It seems that everyone here that builds their own HX using copper coil is using hundreds of feet of coil. I figured this was normal. I had to replace my heating coil on my oil furnace last year and decided to do some math.
It has 28' of 1/2" finned copper tubing. It is rated at 100 degree rise, 3gpm with 180F boiler water.
3gpm x 60 = 180gph
180g x 8.33btu/per gallon = 1500btu/per hour per degree x 100 degrees = 150,000btu/hr
So how is it that this 28' length of 1/2" copper can move 150k btu/hr, but people building their own hx use hundreds of feet of copper and figure they are moving 100k btu/hr ?
It has 28' of 1/2" finned copper tubing. It is rated at 100 degree rise, 3gpm with 180F boiler water.
3gpm x 60 = 180gph
180g x 8.33btu/per gallon = 1500btu/per hour per degree x 100 degrees = 150,000btu/hr
So how is it that this 28' length of 1/2" copper can move 150k btu/hr, but people building their own hx use hundreds of feet of copper and figure they are moving 100k btu/hr ?