On 27/10/2022 17:11, Clive Arthur wrote:
> On 27/10/2022 14:37, Fredxx wrote:
>> On 27/10/2022 14:02, Clive Arthur wrote:
>>> On 27/10/2022 06:27, Alan wrote:
>>>
>>> <snip>
>>>
>>>> Well, its not though is it. He's probably quoting/mistaking the output
>>>> required to get the room from 5 degrees up to 20 degrees. Once it is
>>>> above 18 degrees, it will only need a small amount of power to reach 20
>>>> degrees, unless it is a very poorly insulated room, which is unlikely.
>>>> There is a lot of maths involved in getting the heat output correct
>>>> before fitting an ASHP, and if insulation is poor, that should be
>>>> pointed
>>>> out, so the ASHP and radiators can be sized correctly to heat the house
>>>> to the required temperature.
>>>
>>> I wonder how a gas powered heat pump would fare?  A gas ICE to both
>>> run the pump and top up the pumped heat.
>>
>> It would take low grade heat and convert it into higher grade heat +
>> bit more.
>>
>>
> Yes, what I meant was, how much better that a normal boiler while using
> the existing radiators, IOW how much of a saving in gas.

I might expect 150% return? say 100% heat, + 10-15% electrical power
which with a COP of 3-4 to give 150%?

alan_m <junk@admac.myzen.co.uk> wrote:
> Despite the title of the video this guy is having a dig at a few Youtube
> heating engineers that say that ASHP do not work. He is advocating that
> if do the maths first and correctly size your system then ASHP do work well.
>
> What this video probably confirms is that bolting a ASHP to an existing
> hot water radiator distribution, without modification and without
> existing underfloor heating, is unlikely to give acceptable results.

Heh. I have the 13kW version of that heatpump. House not particularly well
insulated (quite lossy upstairs; open chimney; windows open a lot of the
time for fresh air), but perfectly warm when it's running. We did replace
all the rads, maybe 50% bigger in area than the old ones, which were grotty
1970s single panel single convector units. No UFH. Most of the pipework
was left as-is, apart from the feed to the heatpump (which is in a different
place to the oil boiler) and the replacement cylinder plumbing.

I uprated to the 13kW for cooling purposes (an ongoing DIY project): 10kW
was what the heatloss calcs came out with. There are some efficiency hits
in the design - bigger than necessary heatpump; slightly higher flow temps
given the radiator sizing; hot water is supposed to be 55C but I've reduced
it to 44C which is fine; buffer tank because the installer was lazy and
doing an install like it was a boiler (this is however helpful from a
cooling perspective)

I'll post 12 month energy consumption numbers in December, but so far bills
have been fine.

Theo

The Natural Philosopher <tnp@invalid.invalid> wrote:
> I dont think you understand heat loss.
>
> My house was calculated to need 10kW to *maintain itself* at 19°C with
> an outside temperature of 5°C. Built to 2000 building regs for insulation.

Are you sure that's 5C? That's not even a cold winter day. Typical 'design
outside temperatures' are -5C to 1C in different parts of the country.

Being a 2000 build your heatloss to DOT should be roughly 30-50W/m2 (2006
would be 20-40) [1]. How many m2 do you have?

[1] https://www.heatgeek.com/how-to-size-my-heat-pump-or-boiler-heat-loss-cheat-sheet/

> I looked at a heat pump - it needed something like a 15kW unit on 3
> phase power. £20,000.

15kW is 60A of pure electric heat, so with a COP of 3 would need 5kW -
that's a 20A feed. Not sure why you need three phase. My 13kW ASHP never
takes more than about 3.6kW of electrical power, and the feed is rated at 21A.

To buy the unit itself is £4k+VAT from a plumbing merchant, I'm sure a
proper distributor will sell it for less.

> Cost of 12KW oil boiler., £1500 (then)

Oil boilers are about £3k+VAT.

> And yes, in very cold days it struggles to jeep the house warm

Not had that with my ASHP. We don't run it overnight, and it'll bring the
house up from cold without too much trouble.

> Indeed. My point being that houses need a lot of peak capacity to stay
> warm in very cold weather, and as with all things 'renewable' and green,
> the heat pump efficiency is lowest when you need it most. When there are
> low outside temps.

In terms of efficiency, the sub-zero days in the winter are relatively few.
The days where it's single-digits positive outside are many. The heatpump
efficiency is good on those days, and it's fine to pay a slight efficiency
hit on a freezing day because they aren't too common. (although Scandinavia
have those days a lot more and they use heatpumps everywhere).

> NB I did the maths and so did a consultant heating engineer. In general
> I found that for my very large rooms around 50W/sq meter was needed to
> keep them warm My mistake was in not putting in 100W/sq m and a 20kW
> boiler in order to warm the place up in less than 5 hours. I leave the
> UFH on 24x7 in winter. If I switch the heating on at all, which I
> probably wont do that often this winter.

OK, so 50W/m2 sounds reasonable. If you are trying to run it like a boiler
cycling it on for an hour at a time, that's not going to be very efficient
because the more output you demand from it, the higher the output flow temp,
and the higher the flow temp the less the efficiency.

> Modern homes constructed with 6+" of insulation and pressure tested with
> carefully controlled ventilation are obviously going to be better, but
> that home there was an old bay windowed Edwardian property, that has
> probably just got DG and cavity wall.
>
> Hence the need for such large radiators

My official heatloss calcs:
Design outside temp: -1.8C
Biggest room was the living room (22.5m2) at 1529W (2.5 outside walls and
a loft), 1960s, DG and cavity wall. The other rooms are smaller and less
lossy.

The existing rads were about the size of those in the video, but horizontal.
The replacements are roughly the same size but double convectors.

> The point being that older housing stock needs a lot of heating, and a
> ASHP running off what - a 30A circuit, probably around 7kW, and only
> having a 2:1 power uplift when air temps are around freezing, is going
> to struggle.

It should be OK, as long as you are keeping an even temperature and not
cycling it. It won't be able to move the temperature like a boiler does, I
agree. How much margin it has depends on how tightly the output is matched
to the heatloss (our heatloss was 5.15kW and they suggested a heatpump
specced for 9.6kW output, so plenty of margin)

> And will need a lot of radiator. Which is why UFH is far more
> effective. Floors are big radiators

UFH is a good idea, and should be standard in newbuilds IMHO.

Theo

On 10/27/2022 8:21 AM, Tim+ wrote:
> Tim Streater <timstreater@greenbee.net> wrote:
>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>
>
>>> Given the jury is out on whether fracking is economically viable in the
>>> UK, with unknown, perceived small amounts of methane from fracking, you
>>> haven't been keeping up, have you?
>>
>> The jury is out because research into it has been stymied. You say yourself
>> the amount of gas that might/might not be produced is unknown, so how about we
>> find out, eh? The Yanks seem to produce a lot.
>>
>
> Very different geology.
>
> https://www.ed.ac.uk/impact/opinion/uk-is-280-million-years-late-for-fracking-boom
>
> Tim

"In the UK, results from exploratory drilling were mostly bad.
The drilling triggered multiple small and several medium earthquakes."

Some spots in the USA, suffered on average, three small earthquakes
every day, while fracking was actively being carried out (production).
That's the reason those spots were shut down.

Others, did not have problems quite that bad, with the fracking
materials injected into the ground, causing the plates to slip.

It's the injected material that causes this, rather than just
drilling a hole.

Paul

Theo wrote:

>In terms of efficiency, the sub-zero days in the winter are relatively few.
>The days where it's single-digits positive outside are many. The heatpump
>efficiency is good on those days, and it's fine to pay a slight efficiency
>hit on a freezing day because they aren't too common. (although Scandinavia
>have those days a lot more and they use heatpumps everywhere).

I have worked in an office with air to air heat exchanger units
as the only heat source. They appeared to operate quite well
through the winter. There are defrost cycles, during which the
mode reverses, in order to melt frost on the external heat
exchanger. This means that the internal kit blows cool for a
while, but not to the extent that it compromised overall heating
performance, and they didn't all do this simultaneously. It might
be less acceptable in a smaller space.

How does it work with your type of system?

Chris
--
Chris J Dixon Nottingham UK
chris@cdixon.me.uk @ChrisJDixon1

Plant amazing Acers.

On 27/10/2022 16:42, SteveW wrote:
> On 27/10/2022 14:36, Fredxx wrote:
>> On 27/10/2022 13:21, Tim+ wrote:
>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>>>
>>>
>>>>> Given the jury is out on whether fracking is economically viable in
>>>>> the
>>>>> UK, with unknown, perceived small amounts of methane from fracking,
.....
Has anyone told you that in fact the whole point of fracking is to
extract enormous amounts of methane?

...
> It may well not be viable to extract it, but is that any reason to ban
> someone from trying? You never know, they may be proven right.
>
The reason to ban it is the fear that it might be successful,
profitable, completely safe, do wonders for the balance of payments,
increase energy security, reduce imports of Russian and middle eats gas
by undercutting them on price, generate a nice tax take, and generate
jobs in red wall seats that actually create wealth.

That simply cannot be allowed to happen if Britain is to be reduced to
economic ruin as a precursor to forcing it back into the EU.

No success please, We are Europeans....

--
Microsoft : the best reason to go to Linux that ever existed.

On 28/10/2022 08:15, Chris J Dixon wrote:
> Theo wrote:
>
>> In terms of efficiency, the sub-zero days in the winter are relatively few.
>> The days where it's single-digits positive outside are many. The heatpump
>> efficiency is good on those days, and it's fine to pay a slight efficiency
>> hit on a freezing day because they aren't too common. (although Scandinavia
>> have those days a lot more and they use heatpumps everywhere).
>
> I have worked in an office with air to air heat exchanger units
> as the only heat source. They appeared to operate quite well
> through the winter. There are defrost cycles, during which the
> mode reverses, in order to melt frost on the external heat
> exchanger. This means that the internal kit blows cool for a
> while, but not to the extent that it compromised overall heating
> performance, and they didn't all do this simultaneously. It might
> be less acceptable in a smaller space.
>
> How does it work with your type of system?

I don't think anyone is denying that ASAP can work well just that the
whole system needs to be designed correctly. In the original video I
linked the radiator size was physically 3x that of a comparable radiator
that designed to work on a 70C flow temperature. Bolt a ASHP to a
typical existing system and it's likely not to work too well.

The ASHP hype is that you can get it installed for less than £10K which
suggests just bolting it in as a replacement to a gas/oil boiler.

I note that building regulations (for new builds) are for central
heating systems with a flow temperature designed for 55C, or less.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 27/10/2022 17:11, Clive Arthur wrote:
> On 27/10/2022 14:37, Fredxx wrote:
>> On 27/10/2022 14:02, Clive Arthur wrote:
>>> On 27/10/2022 06:27, Alan wrote:
>>>
>>> <snip>
>>>
>>>> Well, its not though is it. He's probably quoting/mistaking the output
>>>> required to get the room from 5 degrees up to 20 degrees. Once it is
>>>> above 18 degrees, it will only need a small amount of power to reach 20
>>>> degrees, unless it is a very poorly insulated room, which is unlikely.
>>>> There is a lot of maths involved in getting the heat output correct
>>>> before fitting an ASHP, and if insulation is poor, that should be
>>>> pointed
>>>> out, so the ASHP and radiators can be sized correctly to heat the house
>>>> to the required temperature.
>>>
>>> I wonder how a gas powered heat pump would fare?  A gas ICE to both
>>> run the pump and top up the pumped heat.
>>
>> It would take low grade heat and convert it into higher grade heat +
>> bit more.
>>
>>
> Yes, what I meant was, how much better that a normal boiler while using
> the existing radiators, IOW how much of a saving in gas.
>
Probably huge, but it would make people ask the question 'why have
windmills then?' which isn't allowed...

--
"If you don’t read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

On 27/10/2022 17:45, Vir Campestris wrote:
> On 27/10/2022 16:42, SteveW wrote:
>> On 27/10/2022 14:36, Fredxx wrote:
>>> On 27/10/2022 13:21, Tim+ wrote:
>>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>>>>
>>>>
>>>>>> Given the jury is out on whether fracking is economically viable
>>>>>> in the
>>>>>> UK, with unknown, perceived small amounts of methane from
>>>>>> fracking, you
>>>>>> haven't been keeping up, have you?
>>>>>
>>>>> The jury is out because research into it has been stymied. You say
>>>>> yourself
>>>>> the amount of gas that might/might not be produced is unknown, so
>>>>> how about we
>>>>> find out, eh? The Yanks seem to produce a lot.
>>>>>
>>>>
>>>> Very different geology.
>>>>
>>>> https://www.ed.ac.uk/impact/opinion/uk-is-280-million-years-late-for-fracking-boom
>>>
>>> That was my take too. Some people aren't able to take a balanced view.
>>
>> It may well not be viable to extract it, but is that any reason to ban
>> someone from trying? You never know, they may be proven right.
>>
>
> Follow the links, and there may only be 10 years worth of gas.
>
OTOH there may be 100 years.

> Aren't we going to be fully renewable by 2030?
>
Not if we want to actually survive as a post industrial civilisation

> (BTW quoting a reprint of the article on ed.ac.uk is misleading; he
> seems to be in some kind of pressure group)
>
> Andy
>

--
"If you don’t read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

On 27/10/2022 18:09, alan_m wrote:
> On 27/10/2022 17:45, Vir Campestris wrote:
>
>
>
>> Follow the links, and there may only be 10 years worth of gas.
>>
>> Aren't we going to be fully renewable by 2030?
>
> So no plan B or C when the wind fails to blow in 2030?
>
> The 10 years of gas could help substantially with our balance of
> payments and give us a massive energy insurance policy.
>
That's why it must be banned.
A Successful Britain outside the EU is Not Allowed

--
"I am inclined to tell the truth and dislike people who lie consistently.
This makes me unfit for the company of people of a Left persuasion, and
all women"

On 27/10/2022 17:48, Vir Campestris wrote:
> On 27/10/2022 09:43, The Natural Philosopher wrote:
>>
>> Yup. 3.8 is rather optimistic and utterly infeasible at low air
>> temperatures*. Its likely to be half that at best when you need it the
>> most.
>>
>> And that is the killer. The colder it is the less the heat pump will
>> produce.
>>
>> The colder it is the more a nuclear power station  will produce.
>> The colder it is the less a solar power station  will produce.
>>
>> * "Your heat pump may not work as efficiently when the outdoor
>> temperature falls to below -5 ℃. When the temperature outside is
>> around 7 ℃, the average heat pump should have a CoP of around 4.5,
>> however this figure can drop to 2.3 when the temperature outside
>> decreases to -7 ℃"
>>
>> (
>> https://www.viessmann.co.uk/en/heating-advice/heat-pumps/what-temperature-is-a-heat-pump-not-effective.html )
>
> AIUI solar electricity panels quite like cold. The winter problem is
> that there's not much light, not the temperature.
>
Did I say otherwise? Unless you have bought into the climate change
narrative completely, what makes the world warm is not CO2, its solar
activity. So cold weather means low solar activity, by definition.

I assumed people would be smart enough to figure that out....

> Andy
>

--
"I am inclined to tell the truth and dislike people who lie consistently.
This makes me unfit for the company of people of a Left persuasion, and
all women"

On 27/10/2022 18:14, alan_m wrote:
> On 27/10/2022 17:41, Andrew wrote:
>> On 27/10/2022 08:53, The Natural Philosopher wrote:
>>
>>> Ground source is better, because the soil deep down is a fairly
>>> stable temperature source.
>>
>> Err, it won't be stable as you progressively suck the heat out.
>> Only light sandy soil will allow radiant heat from the sun to
>> warm it up quicker and to a greater depth but that is the
>> same soil type  that loses its heat quickly in winter,
>> naturally.
>
>
> Ground source works better but only if you have enough land for shallow
> burial of the pipes or you don't have lots of nearby neighbours all
> drilling bore holes in close proximity :)
>
>
Indeed. In the limit if you go deep it tends towards geothermal energy,
and you end up creating permafrost as the rate of winter heat extraction
overtakes the rate of summer replenishment.

--
"If you don’t read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

On 27/10/2022 22:06, Theo wrote:
> The Natural Philosopher <tnp@invalid.invalid> wrote:
>> I dont think you understand heat loss.

>> And will need a lot of radiator. Which is why UFH is far more
>> effective. Floors are big radiators
>
> UFH is a good idea, and should be standard in newbuilds IMHO.
>
It is, as are ASHPs. And wood burning stoves :-)

> Theo

--
"If you don’t read the news paper, you are un-informed. If you read the
news paper, you are mis-informed."

Mark Twain

On 28/10/2022 10:08, The Natural Philosopher wrote:
> On 27/10/2022 18:09, alan_m wrote:
>> On 27/10/2022 17:45, Vir Campestris wrote:
>>
>>
>>
>>> Follow the links, and there may only be 10 years worth of gas.
>>>
>>> Aren't we going to be fully renewable by 2030?
>>
>> So no plan B or C when the wind fails to blow in 2030?
>>
>> The 10 years of gas could help substantially with our balance of
>> payments and give us a massive energy insurance policy.
>>
> That's why it must be banned.
> A Successful Britain outside the EU is Not Allowed

Says who? John Major, Tony Bliar? I don't see anything of the sort.

If you kept up to date, the EU are suggesting reducing red tape for UK
import and exports.

If only you stopped being so emotional, and actually engaged some
thought before typing such tripe.

On 28/10/2022 10:07, The Natural Philosopher wrote:
> On 27/10/2022 17:45, Vir Campestris wrote:
>> On 27/10/2022 16:42, SteveW wrote:
>>> On 27/10/2022 14:36, Fredxx wrote:
>>>> On 27/10/2022 13:21, Tim+ wrote:
>>>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>>>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>>>>>
>>>>>
>>>>>>> Given the jury is out on whether fracking is economically viable
>>>>>>> in the
>>>>>>> UK, with unknown, perceived small amounts of methane from
>>>>>>> fracking, you
>>>>>>> haven't been keeping up, have you?
>>>>>>
>>>>>> The jury is out because research into it has been stymied. You say
>>>>>> yourself
>>>>>> the amount of gas that might/might not be produced is unknown, so
>>>>>> how about we
>>>>>> find out, eh? The Yanks seem to produce a lot.
>>>>>>
>>>>>
>>>>> Very different geology.
>>>>>
>>>>> https://www.ed.ac.uk/impact/opinion/uk-is-280-million-years-late-for-fracking-boom
>>>>
>>>> That was my take too. Some people aren't able to take a balanced view.
>>>
>>> It may well not be viable to extract it, but is that any reason to
>>> ban someone from trying? You never know, they may be proven right.
>>>
>>
>> Follow the links, and there may only be 10 years worth of gas.
>>
> OTOH there may be 100 years.

By all means provide a cite for such a claim. I know you want to but can't.

>> Aren't we going to be fully renewable by 2030?
>>
> Not if we want to actually survive as a post industrial civilisation

You're pretty much a lone voice, where most would say quite the opposite.

>> (BTW quoting a reprint of the article on ed.ac.uk is misleading; he
>> seems to be in some kind of pressure group)
>>
>> Andy
>>
>

On 28/10/2022 10:03, The Natural Philosopher wrote:
> On 27/10/2022 16:42, SteveW wrote:
>> On 27/10/2022 14:36, Fredxx wrote:
>>> On 27/10/2022 13:21, Tim+ wrote:
>>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>>>>
>>>>
>>>>>> Given the jury is out on whether fracking is economically viable
>>>>>> in the
>>>>>> UK, with unknown, perceived small amounts of methane from fracking,
> ....
> Has anyone told you that in fact the whole point of fracking is to
> extract enormous amounts of methane?

That is the intent, but it hasn't been very successful in the UK, has it?

>> It may well not be viable to extract it, but is that any reason to ban
>> someone from trying? You never know, they may be proven right.
>>
> The reason to ban it is the fear that it might be successful,
> profitable, completely safe, do wonders for the balance of payments,
> increase energy security, reduce imports of Russian and middle eats gas
> by undercutting them on price, generate a nice tax take,  and generate
> jobs in red wall seats that actually create wealth.

Once again your fanatical paranoia shows.

> That simply cannot be allowed to happen if Britain is to be reduced to
> economic ruin as a precursor to forcing it back into the EU.
>
> No success please, We are Europeans....

You've utterly lost it.

On 28/10/2022 10:13, The Natural Philosopher wrote:
> On 27/10/2022 18:14, alan_m wrote:
>> On 27/10/2022 17:41, Andrew wrote:
>>> On 27/10/2022 08:53, The Natural Philosopher wrote:
>>>
>>>> Ground source is better, because the soil deep down is a fairly
>>>> stable temperature source.
>>>
>>> Err, it won't be stable as you progressively suck the heat out.
>>> Only light sandy soil will allow radiant heat from the sun to
>>> warm it up quicker and to a greater depth but that is the
>>> same soil type  that loses its heat quickly in winter,
>>> naturally.
>>
>>
>> Ground source works better but only if you have enough land for
>> shallow burial of the pipes or you don't have lots of nearby
>> neighbours all drilling bore holes in close proximity :)
>>
>>
> Indeed. In the limit if you go deep it tends towards geothermal energy,
> and you end up creating permafrost as the rate of winter heat extraction
> overtakes the rate of summer replenishment.

Have you worked out how many kWhrs of sunlight goes into a modest sized
law in a year? And how many you might extract? And after several years
of operation what the ground temperature might be?

No, I didn't think so. I suspect it's beyond you and all you can voice
is false rhetoric. Trump would be proud of you.

On 28/10/2022 10:05, The Natural Philosopher wrote:
> On 27/10/2022 17:11, Clive Arthur wrote:
>> On 27/10/2022 14:37, Fredxx wrote:
>>> On 27/10/2022 14:02, Clive Arthur wrote:
>>>> On 27/10/2022 06:27, Alan wrote:
>>>>
>>>> <snip>
>>>>
>>>>> Well, its not though is it. He's probably quoting/mistaking the output
>>>>> required to get the room from 5 degrees up to 20 degrees. Once it is
>>>>> above 18 degrees, it will only need a small amount of power to
>>>>> reach 20
>>>>> degrees, unless it is a very poorly insulated room, which is unlikely.
>>>>> There is a lot of maths involved in getting the heat output correct
>>>>> before fitting an ASHP, and if insulation is poor, that should be
>>>>> pointed
>>>>> out, so the ASHP and radiators can be sized correctly to heat the
>>>>> house
>>>>> to the required temperature.
>>>>
>>>> I wonder how a gas powered heat pump would fare?  A gas ICE to both
>>>> run the pump and top up the pumped heat.
>>>
>>> It would take low grade heat and convert it into higher grade heat +
>>> bit more.
>>>
>>>
>> Yes, what I meant was, how much better that a normal boiler while
>> using the existing radiators, IOW how much of a saving in gas.
>>
> Probably huge, but it would make people ask the question 'why have
> windmills then?' which isn't allowed...

1) You've just said it.
2) To power ASHPs

On 28/10/2022 10:11, The Natural Philosopher wrote:
> On 27/10/2022 17:48, Vir Campestris wrote:
>> On 27/10/2022 09:43, The Natural Philosopher wrote:
>>>
>>> Yup. 3.8 is rather optimistic and utterly infeasible at low air
>>> temperatures*. Its likely to be half that at best when you need it
>>> the most.
>>>
>>> And that is the killer. The colder it is the less the heat pump will
>>> produce.
>>>
>>> The colder it is the more a nuclear power station  will produce.
>>> The colder it is the less a solar power station  will produce.
>>>
>>> * "Your heat pump may not work as efficiently when the outdoor
>>> temperature falls to below -5 ℃. When the temperature outside is
>>> around 7 ℃, the average heat pump should have a CoP of around 4.5,
>>> however this figure can drop to 2.3 when the temperature outside
>>> decreases to -7 ℃"
>>>
>>> (
>>> https://www.viessmann.co.uk/en/heating-advice/heat-pumps/what-temperature-is-a-heat-pump-not-effective.html )
>>
>> AIUI solar electricity panels quite like cold. The winter problem is
>> that there's not much light, not the temperature.
>>
> Did I say otherwise? Unless you have bought into the climate change
> narrative completely, what makes the world warm is not CO2

A typical art student belief who hasn't a clue about the greenhouse
effect and denial that CO2 is transparent to light but absorbs IR

> , its solar
> activity. So cold weather means low solar activity, by definition.
>
> I assumed people would be smart enough to figure that out....

You seem to assume many things, including a misunderstanding of the
greenhouse effect.

Chris J Dixon <chris@cdixon.me.uk> wrote:
> I have worked in an office with air to air heat exchanger units
> as the only heat source. They appeared to operate quite well
> through the winter. There are defrost cycles, during which the
> mode reverses, in order to melt frost on the external heat
> exchanger. This means that the internal kit blows cool for a
> while, but not to the extent that it compromised overall heating
> performance, and they didn't all do this simultaneously. It might
> be less acceptable in a smaller space.
>
> How does it work with your type of system?

Pretty similar. Because it's an air to water system, the wet side of it has
decent thermal mass. So you don't notice the defrost cycles because the
outdoor unit simply stops generating hot water for a while, just circulating
the existing water. There's enough volume in the heating loop to keep going
for a while as it does so. You don't notice the radiators going cold or
anything like that.

I can't say I've measured them, but I'd guess a defrost cycle might be a few
minutes an hour sort of frequency, on a freezing-fog kind of day.

Theo

On 28/10/2022 10:50, Fredxx wrote:
> On 28/10/2022 10:03, The Natural Philosopher wrote:
>> On 27/10/2022 16:42, SteveW wrote:
>>> On 27/10/2022 14:36, Fredxx wrote:
>>>> On 27/10/2022 13:21, Tim+ wrote:
>>>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>>>> On 27 Oct 2022 at 09:48:13 BST, Fredxx <fredxx@spam.uk> wrote:
>>>>>>
>>>>>
>>>>>>> Given the jury is out on whether fracking is economically viable
>>>>>>> in the
>>>>>>> UK, with unknown, perceived small amounts of methane from fracking,
>> ....
>> Has anyone told you that in fact the whole point of fracking is to
>> extract enormous amounts of methane?
>
> That is the intent, but it hasn't been very successful in the UK, has it?

No-one has actually been allowed to properly try it.

The one test well that was being drilled was stopped because it
exceeding the artifically low limits set for earth tremors (headlined by
the anti-frackers as Earthquakes), depite the surface effect being lower
than a passing truck! The limits were clearly set to ensure that
fracking would fail in the UK.

On 28/10/2022 10:54, Fredxx wrote:
> On 28/10/2022 10:13, The Natural Philosopher wrote:
>> On 27/10/2022 18:14, alan_m wrote:
>>> On 27/10/2022 17:41, Andrew wrote:
>>>> On 27/10/2022 08:53, The Natural Philosopher wrote:
>>>>
>>>>> Ground source is better, because the soil deep down is a fairly
>>>>> stable temperature source.
>>>>
>>>> Err, it won't be stable as you progressively suck the heat out.
>>>> Only light sandy soil will allow radiant heat from the sun to
>>>> warm it up quicker and to a greater depth but that is the
>>>> same soil type  that loses its heat quickly in winter,
>>>> naturally.
>>>
>>>
>>> Ground source works better but only if you have enough land for
>>> shallow burial of the pipes or you don't have lots of nearby
>>> neighbours all drilling bore holes in close proximity :)
>>>
>>>
>> Indeed. In the limit if you go deep it tends towards geothermal
>> energy, and you end up creating permafrost as the rate of winter heat
>> extraction overtakes the rate of summer replenishment.
>
> Have you worked out how many kWhrs of sunlight goes into a modest sized
> law in a year? And how many you might extract? And after several years
> of operation what the ground temperature might be?
>
> No, I didn't think so. I suspect it's beyond you and all you can voice
> is false rhetoric. Trump would be proud of you.

While I have not, I have seen articles stating that domestic GSHPs are
likely to exhaust their heat supply in as little as 50 years.

alan_m <junk@admac.myzen.co.uk> wrote:

> The ASHP hype is that you can get it installed for less than £10K which
> suggests just bolting it in as a replacement to a gas/oil boiler.

A few days ago we got a leaflet through the door telling us that British
Gas could install an ASHP for £4999. Some small print mentioned ‘depending
on what we need to do inside your home’ (or words to that effect). A
government grant of £5k was also mentioned.

The device shown was by Vaillant and the claim was it would last 20 years.

It would apparently be installed by a tattooed young lady from an ethnic
minority.

I chucked it in the bin.

> I note that building regulations (for new builds) are for central
> heating systems with a flow temperature designed for 55C, or less.

--
Spike

On 28/10/2022 13:12, SteveW wrote:
> On 28/10/2022 10:54, Fredxx wrote:
>> On 28/10/2022 10:13, The Natural Philosopher wrote:
>>> On 27/10/2022 18:14, alan_m wrote:
>>>> On 27/10/2022 17:41, Andrew wrote:
>>>>> On 27/10/2022 08:53, The Natural Philosopher wrote:
>>>>>
>>>>>> Ground source is better, because the soil deep down is a fairly
>>>>>> stable temperature source.
>>>>>
>>>>> Err, it won't be stable as you progressively suck the heat out.
>>>>> Only light sandy soil will allow radiant heat from the sun to
>>>>> warm it up quicker and to a greater depth but that is the
>>>>> same soil type  that loses its heat quickly in winter,
>>>>> naturally.
>>>>
>>>>
>>>> Ground source works better but only if you have enough land for
>>>> shallow burial of the pipes or you don't have lots of nearby
>>>> neighbours all drilling bore holes in close proximity :)
>>>>
>>>>
>>> Indeed. In the limit if you go deep it tends towards geothermal
>>> energy, and you end up creating permafrost as the rate of winter heat
>>> extraction overtakes the rate of summer replenishment.
>>
>> Have you worked out how many kWhrs of sunlight goes into a modest
>> sized law in a year? And how many you might extract? And after several
>> years of operation what the ground temperature might be?
>>
>> No, I didn't think so. I suspect it's beyond you and all you can voice
>> is false rhetoric. Trump would be proud of you.
>
> While I have not, I have seen articles stating that domestic GSHPs are
> likely to exhaust their heat supply in as little as 50 years.

I confess I haven't, but after a search this is the first one I saw with
real numbers and a reasonable study:
https://www.tandfonline.com/doi/full/10.1080/23744731.2019.1648130

This is only talking about interaction between boreholes that are deeper
than conventional horizontally laid pipes close to the surface but still
they claim:
"For example, the ground temperature at 20 m from the borehole of
the previous example decreases by around 0.4 K after 30 years and around
0.5 K after 100 years due to the borehole operation."

On 28/10/2022 13:35, Spike wrote:
> It would apparently be installed by a tattooed young lady from an ethnic
> minority.

ROFLMAO!

--
"Corbyn talks about equality, justice, opportunity, health care, peace,
community, compassion, investment, security, housing...."
"What kind of person is not interested in those things?"

"Jeremy Corbyn?"