Just out of curiousity, how do you get away paying only 20 UK pounds/year ? Is this gas powered ? Or wood from the yard ? Don't you shower or wash dishes/clothes ? That's like 4 m^2/month. I use that in a day or two for DHW.
Rob
These units were tested thoroughly by the University of Waterloo and the Goodlife Fitness chain. They post quite impressive results and stats online. Very thorough and very impressed with them. No personal experience.
anything, on
installing a
It seems to me that the glycol/heat exchanger system has a lot more cost and risks than the simple drain-back system described. For one, the heat exchanger will cost several hundred dollars itself, although it depends upon the heat storage tank being used. I believe a drainback can also be the heat storage tank. For another, it will not be as efficient as directly pumping the water--the exchanger will lose some of the heat, putting it into the ambient temperature of the room if it's a closet install. Then, the extra equipment involved means more things will go wrong generally.
Energy Cost Savings and Return on Investment [ROI]:
. An average family of four uses 70 gallons of hot water per day - . at a cost of $480 per year* . The typical solar water heater will save 80% of heating costs - . or $384.00 per year . A typical heater with hardware will cost: . Do-it-yourself Kit - $1750 . Contractor installation - $2700 . The tax-free return on investment would be: . Do-it-yourself Kit - 21.7% ROI [$384 / $1766] . Contractor installation - 14.2% ROI [$384 / $2700]
*Based on 72°F incoming water heated to 140°F in Florida with an electric rate of $0.09 per kilowatt plus standby heat loss from a new water heater. Your savings may vary based on your usage, temperature, climate and electric rate.Calculate your own Tax-Free Return On Investment [ROI]:
$ _____ Estimated Savings $ _____ Divided by Unit Cost %_____ Equals ROI
It can depend on your personal schedule. If you have to take a shower early in the morning, before going to work, then you aren't going to have time for a solar system to heat up some water.
If you don't need to be showered and out the door so early, then you can wait.
Sure, you could just take cold showers all the time, but that would be a real bummer.
On Wed, 8 Mar 2006 20:22:41 -0800 someone who may be Antipodean Bucket Farmer wrote this:-
If the hot water cylinder is properly insulated then there should be plenty of solar heated water for a shower or two in the morning.
I had a full morning bath the other day from the previous day's sun.
Mary
It might do in Florida, not in cloudy northerly regions.
On Wed, 08 Mar 2006 15:41:59 -0400 someone who may be Derek Broughton wrote this:-
Agreed, but that seems at odds with what you then typed.
I leave the dish-water in the sink until it reaches room temperature. It's a little too low-tech for my taste, but it works :-)
work with my main bathroom - slab on grade, all the plumbing through the slab. I could recover waste heat from the second bathroom & kitchen.
I don't follow? My entire point is if you can't guarantee that - or even that it's a vanishingly small likelihood - then it's too risky for most Canadian homeowners. It'll work for most folks in the UK. When I was a child outside London, we would only rarely have frozen pipes in completely uninsulated outside walls. A little insulation eliminates the problem completely. When you have to spend weeks with temperatures well below freezing, it's a whole different matter.
Sorry, why would one put a lip there? Really, it's not personal, it's just a matter of not buying poor designs.
No need for it to be anything more than a millimeter.
otoh, I was talking about a local Nova Scotian manufacturer, who put a _lot_ of thought into snow...
Also, what makes you think they're "recommending something" for northern climates - they're in Maryland, for heavens sake!
Valves fail. It's not incompetent engineering.
In a glycol-loop system, even if the pump breaks down there's no risk of flooding. Even if it gets cold enough to freeze the glycol (!!) you have at most a few gallons of it in the loop. So far, all you've told me about drain-down systems is that they're safe. Convince me.
On Thu, 09 Mar 2006 09:26:23 -0400 someone who may be Derek Broughton wrote this:-
If there is no such thing as zero risk then wanting a guarantee is a trifle strange.
Zero risk and as low as reasonably practical are two different things.
Indeed. There are a number of countries that have lots of snow to contend with, for at least part of the year, including Canada.
of that and add one of these and DHW should cost a penny or two.
Zenex, in Plymouth has introduced a "top box" that fits on a condensing boiler's flue (patented). Out of the boiler into the box and out again to outside. The return pipe pass through the top-box and out to the boilers return. This appears a big "leap" in making condensers more efficient.
They announced it pre-Xmas, but now it is on sale.
They claim that a combi (for US people a combined hydronic boiler and on-demand DHW heater) can deliver 50% more water flow for the same input - so a 12 litres per min job will be 18 litres, a big hype that fills a bath pretty fast instead of a leisurely fill.
They are developing a 15kW combi that delivers 12 litres/min - a little better than the average combi around. 12 litres is normally only achieved by a 28kW boiler. So, at 15Kw it is not oversized for the CH in flats, and the case size can be kept down.
They plan a box for a non-condensing boilers too, that will bring non-condenser into condensing territory.
They claim the price will fall from £595 as production gears up. If it gets to half, and it does what they say, then this is copst effective and can save a lot of fuel, the bigger the house the more fuel saved.
I beg to differ. I've made it quite clear that, imo, one can not get the risks to an acceptable level for my climate. It doesn't matter whether such a situation is achievable.
I'm not even interested in "as low as reasonably practical". "Practical", from the engineers viewpoint, means there will be failures.
Snow's a smaller problem than cold. In fact, we don't get much snow when it gets really cold.
My Glow-worm 28CXi is 90.3% efficient so by my understanding at full burn that's 31kW being burned and 3kW going out the flue. And they are going to save me 30% of that 31kW = 9.3kW extracted from 3kW. I'll pass.
Calculated using 13C/KW not 9c for a start
Remember this new thing call ed fuel recovery charge - well we get stuffed with it and it is going up again this month
Our KW cost 2 years ago was one of the lowest in the US at 7c/KW
Figure it out
Granted I have a high electric bill from other things but HOT water is defintely the highest cost
OH
Keep in mind we have to wash at least once a day I am from the UK but have developed the habit of washing every day instead of every week I the UK you can get away with it (washing only your smelly bits!) but here you stink about 9 months out of the year in 90F+ weather if you don't shower
Oh - someone takes a bath in our house maybe twice a year. And showers are for about 10 Minutes max
What else uses crap loads of power
Dishwasher? Robert Bosch - good quiet one Electric Dryer? Maytag New within last 3years Pool Pump? 1.25HP Washer (does not heat water)
Comments
Aha. I've been thinking drainBACK, as in "the water drains back when the pump stops, by gravity, with no valve."
Nick
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