On Wed, 08 Mar 2006 11:41:40 GMT someone who may be Tony Bryer
wrote this:-

On Tue, 07 Mar 2006 20:33:24 -0400 Derek Broughton wrote :
OK, I'll accept those numbers. Anyone got a better figure on
the average cost of heating water?

The latest SAP 2005 algorithms for a 100m2 house, 110 litre factory
insulated cylinder give a required raw energy input for DHW of
3172kWh. Divide this by the boiler efficiency to get the actual
energy required.

And the efficiency of the pump and pipework. I doubt if the
conversion of gas into hot water is ever going to exceed 80%
efficiency over a year. That gives 3965kWh gas input. At 3p per kWh
that is 118.95 a year, at today's prices. A solar water heating
system should save at least 75% of this through the year, which is
£89.21 a year saved at today's prices.

If the water is heated by off-peak electricity, in theory 100%
efficient, at 4p per unit, then 3172kWh cost £126.88 at today's
prices.

I have no idea by how much the price of gas and electricity will go
up by over say 20 years, but it will go up. The price of sunshine
will remain the same though.

As for maintenance, an evacuated tube system may need a tube or two
replacing over 20 years, but that will probably be it.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Wed, 8 Mar 2006 12:22:51 -0000 someone who may be "Mary Fisher"
wrote this:-

Why half? I can get 80% at least. You only do laundry when the sun's out
(which is true anyway because I'm off grid), you take showers in the
afternoon, and do dishes in the evening.

It has changed the way we use hot water.

And it's turned us into thermoholics - watching the thermometer every time
we pass!

In some ways changing attitudes to energy use is at least as
important as anything else. The Sustainable Development Commission
looked at the way local power sources change attitudes in
http://www.sd-commission.org.uk/publications.php?id=239 from which
the quote ‘It seems that micro-generation provides a tangible hook
to engage householders emotionally with the issue of energy use…
Householders described the sheer pleasure of creation and of
self-sufficiency: “It’s like growing your own vegetables”’ is a good
one.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Derek Broughton wrote:

S Viemeister wrote:

Derek Broughton wrote:

I don't know how you get your figures, but the average North American
uses
some 40 THOUSAND US gallons of hot water yearly. The water heater
usually
runs in excess of 120F, from a coldwater supply well below 70F. Raising
40,000gal * 50F = 320,000lb * 50F = 16,000,000 BTU, which if I am not
mistaken is going to cost around $25/million BTU to heat. So that comes
out to $400/year. A tad more than £20, and well worth replacing even
with a system that only generates half your hot water.

Where did you get your figures?
About 25 years ago, I was living in a drought-stricken area of the US.
Limits were put on water use - 50 US gallons per person per day. That was
for ALL water, not just the heated stuff. The only thing that suffered
was the garden - which wouldn't have been using heated water, anyway.

See Ron's cite - I'll grant you that you don't _need_ to use 50 gallons of
hot water, but the average family does, anyway. You're right, that's not
40,000 per year, but still an order of magnitude above Meow's figure.

The fifty US gallon figure I quoted, was not for HOT water - it was for ALL
daily water use.

"David Hansen" wrote in message
...


In some ways changing attitudes to energy use is at least as
important as anything else. The Sustainable Development Commission
looked at the way local power sources change attitudes in
http://www.sd-commission.org.uk/publications.php?id=239 from which
the quote 'It seems that micro-generation provides a tangible hook
to engage householders emotionally with the issue of energy use.
Householders described the sheer pleasure of creation and of
self-sufficiency: "It's like growing your own vegetables"' is a good
one.

I couldn't have put it better!

Mary

S Viemeister wrote:

Derek Broughton wrote:

S Viemeister wrote:

Derek Broughton wrote:

I don't know how you get your figures, but the average North American
uses
some 40 THOUSAND US gallons of hot water yearly. The water heater
usually
runs in excess of 120F, from a coldwater supply well below 70F.
Raising 40,000gal * 50F = 320,000lb * 50F = 16,000,000 BTU, which if I
am not
mistaken is going to cost around $25/million BTU to heat. So that
comes
out to $400/year. A tad more than £20, and well worth replacing even
with a system that only generates half your hot water.

Where did you get your figures?
About 25 years ago, I was living in a drought-stricken area of the US.
Limits were put on water use - 50 US gallons per person per day. That
was
for ALL water, not just the heated stuff. The only thing that suffered
was the garden - which wouldn't have been using heated water, anyway.

See Ron's cite - I'll grant you that you don't _need_ to use 50 gallons
of
hot water, but the average family does, anyway. You're right, that's not
40,000 per year, but still an order of magnitude above Meow's figure.

The fifty US gallon figure I quoted, was not for HOT water - it was for
ALL daily water use.

I know that's what you said. Nevertheless,
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm says it IS what
families use.
--
derek

"Derek Broughton" wrote in message
...
Ron Purvis wrote:

I think you are off on your figures. According to
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm the typical home uses
20 gallons of hot water per day for the first two persons and 15 gallons
of hot water for each additional person. That would be 25,550 gallons of
hot water per year for a family of four.

OK, I'll accept those numbers. Anyone got a better figure on the average
cost of heating water? My numbers for heat required are, if anything, on
the low side, but at $25/million BTU, and only 25,000 gallons per year,
you're talking $250/year (somebody else said $20/month, so same ballpark).
Still plenty to make a commercial solar water heater pay off.

--
derek

According to
http://www.powerhousetv.com/stellent...555.hcsp#P-4_0
the typical home uses 17% of their energy consumption on heating water. That
would make it somewhere between $15 and $30 a month for most families. They
also state on that page that "A family of four, each taking a five-minute
shower a day, can cut water heating costs $250 a year by switching to a
low-flow showerhead." Given that, I would have to say that the statement
that you would only save 20 British Pounds a year ($34.73) a year to be
completely ignorant of the actual facts.

wrote in message
oups.com...
Derek Broughton wrote:
wrote:

The figures in this thread have stated the savings amount required to
make it worthwhile. If you think you can save well over £100 a year
with a £2000 water heater, go for it. I dont.

The "figures" are a ridiculously low number for cost of hot water that you
made up. I can _easily_ save £100 a year with a system that will cost me
about that much. Check back next year for real use figures...

Good lord. None of the figures are cost of hot water.

The £20 a year figure is proposed saving from a basic system, and will
vary a fair bit IRL.

The £100 a year figure is how much a £2000 system would need to save
per annum to ever pay its way even if you made the most wildly
optimistic assumptions.

What you don't seem to understand is that just because you made up a number,
doesn't make it valid. Your number has no basis in reality.

Derek Broughton wrote:


The fifty US gallon figure I quoted, was not for HOT water - it was for
ALL daily water use.

I know that's what you said. Nevertheless,
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm says it IS what
families use.

key word being "estimated". There really no way of knowing for sure,
since it isn't metered, and they didn't do a 100% sampling. Our water
usage is less than half that, even when we were on grid.

--
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

wrote:
What exactly is the risk you refer to in a system designed to be
riskless?

The risk that the system will not work exactly as designed.

For what it costs I see no talk of timers/solar/cost comparisons etc

I installed a hot water heater timer in our house 3 months ago

It is on from 7-9:30am then 5:30 to 10pm.

That means it is only actually running (actual power availability that is)
about 7.5 hours
The insulation is good enough that it is not drawing power than for maybe
half of that

At 13C/KW in Savannah GA that ain't much (heater is 4500W 50 Gallon)
Ergo = $4.38/day which is at most $131.63 per month

In reality it is running about 1/2 of that, so it is costing about $65/month
to heat water !!!!!!!!!!!!!!!!!!!!

FYI That is almost $800 per year (minimum) to have hot water

Now does anyone see the value to having a Solar Hot Water heater?!?!?!?!?!?!





--

David B Turner
Island Computers US Corp
2700 Gregory St, Suite 180
Savannah GA 31404
Tel: 912 447 6622 X201
Cell: 912 447 6622 X252
Fax: 912 201 0402
Email:
Web: http://www.islandco.com
=====================================
All orders are subject to the following terms and conditions
of sale. These should be read before ordering.
http://www.islandco.com/warranty.html

"If Progress is good for the people, what is Congress?"
wrote in message
...
wrote:

Lets say it saves =A320 a year heating dhw only.

Would that be 20 UK pounds per year? Sounds like a very poor water
heater.
... American families pay about $20 per month for hot water.

Welcome to uk.diy Nick. Maybe you can give them a pointer or 2 on how
to make a constructive DHW system that pays its way...

It isn't worth doing much to save 20 pounds per year, but it might make
more sense to collect both hot water and space heat from a polytunnel,
which might have a linear parabolic reflective north wall over a 2'x6'x8'
shoebox tank with an EPDM or polyethylene film liner and a $60 1"x300'
piece
of pressurized polyethylene pipe for a heat exchanger and a horizontal
draindown EPDM cover with a small pump to move water up 2" over the cover
when the sun is shining, and a greywater heat exchanger, eg 2 55 gallon
drums with PE pipe in series.

Gary Reysa and I have been working on this sort of DIY stuff. See

http://BuildItSolar.com.

Nick

"Tony Wesley" wrote in message oups.com...
wrote:
What exactly is the risk you refer to in a system designed to be
riskless?

The risk that the system will not work exactly as designed.

These guys show a draindown system as one of their options.
I don't think that they would recommend something unproven.
http://www.thermomax.com/Drain%20Down%20DHW.htm

On Wed, 08 Mar 2006 13:25:24 +0000, David Hansen wrote:

On Wed, 08 Mar 2006 11:41:40 GMT someone who may be Tony Bryer
wrote this:-

On Tue, 07 Mar 2006 20:33:24 -0400 Derek Broughton wrote :
OK, I'll accept those numbers. Anyone got a better figure on
the average cost of heating water?

The latest SAP 2005 algorithms for a 100m2 house, 110 litre factory
insulated cylinder give a required raw energy input for DHW of
3172kWh. Divide this by the boiler efficiency to get the actual
energy required.

And the efficiency of the pump and pipework. I doubt if the
conversion of gas into hot water is ever going to exceed 80%
efficiency over a year. That gives 3965kWh gas input. At 3p per kWh
that is 118.95 a year, at today's prices. A solar water heating
system should save at least 75% of this through the year, which is
£89.21 a year saved at today's prices.

If the water is heated by off-peak electricity, in theory 100%
efficient, at 4p per unit, then 3172kWh cost £126.88 at today's
prices.

I have no idea by how much the price of gas and electricity will go
up by over say 20 years, but it will go up. The price of sunshine
will remain the same though.

As for maintenance, an evacuated tube system may need a tube or two
replacing over 20 years, but that will probably be it.

I thought the 20 GBP/year was a bit conservative.

A realistic saving of around 60-90 per year depending on usage patterns
and cost of alternative methods of heating.

However your maintenance estimates are probably a bit optimistic.

Circulations pumps can and do fail. Some can go the 20 years other don't

I see no reason why this would not be broadly similar to CH pump
reliability. So let's say 50% of system will need one new pump within the
20 years.
The comparator electronics, I imagine these would be similar to the
reliability of say a an electronic time switch?

Anyway: It looks like the answer to my original question is
A few hundred quid system should pay for itself.
Differing systems and differing usage patterns and requirements make a BIG
difference in the decision. Being prepared to wait for the HW is a big
help whereas always wanting instant HW works against the solar methods.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Steve Spence wrote:

Derek Broughton wrote:

The fifty US gallon figure I quoted, was not for HOT water - it was for
ALL daily water use.

I know that's what you said. Nevertheless,
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm says it IS what
families use.

key word being "estimated". There really no way of knowing for sure,
since it isn't metered, and they didn't do a 100% sampling. Our water
usage is less than half that, even when we were on grid.

Sure, and you can figure out how much total water the townies use from
municipal records, but you still don't know how much the well-users pump,
and you don't know how much of any of that is heated, but everything points
to that being pretty well normal. I would think my use is lower than most
- if for no better reason than I have to quit showering when the 10gal tank
goes cold - but that still means we use well over 20gal of hot water daily,
for only two people.

At a guess, we could probably do a 100% sampling of this newsgroup, and get
a significantly lower usage than 50gal/day for a family of four. But then,
we're the people who care about such things...
--
derek

wrote:

Derek Broughton wrote:
wrote:

Derek Broughton wrote:
wrote:

There's no reason a draindown system can't work in wintertime.

You can risk it. I'm investing in the glycol flat-panel system.

Nick's point was that a draindown system without antifreeze can be
designed to be safe in winter.

I know what his point was. He might even be right. I, however, have no
intention of risking it. I can, and will, profitably install a glycol
loop system with heat exchanger.

What exactly is the risk you refer to in a system designed to be
riskless?

There is no such thing as zero risk. It's OK for you to not worry about
freezing. We just had two weeks at -10C and lower. I'm not risking
exposing water pipes to that. The idea of a draindown system is to _not_
permit that - but how do you guarantee that it's always sufficiently
drained?

I could install a drain-down system, but (a) I'm not confident I won't have
a flood, (b) nobody in this area will sell or service them (because _they_
aren't confident, either), and (c) I'm _definitely_ not confident that _I_
could build, or even install one, that would be low-risk. otoh, I can get
a glycol-loop system, built locally, installed professionally, with proven
reliability - and still save money over heating water with propane.
--
derek

David Hansen wrote:

On Wed, 08 Mar 2006 10:24:15 -0400 someone who may be Derek
Broughton wrote this:-

As for maintenance, an evacuated tube system may need a tube or two
replacing over 20 years, but that will probably be it.

I've been looking at one such system, but those glass tubes are fragile.

Do you have evidence for this claim?

Handling them... Maybe they're tougher than they look, but something so
like a 4' fluorescent tube doesn't inspire confidence.

I
can't see them standing up to the frequent very heavy, occasional
hurricane-force, winds I get here, so I'm going with a flat panel system.

Does your house have windows that are broken regularly by the wind?
If so how does the glass in the windows survive but evacuated tubes
would not?

My house hasn't had a broken window yet. However, neighbors have had two
broken windows, and I've had a light on my car broken. So, yes, it's a
risk. An engineer friend tells me that they also frequently suffer from
seal failure.

Another problem, I've been told, is that efficiency of E.T. systems goes
down when you get snow, as it collects between the tubes.

If there are no reflectors between the tubes then it presumably
mostly lands on the roof below the tubes.

The one I was looking at has very little room between the tubes (less
than .5cm). That's small enough to collect.

If there are reflectors
then, unless there are lips on the bottom, it will slide off as
easily as it will slide off anything. I imagine it will slide off
the tubes before anything else.

Since the tubes aren't supposed to get warm, not nearly as fast as with a
flat panel collector.

Flat panel systems, it slides off.

Provided that there is not a lip on the bottom of the panel that
will restrain the snow. If there is then it will presumably need to
be brushed off, like an evacuated tube system, unless one waits for
sunshine to melt the snow.

Why would you put a lip there?
--
derek

On Wed, 08 Mar 2006 19:28:00 +0000 someone who may be Ed Sirett
wrote this:-

However your maintenance estimates are probably a bit optimistic.

Possibly. However, one would also have to allow for a reduction of
maintenance of the gas boiler and associated bits and pieces if it
is hardly used for at least the summer. Of course if the circulation
pump on this stuck due to under-use then the reduction would be
negative:-)

The comparator electronics, I imagine these would be similar to the
reliability of say a an electronic time switch?

I assume so. It probably depends on the make to some extent.

Anyway: It looks like the answer to my original question is
A few hundred quid system should pay for itself.

That would pay for itself in a few years, assuming no price
increases. A couple of thousand quid system would appear to pay for
itself in the long term, assuming no price increases. However, as I
have said, money is not the only reason for doing something.

Differing systems and differing usage patterns and requirements make a BIG
difference in the decision. Being prepared to wait for the HW is a big
help whereas always wanting instant HW works against the solar methods.

Indeed.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"David Hansen" wrote in message
...

Differing systems and differing usage patterns and requirements make a BIG
difference in the decision. Being prepared to wait for the HW is a big
help whereas always wanting instant HW works against the solar methods.

How many domestic hot water systems ALWAYS want instant hot water?

And even if they want it, do they NEED it?

It's nice to have but not essential.

Mary

In message , "David Turner,
Island Computers US Corp" writes
For what it costs I see no talk of timers/solar/cost comparisons etc


David, for someone who works for a computer company, you don't seem to
understand how to post to a newsgroup

you've top posted, and as you've somehow managed to put previous posts
to the thread below your sig sep, they don't appear in future postings

There are plenty of clues about how to do it - go and learn

--
geoff

"raden" wrote in message ...
In message , "David Turner,
Island Computers US Corp" writes
For what it costs I see no talk of timers/solar/cost comparisons etc


David, for someone who works for a computer company, you don't seem to
understand how to post to a newsgroup

you've top posted, and as you've somehow managed to put previous posts
to the thread below your sig sep, they don't appear in future postings

There are plenty of clues about how to do it - go and learn

--
geoff

I personally don't give a darn about top posting.
Some of you seem to care a lot. Get a life.

On Wed, 08 Mar 2006 15:58:30 -0400 someone who may be Derek
Broughton wrote this:-

Handling them... Maybe they're tougher than they look, but something so
like a 4' fluorescent tube doesn't inspire confidence.

The glass is rather stronger than that found in fluorescent tubes.

An engineer friend tells me that they also frequently suffer from
seal failure.

That certainly was a problem with some designs.

Why would you put a lip there?

Why personalise the discussion by asking what I would do? The fact
is that there is likely to be a small lip, if only to retain things.
I have no idea how much attention manufacturers pay to detailing in
terms of shedding snow, but I imagine UK manufacturers pay it no
attention.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Derek Broughton" wrote in message
...
Ron Purvis wrote:

I think you are off on your figures. According to
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm the typical home uses
20 gallons of hot water per day for the first two persons and 15 gallons
of hot water for each additional person. That would be 25,550 gallons of
hot water per year for a family of four.

OK, I'll accept those numbers. Anyone got a better figure on the average
cost of heating water? My numbers for heat required are, if anything, on
the low side, but at $25/million BTU, and only 25,000 gallons per year,
you're talking $250/year (somebody else said $20/month, so same ballpark).
Still plenty to make a commercial solar water heater pay off.


I cut my DHW heating by somewhere between 1/3 and 1/2 by installing a
waste-water heat-exchanger. Running hot water for a shower and letting all
the energy go down the drain (literally), just doesn't make sense. Of
course, this system only recovers heat from *running* water, so baths and
dish washing doesn't affect it.

I have one of the largest units and it is a two-pass type so is not the most
efficient model they have. Mine cost only about $270, did the installation
myself.

http://www.gfxtechnology.com/

daestrom

"Ron Purvis" wrote in message
...

wrote in message
oups.com...
Derek Broughton wrote:
wrote:

The figures in this thread have stated the savings amount required to
make it worthwhile. If you think you can save well over £100 a year
with a £2000 water heater, go for it. I dont.

The "figures" are a ridiculously low number for cost of hot water that
you
made up. I can _easily_ save £100 a year with a system that will cost me
about that much. Check back next year for real use figures...

Good lord. None of the figures are cost of hot water.

The £20 a year figure is proposed saving from a basic system, and will
vary a fair bit IRL.

The £100 a year figure is how much a £2000 system would need to save
per annum to ever pay its way even if you made the most wildly
optimistic assumptions.

What you don't seem to understand is that just because you made up a
number, doesn't make it valid. Your number has no basis in reality.

His '100' number is 5% annual return on a '2000' investment (or, the
interest on a 2000 loan). While one may quibble about the exact interest
rate, 5% isn't all that far off from current reality.

As far as how much one saves, that is open to debate. After all, how much a
household uses can vary quite a bit with the particular residents. And
system performance as well.

daestrom

ditto.

Cutting off the text below the signature is ***YOUR*** browser's
problem. Don't blame others for it.


"SJC" wrote in message
news:aVHPf.11105$G%2.2741@trnddc07...

I personally don't give a darn about top posting.
Some of you seem to care a lot. Get a life.

On Wed, 08 Mar 2006 21:21:10 GMT someone who may be "SJC"
wrote this:-

I personally don't give a darn about top posting.

I personally find that top-posters generally have little interesting
to say, so I tend to ignore them.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

I personally find that most people disregard bottom posts at all if
they are long and not really hot topics.

The effort is too high to scroll to the bottom of the post and then
back up to find the first text that isn't indented and has a ID/header
of the poster somewhere at the top end of the post.

What a stupid system bottom posting was before threading browsers.

I can read either system but many bottom posts I don't even bother.

Best of luck with your obsession.

"David Hansen" wrote in message
...
On Wed, 08 Mar 2006 21:21:10 GMT someone who may be "SJC"
wrote this:-

I personally don't give a darn about top posting.

I personally find that top-posters generally have little interesting
to say, so I tend to ignore them.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP
prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"daestrom" wrote in message
...

"Ron Purvis" wrote in message
...

wrote in message
oups.com...
Derek Broughton wrote:

The "figures" are a ridiculously low number for cost of hot water that
you
made up. I can _easily_ save £100 a year with a system that will cost
me
about that much. Check back next year for real use figures...

Good lord. None of the figures are cost of hot water.

The £20 a year figure is proposed saving from a basic system, and will
vary a fair bit IRL.

The £100 a year figure is how much a £2000 system would need to save
per annum to ever pay its way even if you made the most wildly
optimistic assumptions.

What you don't seem to understand is that just because you made up a
number, doesn't make it valid. Your number has no basis in reality.

His '100' number is 5% annual return on a '2000' investment (or, the
interest on a 2000 loan). While one may quibble about the exact interest
rate, 5% isn't all that far off from current reality.

As far as how much one saves, that is open to debate. After all, how much
a household uses can vary quite a bit with the particular residents. And
system performance as well.

daestrom

My quibble was with the made up number of only saving 20 British pounds a
year. I was not referring to the 5% annual return.

"daestrom" wrote in message
...

"Derek Broughton" wrote in message
...
Ron Purvis wrote:

I think you are off on your figures. According to
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm the typical home
uses
20 gallons of hot water per day for the first two persons and 15 gallons
of hot water for each additional person. That would be 25,550 gallons of
hot water per year for a family of four.

OK, I'll accept those numbers. Anyone got a better figure on the average
cost of heating water? My numbers for heat required are, if anything, on
the low side, but at $25/million BTU, and only 25,000 gallons per year,
you're talking $250/year (somebody else said $20/month, so same
ballpark).
Still plenty to make a commercial solar water heater pay off.


I cut my DHW heating by somewhere between 1/3 and 1/2 by installing a
waste-water heat-exchanger. Running hot water for a shower and letting
all the energy go down the drain (literally), just doesn't make sense. Of
course, this system only recovers heat from *running* water, so baths and
dish washing doesn't affect it.

I have one of the largest units and it is a two-pass type so is not the
most efficient model they have. Mine cost only about $270, did the
installation myself.

http://www.gfxtechnology.com/

What was the payback period?

"Solar Flare" wrote in message
...
ditto.

Cutting off the text below the signature is ***YOUR*** browser's
problem. Don't blame others for it.


"SJC" wrote in message
news:aVHPf.11105$G%2.2741@trnddc07...

I personally don't give a darn about top posting.
Some of you seem to care a lot. Get a life.

Get a proper email editor.

SJC wrote:
"Tony Wesley" wrote in message oups.com...
wrote:
What exactly is the risk you refer to in a system designed to be
riskless?

The risk that the system will not work exactly as designed.

These guys show a draindown system as one of their options.
I don't think that they would recommend something unproven.
http://www.thermomax.com/Drain%20Down%20DHW.htm

Why does he think there is a risk of incompetent engineering in one
system but not another?

NT

David Turner, Island Computers US Corp wrote:

For what it costs I see no talk of timers/solar/cost comparisons etc

I installed a hot water heater timer in our house 3 months ago

It is on from 7-9:30am then 5:30 to 10pm.

That means it is only actually running (actual power availability that is)
about 7.5 hours
The insulation is good enough that it is not drawing power than for maybe
half of that

At 13C/KW in Savannah GA that ain't much (heater is 4500W 50 Gallon)
Ergo = $4.38/day which is at most $131.63 per month

In reality it is running about 1/2 of that, so it is costing about $65/month
to heat water !!!!!!!!!!!!!!!!!!!!

FYI That is almost $800 per year (minimum) to have hot water

Now does anyone see the value to having a Solar Hot Water heater?!?!?!?!?!?!

Your hot water spend is mind boggling. Suggest you sort your system out
asap.

NT

"Solar Flare" wrote in message
.. .
I personally find that most people disregard bottom posts at all if
they are long and not really hot topics.

The effort is too high to scroll to the bottom of the post

Try ctl END

wrote in message
oups.com...
David Turner, Island Computers US Corp wrote:

For what it costs I see no talk of timers/solar/cost comparisons etc

I installed a hot water heater timer in our house 3 months ago

It is on from 7-9:30am then 5:30 to 10pm.

That means it is only actually running (actual power availability that
is)
about 7.5 hours
The insulation is good enough that it is not drawing power than for maybe
half of that

At 13C/KW in Savannah GA that ain't much (heater is 4500W 50 Gallon)
Ergo = $4.38/day which is at most $131.63 per month

In reality it is running about 1/2 of that, so it is costing about
$65/month
to heat water !!!!!!!!!!!!!!!!!!!!

FYI That is almost $800 per year (minimum) to have hot water

Now does anyone see the value to having a Solar Hot Water
heater?!?!?!?!?!?!

Your hot water spend is mind boggling. Suggest you sort your system out
asap.

Or keep out the bath.

wrote in message ups.com...
wrote:
samc wrote:
wrote:

Lets say it saves £20 a year heating dhw only.

Would that be 20 UK pounds per year? Sounds like a very poor water heater.
It seems to me that American families pay about $20 per month for hot water.

Welcome to uk.diy Nick. Maybe you can give them a pointer or 2 on how
to make a constructive DHW system that pays its way, too much talk of
junk designs here.

Yes, its 20 uk pounds. I'm not sure how you use all that hot water



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

In message aVHPf.11105$G%2.2741@trnddc07, SJC
writes

"raden" wrote in message
...
In message , "David Turner,
Island Computers US Corp" writes
For what it costs I see no talk of timers/solar/cost comparisons etc


David, for someone who works for a computer company, you don't seem to
understand how to post to a newsgroup

you've top posted, and as you've somehow managed to put previous posts
to the thread below your sig sep, they don't appear in future postings

There are plenty of clues about how to do it - go and learn

--
geoff

I personally don't give a darn about top posting.
Some of you seem to care a lot. Get a life.

You can not care as much as you like, but then top posting idiots rarely
last long here

and ******s who work in computing who put everyone else's posts beneath
their sig sep (so it disappears if the post is followed up) really
shouldn't be let near anything more advanced than a wax crayon

--
geoff

In message , Solar Flare
writes
ditto.

Cutting off the text below the signature is ***YOUR*** browser's
problem. Don't blame others for it.

'Scuse me you septic ****

that's the point of a sig sep - to remove what comes under it from
subsequent posts

but then, you're arrogant and stupid, a bit of a waste of time telling
you

--
geoff

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.

"Doctor Drivel" wrote in message
reenews.net...

"daestrom" wrote in message
...

"Derek Broughton" wrote in message
...
Ron Purvis wrote:

I think you are off on your figures. According to
http://www.fsec.ucf.edu/solar/apps/sdhw/dhwsave.htm the typical
home
uses
20 gallons of hot water per day for the first two persons and 15
gallons
of hot water for each additional person. That would be 25,550
gallons of
hot water per year for a family of four.

OK, I'll accept those numbers. Anyone got a better figure on the
average
cost of heating water? My numbers for heat required are, if
anything, on
the low side, but at $25/million BTU, and only 25,000 gallons per
year,
you're talking $250/year (somebody else said $20/month, so same
ballpark).
Still plenty to make a commercial solar water heater pay off.


I cut my DHW heating by somewhere between 1/3 and 1/2 by
installing a
waste-water heat-exchanger. Running hot water for a shower and
letting
all the energy go down the drain (literally), just doesn't make
sense. Of
course, this system only recovers heat from *running* water, so
baths and
dish washing doesn't affect it.

I have one of the largest units and it is a two-pass type so is
not the
most efficient model they have. Mine cost only about $270, did
the
installation myself.

http://www.gfxtechnology.com/

What was the payback period?

Stop whining about using it when it doesn't work.

Good luck with that.

"raden" wrote in message
...
In message , Solar Flare
writes
ditto.

Cutting off the text below the signature is ***YOUR*** browser's
problem. Don't blame others for it.

'Scuse me you septic ****

that's the point of a sig sep - to remove what comes under it from
subsequent posts

but then, you're arrogant and stupid, a bit of a waste of time
telling
you

--
geoff

What for? Then I have to scroll all the way back to the top of the
post.

Try reading and don't trim text to support your falacies

"Doctor Drivel" wrote in message
reenews.net...

"Solar Flare" wrote in message
.. .
I personally find that most people disregard bottom posts at all if
they are long and not really hot topics.

The effort is too high to scroll to the bottom of the post

Try ctl END

"Solar Flare" wrote in message
...
Stop whining about using it when it doesn't work.

** plonk **

In message , Solar Flare
writes
Stop whining about using it when it doesn't work.

Just so far from having a first clue

prime presidential material there


Good luck with that.

"raden" wrote in message
...
In message , Solar Flare
writes
ditto.

Cutting off the text below the signature is ***YOUR*** browser's
problem. Don't blame others for it.

'Scuse me you septic ****

that's the point of a sig sep - to remove what comes under it from
subsequent posts

but then, you're arrogant and stupid, a bit of a waste of time
telling
you

--
geoff



--
geoff