How effective are these ? Are they much of an improvement over the old types ?

"Tim Streater" wrote in message
.. .
In article ,
fred wrote:

How effective are these ? Are they much of an improvement over the old
types ?

What are "Thermodynamic Solar Panels" ??

https://en.wikipedia.org/wiki/Thermodynamic_solar_panel

fred wrote:
How effective are these ? Are they much of an improvement over the old types ?

I would imagine you can get a bit more energy transfer but a much more
complex system.
Once the panel has got frost on it then that acts as an insulator and
the efficiency will drop off until the frost has melted.
I have solar thermal tubes and these do very well for 7 months of the
year giving me most of the hot water I need. The remaining 5 months the
gas boiler runs for about 15 mins twice a day for DHW. I suspect the
improvement offered by thermodynamic panels would have a much higher
capital cost and only save a bit of gas and you still need the power to
run the heat pump. All my system needs is a central heating type pump
and temperature difference controller consuming a watt or so.

On 08/01/2019 22:11, fred wrote:
How effective are these ? Are they much of an improvement over the old types ?

Not if the "old types" are PV. ;-

--
Max Demian

So how is this any different to the hot water heaters for roofs that many
already have. A friend of mine has one and it seems to save money, but of
course there is the capital outlay, the need to keep them clean and any
possible issues when they go wrong.

Brian

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"dkol" wrote in message
...


"Tim Streater" wrote in message
.. .
In article ,
fred wrote:

How effective are these ? Are they much of an improvement over the old
types ?

What are "Thermodynamic Solar Panels" ??

https://en.wikipedia.org/wiki/Thermodynamic_solar_panel

Brian Gaff wrote

So how is this any different to the hot water heaters for roofs that many
already have.

It has a heat pump instead of a much simpler
system that just moves the hot water from
the solar panel to the storage tank.

A friend of mine has one and it seems to save money,

Yes, a heat pump is better than just moving the
hot water from the solar panel to the storage
tank because it isnt just moving the captured
solar energy, it is also moving some heat from
the air around it too because it’s a heat pump.

but of course there is the capital outlay,

Yep, that’s the obvious downside.

the need to keep them clean

Less need for that than with a simpler system.

and any possible issues when they go wrong.

And significantly more expensive when the heat pump fails.

"dkol" wrote in message
...


"Tim Streater" wrote in message
.. .
In article ,
fred wrote:

How effective are these ? Are they much of an improvement over the old
types ?

What are "Thermodynamic Solar Panels" ??

https://en.wikipedia.org/wiki/Thermodynamic_solar_panel

In article ,
Brian Gaff wrote:
So how is this any different to the hot water heaters for roofs that many
already have. A friend of mine has one and it seems to save money, but of
course there is the capital outlay, the need to keep them clean and any
possible issues when they go wrong.

Brian

On some newish houses in this village, hot water creating panel were fitted
on the roofs. But they hadn'r been fitted properly. When it snowed all the
panels were completely clear - the snow melted off them!

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Bob Minchin wrote:

I would imagine you can get a bit more energy transfer but a much more
complex system.

I see comparisons where the payback for gas vs thermodynamic hot water
is 30 years, so they make it look justifiable by assuming the boiler
needs replacement after 15 years, they seem to assume the thermodynamic
system won't need replacing inside 20 years.

https://www.greenmatch.co.uk/solar-energy/solar-thermal/thermodynamic-panels#cost

But then, their understanding of power vs energy is summed up by "uses
360 watts an hour"

On 08/01/2019 22:11, fred wrote:
How effective are these ? Are they much of an improvement over the old types ?


Because its a heat pump it can work in the dark, but you get better
efficiency when the sun shines on them.

If you just want hot water then normal passive solar panels are somewhat
easier.

On 09/01/2019 09:09, charles wrote:
In article ,
Brian Gaff wrote:
So how is this any different to the hot water heaters for roofs that many
already have. A friend of mine has one and it seems to save money, but of
course there is the capital outlay, the need to keep them clean and any
possible issues when they go wrong.

Brian

On some newish houses in this village, hot water creating panel were fitted
on the roofs. But they hadn'r been fitted properly. When it snowed all the
panels were completely clear - the snow melted off them!


Maybe that is what you want, once they are clear of snow they stand a
chance of picking up some solar heat. And presumably you don't want them
freezing. I wonder if a smart heat pump system would manage this
automatically?

On 08/01/2019 22:42, Bob Minchin wrote:
fred wrote:
How effective are these ? Are they much of an improvement over the old
types ?

I would imagine you can get a bit more energy transfer but a much more
complex system.

It is able to take more low grade heat but at an enormous increase in
complexity and plenty of moving parts to go wrong. I'd expect price
performance to be risible (much like with ground source heat pumps when
you include all the capital costs and ongoing maintainance work needed).

Once the panel has got frost on it then that acts as an insulator and
the efficiency will drop off until the frost has melted.
I have solar thermal tubes and these do very well for 7 months of the
year giving me most of the hot water I need. The remaining 5 months the
gas boiler runs for about 15 mins twice a day for DHW. I suspect the
improvement offered by thermodynamic panels would have a much higher
capital cost and only save a bit of gas and you still need the power to
run the heat pump. All my system needs is a central heating type pump
and temperature difference controller consuming a watt or so.

What is the payback period for your thermal solar tubes?

Presumably one of the variants that uses a heat pipe in a glass tube
silvered on the back half and plugged into a manifold.

--
Regards,
Martin Brown

On Wednesday, January 9, 2019 at 12:01:39 PM UTC, dennis@home wrote:
On 08/01/2019 22:11, fred wrote:
How effective are these ? Are they much of an improvement over the old types ?


Because its a heat pump it can work in the dark, but you get better
efficiency when the sun shines on them.

If you just want hot water then normal passive solar panels are somewhat
easier.

Given all the above would photo electric panels (or whatever they are called) be more cost effective ?

"fred" wrote in message
...
On Wednesday, January 9, 2019 at 12:01:39 PM UTC, dennis@home wrote:
On 08/01/2019 22:11, fred wrote:
How effective are these ? Are they much of an improvement over the old
types ?


Because its a heat pump it can work in the dark, but you get better
efficiency when the sun shines on them.

If you just want hot water then normal passive solar panels are somewhat
easier.

Given all the above would photo electric panels (or whatever they are
called) be more cost effective ?

No they would not because of the much lower efficiency of PV.

In spades with the latitude of the UK.

On 09/01/2019 12:36, fred wrote:
On Wednesday, January 9, 2019 at 12:01:39 PM UTC, dennis@home wrote:
On 08/01/2019 22:11, fred wrote:
How effective are these ? Are they much of an improvement over the old types ?


Because its a heat pump it can work in the dark, but you get better
efficiency when the sun shines on them.

If you just want hot water then normal passive solar panels are somewhat
easier.

Given all the above would photo electric panels (or whatever they are called) be more cost effective ?


They were better because you got a lot of payments for the electricity
even if you used it all yourself.

As for being green then passive solar water heating is probably greener
than solar PV.

On 09/01/2019 12:07, newshound wrote:
On 09/01/2019 09:09, charles wrote:
In article ,
Â*Â*Â* Brian Gaff wrote:
So how is this any different to the hot water heaters for roofs that
many
already have. A friend of mine has one and it seems to save money,
but of
course there is the capital outlay, the need to keep them clean andÂ* any
possible issues when they go wrong.

Brian

On some newish houses in this village, hot water creating panel were
fitted
on the roofs.Â* But they hadn'r been fitted properly. When it snowed
all the
panels were completely clear - the snow melted off them!


Maybe that is what you want, once they are clear of snow they stand a
chance of picking up some solar heat. And presumably you don't want them
freezing. I wonder if a smart heat pump system would manage this
automatically?

Doesn't need to.
My solar hot water never get lying snow on them and they are installed
correctly.
The glycol stops them freezing.

On 09/01/2019 13:41, dennis@home wrote:
On 09/01/2019 12:07, newshound wrote:


Maybe that is what you want, once they are clear of snow they stand a
chance of picking up some solar heat. And presumably you don't want
them freezing. I wonder if a smart heat pump system would manage this
automatically?

Doesn't need to.
My solar hot water never get lying snow on them and they are installed
correctly.
The glycol stops them freezing.

So the angle and surface finish stops snow settling? Always? Do you
perhaps have a "cotswold" slope?

Martin Brown wrote:
What is the payback period for your thermal solar tubes?


Without RHI the payback calculations would make it a total non starter.
My basic capital costs of the solar thermal are covered by the RHI. I
did a one day training course for around £200 enabling me to do the
installation myself and get it MCS certified - mandatory in order to get
RHI.
I did it as an interesting retirement project together with a PV dumping
diverter - home made. The overall project has covered its costs over 6
years and now is in profit after all my household energy has been paid for.

Presumably one of the variants that uses a heat pipe in a glass tube
silvered on the back half and plugged into a manifold.

Yes exactly that. An array of 30 vacuum tubes each with a water based
heat pipe.

On 09/01/2019 17:08, newshound wrote:
On 09/01/2019 13:41, dennis@home wrote:
On 09/01/2019 12:07, newshound wrote:


Maybe that is what you want, once they are clear of snow they stand a
chance of picking up some solar heat. And presumably you don't want
them freezing. I wonder if a smart heat pump system would manage this
automatically?

Doesn't need to.
My solar hot water never get lying snow on them and they are installed
correctly.
The glycol stops them freezing.

So the angle and surface finish stops snow settling? Always? Do you
perhaps have a "cotswold" slope?

about 30 degrees

On 09/01/2019 09:55, Andy Burns wrote:

But then, their understanding of power vs energy is summed up by "uses
360 watts an hour"

The figures assume that the panels generate enough hot water for the
average family 365 days a year without any need for a top up from any
other source.

Reference their "unit" figures why would an electric boiler be 12 pence
per kWh and an electric immersion heater be 30 pence per kWh?

Quote
thermodynamic water heating systems may cost over 10 times less to
operate than other common types, such as electric immersion heaters
/Quote

It's only 10x because they have used the wrong figures and so their
quoted break even point of 5 years is some what bogus.

As for boiler replacement, wouldn't it still be needed for central
heating and if so the ability to also provide hot water comes for free
(or just for the cost of the fuel).

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