DIY Heat Pump Water Heater. DIY. Home made mini split.

[@imabeapirate]

I agree the lack of available mini-split water heaters is pretty frustrating here.

[@wgoode505]

All water heater tanks are glass lined on the inside to prevent rusting that have been injected inside and baked on after welding the tank together at the factory. Once you weld that tank back together this will destroy the glass lining and expose the raw steel from the weld inside the tank and that will for sure rust rapidly. I done a similar thing with a 8"x12" 50 plate heat exchanger and it works great by running your discharge line from the compressor (hot gas refrigerant line) thru one side of the plate heat exchanger and a 80 watt circulating pump from my 50 gal. Rheem heat pump water heater to the other side of the plate heat exchanger and back to the tank. I used the discharge line (hot gas) on my existing 3 ton package heat pump unit to go thru the exchanger and them back to the outside condensing coil with a temp controller now controlling the outdoor fan. Since I have to use the heat pump to heat my house in the winter this only provides me with almost free hot water (80 watt circ. pump) while I am using the cooling mode of my A/C. But living in the southern US I have almost free hot water for 8 months out of the year from my existing A/C unit. During the winter I just rely on the Rheem heat pump water heater which is super efficient anyway. Great idea on this but I think the rust will be a problem for sure unless you can coat it again on the inside. One other thing to consider is scale forming on the copper coil inside the tank the same way it does the copper coated traditional heating elements. Adding another anode rod and changing them out frequently (they are really cheap) if you have hard water may be a good idea. Love to see people like me and you who think outside the box.

[@ne7s29]

I ordered one of the electric annoyed rods that don't wear out for 30 years so that should hopefully fix my issues

[@ne7s29]

And back in Europe my father would build his own water heating systems for homes out of regular steel pipes and steel plates for tanks and they're still standing 35 years later

[@wgoode505]

@@ne7s29 This is the type of plate heat exchanger I'm talking about that I used, a similar one but 50 plates. Here's the Amazon link: www.amazon.com/gp/product/B0095CFI6K/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

[@ne7s29]

@@wgoode505 I heavily looked at getting one of those but my biggest issue was guessing the internal volume of that plate exchanger to have the proper volume for the gas to flow through it so I would not be undercharged or overcharged. As far as calcium building that you normally get in regular water heaters I should not have that because calcium build-up alone occur with boiling I will never get to a boil my heater internally is only running at 150ﾟF

[@wgoode505]

@@ne7s29 I was a little skeptical at first with the plate heat exchanger but it has plenty of flow through the plates and it worked out great for me. I did have to pump my system down and install the copper lines and fittings and afterwards when recharging the system, after pulling a deep vacuum I had to add a little bit more freon to the system because of the added line lengths but it worked out great. I charged it back up to a superheat of 8 degrees. So almost free hot water when my A/C is running. As far as the build up on the copper coated elements and possibly in your case the added copper coils inside the water tank. The build up will come from not having a very good water source such as hard water. Some people with not so great water have to change their anode rod out every few years along with their heating elements. You may have a good water source like I do, I don't know. My old water heater lasted over 15 years without changing the anode rod or elements. The reason companies like Rheem, Ruud and A.O. Smith use stainless tubing on the outside of the tank is to prevent deposit build up on the coil compared to if it were inside the tank. It would rapidly reduce efficiency for people with not so great water such as well water, if it were inside the tank. And a copper coil coming into contact with the steel tank on the outside will deteriorate the copper fast as well. That's why they use stainless tubing. Would really like to see a one year review on your system maybe by pulling one of the old heating elements and putting a cheap borascope camera inside to see if any kind of deposits accumulated on the coil. I hope it works out good for you, water quality means everything in this case.

[@GRIZYBAER]

Excellent overview. Thanks for documenting all your steps, and all your numbers( tubing length, electric consumption and equivalent heat element consumption)

[@Tanstaaflitis]

As I understand it, code in the US requires a double wall between the refrigerant line and water. That's why commercial hybrid water heaters wrap the refrigerant around the tank. It's less efficient hear transfer, but satisfies this code. I think the desuperheater accessories sold with many heat pumps are constructed the same way.

[@paladain55]

When you say double wall what do you mean? Just outside of the steel tank with the fiberglass liner? Is this the double wall you mean?

[@chargermopar]

I rigged up mine 10 years ago by pumping through the drain port. Made a heat exchange coil and tapped into the line from the compressor to the condensor. A thermostat controls the circulating pump,

[@jimthvac100]

I like your project. I thought of doing this but figured instead I would use a Geothermal Heat pump heat exchanger coil... has water and refrigerant hook up then it can be used with any water heater just need a recirculation pump.

[@twosuns20]

Thank you for making this. I was looking around for a split hot water heater. But the Sanden was just too expensive to even consider.

[@stevemcfarland4661]

Crazy Mitsubishi doesn't adapt a hyper heat unit for this. Make bigger compressors an option for higher demand

[@dorsetengineering]

I've never seen a mini split water heater in Europe, they are usually all air-water monoblock heat pumps. I'm about to start building a 2.5kW unit from a r290 mini-split and my existing DHW tank.

[@Z-Ack]

Danfoss sells a mini split for 1700$.. comes with everything.. only thing is if you cant install it yourself then you’ll be out a good 6-7 grand in the install. But if you have a brain and motivation and ability then for around 2 grand you can set one up and have a 10 year warranty.. and have it insured..

[@pierrerouthier1948]

You should consider getting in the tank with the 3/8 line choking it at the exit with the 1/4 line! If you look at the indoor unit it is multiple parallel runs of 1/4.

[@machaf]

I like the DIY style, but its gotta be cheaper to get a heat pump water heater. I got my 50 gallon hybrid for $670, now its around $1000. In one hour the elements on the water heater wouldn only pull 5kw, not 10kw. There are two 5kw elements, but they won't turn on at the same time. Which is why they require 30amp breaker vs 50.

[@ne7s29]

Well they are 1700$ now not 1000$. I did this for speed of recovery. It is 3-5 times faster water recovery with no heat loss in your home. If yours is in a basement that's fine. Mine is in a living space closet so you always felt the cold air.

[@eivindholthe530]

Running a larger tank. Like 200-300 litres could help with keeping temps for when the shower will be running alot. Either that or supplementing with electrical heaters for a faster heat up when needed could do the trick.

[@ne7s29]

Unit has been running for 2 years. 6ppl and no issue with doing dishes and showers one after another.

[@GRIZYBAER]

Excellent build. Are you still using r410a or did you switch to a different refrigerant. I noticed that it’s not in its final config like in your other videos. Do you recover and reuse?; evacuate and refill? Or there’s another procedure. Thanks.

[@iamwangine8752]

Man... I think you got a sub for this ❤ So you system deliver approximately 28kw heating

[@MichaelGraves3304]

Both Lowes and Home Depot sell hybrid heat pump water heaters from brands like AO Smith.

[@gregorymalchuk272]

Do they sell them as a split system that doesn't freeze your basement?

[@MichaelGraves3304]

@@gregorymalchuk272 They don't sell split systems. Nyle makes a split system that designed to make a traditional electric water hear into a hybrid. They can be installed anywhere, some in very cold places.

[@danbroberg8320]

I am not a HVAC guy. I like this idea . My question is could you still use the AC side to cool a room . I think this could be great system for a cargo trailer conversion. Generating AC and hot with same power consumption could be a huge battery saver. Two for the price of one:.

[@ne7s29]

No because you only have one heat exchanger

[@ur_quainmaster7901]

@@ne7s29 If they mean the outdoor unit, placed indoors, then it is absolutely an air conditioner.... albeit one without any forethought to indoor issues such as condensation , airflow distribution, and most people care more about the room temp vs what exactly their water heater is doing at the moment...

[@alaasadek2908]

If I may ask, why did you not put the whole evaporator with the half way tempreture sensor in the tank? No need for new copper tubes.

[@joergreinicke5945]

Because Copper(Coil) and Aluminium(Fins) are fine together as long as the air is dry. If there is moist or water between them they start to oxidize. This stuff and Aluminium itself you do not want in your drinking water.

[@alaasadek2908]

@@joergreinicke5945 thank you from Egypt

[@luimackjohnson302]

Superb! Thank you for sharing this video.

[@kamal19801982]

You are a smart person

[@Mariusz1975zizu]

what do you think about submerge in the water tank whole original evaporator ,, Im trying it but worrying about corrosion alluminium and copper

[@alaasadek2908]

I just asked the same thing. I do not think tha Al will corode. Best regards from Egypt.

[@Mariusz1975zizu]

@@alaasadek2908 on my exchanger i see after few months only iron part has corode and aluminium and copper not yet

[@alaasadek2908]

@@Mariusz1975zizu iron corods. Maybe a plastic container padded properly and polypropylene pipes will be better and cheaper.

[@Mariusz1975zizu]

@@alaasadek2908 i have plastik pipe only small parts have problem with corrosion

[@Messier45]

Nice Project! How high does the water temperature rise during winter time with outdoor temperatures below freezing? I'm thinking about a similar project but submerging the indoor coil into a small intermediate water tank and a small water pump that pushes the heated water from the intermediate tank through the heat-exchanger in my final drnking water tank. Since the indoor unit's coil with its fins is quite large, I'd assume the heat transfer to the small intermediate water tank should be quite ok. Any opinion on this?

[@XenArena]

You should do more videos more often. Even vlog type. Best wishes,

[@ne7s29]

To be honest my time is worth more than all the gold in the world. I have a family and I value my time with them more than anything else as that can never be returned. So anything that I do my life must must be super important or or of high value to someone else and I will put my time into it. Doing video uploads on KZbin takes many many hours and on top of that Your mind and ideas will be constantly Pondering what you are putting your effort into therefore going back to the beginning of this that is why I dedicate my time to my family And my beliefs that I value

[@XenArena]

@@ne7s29 That is beautiful! Best wishes and regards

[@786otto]

Good try, people in Europe have been doing it for years.

[@TomislavKoren]

Hello. I like your setup a lot, just few questions pop up. First, why didn't you used tank that already has coils inside - like bivalent tank that's used for solar systems? Coil tube diameter size? Second, if coil is located on bottom, it will heat bottom and gradually transfer heat to the top. That means you have to wait for tank to heat up. But if you make coil on top, it will quickly heat up enough water for immediate consumption which if not spent, can be moved to the bottom with additional small pump that can be connected instead of motor (yes, I know you'd need additional electronics with it). Somehow, running that fan motor for nothing seems like a waste. I'm from Europe, on meridian similar to Virginia.

[@ne7s29]

I needed exact size of pipe and leather in tank so I had to make my own. Th bigger portion of the heating coil is on the bottom of the water tank and that is after I did a few test trails prior to permanently placing the coil in tank. I tried it more to the top and then middle. The way it is now heated the water evenly and as the top reaches 125f the bottom is not cold. Maybe 115f. The heat from coilmon bottom goes to the top all by its self when heating so no point of placing it on top and as the top of the tank gets up to 125f its easier for lower part of the tank to receive the heat since the coil is there. Works best this way. Most of the coil on bottom and some middle and less on top. I looked through many pictures of other tanks and they looked similar. The fan motor need to run for heat pump to not have codes. With no fan attached it uses very little power.

[@charlespaine987]

The US REQUIREMENTS for double wall separation may lower transfer rate but would not increasing contact area of condenser compensate for the less efficient heat transfer. Question when cold water is being introduced and creates thermo layers how will that affect the return refrigerant temperature . Will the repurposed controls be able to compensate ? Yes i worked in HVAC for many years i am not an engineer.

[@ne7s29]

I have many other videos showing this unit running in house. Been 2 years. No issues. No weird compressor noise. No loss of heating output.

[@JamesBergeron]

Cool idea, good luck, hope it works for you! I noticed most of the outdoor units won't heat above a certain temperature, they will only cool. Is that an issue with this?

[@ne7s29]

That is something I looked into before I tried this so I turned on the heat and my fugitive Mini split during the summer hot days and it had no issue turning on and providing hot refrigerant. I figure they just give that heat temperature range for for testing purposes. I ran this last summer an 8090ﾟ weather and it had no air codes or issues I figure they just give that heat temperature range for for testing purposes. I ran this last summer an 8090ﾟ weather and it had no codes or issues

[@britboard]

How are you using/adapting the controls to carry out a disinfection cycle? Also have you looked at the "Daikin Altherma" or the US made "Water furnace" range of domestic heat pumps as an option.

[@ne7s29]

Daikin used to make residential type hp water heaters. Not any more. This worried about the Legionnaires' disease and this u need 140f to be safe you need to do some more research on that disease. Above 120f it can not live. I run the tank at 130f. No issues there

[@britboard]

@@ne7s29 Daikin still make and sell the Altherma's here in the the UK and across Europe, its how i make my living, fitting fault finding and servicing those and many other AC, chillers and heat pumps brands. Legionella is not the only bacteria that you need to be concerned with and the temperature difference from the top of the tank to the bottom can be enough to sometimes cause an issue, hence why most of the manufactured units have a disinfection cycle which takes the tank temperature to 80C/175F near the top to account for that difference in temperature. Surprised you say Daikin stopped in the US would of thought that was a huge market for them, is there just not much of a take up of heat pump technology with the US public?

[@ne7s29]

@@britboard America us built on money. If there is a way to make it for some one they will do what's needed to make sure they are the ones making the money. Good old propane water tank heaters her sold like hot cakes at like 60%efficiency.

[@jimthvac100]

I like your idea, but you did this the hard way. You did not need to butcher that hot water tank, All you needed to do was hook up a coaxial heat exchanger and a recirculating pump. the heat exchanger has two ports for the refrigerant lines and two for the hot water lines.

[@iamyourantonberteaux3296]

Could I just divorce the coils from the inside unit and drop them in the water instead of using copper tubing to replace it? Or do you need the temp snesors and other things to be hooked to the coils for some reason? I am thinking of heating up a storage tank with corrosion protected heat transfer fluid, presumably water with anti freeze.

[@ne7s29]

Short answere is yes but not really. That would be like asking can I start off in 3rd gear and then go to 1st then second. To properly release heat inside your tank you need s properly designed coil.

[@idontwantcorporateretaliat6301]

I've seen plenty hybrid heat pump water heaters for sale in the US for years. What am I missing?

[@ne7s29]

They pull the energy from ur home. This uses outside temp

[@johnwahlers4979]

where did you get the meter you used

[@giacomobonetti9134]

A COP of 5 or more 😮😮🤯

[@dlaynd]

I am curious if dropping original heat echanger into the tank would work as well instead of putting a new coil of copper tubing. I suppose corrosion would become an issue because of aluminum fins... I wodner how long it would survive

[@ne7s29]

To get good cop u need to have the coil spread out from top to bottom. Just putting in a hot coil will heat the water but not efficiently.

[@Justin-yg6je]

Luckily here in 🇨🇦 there are a few 2000$ options for h/p water heaters but unfortunately it's been -45c last few days so outside units freeze solid so question is... How hard would I be to submerged outside unit in a tub filled with water circulating through pipes under ground like a geo heat pump. Here mini splits are 1200$ geo thermo units are 5k min.. plus I own a solar company and I'm a red seal electrian building a off grid house on a very limited budget for cash. So any advice would be 👍

[@ne7s29]

Well if it's-45 I think you have some permafrost so I wonder how this would work for you. But the idea is the same what I did with the inside evaporator you would do with the outside condensor. Find out what size tubing is has outside and how many linear feet. Then run that in a tank of water with sufficient water flow. I guessing you will need some serious water flow but that could be tinkered with later in fine tuning The outdoor unit has a ambient temp sensor. I'd put that in the inlet side of the water running through your heat exchanger tank. I think this would work BTW those 12000 mini split are very weak. Unless you have 40deg water feeding your heat exchanger it would out out much heat and as a second you say it gets to -45. Well you need some serious btu's as well so you would need s large heat pump. I'd run a wood stove below -15c outside temp then run this lg red unit above that temperature.

[@David_Mash]

In line refrigerator?

[@slusajgledajpazi7556]

Could you please tell me how to regulate the temperature of the freon flow or water flow from the heat exchanger? Is it possible to somehow influence this?

[@ne7s29]

The short answer to that is no because you would have to reprogram the original computer from the Mini split. that is why I stated to use this exact brand of many split. Because when it turns on and runs at full speed, its efficiency is still very, very good. Most many splits at full speed have a horrible efficiency.

[@slusajgledajpazi7556]

Thank you very much for quick response! What do you think about other brands, Japanese of course like Daikin, Mitsubishi, Panasonic and etc?

[@ne7s29]

@@slusajgledajpazi7556 Honestly, they are good in the general range. As a car at 55 miles an hour, many cars have good fuel mileage, but if you floor them, some have decent fuel mileage, and some have poor fuel mileage. the same goes for heat pumps. The other Japanese brands have a good general rating for efficiency. But under full load, they suffer 30 to 40% loss and efficiency. this L. G brand at full capacity. 5°F outside temperature produces rated capacity at Ar COP of 300%. Most other brands run 200% at full capacity at 5 Fahrenheit. If not, less, some Chinese brands are at 180%.

[@johnwahlers4979]

how did you build this. Could you do a video on how it was built?

[@ne7s29]

Watch the other videos

[@xushenxin]

what is under the bubble wrap? What is inside of the tank looks like?

[@ne7s29]

Watch the other videos.

[@xushenxin]

very cool!!

[@CGrantL]

If it’s so easy for you to successfully mock this up - why is this not sold?

[@ne7s29]

Regulations, safety and so on....... probably 100 loops to go through to actually put something on the market.

[@MrCraciunbogdan]

Why ac without txv? Asking this because I have a 30k BTU Mitsubishi AC that I am thinking to convert to a HP based on your video. It does support heating and cooling by default. The only question would be if this unit has txv on each unit (outdoor and indoor), would it be possible to convert it to a hp? I think In my case I would have to make a coil of the same size as the one from the outdoor unit, right?

[@ne7s29]

Mini splits are inverter driver so mukti speed/load so they have a eev. Elec exp valve. It's on the outside unit.

[@MrCraciunbogdan]

@@ne7s29 thanks for the reply. My model Is also driven by the outdoor unit. So what would you suggest in this case? What do you think I should do? Use the coil from the outside or inside unit?

[@cristianhuepe]

Hi, can you share the COP vs Temperature?

[@ne7s29]

What I did is reset the kw meter November 1st. I'll see what it used for the month of November and compare it to the summer months. That will give the best input. What I did is reset the kw meter November 1st. I'll see what it used for the month of November and compare it to the summer months. That will give the best input. Last night the power went out and that shuts off the unit. I forgot to power it back on so the temp dropped to 60f In the tank when kids tried to take a bath taking 55gal of water at 60f to 125f per a calculation take 8.7kw of power in pure electric resistance heat. I monitored mine for that period in 30f weather and it used 1.9kw via the lg setup I did. That's a cop of 4.57 in 30f. Im very happy with that! I'll say that's a avg temp here in upstate NY.

[@HuskyLuke]

What about the LG thermal v r 32 split

[@ne7s29]

What about it?

[@HuskyLuke]

Can’t you but that to heat your water instead of make one yourself

[@ne7s29]

@@HuskyLuke They do not sell them in US for residential for residential. Maybe they do sell them for commercial purposes

[@tobbee3589]

nice job! but if u replace the indoor unit with a plate heat exchanger that correspond to the indoor unit? i think i saw someone here in the EU was in to that with a mini split system outdoor unit, he was heating a outside pool with it !

[@ne7s29]

I did heavily research that and wasn't contact with suppliers from China but the biggest issue is knowing the exact volume or cc's it is that are inside of the heat exchange and then converting that to make sure that equates to the same amount of volume the indoor evaporator would have because you don't want to be overcharged or under charge and there was too many variables. the price really wasn't too cheap so I just stuck to the basic method that most water heater producers use. My brother is running the AO Smith heap up water here and I am trying to compare and see is how much cheaper mines is but so far looking at the usage that his store bought heat pumped water heaters using I'm fairly amazed it is much less than my General Electric 5 year old heatpump water heater was using almost half less. Mine would pull avg 650watt at 70f intake temp and his ao smith pulls 380watt at 70f

[@ne7s29]

But the other thing to consider is your indoor heap on water heater if it's in a condition space is cooling it at a rate of 6000 btus which is almost 2 kW (6800BTU) equivalent of straight electric heat so you have to deduct that from its efficiency as well

[@rodon91]

@@ne7s29 Say i wanted to use a Plate heat exchanger or a tube in tube heat exchanger from china. Waht would be the exact way to calculate the sizing?

[@ne7s29]

@@rodon91 That was exactly the issue I ran into when contacting them to get the cubic centimeter volume of their headache changer to know how much gas I either have to remove or add based on the charge in the meaning split. They were not able to supply this information properly. Many splits are fairly flexible with under and overcharge so I think if you did a bare bones calculations you wouldn't be too far off

[@rodon91]

@@ne7s29 I assume that would not be the only factor at play here. Surface area of contact with the medium you want to cool or heat is also important, speed of flow of refrigerant, amount of time and length of tube taken to condense properly, etc. Its just too much to know. An inverter heat pump would compensate for most of these though.

[@David_Mash]

Should this not be able to generate electricity?