Could Solar Water Heaters Become Popular Again? (msn.com) 123
An article in the Washington Post remembers a 1980s-era "glass box with metal water pipes running through it" that "converted sunlight into hot water. By trapping solar energy like a greenhouse, it heated the water to a scorching 180 degrees Fahrenheit.
"[T]oday, hardly anyone is using these solar water heaters even as photovoltaic panels have popped up on the roofs of nearly 4 million American homes." Unlike photovoltaic panels, which can power your home, solar thermal panels are mainly used to heat water. But they're smaller and more efficient. The technology converts 60 to 70 percent of the sun's energy into heat. Even the best photovoltaics, which generate electricity, only achieve 24 percent efficiency. Now, a new generation of solar water heater manufacturers is hoping subsidies under the Inflation Reduction Act, and growing interest in net-zero emissions, will reignite their growth.
Theoretically, solar thermal offers a big opportunity to slash emissions. Nearly 20 percent of an average home's energy is used to heat water, and nearly 50 percent globally, according to MIT. By adopting solar water heaters, the average household can keep 2 tons of carbon dioxide out of the atmosphere, the equivalent of not driving your car for four months, estimates the Environmental Protection Agency. Solar water heaters can also save money, cutting the average utility bill by $400 to $600 per year, the Energy Department estimates...
Only about 370,000 solar thermal systems were operating in the United States by the end of 2021, according to the International Energy Agency, many of them on larger commercial buildings...
Since they can cut fuel consumption to heat water by 50 percent to 70 percent, other countries are embracing the technology: Almost all new residential buildings in Israel must include solar thermal, while in countries as far north as Canada and Denmark, solar thermal energy warms millions of homes with district heating systems. Yet these systems represent a tiny fraction of the potential, supplying 0.4 percent of today's global energy demand for domestic hot water.
New U.S. subsidies can cut the price in half depending on location, the article points out.
Cheap photovoltaics still make economic sense for many homes (unless you're heating a pool). "But the cost of solar thermal could look like a bargain if we consider increasingly unreliable electric grids and the cost to the climate from burning fossil fuels."
"[T]oday, hardly anyone is using these solar water heaters even as photovoltaic panels have popped up on the roofs of nearly 4 million American homes." Unlike photovoltaic panels, which can power your home, solar thermal panels are mainly used to heat water. But they're smaller and more efficient. The technology converts 60 to 70 percent of the sun's energy into heat. Even the best photovoltaics, which generate electricity, only achieve 24 percent efficiency. Now, a new generation of solar water heater manufacturers is hoping subsidies under the Inflation Reduction Act, and growing interest in net-zero emissions, will reignite their growth.
Theoretically, solar thermal offers a big opportunity to slash emissions. Nearly 20 percent of an average home's energy is used to heat water, and nearly 50 percent globally, according to MIT. By adopting solar water heaters, the average household can keep 2 tons of carbon dioxide out of the atmosphere, the equivalent of not driving your car for four months, estimates the Environmental Protection Agency. Solar water heaters can also save money, cutting the average utility bill by $400 to $600 per year, the Energy Department estimates...
Only about 370,000 solar thermal systems were operating in the United States by the end of 2021, according to the International Energy Agency, many of them on larger commercial buildings...
Since they can cut fuel consumption to heat water by 50 percent to 70 percent, other countries are embracing the technology: Almost all new residential buildings in Israel must include solar thermal, while in countries as far north as Canada and Denmark, solar thermal energy warms millions of homes with district heating systems. Yet these systems represent a tiny fraction of the potential, supplying 0.4 percent of today's global energy demand for domestic hot water.
New U.S. subsidies can cut the price in half depending on location, the article points out.
Cheap photovoltaics still make economic sense for many homes (unless you're heating a pool). "But the cost of solar thermal could look like a bargain if we consider increasingly unreliable electric grids and the cost to the climate from burning fossil fuels."
What! (Score:3)
They are pretty popular in my country, and have been so for the last 15 years, give or take.
And they are not really expensive either.
Re: (Score:2)
In fact in some countries they are mandatory on new construction, at least they were 20 years ago.
The problem with them in the northern part of North America is that you have to use some kind of non-water fluid and heat exchanger to heat the water. In climates where it never freezes the water can be heated directly.
I've long been interested heating air instead of water, using a box with drain-pipe air channels painted black, covered in glass. Could easily heat a garage even in a cold climate. Even with j
Re: (Score:2)
I have always found that solar water heaters was the smartest, simplest and most efficient use of solar energy.
Re:What! (Score:4, Informative)
Indeed. I live in the Philippines and see them on almost every rooftop.
Whoever wrote TFA needs to get a passport and go see the world.
Even in America, thermal solar is common for heating swimming pools.
Re: (Score:2)
Re: (Score:2)
We had a solar water heater system back in the 80's. I live in Southern New Mexico. It worked great year round for about 7 years, then the hard water got the better of it. We got our moneys worth out of it, but only just.
I suspect like most technology, things have improved over the years. I would consider another system to replace the current NG system when it fails.
Re: (Score:2)
Re: (Score:2)
> Whoever wrote TFA needs to get a passport and go see the world.
Perhaps you should too as I've not seen this stuff since the 90's back in the days before everyone in the UK basically abandoned electric heating and went for boilers and central heating.
We burn gas over here, have done so for around 20-30 years. It would even be difficult to install these today as during that time many households went to systems that dont even have a hot water tank.
Re: (Score:2)
Indeed. I live in the Philippines and see them on almost every rooftop.
Whoever wrote TFA needs to get a passport and go see the world.
Even in America, thermal solar is common for heating swimming pools.
They used to be commonplace in Australia too but better hot water systems came about. They don't work before or after sundown (which is when most Australians shower) and had tiny tank capacities and westerners like hot showers. They were cheap in the 80s but surpassed by better boilers in the 90s.
A solar hot water system will be as useful as a chocolate teapot here in the UK as we get 7-8 hours of daylight in the winter and even in the summer we still don't get that much heat from the sun.
You see the
Re: (Score:2)
I should have added that in Canada, I have seen some where you simply drain the system and put it to rest when freezing temperatures arrive. The heat exchange thing kind of make it more complex and break the simplicity principle. I'd sure incorporate one in a new house if I ever build one from scratch. It seems like a no-brainer to me.
Re: (Score:2)
Perhaps a dual purpose system could be constructed for northern latitudes. During the winter fill the system with antifreeze and redirect the fluid through a radiator that helps the furnace maintain a home's temperature on sunny days (which even in northern Ohio is one in four days in the winter, but at least its something).
Re: (Score:2)
So like a heat pump, but less efficient?
Re: (Score:2)
Yeah, I suppose that would describe it. So hard to come up with energy efficient and green solutions.
Re: (Score:3)
So like a heat pump, but less efficient?
Like a heat pump, but does not require power.
Re: (Score:2)
Except it wouldn't be a heat pump. A heat pump uses a unit of energy to move a certain number of units of heat energy from one medium to another. This would just be a heat exchanger, which passively moves a certain fraction of the energy in one fluid to another. So way less efficient than a heat pump. Except of course that efficiency doesn't really matter here, provided the system was cheap, robust, and consumed little or no electrical power.
Re: (Score:2)
They're called solar liquid collectors. They're nothing at all like heat pumps and they're significantly more efficient.
Ground Source Heat Pump (Score:2)
In northern climates like that you really need a ground source heat pump but these are a lot more expensive to install sin
Re: (Score:2)
While they may technically still be (barely) more efficient than gas or electric heating when it drops below -30C the reduction in their heating power means that you need a huge system that is vastly overpowered for most of the year.
In northern climates like that you really need a ground source heat pump but these are a lot more expensive to install since you need to drill some deep holes.
If you're one of the 6,397 residents who live in Bottineau County, ND, then yes an air sourced heat pump is not for you.
Great White North (Score:2)
If you're one of the 6,397 residents who live in Bottineau County, ND, then yes an air sourced heat pump is not for you.
No, I'm one of the 40 million people living in that nation to the north of ND. It's called Canada.
Re: (Score:2)
Lol.
Do you actually know how many Canadians live north of the 49th? Around 30%.
Yes yes, if you live in Hoth, then a sensible sized air sourced heat pump is only useful for 5 sixths of the winter, not the whole thing and the other fraction of the time you need resistive heating or gas, which is a lot better than using that all the time. And you get an ad for summer.
What on earth is the problem there?
Re: (Score:2)
Re: (Score:2)
The problem is that heat pumps don't work well in such climates and are not a viable solution
Define "don't work well"? How many days per year will it "not work well" for?
Heat pumps are great if you have the climate for them but a lot of people do not.
The majority of the population in Canada has air conditioning. That is EXACTLY the same as a heat pump.
So you have a device most people have and it provides efficient heat most days of the year. Somehow this is "too expensive" and "won't work". WTF?
Re: (Score:2)
And in many places it would not be possible to drill a hole at all.
And in others not even legal to have a HP fitted, depening on housing type. Terraces in the UK for example are never offererd pumps as they cant legally be installed in terraces, thus the vast majority of UK housing wont have them.
Water-only system for deep-freeze climates (Score:2)
> you have to use some kind of non-water fluid
Not necessarily. You can also have the panels drain into a reservoir overnight, with the circulating pump only turning on again in the morning once the panels have gotten warmer than the reservoir. Why have fluid in the panels when there's no heat to be collected?
A DIY system I've occasionally considered building: https://www.builditsolar.com/P... [builditsolar.com]
Re: (Score:2)
Re: (Score:2)
Here people are using anti-freeze and we get very cold winters. For systems that use concentrators water isn't a good fit so they use oil and a heat-exchanger to heat the water.
And in regards to heating air, there was a company that sold such equipment here - intended for small unheated buildings, like garages or cabins. It was just a box you mounted on a south-facing wall, it had a small PV that delivered power to a fan that drew the air through the box and pushed it into the building. Extremely simple des
Re: (Score:2)
They could really use these in Canada. Just think of how much energy is wasted on refrigerator ice makers each year.
Re: (Score:2)
And they are not really expensive either.
Solar water heater system is about $3500 to install in the US, and $5K when I priced one for my place (where everything is more expensive than the national average). A 50-gal electric water heater is about $700 to replace. Since nearly every home in the US is already plumbed for a central water heater, the cost to swap in a new unit is cheaper than installing a whole new system.
I am still thinking about getting one, because I have a good climate for it. Clear sunny days even a few days a week in the winter.
Re: (Score:2)
Solar water heater system is about $3500 to install in the US, and $5K when I priced one for my place (where everything is more expensive than the national average). A 50-gal electric water heater is about $700 to replace. Since nearly every home in the US is already plumbed for a central water heater, the cost to swap in a new unit is cheaper than installing a whole new system.
Have you factored in power consumption?
Re: (Score:2)
Not really. I have solar power and my utility bill isn't very large. Maybe I could use fewer panels or charge my house battery faster if I took the electric water heater off. The power company is corrupt here and I can't run negative billing.
Depends on time of the year (Score:3)
During the past month we've had about four days of sunshine. Not because I live near the Arctic Circle, but because we've had cloud cover for that long. Today started out cloudy and snowy, followed by about a total of two hours of sunlight. Now the clouds have returned and we won't see clear skies until sometime next week.
And this is every winter. While I'm a big fan of letting the Sun warm my place by having its light come through my windows, when you don't see it for two months at a shot it's a big difficult to heat your water using this system.
Re: Depends on time of the year (Score:5, Informative)
Re: (Score:2)
Temperature inversion is a bitch. Same here in Northern Ohio.
Re: (Score:2)
And this is every winter. While I'm a big fan of letting the Sun warm my place by having its light come through my windows, when you don't see it for two months at a shot it's a big difficult to heat your water using this system.
The systems I have seen simply preheat the water going into the water tank, no pumps no nothing. An home made series of pipes painted in black on your roof do the trick. Near Arctic circle, drain the pipes in winter and bypass the system, standard water pipe valves do the trick. In summer, a lot of sunshine near the Arctic circle, use your home made pipe system and save on water tank heating cost.
Re: (Score:2)
During the past month we've had about four days of sunshine.
So you're saying that if you had a solar hot water system you'd have saved energy 4 days in the past month. What's the downside again? I assume you realise that these systems do not rely 100% exclusively on sunshine right?
...and location (Score:2)
Re: (Score:2)
"Systems like this will not work as expected under the most extreme conditions, therefore they're completely useless for everyone everywhere."
Re: (Score:2)
A simple rule... (Score:2)
If the cost is more than recovered over the expected lifetime of the option, by a higher margin than other options, go for it.
If the upfront cost is too high, but still results in a net savings for everyone... it's time to consider a subsidy.
Re: (Score:2)
Okay, but what about personal and societal benefits that cannot necessarily be assigned a dollar value?
=Smidge=
Re: (Score:2)
When you're talking about providing subsidies funded by taxation... you get experts to guess at it and use their analysis to make your determination.
I mean, if you're doing it correctly. Realistically I suppose you do whatever the biggest lobby bribes/convinces you to do.
It IS very popular (Score:5, Informative)
I understand it's not popular in the US, but there is no need to quote anecdotes from the 1980s. This technology has been very popular in the Mediterranean area. According to Wikipedia:
* 90% of Israeli homes are equipped https://en.wikipedia.org/wiki/... [wikipedia.org]
* 30-40% in Greece https://en.wikipedia.org/wiki/... [wikipedia.org]
* installation now compulsory in new buildings in Spain (by the building code) https://en.wikipedia.org/wiki/... [wikipedia.org] .
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
I understand it's not popular in the US, but there is no need to quote anecdotes from the 1980s. This technology has been very popular in the Mediterranean area.
Not just. You can barely drive down a street in Australia without seeing solar hot water. They are also insanely popular in China, and even places like Austria, which has miserable weather for a large part of the year.
Re: (Score:2)
It isn't as popular in Australia as it was in the '80s. You used to see a lot more of them.
Re: (Score:2)
I remember in the tropics like Singapore they had lots of solar water heaters on the roof as well. They had a solar component and a tank on top to hold the hot water. They do have electric heating elements to provide supplemental heating if required. (These heating elements aren't powered normally - but are often turned on manually a few minutes before showering or taking a bath to ensure adequate hot water - if the tank is hot enough, the heating won't run, but if it was a cooler day it will top it off).
If
Re: (Score:2)
Dude, it is popular everywhere that it is actually trivially useful to use it. Go to the Middle East. Every single structure has a water tank on top using the sun to heat the water. On average, the USA doesn't have enough ambient heat to trivially make use of this, which means it is almost unheard of (in the USA), even in applications that would definitely benefit, such as for pools.
Now comes the question as to why, if it really isn't usable in Montana, why is it off the table in Alabama or Texas? Top down
One of the advantages over PV cells... (Score:5, Insightful)
New U.S. subsidies.. (Score:3, Informative)
New U.S. subsidies , that is poor people paying for rich people's toys. See also EVs.
Re: (Score:2)
Re: (Score:3)
Would rather not have leaks from a water system that is overhead. And roof leaks from the water connection through the roof. And the significant added expense to remove and reinstall the system when the house needs a new roof, as it does at least every 30 years. But otherwise, great idea.
Roof penetrations are easily weather proofed, just use a vent cover with a 90 so that the hoses from the system pass through the gooseneck and into the attic. PEX lasts a looooong time, as do sun-resistant hoses. Plug those into the hot water system and you have a bulletproof solution.
Re: (Score:2)
> as it does at least every 30 years
What the hell do you do to it?
Put up a roof that will last 60 or 100 years already.
Required in all new houses in Hawaii (Score:5, Informative)
Re: (Score:2)
I think you can get away with PV and a heat pump now legally, but yes they are widely used (and required) for low-rise residential. Still bothers me that highrises don't require solar hot water tempering, but such is life.
Re:Required in all new houses in Hawaii (Score:4, Informative)
Except that PV is more expensive and less efficient, a heat pump water heater is more complex, lasts less time, etc...
Or you just go simple - pipes on the roof that collect the solar energy as heat directly.
Re: (Score:2)
I only really have statistics for Hawaii, but solar hot water is very expensive. A replacement system for me is about $30k in plumbing cost, plus I will need carpentry and drywall work to replace the big tanks if I go like-for-like. It also isn't foolproof; if it malfunctions it dumps a lot of water quickly. It is hard on check valves and you absolutely need to make sure the plumber isn't lazy with roofing details... oh yeah, you need a roofer too for the replacement, but it still doesn't guarantee no le
Re: (Score:2)
Huh. I just priced it out at 1/10th your price. Florida vs. Hawaii, mind you.
Camping (Score:2)
Re: (Score:3)
Not great for the environment because it uses disposable plastic. I'm sure one could devise a reusable one. But single use bags are pretty darn inexpensive.
I'm sure these are illegal in California. Or they cause cancer. Or both.
Re: (Score:2)
https://www.amazon.com/Portabl... [amazon.com]
No reason it has to be disposable.
Re: (Score:2)
IIRC, evacuated tube collectors are mostly made from glass and have a very long service life.
Subsidies? (Score:5, Insightful)
The reason we don't have those are the subsidies in the first place.
Good luck with that!
Back in Arizona, I was visiting a friend who was getting a price quote for exactly this to be installed. A dummy water tank that will be integrated with his hot water plumbing at home. And the prices, somehow started just over the subsidy levels. And given the subsidy was large all option prices were amplified as well.
(So, you could get a similar system in any other country say for $500 to $2,500. Here can't remember the exact number but say the subsidy is $3,000, then the prices were something like $3,500 to $10,000. I might not be exact, it has been a while, but should be in the ballpark).
That is why "we can't have nice things". Anytime there is a subsidy, the pricing immediately includes that (remember the $40 HDTV/ATSC conversion boxes)? And not only that, but can make the overall product totally unaffordable (looks at college with guaranteed loans).
Re: (Score:3)
Re: (Score:2)
Sell, yes. Store, not so much. Storage requires a larger battery bank and messes up the ROI economics of your system.
Storage in a solar collector system requires more hot water tanks. A relatively low tech (read: cheap) solution.
Not everyone can sell power back onto the grid at an economically useful price. Privately owned utilities hate the competition. Public utilities hate the loss of revenue that they can shuffle through their Three Card Monte revenue distribution system.
Re: (Score:2)
Solar panels likes to be cold. Why not combine the two? I suppose it would create way too much hot water.
Re: (Score:2)
As a first stage preheater, perhaps. But the laws of thermodynamics [youtube.com] dictate that the panel will have to be at a higher temperature than the water (coolant) exiting.
and amount used (Score:3)
>Down here in Belgium, it is by many considered as a waste of money
>for a simple economical reason.
there's also the question of the amount used and needed.
When my gas water heater failed a few years ago, I considered one of these systems.
Living in the desert, my most recent summer gas bill had been $17. $10 of that was for the connection charge, and only $7 for the gas used--with three long haired females showering daily!
Of that $7, most would be for the water heater, with some for the stove, and may
Re: (Score:2)
That is why "we can't have nice things". Anytime there is a subsidy, the pricing immediately includes that (remember the $40 HDTV/ATSC conversion boxes)?
Same thing with medical insurance. The co-pays are roughly the same prices you paid previously without insurance. I am certain that money gets siphoned to somewhere useful as a life saving surgery for some poor person who otherwise wouldn't be able to afford medical care, but I fear that the money is being used to keep people who are effectively in limbo on machines that generate huge amounts of profit.
Re: (Score:2)
The thing that does often drive up prices is dealing with the bureaucracies of our cities and counties. The installer cannot just install the system. They have to meet the city on location to get approval to proceed. They do the work, they have to meet inspectors on site once the job is done and sometimes during the job. Cities are horrible at scheduling and keeping these required inspections and time is wasted. The wasted time is a real cost for the installing company that has to pay its employees to wait for the city and the subsidies have to cover those costs or they will not be taken advantage of.
There has always been overhead in terms of permitting and inspection. Doesn't explain increases in US rooftop PV pricing despite dramatic decreases in underlying material cost.
Subsidies do not drive up prices in a market like this unless there is some sort of artificial barrier to entry that generates a monopoly for the installer which I highly doubt is the case for solar water heating.
Subsidies obviously drive costs - the only question is by how much.
Re: (Score:2)
What possible mechanism do subsidies have to drive costs?
You start overcharging because of the subsidy - all one of your competitors has to do is keep charging a fair price and they'll drive you out of business. Widespread collusion between small businesses is actually fairly uncommon - that's more megacorp territory, where the precautions and lawyers to avoid getting caught are a tiny marginal cost of doing business, and it's incredibly rare that anyone "who matters" ever goes to jail.
What they may do is
Re: (Score:2)
Hot water and electricity simultaneously (Score:4, Interesting)
Re: (Score:3)
I came here to say the same thing. Cooling the PV cells makes them more efficient, just like water cooling your CPU/GPU helps keep them in their optimum temperature range.
Actually, the best time to cool the PV cells is when the sun is at its strongest, so summer would actually be the best boost for the cells efficiency. In the winter, if the sun is less strong or the temperature falls below freezing, you automatically divert and drain the system until it is beneficial again.
https://link.springer.com/arti. [springer.com]
Re: (Score:2)
Some manufacturers (eg DualSun) make it possible to have both in one panel.
Dude, the Rolling Stones had a solution far more elegant and simple 50+ years ago: Paint it Black
no way (Score:2)
Re: (Score:2)
Re: (Score:2)
Of course the cost of heat pumps plus 3x the area of PV panels is dramatically higher than solar thermal, so if your limiting factor is money rather than available area with good solar exposure that's not such a great trade.
Re: (Score:2)
Solar water panels exceed the efficiency of a PV and heatpump by a large margin.
Seems like heatpumps are better (Score:2)
It seems like nowadays you would be better off just using a heatpump. Before heatpumps became popular, I often wondered why we don't have more thermal solar. But now that heatpumps are widely available it probably makes more sense to use PV on the roof and a heatpump for hot water.
Of course it does depend somewhat on the climate where you live. There are some sunny cold places. Maybe direct solar heating would be better in those places since the heatpump COP is degraded when it is cold. I mean, the therma
Re: (Score:2)
Well the HP might be better, if you could afford the 15 grand to install one.
However installing these is a mere fraction of that cost.
Evacuated tubes are inherently expensive (Score:2)
For people near the equator, sure a couple cheap black plastic connectors make sense if they can't afford to fill up their roof with PV. Those will work for them for most of the year.
If you live anywhere which requires evacuated tube collectors, you're better off with more PV and an electric/heatpump boiler.
I love mine... but will rip it out. (Score:2)
My situation might be unique, but my 15-year old system has another 3-5 years of life in it and after that it is gone. A heat pump water heater plus extra PV and battery makes significantly better use of space for us. Solar hot water doesn't work well (at least in my climate) to temper inlet hot water for a heat pump system, so any supplemental heating needs end up with resistive load. Solar hot water needs a lot of storage, but storing heat in a water tank is only good for a ~2-3 day buffer, and most of
Headline news! (Score:2)
Well, I guess better late than never.
Heat pump hot water from solar PV has advantages (Score:2)
Compare 70% efficient direct solar with 20% efficient solar PV driving a hot water heat pump. Those pumps can easily exceed 350% efficiency, making PV the winner. I have a system that uses CO2 as the refrigerant and it works down to 10C (and has no booster). It's probably not suitable in colder climates but then direct solar hot water can struggle there too. A big advantage is that you can program the heat pump to come on during the middle of the day, when the air is hottest (making it most efficient) a
Re: (Score:2)
works down to 10C
Slashdot ate my −. I meant -10C.
We had solar hot water (Score:3)
We bought a house ~5 years ago.
It had solar hot water panels on the roof, installed in the 80s or 90s.
They worked; they gave a boost to the heat and H/W.
But...the panels were at end-of-life, and were starting to leak, and nobody, nobody, services these things any more.
We ended up scrapping them and installing solar electric panels in their place.
Cost and clouds (Score:2)
As others have observed, actual insolation is a big input to the utility of solar water heating. Here in eastern Ontario we have had an extraordinary spate of cloudy weather that greatly diminishes what might otherwise have warmed our water. Another factor at play in the Canadian renewables market is the greed of the local contractors, marking up even locally made equipment to the point that cost recovery is out of reach. One vendor we encountered was selling a made in Canada wind turbine at major multiples
Popular again? (Score:2)
I live in Europe and every new house seems to have one or 2 of them on the roof to complement their heat-pump.
The rest of the roof is photovoltaic though.
These houses also use the heated water for the washing machine and dishwashers, there are special models mixing the hot and cold water to get at the desired temperature.
Re: (Score:2)
'It just did not make sense economically to keep the system. To integrate the existing panels in the new system would have cost EUR 5000.'
Indeed, the systems have to be compatible, so only when everything is newly installed it makes sense.
They don't use electricity (Score:2)
I remember these! (Score:2)
Here in the UK growing up during the 90's I saw these plonking onto roofs often. I've even been thinking of using them myself now I have a house.
These days I very rarely see any. You do see the odd house with solar instead.
Most people seem to have moved to combi boilers, which heat the water on demand. Those households threw out the hot water tanks, quite happily so. In order to have this system installed they will need to reinstall the copper tank too, and that means giving up the extra cupboard space
Re: (Score:2)
Re: (Score:2)
Good old MacMann, back spouting bullshit every time he can to support his nuclear nonsense.
It's not "crazy stuff" - it's proven, existing technology in a number of countries outside the USA. But then having fact based arguments refute your points has never changed you in the past, has it?
A society heating water from sunlight is a society that doesn't need nuclear. And that's what you're afraid of - that people will see your industry for the uneconomical, unsustainable, unwanted crap that it is.
Re: (Score:2)
The great thing about heat is that water is actually a *really* cheap and easy way to store a LOT of it.
Most solar water heated systems I've seen store at least 5-10 days worth of heat - after all it only costs you the price of an insulated water tank. Unlike electric batteries, it's easy to budget for the a worst-case scenario.
Heck, I know one guy that has a huge enough tank that he stores heat in the summer to heat his house through the winter.
Re: (Score:2)
In countries where this is used, in the morning water is still pretty warm from the previous evening.
Re: (Score:2)
You have likely not used solar heaters. They are very common here in India. The heater stores hot water in a large tank on the roof (typically 100 or 200 litres tank). Any they have great insulation. The water coming out of the tank into the taps the next morning is still piping hot. Even cloudy days make sufficiently hot water for taking bath. It is, as some one earlier commented, the best simplest contraption to heat water for free - and not running costs or maintenance either.
Re: (Score:2)
Re: (Score:2)
> Also, it was mostly useless during the winter time and of course at night-time, or basically any time it is cloudy
Well same with a PV then...
Re: (Score:2)
> the water cylinder also has to have a heat exchanger built into it
Well duh, thats how a water cylinder heats up...