W2W HX questions....

[trialanderror]

since it's summer time, looking to take my system down and plumb up my dhw....


it's LP... there's 'ports'.


cold in
hot out
drain on bottom
pressure relief on the side near the top.

i looked at my friends CB's water to water HX, and since his is electric, his W2W HX goes from the drain, up to the top, then tee's over to the center and down into the water heater; in my LP is where the exhaust vent is...

how would i plumb up a LP water heater? use a 'T' into the pressure relief and the drain? or just install a plate exchanger and have that pump pre-heated water into the water heater? i have oodles of 1 1/2" copper and 3/4" copper, so i thought about making my own tube in a tube heat exchanger; i have time, and the 'free' resources....

which of the two is better? maybe use both if i'm making one for free?
what should i do?

 

[trialanderror]

not finished yet, whipped it out in about an hour....on emergency standby this weekend, so, i'm limited to my '10 minute drive' rule....figure if they cut out my freedom, i'll use their brazing rod and kangaroo pack...



1/2" inside with 1 1/2" outside

outside tube is 60" long
inside tube is ~70" long...

still need to make the outer water jacket inlet and outlets...but, before i braze those on, if i make only 1 exchagner, i'll use 1" in's and outs..

if i make 2 more, which is what i want, then i'll use 1/2" in's and outs"....

i plan on using all 3, side by side, boiler water manifolded all 3 from bottom, and manifolded at the top, and the inner tubes hooked together in series from the well, through the exchangers, then to the hot water heater...

not bad for 99 cents into it....the 1/2" coupler joining the two inner tubes together...

i figure 15 foot of 1/2" should be able to keep up with any heat demand, assuming the 40 gallon is depleted before fresh well water begins to need heat...

 

[trialanderror]

i guess my idea sucks....

 

[mtfallsmikey]

No, it doesen't suck....I was thinking about doing the same thing, only with eiether 2"or 3", just don't have the physical room to house such a beast. I don't have much in the way of leftover pipe anymore, and if you had to buy
2" or 3" "L" copper now...sheesh. I'm going to do the plate-type HX thing myself.

 

[trialanderror]

i suppose it wouldn't be cost effective to buy the material to do it.


i made 9 more. each one is about 6'

there's about 60ft of 1/2" pipe with 3/4" of water around it.
i stacked them in the furnace compartment, one on top of the other, starting along the floor.

only up off the ground maybe 2ft at the most. quite compact.

 

[mtfallsmikey]

got it now...my ideer was to make a pass-thru stand-alone type HX, 2" or 3" pipe outside, 1" or 3/4" on the inside, use a pipe reducer at both ends, grind out the stop, slide the pipe thru it, braze it up...I'll be curious to see how that works for 'ya, keep us posted.

rep 4 u 2

 

[trialanderror]

it'll be just like a sidarm on a water heater. but the boiler in and out ports will alll be manifolded with 1" tube....

boiler water comes in the 1" tube, manifolds off into all 10 on the one end, water works it's way to the other then, comes out the same way into another 1" manifold, then continues to the water2air hx, etc etc.

with the domestic water from the well zig zagging from one to the other in series before reaching the water heater....

like a plate exchanger i suppose, same concept...just preheats the water.

my heater is suppied with 1/2" pipe, so i made mine all 1/2" pipe. figured smaller inside pipe will let me have more boiler water since i can't find any 2 or 3 " copper.