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-   -   Heat pump hot water heaters (https://ecorenovator.org/forum/showthread.php?t=5422)

oil pan 4 09-12-17 08:48 AM

Heat pump hot water heaters
 
Does any one know how many BTUs the heat pump side of these water heaters move?
The ratings I find appear to include the electric heating elements too.
I'm thinking about getting one and using the heat pump only during the summer.
They are only $1,000 to $1,800 each and the place is already wired for an electric water heater, the water heater is right next to the A/C handler with it's condensate pump and I can rip out the old one and plumb in the new one with out any problem.

jeff5may 09-12-17 10:34 AM

The smaller, residential units have 1/3 to 1 ton compressors in them, plus resistance heating elements for "turbo boost" demand water heating during high usage. Most of the units have an average COP (aka energy factor) of 2 - 2.5. The commercial units (above about 80 gallons) go up from there in both compressor size and COP. Nearly all of the units produced before 2015 had cap tube metering systems in them. Many of the modern units still do, but some are now being built with electronic expansion valve systems, which should theoretically boast higher COP as long as they don't fall back on resistance heating very often.

oil pan 4 09-12-17 06:10 PM

I like the idea of a 1 ton, no so much the idea of a 1/3 ton.

mejunkhound 09-13-17 07:54 PM

We have a GE geospring WH. Got it on a closeout ($700) at Lowes 2 years ago, and the POCO 'rebate' paid for 100% of it (I still got stuck with sales tax though, but the federal tax credit just about covered the sales tax, so close to 'free')

Best I can tell it is just 1/2 TON HP. 550W, 3.2 COP.

Only the 2 of us at home now, we run it in HP mode only.
Installed about 2 years ago, have a separate wh meter on the WH.

Installed just under 2 years ago in Sept, it has used 723 kW-hrs in 2 years, average of about 11 cents a day for hot water. Installed in the 'unheated*' basement where temperature is in the low 60s most the year.

2 or 3 times a year when we have overnight guests we do set it for 'demand', otherwise the resistance heaters are never on.

*WSHP compressor is in the basement as are only partially insulated ducts, so there is some basement heat.
I did build a box around the tank area and added R-22 insulation.

oil pan 4 09-13-17 09:05 PM

Half ton is good enough.
Wonder if I can get a 80 gallon GE.

I would install this one in the main part of the house and use the cool air given off to help cool the house. So there should be plenty of heat available to warm the water.

jeff5may 09-13-17 10:29 PM

Lowes has it advertised for around $1350:
https://www.lowes.com/pd/GE-GeoSprin...ology/50335969

oil pan 4 09-14-17 05:06 AM

That's weird I searched for it and it didn't come up. They would have to order it where I am. I saw the 80 gallon A.O. Smith one for $1,900. I would just prefer to not spend $1,900.

For whatever reason the 80 gallon GE one is not available where I am.

jeff5may 09-14-17 07:05 AM

I asked my plumber buddy and he said the 80 gallon geospring units have recently been discontinued. He didn't have anything good to say about them, but said the voltex units by a o smith are built better anyways.

Straight from Treehugger:

"The GeoSpring water heater was a clever design with an air source heat pump mounted on an insulated tank. Heat pumps are more efficient because they move heat instead of making it, and the GeoSpring could save homeowners hundreds of dollars per year and could pay for itself in just two or three years.

But alas, that’s not good enough for the I Want It Now culture; Scott Gibson writes in Green Building Advisor that GE is pulling the plug on it writing that " according to published reports, GE Appliances will stop manufacturing the water heaters at the end of the year because of low sales, just four years after the energy-efficient appliances were introduced."

Evidently they cost too much, (two to three times what regular resistance water heaters cost) and GE has been losing millions on them. But there were other issues, raised by commenters at GBI:

Regular water heaters are silent, while the GeoSpring had compressors and was actually noisy, some complain that it was noisier than a fridge;

The quality, at least at the beginning, was not very good;

Lack of clear contractor serviceability; the plumber doesn't know HVAC or refrigeration and the HVAC guy doesn't know plumbing or water heaters;

And my favorite comment:

People just don't care about energy efficiency here in the USA. That's my take on it. Everyone is into the house lipstick. It's not what's inside the walls but what's the wall painted with. Those concerned with true house energy efficiency is a very small minority, especially here in the USA where electricity is still cheap.

The whole story is just sad; when you read Brian’s post there was so much excitement, optimism and hope about high tech manufacturing returning to America with a great energy saving product. Except when it isn’t, and when everyone is into my favorite new term, house lipstick."

mejunkhound 09-14-17 07:52 AM

Sorry for the confusion, did say I got mine on a closeout.

Meant the post only to convey the energy use I'd had and the wattage, 1/2 ton, 550W, cop of 3.2 information.

Even 2 years ago there were only 4 or 5 GE HPWH left at the Lowes 'locally' (> 10stores in Sea-Tac metro area) and noticed that when they were gone there were no more. Had to drive 20 miles to get mine, 3 other stores within 6 miles were out and did not want to move one from another store being they were priced as closeouts. .

Lowes in our area now stocks only AO Smith, 50 gal at $1200.

BTW, definitely LOUDER than a refrigerator, you would not have wanted the GE one in an area where you wanted to watch TV or have a quiet conversation. Do have to say that the one I got has been trouble free for 2 years.
You might want to closely review any HPWH noise rating on sone numbers.

oil pan 4 09-14-17 07:58 AM

Sounds like I'm qualified to work with one of these.
Since I do refrigeration, plumbing and electrical.

Where this heater would go is by the kitchen and bathroom, not really close to the living room or bedroom.

They do cost a lot.

If I remember correctly these were part of Obama's green environmental economic stimulus package, give money to companies to encourage them to make stuff either no one will want or can/is made cheaper in china.

I think a heat pump water heater is brilliant. As long as you live in warmer climate or need a dehumidifier in the basement.
During the winter it gets so cold here I'm switching to a gas heater. I will have room for both soon.

I think I will get the A.O. $mith water heater, if it costs more, but is quieter and more efficient how can I argue with that.

oil pan 4 09-23-17 06:04 AM

I have my first heat pump water heater unit up and running.
It's just hot wired to run on a switch and water being fed by supplied by a 5 gallon container at the moment.
The compressor is very quiet even with the cover compressor cover plate off. With the cover installed it's even better. The fan is kind of noisy but not bad.
For a 6,000btu unit it's not bad. Running on 1.8 amps of 240v power with cool water, it's cooling the air off about 10F per pass and warming the water about 0.2F per pass, the water is being circulated at a few gallons per minute by the pump.
I don't think it would make a good ground source go thermal unit unless it's doing a lot better than 6,000btu.
What I have found when you cool the condensers on fixed speed air conditioners like this by say spraying water on them is they don't draw much less power but they do provide slightly cooler air.

With 122F water I am getting 2.6 amps of draw and 5 degree temp drop on the air.
I am using a flir to measure the air discharge and process thermometer totally immersed in the water to track it's temp.

I think I want to take 2 of these, put them on a 50 to 80 gallon tank for use during the A/C season which here runs from about March to as late as November.
Even then 1 ton of heat pump water heater is only about like using about a 4000w heating element. That should be plenty.

What my plan would be is take 2 of these put each on its own thermostat. Have one wired and plumbed as a line circulater. Have a DPST count down timer switch that can be manually turned on to get the water flowing in the morning and give the water heater a head start of the incoming demand. By the time the switch turns off the thermostat should be closed.

I also have a hot water heater timer I bought from lowes on clearance for $13. I would like to do most of the heat pump water heating during the day to help the air conditioners and that is when the house should be warmest.

I would probably add in a safety thermostat incase some one turns the timer to the max (30 minutes) with the water heater at max temperature and doesn't use any hot water or incase the timer switch breaks and fails closed.

ecomodded 09-23-17 09:26 PM

Ive been reading about the Helical coils being used in Water heaters , seems like a easy DIY project thought I would add a link to one paper on it in case its worthy of hacking


My thought is it can be used to scavenge heat from the heat pumps compressor or other parts or any heat source

This is a pdf file on it
https://www.google.ca/url?sa=t&rct=j...zUeGr5TuRuJgug

oil pan 4 09-25-17 10:57 PM

To go from a 50 gallon electric hot water heater to an 80 gallon electric the price just about doubles.

ecomodded 09-28-17 01:22 PM

Was going to swap in a 30 gallon tank instead of the original 60 gal tank at the time 2 months ago they wanted $200 MORE for the 30 gal tank so put a 60 in as Im moving anyways.

Today looked at prices at home hardware once more and the 30 and 40 gallon tanks are $200 cheaper.
It was either a typo a few months ago or they realigned the prices to match reality.
Had thought they reversed the prices as a way to milk people who wanted to conserve.

Oddly the 60 gal has a reported 57 watts standby loss the 30 and 40 gal a 54w and 57w loss.
Makes little sense to me or I don't understand standby losses correctly giving surface area differences.

oil pan 4 09-28-17 02:13 PM

My guess is the bigger tank is insulated better.

ecomodded 09-28-17 04:14 PM

Makes sense.
Next place I'll likely use a 40 gallon wrapped with R50 insulation and a plywood box with removable lid or some such thing.

Be nice to cut the losses down to 20 watts or less being it will be off grid

oil pan 4 09-28-17 07:12 PM

Any insulation will be an improvement.
Just start with wrapping with foil coated bubble wrap and putting 2 inches of foam on top.

TechShop 09-28-17 07:29 PM

Quote:

Originally Posted by ecomodded (Post 55798)
Makes sense.
Next place I'll likely use a 40 gallon wrapped with R50 insulation and a plywood box with removable lid or some such thing.

Be nice to cut the losses down to 20 watts or less being it will be off grid

I use a 28 gallon electric unit in my shop. The slab is heated, but I put it on 2" R-10 foam. My only hot water requirements are showers each day and a load of laundry once or twice a week.

If you have a spouse or other roommate, the 40 would be a good choice.

ecomodded 09-28-17 07:29 PM

Could also leave it in the box it came in and add some insulation to the voids.

It was right after I recycled the box that thought of using it for the tank now I wish I kept the box to use to make the portable ac heaters vent system.

Next house I think I may well keep the tank in the box now that I think about it and fill it with scrap insulation as its first layer and do a 2nd plywood case over it and keep it in a warmer part of the house.

That would smarten it up past Eco standards

ecomodded 09-28-17 07:44 PM

Quote:

Originally Posted by TechShop (Post 55800)
I use a 28 gallon electric unit in my shop. The slab is heated, but I put it on 2" R-10 foam. My only hot water requirements are showers each day and a load of laundry once or twice a week.

If you have a spouse or other roommate, the 40 would be a good choice.

Nice , my tank is in the cold part of the basement with cement floor. I slid a 3/4 inch piece of plywood under it to help. Thought to myself sleeping on a sheet of plywood on a cement floor sure would beat sleeping directly on it

Cement is a hell of a heat sink it keeps sucking and sucking

The foam base is a great hack.
I was thinking a 40 would be better for a hot bath which I prefer to showers atm , the 30 may work or be border line. I did the math and 30 sounded like it might work for a tub but it would be close and may have to kept hotter to make it work , the 40 would seal the deal

TechShop 09-28-17 07:52 PM

Quote:

Originally Posted by ecomodded (Post 55801)
Could also leave it in the box it came in and add some insulation to the voids.

It was right after I recycled the box that thought of using it for the tank now I wish I kept the box to use to make the portable ac heaters vent system.

Next house I think I may well keep the tank in the box now that I think about it and fill it with scrap insulation as its first layer and do a 2nd plywood case over it and keep it in a warmer part of the house.

That would smarten it up past Eco standards

Filling the box with fiberglass is a great idea.

You could also use a large tarp or scrap piece of poly sheeting to wrap around the insulation to keep it tidy.

For the price of even the cheap plywood, you could use 1" thick structural XPS foam to build the box it's R5, so it can only help. The 2" stuff gives R10 and is very stout if you buy it without the cut-lines. If it needs to look nice, put some wallpaper on the foam.

ecomodded 09-28-17 08:21 PM

What was it now I think the 5 1/2" nch I used in the basement wall was R25 I forget what I paid for a bag now.

I will be using rigid foam on the new houses walls and 11 inches or R50 worth of fiber insulation for the floors and roof so will have left overs of both kinds to work with

ecomodded 09-28-17 08:51 PM

The Rigid would be good with the logo on the inside and foil taped edges.

My fridge is wrapped with layers of the black wood floor insulation the last layer was using the blue type I like the look.Plywood is durable and has a decent enough insulation value costs $50 a sheet for good one side 3/4 inch / 16 sq. ft

I have to edit that ~
Just checked the 3/4" ply would has a .94 R-value , that's no good. Rigid blue is the way to go. For sure for sure.

TechShop 09-29-17 01:08 AM

Quote:

Originally Posted by ecomodded (Post 55806)
The Rigid would be good with the logo on the inside and foil taped edges.

My fridge is wrapped with layers of the black wood floor insulation the last layer was using the blue type I like the look.Plywood is durable and has a decent enough insulation value costs $50 a sheet for good one side 3/4 inch / 16 sq. ft

I have to edit that ~
Just checked the 3/4" ply would has a .94 R-value , that's no good. Rigid blue is the way to go. For sure for sure.

Yeah, foam is a kick-*** value in a situation like this, you get some structure and some decent R-value too.

They have 2" thick foil-covered stuff at the box-stores around here for around $23 a sheet. The R value is superior with the mylar foil, but it's Expanded Polystyrene (EPS) foam so it's not as strong as that blue or pink Extruded Polystyrene (XPS).

The foil tape is a a good idea for the joints.

The R-30 fiberglass rolls meant for attics are 25' long and do not have a vapor barrier. That's about the best value per square foot and R-value you can get from a hardware store. For someone without a bunch of leftover glass, it would be a great way to get enough to stuff an enclosure or box around a water tank.

oil pan 4 09-29-17 07:58 AM

I put a piece of foam under my 19 gallon tank.
I don't think it will work so well for a 50 gallon tank, same diameter but weigh almost 3x as much, I think it would flatten the foam unless it was special high density foundation foam.

ecomodded 09-29-17 09:57 AM

Its good to talk about this stuff and work out the details , thought it best to double check the psi

Im thinking plywood (again haha) on top of the foam base would work well to spread the 800 lbs or so load from a big 80 gal tank. Although the tank bottom is flat enough to spread the weight good enough I guess.

The math at 24 sq.in works out to 5750 lbs load at 10 psi per sq. inch.

Type I EPS has been tested and found to fall within 10 to 14 ps
i. The resilience of EPS insulation board provides reasonable absorption of building movement without transferring stress to the interior or exterior finish at the joints

TechShop 09-29-17 10:27 AM

Quote:

Originally Posted by ecomodded (Post 55814)
I thought it best to double check the psi , the math at 24 sq.in works out to 5750 lbs load at 10 lbs per inch

Im thinking 3/4 inch plywood (again haha) on top of the foam base would work well to spread a 800 lbs or so load from a 80 gal tank

Type I EPS has been tested and found to fall within 10 to 14 ps
i. The resilience of EPS insulation board provides reasonable absorption of building movement without transferring stress to the interior or exterior finish at the joints

XPS foam has far more dimensional stability than EPS foam. The blue stuff at the local stores is usually 15 PSI structural XPS. I special-ordered 25 PSI for use under my concrete slab foundation and used a leftover 2' x 2' square under my water tank.

80 gallons of water is about 667 lbs. Add the weight of the tank and the heat pump and that's the load on your foam when filled.
If your water tank is 24" diameter and only sits on a 2" wide ring / lip around the circumference, the surface loading of the foam would work out like this:

P = M / ((π * R^2) - (π * r^2))

Where P is pressure, M is mass, R is major radius and r is minor radius

P = 750 lbs / ((π * 12 in ^2) - (π * 8 in ^2))
P = 750 lbs / 251.33 in^2
P = 2.98 PSI

So for a large water tank, you may be in the 3 PSI to 5 PSI ballpark.
10 PSI foam is more than enough to handle that load.

I swear I have nothing against plywood... :thumbup:

ecomodded 09-29-17 10:35 AM

I was thinking to myself they use spray foam under houses foundation I should check on the psi of the wall board and yup its tough enough.

You used the XPS 1000 for your foundation or equivalent hey ? I know little about the XPS / EPS but need to learn it.

TechShop 09-29-17 02:12 PM

Quote:

Originally Posted by ecomodded (Post 55816)
I was thinking to myself they use spray foam under houses foundation I should check on the psi of the wall board and yup its tough enough.

You used the XPS 1000 for your foundation or equivalent hey ? I know little about the XPS / EPS but need to learn it.

The main difference is in the manufacturing process used for each foam.

EPS starts with a bunch of tiny polystyrene beads. They pour them into a mold and then heat it all up with steam or hot gas. The beads expand and bond together. That's why most styro-foam packaging and the EPS foam looks like it was made from a million little tiny BB sized beads. It has voids that don't completely close and when you break it, it breaks along those random voids.


XPS foam starts with melted polystyrene. They agitate it and foam it with a gas as it is forced through an extrusion die and cooled. The extrusion die can be of any 2 dimensional shape and the 3rd dimension is a continuous length.

For boards, planks, rounds and other simple shapes, the extrusion process is great. The density of foam can be controlled by foaming it with more or less volume of gas. Also, it is one big contiguous structure of polystyrene with air bubbles.

For complex shapes, the mold filled with beads used in the EPS process is extremely versatile. EPS foam is used in the lost-wax or investment casting process for automotive aluminum parts. You can see the EPS foam bead texture carried through from the foam pattern on plenty of aluminum cylinder heads and engine blocks.

In reality, the two types of foam are almost the opposite structure of each other. XPS (extruded foam) is a big block of polystyrene with air bubbles (tiny spherical voids). EPS (expanded foam) is a bunch of tiny spheres packed closely and expanded until they touch each other and bond together.
(Of course, it is true that each bead has a bunch of little air-pockets inside it from the steam or hot gas).

DMull 10-07-17 12:46 AM

I think the decision of going with the hot water heaters installation is much clever. If you want to know more about the BTUs of heat pump, then an expert heating system serviceman can give you better knowledge about this. Either you can consult home heating NJ team or else can go with NJR home service. Both are the expert contractors who are well aware of the heating system working and can even help you to choose an efficient water heater.

oil pan 4 10-07-17 11:12 AM

Here is the problem, most of us don't live any where near dirty jersey.

ecomodded 10-12-17 10:17 AM

I suspect both the companies mentioned are strongly affiliated with each other as is the OP !

jeff5may 10-12-17 12:50 PM

Quote:

Originally Posted by DMull (Post 55951)
I think the decision of going with the hot water heaters installation is much clever. If you want to know more about the BTUs of heat pump, then an expert heating system serviceman can give you better knowledge about this. Either you can consult home heating NJ team or else can go with NJR home service. Both are the expert contractors who are well aware of the heating system working and can even help you to choose an efficient water heater.

Yes, but what if I have already chosen and installed an appliance and just need it signed off by a licensed journeyman for my insurance company? Could you travel to Kentucky, look over my install, and sign off on it? How much is dat? Could I take pictures, mail you a form to sign, and have it done that way? I believe it would be more economical for both of us that way. I could mail the signed form to my insurance company. If anything ever went wrong, I could just fix it myself, or let my fingers do the walking and find a local expert to fix my "hack job".

DMull,
Please try to add something useful to the site when replying to threads. I have noticed more posts from you just like this, where you are discouraging DIY. I respect skilled trades and service professionals and the value that they provide to society. However, this is not a site people seek out to find listings of local service professionals. Most are seeking specific information that is difficult to find elsewhere. If you have the expertise to add insight, please write your posts from that angle.

oil pan 4 10-12-17 01:17 PM

Who am I allegedly affiliated with?
I'm confused.
First I was talking about gating a GE, then an A.O. smith finally I ended up getting a used obsolete heat pump water heater made by a company that I believe went under like 10 year ago.

My recommendation for an installer is your self. I believe in self sufficiency. You should be able to install and maintain these systems your self to some degree.
Unfortunately plumbin and hvac companies try to hire people with a criminal record so they can pay them next to minimum wage.

I think some people are just but hurt because I make it known that man made global warming is a scam yet I do things to increase efficiency and reduce my carbon footprint that a lot of these city dwellers can only dream of.

jeff5may 10-12-17 10:38 PM

Ok, now that we have begun to derail this thread because of another troll, let me ask something relevant:

Oil pan 4,
What did you actually purchase? All I can really tell is that it is rated at 6KBTU. I commend you for your contributions to this site and wish more people had as much courage and motivation.

oil pan 4 10-13-17 01:47 PM

Etech R-22 charged 240v powered water heater heat pump made some time around 1999 to 2000.
The unit I bought looks like it was installed long enough to be tested but isn't dusty inside the coils or any where else.
I know etech is still around but this appears to be their only attempt at building any kind of water heater.
I think it was too far ahead of its time.

oil pan 4 10-13-17 01:48 PM

Etech R-22 charged 240v powered water heater heat pump made some time around 1999 to 2000.
The unit I bought looks like it was installed long enough to be tested but isn't dusty inside the coils or any where else.
I know etech is still around but this appears to be their only attempt at building any kind of water heater.
I think it was too far ahead of its time.

ecomodded 10-13-17 02:40 PM

To clarify my post , I was trying to indicate the op from dirty jersey with service advice is likely an employee /shill. Not you oilpan4 haha

I should of wrote "the last poster" as he was original only to his last post


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