nice hot day.

Since the interesting discussions on solar PV, am now pondering DIY
solar water heating possibilities, anyone care to share? or links,
pointers, suppliers (good/bad/cheap/expensive) all (constructive)
suggestions welcomed..

trawled on here first and been reading about Solartwin (seems ££££?)
and Navitron DIY kits - any experiences? other suppliers? other ideas?

TIA
Jim K

On Sun, 26 Jun 2011 04:10:43 -0700 (PDT), Jim K wrote:

Since the interesting discussions on solar PV, am now pondering DIY
solar water heating possibilities, anyone care to share?

Before you DIY do some research into the Renweable Heat Incentive
(RHI) which is due to come in for domestic installations late next
year. In the mean time dig about for Renewable Heat Premium Payment
and/or Green Deal.

IIRC the Renewable Heat Premium Payment is £300 for solar thermal.
Can't remember what the Green Deal is but that seems to coincide with
the start of RHI for domestic installs so might not be relevant.

The RHI will pay you for the heat captured... Unfortunately this
money appears to be HMGs money now not froma levey on energy bills as
in the case of FIT payments. The domestic rates and eligibilty
critera have yet to be set. Though there are some strong hints on the
latter, on rate 18p/kWHr was mooted for solar thermal by Department
of Energy and Climate Change's original consultation on the Renewable
Heat Incentive on the 20th October 2010. Pass the salt...

As with all these schemes DIY is out, approved Microgeneration
Certification Scheme (MCS) installers are in.

--
Cheers
Dave.

Jim K wrote:

nice hot day.

Since the interesting discussions on solar PV, am now pondering DIY
solar water heating possibilities, anyone care to share? or links,
pointers, suppliers (good/bad/cheap/expensive) all (constructive)
suggestions welcomed..

trawled on here first and been reading about Solartwin (seems ££££?)
and Navitron DIY kits - any experiences? other suppliers? other ideas?

I spent some of last week commissioning our solar heating installation.

The thermal store is a Heatbank from DPS who have now gone bust but the
defunct company was taken over by a larger company (I forget which one)
and they now trade as Thermal Integration Limited - www.heatweb.com.

I can't fault the product, it's excellent. We have a 300 litre Xcel unit
that provides points for underfloor heating, radiators, and a heat
exchanger for mains pressure hot water. Inputs are taken from an LPG
boiler, solar panels and a wood burner in the kitchen.

At the moment the solar panels and wood burner are not connected. The
LPG boiler is connected and is functioning well. This week the unit is
operating on a low setting as we bring the underfloor heating up to
temperature. All seems fine and installation was a doddle because the
thermal store has the pump and mixer for the UFH and there's no need for
the UFH heating manifold to have either of those - saves on cost.

Although the install looks hideously complicated it's a doddle. The
thermal store is vented so no sealed system worries.

The solar panels are vacuum tube units bought from a business called LC
Solar, but they are clearly re-badged Chinese units and were forgettably
cheap. These will be connected to a Resol controller and the only
headache at the moment is working out what to do with excess heat. In
the long run this will go to the swimming pool in the short term I
suspect that a black painted radiator on a north facing wall will have
to do.

I wouldn't touch Solartwin with yours, it's a cack, cheapskate design
and it's hideously expensive. For the cost of one of their units I
bought a Heatbank, two solar panels, two log burners an LPG boiler and a
2500 litre underground LPG tank, paid for an LPG certified plumber to
connect the boiler and still had cash left over for the installation of
drainage.

On Sun, 26 Jun 2011 14:06:56 +0100, Steve Firth wrote:

I can't fault the product, it's excellent. We have a 300 litre Xcel unit
that provides points for underfloor heating, radiators, and a heat
exchanger for mains pressure hot water. Inputs are taken from an LPG
boiler, solar panels and a wood burner in the kitchen.

What output to water will the woodburner give you? I'm in the
planning stage of a very similar setup (s/LPG/oil/ and
s/kitchen/snug/). The woodburner I'm looking at will give 6kW normal
(8kW flat out) to water, I'm thinking that a 300l tank is a bit small
and will overheat rather to easiyly.

But one has to balance that against getting a sensible raise in store
temp from just the solar though. I guess when the wood burner is on
the house will be demanding so maybe overheat of the store in "normal
use" won't be an issue. Doesn't the DPS use a passive thermal valve
and a mains water dump to cool the store in extremis, normally it
just runs the CH pump to loose heat.

The DPS Xcel looks good but I think I've said before I don't like the
external plate heat exchnager for DHW I'd rather that was a coil
within the top of the store like the Akvaterm ones.

--
Cheers
Dave.

"Dave Liquorice" wrote:
On Sun, 26 Jun 2011 14:06:56 +0100, Steve Firth wrote:

I can't fault the product, it's excellent. We have a 300 litre Xcel unit
that provides points for underfloor heating, radiators, and a heat
exchanger for mains pressure hot water. Inputs are taken from an LPG
boiler, solar panels and a wood burner in the kitchen.

What output to water will the woodburner give you?

I'm considering a 12kW woodburner with 6kW estimated to the hot water.

I'm in the
planning stage of a very similar setup (s/LPG/oil/ and
s/kitchen/snug/). The woodburner I'm looking at will give 6kW normal
(8kW flat out) to water, I'm thinking that a 300l tank is a bit small
and will overheat rather to easiyly.

I don't think so. I have a standard DHW setup with a log burner of similar
size. I've never had it boil even when blasting it with heat in winter. I
expect to have a diversion valve and a radiator as a heat dump when the new
log burner is installed.

But one has to balance that against getting a sensible raise in store
temp from just the solar though. I guess when the wood burner is on
the house will be demanding so maybe overheat of the store in "normal
use" won't be an issue. Doesn't the DPS use a passive thermal valve
and a mains water dump to cool the store in extremis,

Not mine, but it is an option.

normally it just runs the CH pump to loose heat.

That's the only option that I have.

The DPS Xcel looks good but I think I've said before I don't like the
external plate heat exchnager for DHW I'd rather that was a coil
within the top of the store like the Akvaterm ones.

I went for the DPS because of the tech support which is outstanding, the
high output of the plate heat exchanger, and the fact that the exchanger
can be changed if necessary.

It's working well with a 30kW boiler. No sign of short cycling and after
the first test firing to 70C the temperature in the store held at 60C until
late the next day.

On 26 Jun 2011 21:54:51 GMT, Steve Firth wrote:

What output to water will the woodburner give you?

I'm considering a 12kW woodburner with 6kW estimated to the hot water.

So 6kW to the room... This is a large room or one very poorly
insulated then?

You don't want a Coalbrooke Dale Muchwenlock stove with boiler do
you? Sneaky feeling that you aren't in the UK though. Not quite that
output but too big for the room that the stove will be in. It would
have been OK for the current living room (4.5m x 9m x 2.4m ish).

I don't think so. I have a standard DHW setup with a log burner of
similar size. I've never had it boil even when blasting it with heat in
winter.

Fairy Nuff.

Doesn't the DPS use a passive thermal valve and a mains water dump
to
cool the store in extremis,

Not mine, but it is an option.

normally it just runs the CH pump to loose heat.

That's the only option that I have.

The cautious side of me says "what happens if there is no power"...
Thats just when I'll be wanting to have the woodburner on not off
'cause the store is overheated.

I went for the DPS because of the tech support which is outstanding, the
high output of the plate heat exchanger, and the fact that the exchanger
can be changed if necessary.

Our water is soft so scale is not a problem. It's also "what happens
if the power is off" again. KISS and passive rules... I'm almost
presuaded about mains pressure HW or at least HW from the mains via a
pressure reducing valve but not having stored water makes me nervous.

--
Cheers
Dave.

"Dave Liquorice" wrote:
On 26 Jun 2011 21:54:51 GMT, Steve Firth wrote:

What output to water will the woodburner give you?

I'm considering a 12kW woodburner with 6kW estimated to the hot water.

So 6kW to the room... This is a large room or one very poorly
insulated then?

Very high room with a different layout to the UK. It's "piano nobile" which
means that the stove will heat three rooms.

You don't want a Coalbrooke Dale Muchwenlock stove with boiler do
you?

Are you offering free transport?

Sneaky feeling that you aren't in the UK though.

Saw through my cunning plan, eh?

[snip]

That's the only option that I have.

The cautious side of me says "what happens if there is no power"...

The diesel generator with ATS should cut in. If it doesn't then I'll have
to start the petrol gennie.

Thats just when I'll be wanting to have the woodburner on not off
'cause the store is overheated.

I went for the DPS because of the tech support which is outstanding, the
high output of the plate heat exchanger, and the fact that the exchanger
can be changed if necessary.

Our water is soft so scale is not a problem. It's also "what happens
if the power is off" again. KISS and passive rules... I'm almost
presuaded about mains pressure HW or at least HW from the mains via a
pressure reducing valve but not having stored water makes me nervous.

UPS, generator, 1200 ft above sea level so no chance of a tsunami. What
could possibly go wrong?

On 26/06/2011 2:06 PM, Steve Firth wrote:
Jim wrote:

nice hot day.

Since the interesting discussions on solar PV, am now pondering DIY
solar water heating possibilities, anyone care to share? or links,
pointers, suppliers (good/bad/cheap/expensive) all (constructive)
suggestions welcomed..

trawled on here first and been reading about Solartwin (seems ££££?)
and Navitron DIY kits - any experiences? other suppliers? other ideas?

I spent some of last week commissioning our solar heating installation.

The thermal store is a Heatbank from DPS who have now gone bust but the
defunct company was taken over by a larger company (I forget which one)
and they now trade as Thermal Integration Limited - www.heatweb.com.

I can't fault the product, it's excellent. We have a 300 litre Xcel unit
that provides points for underfloor heating, radiators, and a heat
exchanger for mains pressure hot water. Inputs are taken from an LPG
boiler, solar panels and a wood burner in the kitchen.

At the moment the solar panels and wood burner are not connected. The
LPG boiler is connected and is functioning well. This week the unit is
operating on a low setting as we bring the underfloor heating up to
temperature. All seems fine and installation was a doddle because the
thermal store has the pump and mixer for the UFH and there's no need for
the UFH heating manifold to have either of those - saves on cost.

Although the install looks hideously complicated it's a doddle. The
thermal store is vented so no sealed system worries.

The solar panels are vacuum tube units bought from a business called LC
Solar, but they are clearly re-badged Chinese units and were forgettably
cheap. These will be connected to a Resol controller and the only
headache at the moment is working out what to do with excess heat. In
the long run this will go to the swimming pool in the short term I
suspect that a black painted radiator on a north facing wall will have
to do.

I wouldn't touch Solartwin with yours, it's a cack, cheapskate design
and it's hideously expensive. For the cost of one of their units I
bought a Heatbank, two solar panels, two log burners an LPG boiler and a
2500 litre underground LPG tank, paid for an LPG certified plumber to
connect the boiler and still had cash left over for the installation of
drainage.

I installed an XCel (475 litre) 18 months ago and concur it's a doddle.

Inputs are Gas, Leccy and solar. Solar loop uses a Navitron SFB30-47.
30 tubes. I use a Resol Deltasol BS plus controller

For excess heat the top stat on the XCel turns on the pump at IIRC 85C.
For me this has NEVER happened. On the sunniest of days the
temperature simply never gets that high. In any event the BS plus has
also got the ability to switch a pump at a preset temperature, and this
could be used to dump heat to an external rad of some kind with no problem.

You might find this interesting:

http://home.btconnect.com/vortex/110624_26solar.pdf

Temp readouts from my XCel over the past 48 hours (today sunny, day
before overcast). Note the timeline is gibberish.

The Deltasol has 4 PRT inputs.

GREEN is temp top of XCel. Each upward jink is a boiler burn.
BLUE is solar "flow" temperature
PURPLE is solar "return"
RED is temp at bottom of XCel

Today 16.5 kWh of solar energy (7.4 thermal, 9.1 electrical) was input
and the temperature did not even get to 80.

+++++++++

Doesn't surprise me that DPS went bust. Smart people and excellent
technology but when I visited their office it was very evident they had
cashflow issues. With passion and investment I have no doubt they can
succeed. They really need a "dragon" to get there. I hope they have
found the right partner.

Vortex10 wrote:

GREEN is temp top of XCel. Each upward jink is a boiler burn.
BLUE is solar "flow" temperature
PURPLE is solar "return"
RED is temp at bottom of XCel

I assume the return temp is measured close to the store, rather than
close to the collector, by the fact that it remains warmer than the flow
temp overnight.

But how does the return get to be colder than the bottom of the store
during the day?

On 26/06/2011 9:58 PM, Andy Burns wrote:
Vortex10 wrote:

GREEN is temp top of XCel. Each upward jink is a boiler burn.
BLUE is solar "flow" temperature
PURPLE is solar "return"
RED is temp at bottom of XCel

I assume the return temp is measured close to the store, rather than
close to the collector, by the fact that it remains warmer than the flow
temp overnight.

Yup. Just before the pump. About 2 feet from the store.

Flow sensor is on the roof.


But how does the return get to be colder than the bottom of the store
during the day?

I've noticed that. I don't know how the indirect coil within the XCel
is constructed but I believe it goes lower than the sensor pocket.

ALSO I have solar PV and put together a setup to divert surplus leccy to
the XCel, rather than export it. Mentioned about 2/3's down the "Solar
PV --- so anyway" thread. There's some interaction going on.

ALSO the red PRT is a dodgy Chinese device from Ebay. I've been meaning
to try another.

On Sun, 26 Jun 2011 22:31:12 +0100, Vortex10 wrote:

ALSO the red PRT is a dodgy Chinese device from Ebay. I've been meaning
to try another.

PRT? I've tried google.

--
Cheers
Dave.

On Sun, 26 Jun 2011 21:06:59 +0100, Vortex10 wrote:

I installed an XCel (475 litre) 18 months ago and concur it's a doddle.

Inputs are Gas, Leccy and solar. Solar loop uses a Navitron SFB30-47.
30 tubes. I use a Resol Deltasol BS plus controller

For excess heat the top stat on the XCel turns on the pump at IIRC 85C.
For me this has NEVER happened.

Ah but you don't have the "uncontrolled" heat source that I intend,
the wood burner. If a store is sized correctly for the solar panels
it would have to be a very long and bright day for it to overheat the
tank. It might happen if you are away and there is no use of hot
water.

I've been fiddling with the DPS online designer thing and what it
comes up with ticks more "like" boxes than "dislike" ones. I'm still
not happy about the active DHW via the pumped plate heat exchanger.
One question that those with such things do you get any warming of
the DHW if the pump doesn't run? Thinking that there might be some
gravity flow in the primary of PHE.

Now to find an MCS registered installer who is willing to do what I
want not just what they want to sell. Rang a couple of companies
yesterday, still waiting for them to get back to me... Like some one
else mentioned, no one seems interested in new work, maybe they are
all just too busy?

--
Cheers
Dave.

On 28/06/2011 3:37 PM, Dave Liquorice wrote:
On Sun, 26 Jun 2011 21:06:59 +0100, Vortex10 wrote:

I installed an XCel (475 litre) 18 months ago and concur it's a doddle.

Inputs are Gas, Leccy and solar. Solar loop uses a Navitron SFB30-47.
30 tubes. I use a Resol Deltasol BS plus controller

For excess heat the top stat on the XCel turns on the pump at IIRC 85C.
For me this has NEVER happened.

Ah but you don't have the "uncontrolled" heat source that I intend,
the wood burner. If a store is sized correctly for the solar panels
it would have to be a very long and bright day for it to overheat the
tank. It might happen if you are away and there is no use of hot
water.

I've been fiddling with the DPS online designer thing and what it
comes up with ticks more "like" boxes than "dislike" ones. I'm still
not happy about the active DHW via the pumped plate heat exchanger.
One question that those with such things do you get any warming of
the DHW if the pump doesn't run? Thinking that there might be some
gravity flow in the primary of PHE.

Now to find an MCS registered installer who is willing to do what I
want not just what they want to sell. Rang a couple of companies
yesterday, still waiting for them to get back to me... Like some one
else mentioned, no one seems interested in new work, maybe they are
all just too busy?


I take the point on the uncontrolled heat source.

re the XCel you get no significant hot water with no pump operation. In
my case the heatbank has 3 identical pumps with isolator valves, so I
purchased a spare. Pump failure is a 15 minute problem. Not happened
in 18 months. Don't forget there is also the option of a passive
(90C???) relief valve that would release water (from the top) to drain
as the ultimate failover.

If you have no electricity at all then that's a different matter, so
either you could have a UPS backing up the whole heating system (Sub
£200 for a quality 500VA APC UPS). Where I live that would simply be
completely neurotic.

Don't forget with a large heatbank you need a hell of a lot of corrosion
inhibiter....And if you have an outdoor heat dump rad then maybe
antifreeze too.

I would stick with indoor rads for a heat dump. Antifreezing a 500+
litre primary circuit would be ridiculously expensive

On Tue, 28 Jun 2011 19:14:57 +0100, Vortex10 wrote:

re the XCel you get no significant hot water with no pump operation.

Ta, I didn't think you'd get much considering how much energy it
takes to heat water. IIRC the normal PHE with the XCel system is over
100kW for 45l/m water... (Now we know why combies are so crap at 40kW
for a big one...)

In my case the heatbank has 3 identical pumps with isolator valves, so I
purchased a spare. Pump failure is a 15 minute problem.

I don't envisage pump failure being a problem. I've spent a day
changing a pump in the past, flange nuts siezed onto pump and bloody
gate valves... Think they are screwdriver ball valves on the XCel
rather than gate valves though.

Don't forget there is also the option of a passive (90C???) relief valve
that would release water (from the top) to drain as the ultimate
failover.

It doesn't release the primary water. Mains water goes through a coil
at the top and thence to a drain. The coil is only 12kW so not enough
to use for normal DHW. But if all you wanted was a slow flow for
basin/sink filling under power fail conditions it would do...
Hummmm....

If you have no electricity at all then that's a different matter, so
either you could have a UPS backing up the whole heating system (Sub
£200 for a quality 500VA APC UPS). Where I live that would simply be
completely neurotic.

It is loss of mains power that I'm concerned about. It does happen
about once a year to 18 months on average. If the power does go it
will quite often be gone for up to 12 hours which is long enough for
things to get rather too cold in the middle of winter. It's only in
the last week that the heating hasn't been kicking first thing in the
morning and that's with the room stat set for 18.5C.

Trouble is with a UPS is the size of batteries required to provide
and sensible amount of up time. The XCel system I'm looking at has 5
pumps and the oil boiler, guesstimate that lot to be not far short of
500W. Computer type UPS's generally only have uptimes of 10 minutes
or so at full load.
That's why I have 2kVA genset...

I would stick with indoor rads for a heat dump. Antifreezing a 500+
litre primary circuit would be ridiculously expensive

Oh yes, indoor heat dump without a doubt I've paid for it I'm not
going to throw it away unless I *really* have to. B-) If it gets
too hot inside that's what windows are for!

--
Cheers
Dave.

On Jun 26, 12:10*pm, Jim K wrote:
nice hot day.

Since the interesting discussions on solar PV, am now pondering DIY
solar water heating possibilities, anyone care to share? or links,
pointers, suppliers (good/bad/cheap/expensive) all (constructive)
suggestions welcomed..

trawled on here first and been reading about Solartwin (seems ££££?)
and Navitron DIY kits - any experiences? other suppliers? other ideas?

TIA
Jim K

I have a home made Solar water panel. However, I also have a PV
panel.

I think an issue you need to consider is that why not just turn the
immersion heater on on the sunny day , ie, never bother with the
thermal panel.
After all, you get paid for the electricity anyway whether you use it
yourself or not.
Much better use for the cash.

So, go for the biggest PV panel you can & bugger the solar heating.

I have electric undersink storage heaters (5liter). I turn them on
through the (sunny) day for hot water at night.

"harry" wrote in message
...

I have a home made Solar water panel. However, I also have a PV
panel.

I think an issue you need to consider is that why not just turn the
immersion heater on on the sunny day , ie, never bother with the
thermal panel.
After all, you get paid for the electricity anyway whether you use it
yourself or not.
Much better use for the cash.

mmm I think that's still out with the Jury (at least back in normal
space)......

So, go for the biggest PV panel you can & bugger the solar heating.

And pay what £12-15000 for the priviledge? Vs abt £600 for a solar thermal
add on to my heatbank? erm....hang on a mo....

I have electric undersink storage heaters (5liter). I turn them on
through the (sunny) day for hot water at night.

5 litres? less than 10pints? do you not wash very often?

Jim K