Oversize panel radiators - worth the extra $$?

[mousebndr]

Hi All

I remember reading once that oversizing your radiators, say by 15-20% gives you more flexibility on the temperature of the water. Allowing you to drop down to lower temps. I guess the theory is that the more you drop away from the ideal temp of 80degC then the less kw output the radiators achieves so you need a bigger radiator to make up the difference....

Bigger always is better right?

 

[BoilerMan]

Yes, the panel rads are rated for BTU (Kw) output at 80C so if you want the same output at a lower water temp you need more surface area = larger rad.

 

[jimbom]

Panel design takes into account temperature difference and the area of the panel. Greater temperature difference, more heat transfer. Greater area, more heat transfer.

My home floor operates at a very low temperature difference, but has a very high area - the entire livable area of the home.

My childhood school had steam radiators that operated at a very high temperature difference, but had a small emitter area. Both work fine.

 

[woodsmaster]

One thing to consideris how low of temp you can heat your dhw with if your doing that. I can probably heat my house with 110 degree water, but I need at least 130 degrees for dhw. So I never let my storage drop below 130.