Hello folks ! I have just got my woodmaster 4400 all running and I'm ready to add hot water to the sink in my shop .i'm curious if anyone has suggestions on the size of plate exchanger required for on demand hot water. I really would like to avoid installing a hot water heater if I have to. Thanks in advance. Matt
Plate exchanger for on demand hot water
- Thread starter Mdurr01
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Not to be overly scientific, I think the answer is 'pretty darn small'. Most faucets flow only a couple gallons per minute. At a worst-case temperature rise of 70 degrees, that's about 70k btu/hr. Assuming boiler water at something around 180, it doesn't take a very large HX to transfer that much.
Most of the time, people are agonizing about 'approach temperatures' where you're trying to get storage as close to 180 as possible with boiler water at 180. It takes a big HX to get close.
In your case, you're only needing to produce water at around 120 with water around 180 on the other side. Pretty easy to do.
Most of the time, people are agonizing about 'approach temperatures' where you're trying to get storage as close to 180 as possible with boiler water at 180. It takes a big HX to get close.
In your case, you're only needing to produce water at around 120 with water around 180 on the other side. Pretty easy to do.
What temperature will you maintain on the boiler?
If you maintain 180F, a 5X8 10 plate will get you about 2 - 2.5 gpm depending on incoming water temperature. Many of the combi boilers have a HX about that size.
I use a 5X12 30 plate on my systems and I can get 3 gpm, 105F even with the boiler or buffer tank down around 120F.
Most of the plate HX manufacturers have free online sizing programs. www.flatplate.com might work
Harwill has nice PVC .5 gpm flow switch. Sika is another brass flow switch common on many combi boilers. The flow switch triggers the pump anytime a faucet flows.
Good delta T. Now how many gpm do you want or need? I'd suggest generous sizing, as they do scale up and lose some efficiency as time goes by.
Install it so you can acid flush it if needed. a pair of Webstone valves works nicely. Or a tankless water heater connection valve.
Install it so you can acid flush it if needed. a pair of Webstone valves works nicely. Or a tankless water heater connection valve.
I would imagine at the most would be 2.5 gpm. would a 10 plate do the trick? I plan to use 1 inch lines on the supply and return feeding it. and I have a 1/2 domestic line run. thanks for the help!
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