind tells me that this relationship is non linear, so what's the maths look like?

 

Thanks in advance

 

 

 

[Carrerahill]

5 minutes ago, Miek said:

Hi folks

 

How do I calculate the actual heat output of a radiator at different temperature differences?

 

As far as I can work out a 2kW radiator is rated when it's running at 70 degrees in a 20 degree room, so 50 degrees difference, is that about right?

 

If for example I wanted to run the same radiator at 45 degrees (on a heat pump potentially) what would the output to room be if the rooms at 20? 

 

My mind tells me that this relationship is non linear, so what's the maths look like?

 

Thanks in advance

 

 

 

I don't know the formula, but I do know that some radiator manufacturers have a table which list their radiators with all the different outputs at 5°C increments from about 35-85°.

 

I found most of the rads were listed at maximum potential output and not realistic outputs with normal water temps. 

 

So if it was me, I would be looking for some manufacturers datasheets listing models and there outputs by water temp.

 

 

[Miek]

3 hours ago, Carrerahill said:

I don't know the formula, but I do know that some radiator manufacturers have a table which list their radiators with all the different outputs at 5°C increments from about 35_85

 

Thanks, that will help I'll have a dig around some datasheets.

 

[A_L]

@Miek , Relative to 70°C outputs at 30°C/13.5%,  40°C/32.1%,  50°C/53.0%,  60°C/75.8% for rooms at 20°C and 'ordinary' radiators