How To Make A Heat Exchanger For Shower Hot Water Recovery
ฝัง
- เผยแพร่เมื่อ 4 ต.ค. 2024
- Add me to G+ Subscribe and go to my website www.plumboogle.com
A great way to save money is to install a heat exchanger on the drain of your shower. By warming your cold water feeding the hot water tank or instantaneous unit you can reduce the amount of energy to replenish the heater.
My website: www.plumboogle.com
How to make a heat exchanger, first video : • How To Make A Heat Exc...
How to prepare and solder copper: • Plumbing How To, Sold...
See how a plate exchanger works:
• Plate Heat Exchanger -... - แนวปฏิบัติและการใช้ชีวิต
Hi Rob, if you swap the way water enters and leaves the heat exchanger it will be more efficient. IE Cold water coming in on right and going to tank (or shower) on left (counter flow heat exchange)
Yep, it's called the countercurrent exchange: en.wikipedia.org/wiki/Countercurrent_exchange
Very cool.
If you ran an experiment with a before and after of this rig installed actually measuring the water temp difference it would make a great video.
except it might show that it's not very effective. There will be MORE heat lost through the outer pipe - bc it has a significantly larger surface area to dissipate from - as is gained from the inner pipe. If the outer pipes was PVC and lagged then it would help a lot.
@@CosmicSeeker69 the inner to outer pipe heat transfer is water based. The outer to the atmosphere is air based. So outer would lose less heat than you're suggesting. But defo lag it anyway for the best efficiency.
Nice one mate - been doing that for years in a camping set up.
Very few understand waste heat applications.
loads of applications for this brilliant idea, thank you
I liked your design. Excellent ideas 👍
Great job on making the cheap Het Exchanger but the Diagram showing I think is wrong...the shower trap should be on the other side to have the counter flow and have a better heat transfer...but any degree increase in the cold water before it goes to the hot water tank, is many into your pocket.
shkodrajone100 You are 100% correct. It was for the convenience of keeping the drawing simple. I never thought many people would catch on to it. I was worng, lol.
great idea friend , hey i have an idea to save you money on pipe, if you simply heat the incoming cold water pipe to the shower with your hot drain water you would need less hot water to get the desired temp but without having to run a pipe all the wat to and from the hot water heater.love your heat exchange design you have very good resourcefulness skills
Also this section of pipe should be insulated (all pipework should)
Ever thought about circulating the central heating pipes to keep your bath warm *and use the bath as a radiator* when no-one is in it?
Remove bath, coil some PEX pipe around it, insulate it with celotex and expanding foam [ideally frame it with timber] leave some 'tails' on, to insert your new PEX bath pipes into your central heating system.
Have a L..O..N..G soak, don't be afraid to turn into a prune. ;) lol
NOBOX7 Yep I have tried it. does not work as well as it sounds. The whole reason for doing this is raising the cold water entering the hot water tank to reduce the amount of energy to heat that incoming water. The shower is not the consumer of energy, the hot water tank is. And most energy can be saved in the initial heating of the cold water.
***** Back in the 30's there were companies that had cast iron bath/radiators. Problem was they got too hot. Did not last long. For rad heating you need to have 180°F water. Ouch! Good idea on the PEX tail thing, may work with copper tails but plastic is a horrible heat transfer material. Thanks for watching and taking the time to comment.
I have a diesel heater that provides heat to my RV. I installed a heat Exchanger to the exhaust and plumbed it with a small circulation pump into my water tank. In the winter it heats my RV and keeps the water HOT! The result is no more heating water with propane in the winter! It safes me a boat load of 💰!
Can you please email me a diagram or a photo or a video? Maybe even post one? This sounds great!
The best way is to run the cold water in the opposite direction, that way you have the best heat transfer!
Yeah, you want flow in the opposite direction.
Agree counter-flow gives the best heat exchange.
Hey Rob, I stumbled here to verify my hypothesis, which has been verified. The video is great.
I have one question though.
After seeing the semantics at time stamp 4:53, it is clear that the inner pipe is to carry the Hot Water, the outer surface of this pipe will be the interface where the actual heat exchange will be taking place.
As per my understanding, the outer pipe is not participating in the heat exchange at all. We can effectively reduce the cost of material by 50% by using a PVC pipe instead. Why do we need the outer pipe made of copper? Right?
Exactly my thoughts - there will be MORE heat lost through the outer pipe - bc it has a significantly larger surface area to dissipate from - as is gained from the inner pipe. A Plastic outer lagged would be my choice.
My understanding is the outer is copper for ease of construction and certainty to withstand high water pressures. Aside from the use of a Dremel, all these parts are standard and being used within spec (sort of). He does do a video using plastic for the outer. That's cheaper to do but much more faff and I wouldn't feel super comfortable to put mains water pressure through it.
Insulated it.
Would a solar heatpipe not work better? Like the ones used in a vacume tube solar system? Leak & maintenance wize.... And cheaper?
Couldn't you just have used tees that reduce on one side of the run? Like 1" x 3/4" x 3/4" or whatever sizes? Do you prefer to use the fitting reducers for any reason? Great video. Thanks for posting.
He said he couldn’t find them
Your outer tube needs not be copper; it will lose a lot of heat,if in contact with anything (insulate it at least); it may be made of pvc pipe.
it is easier to fit copper with copper but it can be insulated after installation !
all the beast !
Copper has relatively low emissivity. That's why heat exchangers often have copper pipes but aluminum fins.
I have a couple of questions if you are still replying to this video. I have an on demand water heater that has a long run to the shower. I am wondering if it will be beneficial to just pre heat the cold water to the shower instead of to the water heater? My shower drain is 2 inches, can I reduce it to 1 1/2"?
Even more optimal if all the shower water goes thru the heat exchanger.
Hi Rob, are you still around?
Thanks
if installed as the bottom of a trap,wouldn't it remain full of the hot waste water for better exchange.the way it looks here ,only part of the exchanger will have hot waste water on it..this one thing could save lots of oil.
wouldn't it be best to heat up the cold water as you take your shower so you don't need to go back to your tank?
no, this takes cold water and makes it tepid. the tepid water then goes to the cold feed on your hot water tank where it is heated to the final temperature.
Agree - raise the cold water temp slightly on the way in. If you're really into cold showers - you can still have them since when the waters cold - there's no heat to recycle
The energy savings should be about the same, and you wouldn't need to run 2 new lines (one up one down), isolating all the work to the shower area itself.
@@lendoggthekingnah better to send directly to the shower mixer to get used instantly
M for acidic wastes water that is within copper wall thickness of your potable water? I don’t think so Rob. Not in my house
very nice video!! are there any plans for making a steel fireplace with water heating ?
it's getting more effective if made the inner pipe twisted
More blockages maybe?
You can increase the power if you add round fins
that's what a hot water return line is for!!!!
Anyone found any numbers on how much heat this can transfer in a given setup please? It's going to do something, but I'd like to figure out to what extent before I stump up for the big copper and find time to do this. I know there are many variables in this so an example may not exactly fit my proposed setup.
nice liebig, are you sure that it is not for a moonshine still?
Hello .. How to make HEAT EXCHANGER for water and refrigerant.??? Heat pump...
Pipe this into a towel warmer and have a nice hot towel when your done =-]
Karsten Elliott Fantastic idea! Maybe I will try that someday.
Although it will only be as warm as your showers waste water, at theoretical best. Will be warmer than not doing it though
And you'd need a pump to move the water which needs power. Perhaps a small electrically heated towel rail could achieve the same result
@@davidkeith659don’t need a pump if it’s part of the cold pipe to the shower.
Maybe better just to have the hot water to shower go via the heated towel rail.
I take it this is primarily for people in cold climates?
Does not have to be. You could use something like this anywhere!
How much heat transfer is there? Would this design shortened work off engine coolant to heat water? I'm trying to build a unit for hot water to shower and do dishes on a boat. Thanks :)
Lol...always someone will catch you.great job Rob we all know heat exchangers can be more sophisticated for a better heat transfer and different applications...but more mula .....$$$$$$.
shkodrajone100 Yea for sure. When I made these videos I never had expected more than maybe a couple hundred views.
Awesome
Hi Rob...I have a question....I have a outdoor wood boiler...and want to heat my hot water tank.....this is pretty close to what I need...my boiler water is 180 degrees...how can I control my temp?...bring it down? and do you have any tips to share?....thx Kevin
You run it through a heat exchanger. If it is still too hot you can throttle the flow. If that is not possible you may need to use a mixing valve. I hate mixing valves, as they are a waste of heat energy!
Rob The Plumber y
@@RobThePlumber How are they a waste of heat energy? The total energy going into and out of the system is equal. You're just creating a greater volume of lower temperature water. No energy lost. Basic physics.
These are commonly used. You'll have to use a tempering valve on the output of your water heater.
On average people shower at about 40 degrees C, so by the time that water drips down to the feet your looking at a 10 degree drop and depending on the room temp could be 20 degree drop, so by the time its collected and travelled through the waste trap its now at another 5 to 10 degree drop, so lets say 25 degrees for the summer and 10 degrees within the trap for the winter : Therefore your now mixing 10 degrees waste with say minus 5 degrees winter cold mains ? So how significant would this method really work ? by the time the cold feed reaches the storage heater its probably gonna still be within the minus sector. Going back to the summer period lets say 25 degrees waste mixing with 5 degrees C summer mains water, that would seemingly make a difference possibly of about 30 degrees going into the storage heater. Therefore to conclude this method it seems only really any good for Hot climate countries or summer only, To which energy bills are low any way as room temperature during the summer period sustains the Hot water stored within the storage Cylinder.
Barrington Bond how do your water supply companies pump ice to your home?
+Barrington Bond - 100%... I was thinking of that. The amount in the " Recovery " is so small. Just take the Money that you spend on making it, and pay for the heat to heat the Water, LOL.
@@whatyousaidbud lol no kidding eh?
@@JodBronson ok yes its small. If everyone did this then it would be a huge impact, should be code for every house to do this. think of it this way. if everyone in the world paid one dollar to whatever cause then that would be 7 billion dollars. not so small now huh?
Your numbers are outlandish. If you're taking a shower, you will notice a fraction of a degree temperature change. If the water was below room temperature at your feet, you'd be the first to notice. Do some research. Waste water heat reclaimers are very effective devices.
the main tools we need are bigger speakers so we can hear what your saying
You can buy a better version of this at big box stores. Highly recommended for shower drains. It has no moving parts and just works.
I think its more work than it’s worth
Having made one of these before I know how much heat transfer happens with this type of Copper pipe in a pipe exchanger. NOT MUCH. I made one for a solar water heater and had water running a 135F collector loop through it at 2 gal/min. and it only transferred 4F to the storage loop at the same flow rate. I was very disappointed. I figured I'd need at least 6 to 8 linear ft. of this type of exchanger to do any good. It cost me about $60 to make a 2 ft. tube in a tube exchanger like yours' but to tell you the truth, I'd rather have my money back. It would more than pay for the 4 plate heat exchanger I ended up using.
It's a great idea to reclaim heat off the shower but a good solar water heating system will nullify the money lost on waste water heat that goes down the drain.
Yep
STARFIRESOLAR b@
Did you run it counter flow? What was the temp of the opposing fluid?
Mine raises tens of degrees. But the heat flow will be lower with less temperature difference. Which is why a heat exchanger running 160 degrees will only heat a water heater to 130 degrees effectively.
@@wiredforstereo yes it was counter flow. I'm glad it works for you.
why not take the recycled heated water and run it to your cold faucet. and then use less hot water.. unless you don't use high enough hot water tank temps to require dilution. if that was the case then running it to the hot water tank entry might make sense. nice job. you might as well use the full 6-8 feet of the pipe availible if possible. and insulate the outer tube.
Joseph DuPont
Correct. The heat exchanger should run ALL cold water through it for best efficiency.
@@wiredforstereo There is no point to running all house water through it. It only works when the shower is on.
@@robtaft9139 It works no matter what is on.
@@wiredforstereo except it doesn't do anything if the shower isn't flowing hot water through it, other than add flow resistance to the main system
I think the *ratio of cross-sections between the interior pipe and the trapped space* between the pipes is way off... shouldn't it be about equal?
A better fit might be 1" inside 1-1/2", where the inner area is 0.87in2, and the interstitial space is 0.83in2, but I suppose this might not be enough for some applications.
Drains are 1.5" so you have to start there. The important factor is the area of the flowing water in the annular space. The drain pipe in this configuration is not full.
First at all, I like your idea to 'recycle' wasted hot water back to the boiler (hot water tank).
What I don't like, is amount of copper used.
Here is the suggestion to change the concept:
Feed fresh, cold water to inner tube - thermal exchange rate will be the same as feeding outer tube with pressurized water from the tap. I think that as long as the contact surface area for thermal exchange is the same, changing design will suffer no losses.
If you do this change in concept, then outer tube can be plastic - much cheaper, providing good water tight sealing. It may little bit complicate construction (different plastic element than you propose), but at end, it will be still much cheaper than using two copper tubes.
Outer tube, if plastic and if going from bath sink has no significant pressure, since water column will not be high (then, instead feeding outer tube with high pressure water inlet, inner tube will serve as high pressure tubing).
If warm spent water is inside this outer tube, it will tend to radiate heat through this plastic outward, but as soon as you cool water with inner tube (from facet, or tap) by heat exchange, there will be minimal loss this way. Aside that, to prevent any thermal loses, this plastic (outer) tube may be even further protected by some insulating material.
I am not sure whether I am clear on my suggestion? What you think?
Cheers!
What about the fact that its a shower drain! how long do you think it will take before your drain cloggs due to the reduced opening at any given point in the outer ring of the exchanger... stick with the original idea, if your going to try this.
How are you going to seal this monstrosity? After you figure that out, it will plug almost immediately. Then it will be ineffective because your hot water is on the outside, losing heat to the environment.
The design is optimal as is. Commercially produced units are available in north America.
Nope, that thing is going to plug up with soap scum and crap in less than a year... maybe good for heating water with a fire though.
🤢Please don't poop in your shower.
you should patten then getit to be made mandatory by codes around the world.no moving parts,cheap to make and no operating cost.i think we would be amazed of the estamated globle oil savings.all of the laws and bills would pass without objections.[as long as al gore gets his slice of the fame and cash.]
Call me slow. It took me a minute or two to understand the benefit and I'm ready to take a stab at it. So, the purpose for a heat exchanger located here is to use recovered hat wast water to preheat the cold supply to the water heater thus saving heating costs? This seems plausible. All the arguments of nay-Sayers e.g. Soap scum buildup, the accumulative drop in hot waste water by the time it leaves the shower head and reaches the heat exchanger sound dubious at best. No soap scum anywhere but in the original drain where if it were to build up would do so anyway (which it doesn't) and even diminished hot wast temperatures are beneficial especially considering the one-time minimal investment required of your project. My final appraisal is keep up the good works; it is inquisitive and thought-provoking minds and creativity such as you have displayed here that lead to exponential improvements to energy savings. Just a simple added suggestion and I think someone might even have alluded to it already, would be to insulate the hat water drain, the heat expo hanger itself and the line from it back to the water heater. Good job.
The amount in the " Recovery " is so small. Just take the Money that you
spent on making it, and pay for the heat to heat the Water, LOL.
whole thing about scummy water is ridiclous. just run a double line from hot water heater, and be done with the waste. it will kill your hotwater heater. The clean second line can be recovered will yield clean water to hotwater heater.
The only thing you missed is that you'd want to heat both the cold water going to the water heater AND the cold water going to the shower, for maximum efficiency. I own a commercial unit, 3" diameter, six feet tall, vertical, I'm very happy with it.
@@JodBronson If you do the math, you'll find the payback period can be under two years. It also serves to increase the effective amount of hot water you have, very useful in larger households.
@@JodBronsonif it’s sent straight to the shower mixer cold side I think it’ll work.
The amount in the " Recovery " is so small. Just take the Money that you spent on making it, and pay for the heat to heat the Water, LOL.
Actually, waste water energy recovery devices are one of the most cost effective efficiency improvements, recouping their cost in as little as two years, with commercially available double wall units.
This one must be far better with lower cost and higher efficiency.
Many people are ignorant of the cost of their hot water.
Why not return the shower water back into the hot water tank directly? That way you don't have to wait to get sick. Who wants to wait for the copper pipe to fail and contaminate your potable water system!
This is a bad idea right from the start. The reason heat exchangers are expensive is they are made to fail safely and not potentially kill you. If this failed internally one would never know until it was to late.
acemannotsomeother tanked water isnt potable
@@gazs7237 Wrong country. It's potable in the civilized world.
The potable water is pressurized. Very little danger.
@@wiredforstereo how is the water that has gone over ones soapy body potable? The point I was trying to making is that he creating a potential problem that will not be evident in a failure situation.
@@acemannotsomeother What I said was the potable water is pressurized. It will shoot into the drain, the drain water will not shoot into the potable water.
If there is ever a pinhole developed in either of those pipes you are going to get cross contamination and possibly a lot of sick people . Very illegal I would think by most plumbing codes. A 50 year licensed master plumber.
Tributary House Ltd. That might be the best response in TH-cam history. Saw 1 of your videos about flooding fields awhile back I think...not a ram pump but complex. Keep up the good work
I always wondered why kid shave to go to Africa to send food when they could just send it, save the cost for the tickets and buy more food to be sent.
BTW, i loved your argumentation... i work in plant commissioning and start-up and i hear those arguments all the time... "what if..."
kek
@Tributary House Ltd. wow is all I can say lol
So you consume water from the hot water tank?
Wouldn't use this in my house, too much danger with the waste water being so close to the clean water. That being said, I like how you made use of common materials, it could have other useful applications when sanitation is not a concern. If you want to increase the efficiency, use the unit vertically like other DWHR units so the drain water will stick to the pipe walls instead of sitting at the bottom of the pipe. Also, keep one end of the unit hot and the other cold with respect to how the connections are made. You have it backwards in the diagram.
Trent McKone i wouldnt call tanked water "clean"
gary Strickland Then what would you call it?
Trent McKone tanked water... you wouldnt want to drink water thats been sat in a tank.... maybe your countries system is different? In the uk you cant drink tanked water because it can be contaminated
gary Strickland I live in Canada. Water from hot water tanks is safe to drink. It comes out of the same tap as the cold water unlike what I've heard about the UK where they are separate.
Trent McKone fair enough. Here it depends on whether you have a combi or system boiler. Combi is fine as its direct from mains. But with a system boiler you would have an open cold water storage tank in the loft that feeds the hot cylinder... not good to drink either hot or cold in this setup. The mains would go to the cold kitchen tap though so its safe to drink that. Its why we used to never use mixer taps. However times have changed and we are doing aqay with tanks and cylinders in favor of the combi
The outer pipe should not be copper. Make it an insulator, keep the heat inside.
Whats the point of installing the heat exchanger if your boiler is warming the water for the shower you could drain your shower directly, why are you mixing two liquids for no reason, this drawing is not the application for a heat exchanger
bil ahm To heat the cold water feeding your hot water tank or boiler with the waste water from the shower. You are not mixing the liquids. You are simply transferring the heat energy from one liquid to the other with the heat exchanger. Thanks for watching.
you dont need to heat the cold water feeding to your tank boiler works fine without the heat exchanger.
bil ahm If you raise the cold water temperature feeding the boiler, the boiler in turn uses less fuel requiring less BTU's to heat that cold water. Saving energy and costs of fuel. Fuel will not always be cheap and any savings will be of benefit.
if the cold water temperature is 20 deg, how much will you raise it 40 deg? the max it will go to is 15 or 20 deg
bil ahm The process is called waste heat recovery. The method is used quite a bit in many sectors to reduce the energy required to heat liquids or masses. The energy required to heat anything is proportional to the difference in temperature. So even if 10 Litres of water flowing into the the boiler is only heated up 3 degrees, its 3 degree worth of energy that the boiler won't need.
Good Idea Rob, just make sure the lines to the boiler are insulated to reduce heat energy loss
Taking heat from your heating system won't help you save money or energy. The video re-purposes waste heat that was previously destined for the drain.
Looks like a potential hazard for cross contamination..this definitely isn’t worth the effort or money in my opinion. I like the design, but the application isn’t right.
Minimal danger. The potable water is pressurized. If there is a hole, it will shoot water down the drain, not contaminate the water with waste.
55 people saw your vid ... Immediately called B.A.T.F.E. ( former ATF )
Umm... Not a great idea pipeing waste and fresh water together... Fail
S Upchurch watch the video again than edit your not so well thawed out message.