preheating boiler water

[daveindigby]

Hello all
I have a Kerr tw2000 wood fired boiler with in floor heat. I also preheat my domestic hot water
with 2 solar collectors and a solar boiler (thermal dynamics)
On sunny days I seem to have an abundance of hot water could I circulate this surplus through the domestic
intake on the Kerr boiler and maybe pre heat boiler water, or get a little heat without a fire?
Normally the domestic coil in Kerr is valved and solar heated water bypasses the furnace when there is no fire.
The other day my wife did a wash without turning this valve the solar heated water was running through the domestic
coil in furnace, and this inturn heated the boiler water to 110F
Any help would be appreciated
Dave.

 

[BrownianHeatingTech]

Yes, you could do that. The exact point at which it makes economic sense to do so (ie, by "using up" the solar energy stored in your tank, you could end up making the oil boiler fire to heat the tank when you use hot water later on) will vary from system to system.

Joe

 

[daveindigby]

Thanks for the reply joe, I have been wondering about this for a few wks now, would
I use the same type pump as I am using now, a run of the mill Grundfos circulating pump?
would the rate of the flow come into question?
Today would have been a good day for such a rig, the solar boiler shut down at 90C and I didnt use any hot domestic water. today was cool a north breeze, but not quite cool enough for me to make a fire and run the Kerr boiler.
Thanks again
dave

 

[BrownianHeatingTech]

Thanks for the reply joe, I have been wondering about this for a few wks now, would
I use the same type pump as I am using now, a run of the mill Grundfos circulating pump?
would the rate of the flow come into question?
Today would have been a good day for such a rig, the solar boiler shut down at 90C and I didnt use any hot domestic water. today was cool a north breeze, but not quite cool enough for me to make a fire and run the Kerr boiler.

The exact pump sizing will depend on your particular system.

Since you are pumping domestic water, you need a stainless or bronze pump, to prevent corrosion.

Joe