Anybody try to use the Boiler like, heater exchange.

[vio]

Mods. please close the thread. Thank You, all.

 

[strgazr27]

Water heaters are for hot water in you're whole house boiler is for the heat

Unless the boiler has a hot water coil built into it which many still have. Than it serves a dual purpose of providing heat for your heating system and hot water for bathing etc.

 

[jamesonwhiskey]

Unless the boiler has a hot water coil built into it which many still have. Than it serves a dual purpose of providing heat for your heating system and hot water for bathing etc.

Right, which I believe is what his system has. It's what my house has a well. My boiler/furnace (they're interchangeable terms) provides 2 zones for heating my house and a 3rd zone which is a loop into my in-direct water tank which provides hot water for sinks/showers. It's called an indirect water tank because it has no heating elements. It's heated indirectly by my boiler.

It's a very good idea but flawed in a number of aspects, most notably using PVC for either end of the heat exchange due to comments above. And the fact that the hot water tank has a couple of inches of insulation behind the fancy metal cover so using it as a heat exchange would involve putting the coil under the insulation. I do agree though since you're only trying to get 10 degrees warmer that it could work with more thought and you'd be heating your tank essentially with a <100W pump rather than 100's of Watts of traditional tank heaters.

 

[strgazr27]

J a furnace is actually for forced hot air systems not hydronic systems

With that much volume and surface area I'm pretty sure radiational cooling and evaporative cooling would have that system running almost non stop as compared to using heaters.

 

[NewfiDog]

Everything strgazr has posted is correct. Even the link shows copper has 20 times greater heat transfer than SS.
Jameson if your looking to do something like this the second RC thread posted with the water heater is done well but I think you would be better off with the boiler the high temp would give you a better heat transfer. Someone touched on something you should know about though. If the return water to the boiler is to cool (under 140) on a cast iron boiler the flue gases will condense and will clog the boiler flue passages over time. To avoid this a heat exchanger between would solve that problem. You could also then regulate the water temp of the coil in the sump just incase you need to lower it. This of course would not be cheap and none of these are a free way to heat your tank your still using gas or oil but in a large tank may work better than a heater for you but im not sure its worth the effort.

 

[jamesonwhiskey]

Everything strgazr has posted is correct. Even the link shows copper has 200 times greater heat transfer than SS.
Jameson if your looking to do something like this the second RC thread posted with the water heater is done well but I think you would be better off with the boiler the high temp would give you a better heat transfer. Someone touched on something you should know about though. If the return water to the boiler is to cool (under 140) on a cast iron boiler the flue gases will condense and will clog the boiler flue passages over time. To avoid this a heat exchanger between would solve that problem. You could also then regulate the water temp of the coil in the sump just incase you need to lower it. This of course would not be cheap and none of these are a free way to heat your tank your still using gas or oil but in a large tank may work better than a heater for you but im not sure its worth the effort.

Agreed, it definitely needs to be thought out more if I plan to try this. I haven't done the calculations yet but my gut is telling me since my hot water tank is always maintained at 130 degrees by my boiler... I should see a significant savings from my using my current heaters which are 300W, 300W & 250W running continuously 24x7. On the cold 10 degree days we had this winter even this couldn't keep up aand I had to throw a couple 100W heaters in to keep the tank above 76.

I'm also looking to move my domestic hot water to an instant-on water heater so I can shut my boiler down in the summer. If I go this route then I can re-purpose the output on my boiler currently being used for the hot water tank.

Again, it all requires more thought and some tests but I like the challenge (and the potential savings

 

[NewfiDog]

Off topic but you may want to rethink that on demand. The cost is high depending on the home. The savings is actually extremely low. If you even read the fine print from the manufactures the average savings from a gas water heater is 30 dollars a year and that's not for the north east. Your indirect heater is actually the better choice an indirect water heater losses 2 degrees a day a standard gas water heater looses 2 degrees an hour. On demand water heaters need annual service to keep the warranties and the do not last very long like this old house keeps saying on there shows there average life is the same as a gas water heater.


There good for apartments and small condos and don't buy into the BS "that's all they use in Europe" there used as point of use in Europe or in largewr homes they have used indirect water heaters for a long time.

 

[jamesonwhiskey]

Off topic but you may want to rethink that on demand. The cost is high depending on the home. The savings is actually extremely low. If you even read the fine print from the manufactures the average savings from a gas water heater is 30 dollars a year and that's not for the north east. Your indirect heater is actually the better choice an indirect water heater losses 2 degrees a day a standard gas water heater looses 2 degrees an hour. On demand water heaters need annual service to keep the warranties and the do not last very long like this old house keeps saying on there shows there average life is the same as a gas water heater.

Yeah sorry for hi-jacking everyone I disagree with the comments related to savings, but it also depends on your situation. I have a hot water tank in my uninsulated basement. My boiler cycles on about every 30 minutes on cold days to keep my 40g of hot water at 130 degrees. It's dropping 10/degrees an hour if not more.

Most days I shower in the morning and head to work by 7am. I'm home at 7pm and might shower again or wash some dishes or whatever. I'm firing up my boiler way to often (18,000 times in the past year). I'm heating water up for over 12 hours/day that's never being used. My gas bill in the summer has been ~60/month, with an instant on it would be closer to $25/month. FYI I also set my heat to 60 degrees while I'm at work so the boiler really is only firing up during the day to heat domestic water.

Warranty points you mention is something I'll def take into consideration as I didn't know that!

 

[NewfiDog]

That's very strange all the indirect heaters Ive used loose 2 degrees in 24 hours when not drawn on. There are a lot of draw backs to on demands so do your research the trend has already turned its gone to removing them. My main distributer has already stopped stocking on demands.

 

[vio]

Mods. please close the thread. Thank You, all.

Mods. Please close the thread, I will post pics. If I would build one. Thank You.