faucet pressure powered water heater.

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What you think of using a Tesla turbine, or whatever turbine, running off the faucet water pressure, turning a generator with nichrome wires, that the water also runs through? ( I guess just short the motor wires)

This place claims 110watts of electricity (at unknown details):

https://www.prnewswire.com/news-releases/generate-electricity-whenever-you-use-water-at-home-with-the-vortical-tech-hybrid-tesla-turbine-300610633.html

but if only trying to convert solely to heat I think u could get much better efficiency. If converting to heat..and catching it all with water..wouldnt all the energy be converted to heat or what other losses could there be?
 
The price of the water will out weigh any energy gains. No running of water just to make power. Water in our house is just a few gallons per use. Unless you had a backup battery installed don't think it would be worth it. A new house would be good in an energy saver house.
 
I assume you're trying to emulate one of these:
9600W Point-of-Use Electric Tankless Water Heater 240VA
https://www.amazon.com/Undersink-Electric-Tankless-Water-Heater/dp/B07GSPP1KV
https://m.media-amazon.com/images/I/61VRMj4YlJL._SL1125_.jpg
61VRMj4YlJL._SL1125_[1].jpg
but with a flow-powered generator in the flow you're trying to heat up, instead of a heater powered by the house AC electrical system?

Water takes a lot of energy to heat up: "As a general rule of thumb, it requires 2.47 watts of power to raise the temperature of one gallon of water one degree in one hour." (from a 10-second google's first answer)--that's why those heaters take a lot of power (that one is 9600W so it can rapidly heat a regular faucet-flow-rate of around 1-2 gallons per minute. (from a 10-second google's first answer: "The average flow rate for faucets is between 1.0 gpm and 2.2 gpm. In the US, the maximum flow rate for kitchen and bathroom faucets is 2.2 gpm at 60 psi.")

Assume the link you have is right about 110w from the generator...but what rate of flow (GPM) to generate that?

For math's sake, let's just go with the 110w and ignore the flow rate: 110 / 2.47 = 44.5. So, assuming you're dealing with only one gallon of water just sitting in an insulated container (so it can't lose "any" heat), that's 1/44.5 of an hour (just under a minute and a half) to heat that up by one degree. Or, in one hour it would raise the temperature by 44.5 degrees instead of just 1 degree.

I don't think you could even measure (with typical equipment) the difference in temperature of the water if it was the actual water flowing thru the generator driving it.




Hummina Shadeeba said:
What you think of using a Tesla turbine, or whatever turbine, running off the faucet water pressure, turning a generator with nichrome wires, that the water also runs through? ( I guess just short the motor wires)

This place claims 110watts of electricity (at unknown details):

https://www.prnewswire.com/news-releases/generate-electricity-whenever-you-use-water-at-home-with-the-vortical-tech-hybrid-tesla-turbine-300610633.html

but if only trying to convert solely to heat I think u could get much better efficiency. If converting to heat..and catching it all with water..wouldnt all the energy be converted to heat or what other losses could there be?
 
“it requires 2.47 watts of power to raise the temperature of one gallon of water one degree in one hour."

Why is time in the equation?

Given all the great numbers you found and math u showed (very appreciated) can you guess as what wattage needed to produce a lukewarm weak flow of maybe 1/8th a gallon a minute? I’d rather have warm drinking water than standard a warm trickle is good enough for everything other then a hot shower. Who wants standard faucet-temp water anyway? 98.6f?






[/quote]
 
Using electricity to heat water is crazy inefficient. Best way to get heat from electricity is with a heat pump, as long as you don't live in the artic. Still have gas water heater it's cheaper than a heat pump. That also depends on the efficiently. Older Gas was only 60%, newer devices are up to 98%.
 
Why wouldn’t nichrome wire submerged in water be completely efficient at converting from electricity to heat? I thought would be energy efficient but maybe not financially efficient


Looking on wiki it’s confusing and says using resistance heating is about 100% efficient yet heat pumps are said to be more efficient


Maybe the efficiency of the whole process to make the electricity is being included sometimes in the assessment.


I’m thinking the resistance heating of the water is the most efficient and the generating of the electricity for that coming from the water pressure is free (although the turbine is likely not very efficient in smaller sizes for some reason. ?).
 

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"As a general rule of thumb, it requires 2.47 watts of power to raise the temperature of one gallon of water one degree in one hour."


Ok. If assuming 110 watts available (or say 100 watts to make it even simpler), and adjusting so there was only a flow of one gallon an hour..(wouldn’t the flow be forced to be a trickle anyway as the momentum is converted to electric?). how many degrees would that be heated? I’ll be thinking about it and trying to do what’s likely simple math.


At some point the ratio of wattage to flow can be adjusted and can result in hot/warm water at a very slow rate. That sounds great. I want to make this.


Maybe could adjust the heater simply while attached to the faucet


The goal being utilizing the pressure with least water flow. Not a new goal. So likely no hot drips possible and a certain amount of water flow is needed.
 
Heat pumps gather available heat from around the condenser and do not create usable heat from the current being used. So both are true to a point if there the outside air temperature -40 deg F then the resistive heating is more efficient.
 
if you just want to take the chill out of tap water, i'd try a heat tape. $34
wrap it around the pipe near the faucet
https://www.ebay.com/itm/265806517621?epid=1438869902&hash=item3de34d9575:g:LnUAAOSwxaBi5uIm&amdata=enc%3AAQAHAAAAoHawJdlHnL4V9JGKM2SAdZepEdA%2BiMzf1BzHWXKMA%2BqzrqTMTOgHxLD%2BxBykNc8Q1x1aZUoxZMaWYzbUloFTucYTAdh2LYLh33Z8H%2BVe1X0sYsz5%2F7KVP12CVlfvFU8ft4DhYMXJrma3k4WV7JEyDNhKO4k3uJVHa8RT9ttFmCj0mgJBRu5AX7BiX%2B0yjnITVnBakRHzJ2DZV4WjbCs8FzY%3D%7Ctkp%3ABk9SR9zlroi2YQ
 
Hummina Shadeeba said:
Why wouldn’t nichrome wire submerged in water be completely efficient at converting from electricity to heat? I thought would be energy efficient but maybe not financially efficient


Looking on wiki it’s confusing and says using resistance heating is about 100% efficient yet heat pumps are said to be more efficient

They manipulate the heat pump numbers to sell them to unknowing people with money in the bank. Who think they are good cause they read the skewed biased " efficiency numbers" that ignore actual engineering.
Quote from: An actual practicing, certified, business owning, 50 years in the industry, mechanical power systems engineer.

You wont see any power industry engineer using heat pumps much...

Look at the breaker size and code adhering UL listed requirements for installation and you will see how " effectively efficient they are"... Lol@heat pumps.

50A @ 220v is not cheap. Most heat pumps are int his range. Horrendous actual efficiency. Its a joke, a gimmick, all the numbers they give you ( heat pump sellers)...

Most electric water heater use a 20 or 30A breaker, and yes, restive heating IS 100% efficient.

Now, heat pumps have their place... like in an RV or truck or car where the delta and gradient of temperature to bee seen is great.. but for a home? Gimick to be sold to those with money.

Fuel oil is 5$ a gallon for its 33kWh of energy it holds after effective efficiencies.. here where I live.
33kWh of electricity from the wall is 4.62$.
To get the same BTU output heat, out of a heat pump, you would spend 15$ in electricity.

Electric heat is cheaper here where I live. Vs fuel oil.

Wood is virtually free though, BTU for BTu... so we should all heat our water off of wood burning furnaces.

Steam is still the best way to transfer heat energy. Has been for hundreds of years. Will be, for a while, yet.

I have two hot water heaters in the home. One is propane fired, big one, family size one, and I have a backup PointOfUse 4300w under the sink type.... for backup if I run out of propane. It will heat up my dishwater sink to about 120-130*F at a flow rate of about 2-2.5gpm out the faucet. 30A breaker I think ( 240v single ).
 
can get some free warm water if you have a sunny spot and a garden hose. just put 50-200 feet of hose in the sun for 2 hours, hopefully against the south side of a building.
i just put some 33F jugs in the sun, they will be 80f by noon for my garden plants. will only be 50F today.
 
Matt Gruber said:
can get some free warm water if you have a sunny spot and a garden hose. just put 50-200 feet of hose in the sun for 2 hours, hopefully against the south side of a building.

Mmmm, plasticizers. Spicy!

Following this thread did make me think about the black-box solar water heaters I used to see more often. I guess that was back when copper tubing was cheaper, when drug addicts were less likely to invade your castle and plunder your precious metals. I guess it would work about as well with galvanized pipe, though.
 
i keep a gallon jug on the counter. it might be 70F while the tap is 47F. that might be all he needs.
 
You can let water sit in a jug on the side or lay a garden hose in the sun or use heat tape but nothing new in that.

What of the potential of the 60psi water pressure at the tap? That’s a lot of pressure and surely could spin out some decent wattage. I think for sure more than 110watts.

I want a warm trickle and think that’s possible.


Tell me what you think of a turbine feeding into a permanent magnet motor/generator with nichrome wires? Could I just add more nichrome wire to create more electrical resistance, resulting in more heat and less water flow? How would you do it?
 
You have to look at the energy, not power. Water going from 60psi to zero psi can only do so much work, and it isn't much. While you could use some kind of turbine to generate electricity and convert that to heat, you could get the same effect by passing the water through a zig-zag path which could turn all the lost energy into heat with near 100% efficiency. I'm sure there's a way to do the math on it. I'm sure it won't heat the water more than one degree.

Heat pumps work. One watt of input can produce 3 watts worth of heat if the temperature difference isn't too great. The other two watts are extracted from the outside air. It's just an air conditioner in reverse. But they are expensive and require maintenance.
 
fechter said:
You have to look at the energy, not power.


:thumb:



Water going from 60psi to zero psi can only do so much work, and it isn't much.

isn’t it possible to know exactly how much energy is there?


While you could use some kind of turbine to generate electricity and convert that to heat, you could get the same effect by passing the water through a zig-zag path which could turn all the lost energy into heat with near 100% efficiency.
from friction? You have an example you could post.

I'm sure there's a way to do the math on it. I'm sure it won't heat the water more than one degree.
but how much water? Maybe could divert a lot of the flow to the side so could use a high flow rate and end up with a smaller quantity of water that’s heated
 
Here's a calculator for big systems, but the formula will be the same. Have to do some units conversions to fit the formula.
https://www.engineeringtoolbox.com/hydropower-d_1359.html

1 Gallon (US fluid) per minute is approxminately 6.309 019 64 x 10-5m3/s.

mH2O value = psi value x 0.703070.

Assuming 60psi @ 3 gallons/min,
hydro power calc.JPG

You could get around 70W of power if your generator was 90% efficient.

We can calculate the temp rise next time....
 
Hummina Shadeeba said:
“it requires 2.47 watts of power to raise the temperature of one gallon of water one degree in one hour."
Why is time in the equation?
Because it takes time to do work. Nothing happens instantaneously. The faster you want something to happen, the more power (over the shorter time you have) it takes to do that. Technically for the above equation, it would be 2.47Wh, not 2.47W, because you would be applying the 2.47W continuously for the entire hour.


Here's some basic math that could be wrong (me and numbers do not always get along), and I'm assuming the degrees in the original formula are F not C as none of the places I saw it said one way or the other but were using non-metric numbers for most things, but may show you something of what you need:

If you want to raise the temperature of one gallon of water from say, 50F (because the pipes usually run in your cold attic or slab, keeping the water cold in this season on this end of the world--could be kept even colder), to 120F, that's a 70F difference. So it would take 70 x 2.47W to change that temperature, in an hour, assuming perfect insulation on the water containment with element in it, so that there is zero heat loss. (if you include realistic heatloss, it gets a lot more complicated). That's 172.9W, applied continuously for the entire hour. Or 172.9Wh.

If you need to raise it to that temperature in a tenth of a second (which is really probably more time than the water will actually be inside the heating segment of a small point-of-use heater, so it would realistically take even more power), then you need to apply the power all in that tenth of a second, rather than over an hour. One hour is 60 minutes. 60 minutes is 360 seconds. 360 seconds is 3600 tenths of a second. So it would take 3600x the amount of power in that tenth of a second to heat the water, vs doing it in an hour...that's 622,440w.

622kW. It's still taking the same amount of energy, 172.9Wh, but applied in a much much faster time, so it takes a higher power to do it.

If you have a 10x longer heating element, for the water to contact for longer, it would take 1/10 the power. 100x longer, 1/100 the power...because there is more time for the energy to transfer from element to water before the water is pushed past the element and replaced with colder water (which is a continuous process in a point-of-use heater).

The above also assumes that you get perfect heat transfer from the heater to the water, so that the water absorbs all the energy coming out of the element, which probably won't happen either, so it would take even higher power.


The less the temperature difference that is required between incoming and outgoing water, the less energy it takes to do that work. If you only needed to change it from "room temperature" (around 72F) to 100F, that's only 28F difference, so it takes less than half the amount of energy....


I also ran across a more complete set of numbers:
The specific heat of water is 4190 J/(kg*°C). It means that it takes 4190 Joules to heat 1 kg of water by 1°C
You can then convert the units as needed, and find or make formulas to determine actual power input required to do the amount of heating you want to do.
 
Hummina Shadeeba said:
but how much water? Maybe could divert a lot of the flow to the side so could use a high flow rate and end up with a smaller quantity of water that’s heated
My gut-feeling-guess is you're talking about hundreds to thousands of times the amount of wasted water vs heated water.

Where are you going to store that water for later use?

Or are you just throwing it away down the drain? If so, you've just spent far far more on your water than you would have on the power to heat it "normally", and wasted all the energy that was spent processing that water and sending it to you, as well as making it unavailable for someone else to use that water for a critical use.
 
Heating water takes a lot of energy. Running LEDs seem a more reasonable expectation. That’s done and being sold
Thanks for your help and lost interest in making something
 
I did the math on it and by recovering 100% of the energy from the water pressure, you could increase the temperature by about 0.1C.

A much better thing would be a DIY heat exchanger you place in the drain pipe under the sink and pre-heat the cold water coming in. Then you can use a little less hot water to get the same output temperature.
 
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