Thoughts on alternative water heating - What are you doing?

[Crossy]

Prompted by another thread which got a bit off track I thought we could continue here.

 

So, what are you doing?

 

As a starter there are a number of options to think about: -

 

Direct heating of water with the sun. 

Could be anything from a simple coil of black pipe to an expensive vacuum-tube system.

 

Electrical heating of the water powered by solar.

Directly coupled to panels, use an inverter, use as an energy dump etc. etc.

 

Something else

Bio-gas from your chooks or pigs??

 

[worgeordie]

i have had solar heating installed since 1990 ,when I first built the house ,i think it's best installed

on a new build ,then you can have all the hot water pipes installed to all the sinks ,showers.

 

It was quite expensive to install at the time ,plus it was an import from Australia ,called SolaHart ,

but well worth it ,to have hot water going to the showers sinks ,without having those electrical

shower units ,don't know how many of those I have changed in our rental properties over the years.

water and electricity not good friends..

 

It provides very hot water throughout the year ,except for maybe 2-3 days* in the cold spell when

there is no Sun ,i would say it certainly paid for itself ,  and now there is a much bigger choice of

cheaper stuff from China ,but don't know how well those work or how long they last ,but i believe

SolarHart is still been sold in Thailand   * You can have electrical heaters installed in them for times like that

but I would rather have no electric going to it.

 

regards worgeordie

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Woof999]

The amount of hot air coming out of the sister-in-law should mean my water heating costs are free. Unfortunately not.

 

Current house has individual 6kW heaters at each hot water point which, of course, is convenient but expensive and neither alternative nor renewable.

 

For me, either in this house or the one I plan to build, the solution has 2 main parts.

 

1.) House water for showers and sinks. I like the idea of water tanks directly powered by their own solar panels, totally isolated from the main house solar. For backup, if those same tanks can also support an old school UK style immersion heater which IS powered by the main house solar then even better. Wouldn't have to wait more than 20 minutes or so for decent hot water even if solar levels have been low or hot water usage high.

 

2.) The pool. Gets just a little too cold for 3 months of the year. Partly because of shade from the house, but mostly because of the ambient temps. It also gets too warm in the summer. 10+ hours of sun per day, no shade from the house and almost 10 degrees higher ambient. So heat pump it will be, solar powered of course.

[JBChiangRai]

  On 12/28/2023 at 1:25 AM, Crossy said:

Electrical heating of the water powered by solar.

Directly coupled to panels, use an inverter, use as an energy dump etc. etc.

 

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Put a capacitor across the thermostat and lose the inverter, run it on DC straight from 4 solar panels.

[Crossy]

  On 12/28/2023 at 2:14 AM, JBChiangRai said:

Put a capacitor across the thermostat and lose the inverter, run it on DC straight from 4 solar panels.

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I'd probably use an SSR to extend the life of the AC-rated thermostat (or even just bypass it completely), but electrical direct-coupling is definitely a viable method.

[JBChiangRai]

  On 12/28/2023 at 2:17 AM, Crossy said:

 

I'd probably use an SSR to extend the life of the AC-rated thermostat (or even just bypass it completely), but electrical direct-coupling is definitely a viable method.

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Yes, a solid state relay is a better solution.

[Bandersnatch]

 

I’ve had solar thermal at my house in Surin for 6 years. 200L insulated tank. Has an immersion heater for topping up the heat but have never used it. The water circulates via convection pushing colder water out of the tank to be reheated. 
 

Water from my rainwater tanks is pumped through a filter system to fill 2 500L tanks. The float sensor keeps the tanks filled. Cold water from these tanks is pumped to the solar thermal system via a demand pump the also pumps cold water around the house.
 

All my bathrooms that require hot water and the kitchen are located together on the ground floor and share a wet wall.

 

There is no pump to send the hot water out as it’s naturally pressurized.

 

 

[Muhendis]

  On 12/28/2023 at 2:17 AM, Crossy said:

but electrical direct-coupling is definitely a viable method

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Yep.

Water heaters are resistive so don't care if they get AC or DC. In fact DC should be more efficient.

 

My system is a home made flat panel on an outhouse sloping roof.

The panel is a number of 15mm vertical copper pipes between 22mm input/output horizontal pipes.

15mm pipes have sheets of aluminium attached for heat capture.

All this is mounted in a wood frame with polycarbonate cover 

Below, in the outhouse, there is a small circulating pump powered by a similarly small solar panel and a 200 litre insulated tank for storage.

Water temperature varies between OUCH BLOODY HELL! and lukewarm depending on time of year and weather.

At the moment it's cold here and there's been one day with a fair bit of cloud but I still got lukewarm.

 

As it's a direct system I have to watchout for minerals in the water. Bore hole water is way over the top with CaCo_4.  

That stuff plays havoc with copper and creates problems with dissimilar metals of the storage tank (stainless) and the copper pipes/brass fittings.

It gets to behave like a battery.

I stopped using the borehole a few years ago and use well filtered surface well water which is so soft the soap lasts forever. Being as how I'm a cheap Charley that's a plus.

 

Cost was about a fiver 'cause it was built in the UK 11 years ago hence the copper pipe sizes.

It's a fun project and does what it says on the tin so to speak.

[Lacessit]

  On 12/28/2023 at 5:35 AM, Muhendis said:

Yep.

Water heaters are resistive so don't care if they get AC or DC. In fact DC should be more efficient.

 

My system is a home made flat panel on an outhouse sloping roof.

The panel is a number of 15mm vertical copper pipes between 22mm input/output horizontal pipes.

15mm pipes have sheets of aluminium attached for heat capture.

All this is mounted in a wood frame with polycarbonate cover 

Below, in the outhouse, there is a small circulating pump powered by a similarly small solar panel and a 200 litre insulated tank for storage.

Water temperature varies between OUCH BLOODY HELL! and lukewarm depending on time of year and weather.

At the moment it's cold here and there's been one day with a fair bit of cloud but I still got lukewarm.

 

As it's a direct system I have to watchout for minerals in the water. Bore hole water is way over the top with CaCo_4.  

That stuff plays havoc with copper and creates problems with dissimilar metals of the storage tank (stainless) and the copper pipes/brass fittings.

It gets to behave like a battery.

I stopped using the borehole a few years ago and use well filtered surface well water which is so soft the soap lasts forever. Being as how I'm a cheap Charley that's a plus.

 

Cost was about a fiver 'cause it was built in the UK 11 years ago hence the copper pipe sizes.

It's a fun project and does what it says on the tin so to speak.

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Please. It's CaCO3.

If you have scaling on the copper, that is only to be expected with hard water. If you have corrosion, there's something else going on, such as galvanic corrosion.

[Muhendis]

  On 12/28/2023 at 5:56 AM, Lacessit said:

Please. It's CaCO3.

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Thanks for spotting typo.

CaCo₃ owes it's existence to the huge amounts of gypsum 51 metres below ground. It was coming in at over 2000 ppm.

 

  On 12/28/2023 at 5:56 AM, Lacessit said:

If you have corrosion, there's something else going on, such as galvanic corrosion.

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Yes there certainly was.

Note my comment "It gets to behave like a battery."

[Lacessit]

  On 12/28/2023 at 6:09 AM, Muhendis said:

Thanks for spotting typo.

CaCo₃ owes it's existence to the huge amounts of gypsum 51 metres below ground. It was coming in at over 2000 ppm.

 

Yes there certainly was.

Note my comment "It gets to behave like a battery."

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Er - gypsum is actually calcium sulphate dihydrate.

Bear in mind if there is any ammonia in the bore water, that will attack copper too.

[Crossy]

CaCo₃ ? 

 

I don't think Calcium (Ca) and Cobalt (Co) can form that compound and be stable; closest I know of is CaCoN₂ - Calcium Cobalt Nitride

 

Fetching my coat!

 

But we are WAY off topic, let's leave the chemistry lesson for the Teaching forum

[Muhendis]

Can we settle for Calcium carbonate please?

[Muhendis]

Here is the lab report so make of it what you will.

Bore hole Water Analysis 2018.pdfFetching info...

[Lacessit]

  On 12/28/2023 at 6:25 AM, Muhendis said:

Here is the lab report so make of it what you will.

Bore hole Water Analysis 2018.pdf 870.97 kB · 2 downloads

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According to the report, there is no CaCO3 there. It's all calcium sulphate.

They don't do an analysis for ammonia, NH3. Using Occam's Razor, the copper corrosion is most probably galvanic.

What with aluminium, copper, brass and stainless all in the mix, there are multiple opportunities to create a battery.

[Lacessit]

  On 12/28/2023 at 6:16 AM, Crossy said:

CaCo₃ ? 

 

I don't think Calcium (Ca) and Cobalt (Co) can form that compound and be stable; closest I know of is CaCoN₂ - Calcium Cobalt Nitride

 

Fetching my coat!

 

But we are WAY off topic, let's leave the chemistry lesson for the Teaching forum

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Well done, I just assumed the small "o" was a typo. Please note, I used a big "O". I'd hate to be caught out by an electrician.

[BenStark]

Water heater?

 

I have 4 individual water heaters in this house, and in the 12 years since i moved in, i have never switched on one.

 

I shower 365 days a year outside, which obviously doesn't have a water heater either.

[Crossy]

  On 12/28/2023 at 7:23 AM, Lacessit said:

I just assumed the small "o" was a typo

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I'm 100% sure it was, but since there was already a chemical engineering discussion ...

 

Anyway, let's leave it for now shall we and worry about how to warm up the H₂O with or without the CaCO₃

[VocalNeal]

  On 12/28/2023 at 1:25 AM, Crossy said:

Prompted by another thread which got a bit off track I thought we could continue here.

 

So, what are you doing?

 

As a starter there are a number of options to think about: -

 

Direct heating of water with the sun. 

Could be anything from a simple coil of black pipe to an expensive vacuum-tube system.

 

Electrical heating of the water powered by solar.

Directly coupled to panels, use an inverter, use as an energy dump etc. etc.

 

Something else

Bio-gas from your chooks or pigs??

 

Expand  

 

Not seen here, as in Indonesia, using the waste heat from the AC to heat or preheat water. Put a copper coil in a tank and connect it before the heatX in the outside AC unit,