Thinking of adding heat exchanger to continuous flow WC system.

[Edward Shave]

With the rising cost of energy in mind it occurred to me that a heat exchanger could help in the context of my continuous flow WC system.
Unfortunately I know nothing about the subject but after a bit of googling I have a vague idea of coiled copper pipe inside a larger vessel.
Hoping someone out there will be able to advise me if this could be a practical proposition.
Max flow is about 5L/H. output is 24C and input is straight from cold water mains.

 

[Ghettofarmulous]

Well in milk production they use flash pasteurisation. The milk is brought up in temperature very quickly and cooled just as quick. This avoids denaturing of the proteins and spoiling the milk. The heat exchanger uses is a very thin walled assembly that maximises surface area and spreads out the liquid over a large area thus allowing rapid heat transfer. I think in a continuous flow system you will need a large surface area (not to say a large piece of kit). Sorry it’s not very helpful

 

[Edward Shave]

With a bit more googling I found the home brew hobby use heat exchangers for cooling wort so I'm thinking maybe these would work in my application...
Amazon product ASIN B084WTZLZ2

 

[Dogtemple]

Something to consider here is the use of copper, it’s toxic to crustaceans et al.

Not sure if there is such a thing but stainless steel heat exchanger would be safer.

Also that cooler appears to release heat to the air through those plates rather than gather it. Unless it’s sat in something hot it will cool your water.

Heat exchangers to gather heat are usually a coil that go in a hot water tank or wrap around something hot etc

Wrapping pipe around copper pipes that go to your radiators might not be a bad way of doing a heat exchange, free heat when your heating is on at least.

Just need to make sure you have some sort of thermostat so there’s not too much heat going in your tank.

 

[Edward Shave]

Also that cooler appears to release heat to the air through those plates rather than gather it. Unless it’s sat in something hot it will cool your water.

No it is water cooled. Hot wort runs through in one direction and cold water from the tap in the other direction. It has the effect of cooling the wort but must also heat the water so my thought was this could be used for heating or cooling according to need. But I'm going off the idea due to fears of clogging and or calcium build up.

Heat exchangers to gather heat are usually a coil that go in a hot water tank or wrap around something hot etc

I like that idea and I may have thought of a novel twist that could be both cheap and simple to implement as a DIY project.
The overflow from my tank currently runs through a PVC pipe (12mm ID) more than a metre down to the floor. So if I run a copper/steel pipe inside the PVC pipe then that should work subject to efficiency. Currently the overflow just trickles down the PVC pipe but if I make the pipe 3 times as long and bend into an S shape so that it runs back almost to the top and then down again two thirds of the pipe will be full of water, so overall about 2 metres of metal tube at work.?

 

[Dogtemple]

No it is water cooled. Hot wort runs through in one direction and cold water from the tap in the other direction. It has the effect of cooling the wort but must also heat the water so my thought was this could be used for heating or cooling according to need. But I'm going off the idea due to fears of clogging and or calcium build up.


I like that idea and I may have thought of a novel twist that could be both cheap and simple to implement as a DIY project.
The overflow from my tank currently runs through a PVC pipe (12mm ID) more than a metre down to the floor. So if I run a copper/steel pipe inside the PVC pipe then that should work subject to efficiency. Currently the overflow just trickles down the PVC pipe but if I make the pipe 3 times as long and bend into an S shape so that it runs back almost to the top and then down again two thirds of the pipe will be full of water, so overall about 2 metres of metal tube at work.?

Certainly worth playing with. I love the idea of getting free energy in this way and making a system efficient. It’s worth trying and seeing what results you get.

Only thing I would really have to put thought in is how you would control the heat going in to the tank.

It would either provide a bit of a boost to the existing heater so it doesn’t need to work so hard or get so hot that it needs controlling to keep the water from boiling your inhabitants.

 

[Edward Shave]

It would either provide a bit of a boost to the existing heater so it doesn’t need to work so hard or get so hot that it needs controlling to keep the water from boiling your inhabitants.

It would be the former as any heat exchanged is coming from the overflow from the tank.

 

[Dogtemple]

It would be the former as any heat exchanged is coming from the overflow from the tank.

I was awake in the middle of the night thinking about this.

I don’t know if it would suit your setup but as a general idea it could work for people.

My tank, although currently empty is close to a radiator. I was thinking of wrapping copper pipe tight around the pipe work that goes to the radiator or running pipe work between the fins of the radiator. This would then lead to the nearby cabinet and to a stainless coil of pipe.

This stainless coil would then go inside it’s own vessel which would run parallel to the intake, before the filter. It turns on and off with a thermostat and the initial hotter water would get mixed up with the cooler water in the filter.

Alternatively, the coil would go in my co2 mixer thing, which is a large water filter canister.

I would suspect a small pump would be needed to circulate the coil/exchange system.

So a thermostat could go on the pump to control it.


This is just half awake ideas so feel free to pick apart and point out any errors or build upon this.

I may have a go too when I get some time as it’s in the ethos of my build.

 

[fredi]

With the rising cost of energy in mind it occurred to me that a heat exchanger could help in the context of my continuous flow WC system.
Unfortunately I know nothing about the subject but after a bit of googling I have a vague idea of coiled copper pipe inside a larger vessel.
Hoping someone out there will be able to advise me if this could be a practical proposition.
Max flow is about 5L/H. output is 24C and input is straight from cold water mains.

You could use a liquid to liquid stainless steel heat exchanger from a central heating boiler
A few years I used one as a heat exchanger for a vegetable oil fuelled diesel engine, it worked very well

 

[Edward Shave]

This is just half awake ideas so feel free to pick apart and point out any errors or build upon this.

Sorry to tell you I don't think this would work..! I'm no expert but my initial thoughts are...
Any heat you manage to extract from the radiator/pipework would be automatically made up for by the boiler and so would come at a cost. The efficiency of heat transfer would be so low it would be cheaper to let the tank heater do it's job.

 

[Edward Shave]

You could use a liquid to liquid stainless steel heat exchanger from a central heating boiler
A few years I used one as a heat exchanger for a vegetable oil fuelled diesel engine, it worked very well

I have just purchased the stainless steel flat plate heat exchanger I mentioned earlier in this thread.
I don't know how well it will work in my application. I will post results here when I have them.