Heat Pumps, the great deception?

[Cornish Ian]

So again How does this explain the fact places with massive snow cover for long periods of the year still can use ground source heating? Snow can reflect 90% of solar radiation so how is the sun going to heat the soil back up?


Then there places with weeks and months of darkness's like Alaska with zero sunlight but again the system still works?

Once you get below the very top layers of soil the sun will provide all most no effect on soil temps

Remember there are two different ground source heat systems that have different heat sources.
The vertical borehole type which take heat from the rocks at depths circa 100 metres so will take heat from the surrounding rocks and ultimately the earths core so the sun has no input to these.
The other is the cheaper to install horizontal type that take heat from closer to the surface and this is the type that makes use of solar radiation.
The cold climate housing research centre ( Fairbanks Alaska ? ) are looking at this horizontal type with the possibility of restoring ground temperature by pumping surplus heat back in the summer. They are hoping this can be achieved by reverse feeding heat into the ground pipes collected from an array of solar collectors mounted on a buildings roof.

 

[Cornish Ian]

Would you believe that a small house can be heated with a heat pump which only draws 0,8 - 1 kWh of energy? It also dries the indoor air, filters it and keeps it nice and warm. All other electric heaters can be shutdown. Each heater draws 0,6 kwh-1 kwh of energy already, so there's great savings for those who use electricity to heat the house. No conspiracy there either. They're just that great, even here in Finland where the outdoor temperature can range 20 degrees C during one day.

Other issue is the new EC directive for building's energy efficiency. I can see conspiracy there. Be glad that you in the UK are not part of this madness. However I believe that Italy and other southern countries aren't going to implement the changes. Here they're even talking about tearing down the walls to add more insulation to the already thick walls, otherwise whole building would need to be demolished.

That sounds like the passive house system that we planned to use for an accommodation block. Very thick insulation, good quality tight fitting windows, pretty much an airtight system with heat recovery from the ventilation system.
Air source heat pump to top up any losses?
We had a supply problem with the heat recovery and air source heat system so in the end we side stepped that and went for a more basic wet underfloor heating system.

 

[vexorg]

So again How does this explain the fact places with massive snow cover for long periods of the year still can use ground source heating? Snow can reflect 90% of solar radiation so how is the sun going to heat the soil back up?

And there are only two options that I've seen available, deep bore vertical around 50m to 150m, and for horizontal surface type about 1m deep.

The problem with the horizontal seems to be the total area needed. If depth is not an issue, then why not layer it, pipes a 1m, 2m, 3m, 4m, etc, then you need a much smaller top surface area?

 

[porta]

So ground source heat pumps DO work, but only if fitted right and you have the space…however air source heat pumps, in this country, the ones supported by this inept g’ment, are sadly useless

Man facing £7k a year energy bills wants to 'rip out' government-backed heat pump that's 'left home cold' — Manchester Evening News

Steve Mason forked out thousands of pounds on the heat pump system that has been championed by government ministers

apple.news

“Based on the same technology as refrigerators, the air pump pulls heat out from outside air and into the house, and can be run on renewably generated electricity - making them carbon neutral. However with the highest electricity prices, the least insulated homes in Europe and the apparent inefficiency in colder temperatures, early adopters are counting the cost of going green.”

 

[Cornish Ian]

And there are only two options that I've seen available, deep bore vertical around 50m to 150m, and for horizontal surface type about 1m deep.

The problem with the horizontal seems to be the total area needed. If depth is not an issue, then why not layer it, pipes a 1m, 2m, 3m, 4m, etc, then you need a much smaller top surface area?

A bit of creative thinking there. However pipes would all be drawing on the same block of ground that acts as the accumulator so there might :be a danger of the centre of the block getting a bit too cold towards the end of the winter and perhaps reducing efficiency. Who knows.
The biggest problem if you have restricted space is what would you do with the 1000+ tonnes of ground while you install the first layer of pipes.
Probably easier, cheaper and safer to go for a borehole system though if space is tight which is the conventional wisdom.

 

[vexorg]

A bit of creative thinking there. However pipes would all be drawing on the same block of ground that acts as the accumulator so there might :be a danger of the centre of the block getting a bit too cold towards the end of the winter and perhaps reducing efficiency. Who knows.

Does that also mean you can can only have 1 bore hole, since multiple bore holes would have similar issues of interaction between them affecting the thermal flow back into the soil.

 

[Cornish Ian]

Does that also mean you can can only have 1 bore hole, since multiple bore holes would have similar issues of interaction between them affecting the thermal flow back into the soil.

I believe 6 to 8 metres apart is the minimum spacing for that reason.

 

[AndyRKett]

For those thinking the ground needs “recharging” as the analogy of a fridge has been posted above, consider that a fridge or freezer runs largely continuously and despite the inside of the fridge or freezer sitting somewhere between -5 °c to +5°c they still pump heat out the back and the back of the unit will still always be warm.

Even ground at -10°C contains energy that a heat pump can take advantage of, which is why they work in very cold climates and locations, it is just the colder your heat source the more energy the pump needs to work, exactly the same as the hotter the day the more energy/fuel is needed by a car to run the air conditioning

This is why we have the condenser in front of the radiator in cars because the aircon is more efficient if the gasses are cooled down further by the airflow

 

[vexorg]

For those thinking the ground needs “recharging” as the analogy of a fridge has been posted above, consider that a fridge or freezer runs largely continuously and despite the inside of the fridge or freezer sitting somewhere between -5 °c to +5°c they still pump heat out the back and the back of the unit will still always be warm.

There's airflow behind the fridge/freezer, it will dissapate into the large ambient and the cooling power required is very low due to the insulation and size. 24 to 48hours for an avaerage fridge/freezer to get to operational level.

The air around the condenser is being recharged by convection, and the energy flow is different, you are getting rid of energy rather than pull it from the sourrounding. If you are cooling the surrounding earth with the pipes then there must be some thermal energy flow back to replace than energy otherwise the pipes will be at equilibrium with the soil and you'll be stuck. If not then the soil has infinite thermal capacity and we're looking at free power.

 

[OrGazM]

SOOO much miss information floating around in UK.

In Norway (where I now live, after deserting "Yarksheer" 16 years ago, almost all houses outside the cities use Air to Air heatpumps.
OK, you also need a hot water "boiler", and that is a 200 litre, well insulated, 2kW unit. (So well insulated, that we turned the electric off to it for a 4 week trip to UK, and when we got home, water was still at 55C.....it's set to the 65C MINIMUM, to avoid bacteria!)

Our house is all wood framed.
"Fir-tommer-fir-tommer" (4x4") frame.
NO insulation, just the air-gap.
Wood panels inside and timber "lapping" outside (but with an aluminium skin, as my wife's (long dead) father didn't want to have to paint the wood every 2 years!
NOT an "old house" by UK standards, but it was built CA 1935
Basement is half underground (sloping land, up to a mountain), and concrete.
Ground area is 12m x 10m.
Basement, 2 floors and a loft.

Strangely, apart from underfloor heating in the toilet/shower room, 2 x 1.5kW AIR-AIR heatpumps can keep every room we use at a VERY comfortable 23C.
OK....if you close the doors to unused rooms, they rely on simply conducted heat....but even the basement (with NO heating) is a reasonable 15C when it's -20C outside.

The WHOLE problem UK has is....they want to keep the Victorian style water radiators!

Yeah, the internal "hot air blower" is NOT silent....but it's damn quieter than the PC I have at the side of me as I type this!

BIG BONUS!!!!
When (IF) summer comes along, another setting on the remote makes it COOL the house.
30C in the sun, a VERY nice 18C indoors.
Try getting that with your old water heating systems!

 

[AndyRKett]

There's airflow behind the fridge/freezer, it will dissapate into the large ambient and the cooling power required is very low due to the insulation and size. 24 to 48hours for an avaerage fridge/freezer to get to operational level.

The air around the condenser is being recharged by convection, and the energy flow is different, you are getting rid of energy rather than pull it from the sourrounding. If you are cooling the surrounding earth with the pipes then there must be some thermal energy flow back to replace than energy otherwise the pipes will be at equilibrium with the soil and you'll be stuck. If not then the soil has infinite thermal capacity and we're looking at free power.

This highlights the problem which is you're not understanding how a heat pump works.

The condenser in a fridge is generating the heat it is not being "recharged" the fridge works the same way as a heat pump they all just heat pumps.

In the fridge analogy the ground is the inside of the fridge and the back of the fridge is inside the house.

So while the fridge is highly insulated and cold inside, heat still gets into the fridge and the temperature will go up and the compressor needs to work to bring the temperature back down again.

The fridge doesn't just get colder and colder till it reaches absolute zero, it sits at a 5'C or what ever the chosen inside temperature is. However the back of the fridge is much hotter than the surrounding air because while the heat energy is being removed from inside the fridge, some additional energy gets added by the compressor.

You need to stop thinking about it as hot and cold, you need to start thinking about it as energy.

You also need to consider that energy moves only in one direction which is from a higher to a lower energy state - so the heat moves into the cold.

In the ground it is the heat from the ground moving into the cold pipes the pipes to not make the ground cold, the ground warms the pipes up. if the energy wasn't there then it would not warm the pipes and the system would stop working, for there not to be energy in the ground it would need to be at absolute zero -273'C

If there is not enough energy in the ground then the system is less efficient and more energy needs to be added from the pump, but there is no situation where the system would just stop working because the ground was cold.

This gets very complicated but its not regulated by electronics its regulated by the pressure of whatever you are compressing and how that pressure changes round the system.

The working of a fridge or freezer is exactly the same, just one gets colder than the other, that's managed by changing the pressures in the system.

The more efficient system extracts more energy from the ground so if you are making the ground really cold and not needing to add as much energy from the pump you have a more efficient system.

 

[porta]

I can attest to ground source, my mate had one (bore type) fitted wehn carrying out a barn refurb. This system has an integral air source pump/heat exchanger which keeps fresh air circulating and works as a further heater or cooler dependent on personal input (cooler or hotter) or set to maintain a temperature. He also has solar collector and PV panels which also work with the systems…I should say, he’s not short of a bob or too, (I think I could have bought a terrace house for what he paid for the whole), but he is trying to be green, despite a penchant for big Audis and classic VWs
It wasn’t cheap but it runs underfloor heating throughout and supplies heated water into a big insulated tank.

 

[Cornish Ian]

This highlights the problem which is you're not understanding how a heat pump works.

The condenser in a fridge is generating the heat it is not being "recharged" the fridge works the same way as a heat pump they all just heat pumps.

In the fridge analogy the ground is the inside of the fridge and the back of the fridge is inside the house.

So while the fridge is highly insulated and cold inside, heat still gets into the fridge and the temperature will go up and the compressor needs to work to bring the temperature back down again.

The fridge doesn't just get colder and colder till it reaches absolute zero, it sits at a 5'C or what ever the chosen inside temperature is. However the back of the fridge is much hotter than the surrounding air because while the heat energy is being removed from inside the fridge, some additional energy gets added by the compressor.

You need to stop thinking about it as hot and cold, you need to start thinking about it as energy.

You also need to consider that energy moves only in one direction which is from a higher to a lower energy state - so the heat moves into the cold.

In the ground it is the heat from the ground moving into the cold pipes the pipes to not make the ground cold, the ground warms the pipes up. if the energy wasn't there then it would not warm the pipes and the system would stop working, for there not to be energy in the ground it would need to be at absolute zero -273'C

If there is not enough energy in the ground then the system is less efficient and more energy needs to be added from the pump, but there is no situation where the system would just stop working because the ground was cold.

This gets very complicated but its not regulated by electronics its regulated by the pressure of whatever you are compressing and how that pressure changes round the system.

The working of a fridge or freezer is exactly the same, just one gets colder than the other, that's managed by changing the pressures in the system.

The more efficient system extracts more energy from the ground so if you are making the ground really cold and not needing to add as much energy from the pump you have a more efficient system.

Andy, perhaps you should reread vexorg’s post and try to understand what he’s getting at.

 

[AndyRKett]

Andy, perhaps you should reread vexorg’s post and try to understand what he’s getting at.

Shall we take a look Ian !!!

The air around the condenser is being recharged by convection, and the energy flow is different, you are getting rid of energy rather than pull it from the sourrounding.

So lets apply this to a fridge.

The condenser is the bit set of pipes on the back of a fridge. What he is saying that the condenser is recharged by convection?

@Cornish Ian explain to me how an already hot element is being "Recharged" ?? this is fundamentally incorrect.

Then there is the comment about how the flow of energy is different.....Yet the energy in a fridge is flowing from the inside of the fridge and being put on the outside cooling down the inside.
In a heat pump the heat from the ground is being pumped into the house cooling down the ground (if you want to look at it in terms of cooling) so the energy flow is no different at all.

All heat pumps work in exactly the same way and a fridge, freezer, aircon, are all heat pumps.
So again this is incorrect.

If you are cooling the surrounding earth with the pipes then there must be some thermal energy flow back to replace than energy otherwise the pipes will be at equilibrium with the soil and you'll be stuck. If not then the soil has infinite thermal capacity and we're looking at free power.

@Cornish Ian I will address this point once you acknowledge and explain how the ground in places where the sun doesn't reach which are buried under feet of snow, still have ground temperatures of about ~15'C
So far you keep ignoring this fact because it doesn't fit your narrative of the Sun warming the ground

 

[Cornish Ian]

Shall we take a look Ian !!!

So lets apply this to a fridge.

The condenser is the bit set of pipes on the back of a fridge. What he is saying that the condenser is recharged by convection?

@Cornish Ian explain to me how an already hot element is being "Recharged" ?? this is fundamentally incorrect.

Then there is the comment about how the flow of energy is different.....Yet the energy in a fridge is flowing from the inside of the fridge and being put on the outside cooling down the inside.
In a heat pump the heat from the ground is being pumped into the house cooling down the ground (if you want to look at it in terms of cooling) so the energy flow is no different at all.

All heat pumps work in exactly the same way and a fridge, freezer, aircon, are all heat pumps.
So again this is incorrect.




@Cornish Ian I will address this point once you acknowledge and explain how the ground in places where the sun doesn't reach which are buried under feet of snow, still have ground temperatures of about ~15'C
So far you keep ignoring this fact because it doesn't fit your narrative of the Sun warming the ground

1.He is referring to the air being warmed by the condenser then rising / being replaced by convection or recharged as he put it.

2.“different” as in a different or opposite direction

3. @15 deg. I’m not sure where you we’re referring to but assuming that’s correct then obviously if the sun is not warming the ground then the heat / energy must be coming from below, a bit like a borehole system that takes its heat from the surrounding rocks and ultimately the earths molten core. Snow is insulating the ground and so the heat is not escaping into the atmosphere.
This is a very different situation from clear ground such as in the uk so I don’t see any relevance to our discussion.

 

[OrGazM]

Just use air to air!

I don't give a sh*t WHERE the heat is coming from, but the INSIDE of our NON insulated, wood house is at a very nice 23C.
Current temp (according to my outside thermometer, is now at -12.5C.
Only ONE (the downstairs) heatpump is currently running, I know this as my PC chair is less than a metre from it, and the fans in my PC make almost as much noise as the blower does anyway.
That's 1.5kW of electric, producing 6.5kW (equivalent) of heating!
It HAS been down to -23C here overnight (outside), but we get up to a house that has never been less than 22C inside.
That is apart from the bedroom.....we have NO heating in there, and we close the door.
Average temp in winter is about 15C...VERY comfortable to sleep in with a good duvet, but we do have another system for the bed.
It uses Peltier devices to heat or cool a water flow system that is no thicker than the electric cables in the old style heated blankets.
Advantage is......my wife likes her side at 40C, I have mine at 24C,
Gonna be GREAT if we get another "tropical summer".....I can set mine down to 15C if I want.

The major problem in UK is.....people are hooked on Victorian designed systems.....water running through pipes and metal panels....SO inefficient.
Go air to air and and a press of a button, you get aircon for summer.
Can also be used to de-humidify, which I read is a major problem in old blighty.
Not here....we ALWAYS have 1 downstairs window cracked open, and one upstairs....guess what?
Warm, damp air goes out the top window, fresh air comes in the bottom.

It's about time UK people realised that if you exclude airflow, yez gonna get damp forming!

 

[OrGazM]

There's airflow behind the fridge/freezer, it will dissapate into the large ambient and the cooling power required is very low due to the insulation and size. 24 to 48hours for an avaerage fridge/freezer to get to operational level.

You must have an very poor fridge/freezer, or poor location!
Our Samsung double was installed, and the fridge was down to 4C in an hour, and the freezer only took 3 hours to get to -20.
After that, we started transferring food into it.
Even the 5 feet wide chest freezer in the basement only took 6 hours to hit the -20C on the thermometer I had inside it.

ONE thing I don't understand is;
They say you shouldn't install a chest freezer in an outside garage, as it be LESS efficient....?

 

[AndyRKett]

1.He is referring to the air being warmed by the condenser then rising / being replaced by convection or recharged as he put it.

2.“different” as in a different or opposite direction

3. @15 deg. I’m not sure where you we’re referring to but assuming that’s correct then obviously if the sun is not warming the ground then the heat / energy must be coming from below, a bit like a borehole system that takes its heat from the surrounding rocks and ultimately the earths molten core. Snow is insulating the ground and so the heat is not escaping into the atmosphere.
This is a very different situation from clear ground such as in the uk so I don’t see any relevance to our discussion.

As i expected you’re twisting things to suite your narrative.

1. If air is being warmed by the condenser is rising that is convection (warm ait rising) I have no idea what you mean by “replaced by convection” but the only thing being “charged’ is the air, as it is being charged with heat from the condenser, there is no “charge’ going into the heat pump system in this case the fridge

2. but its not going in a different direction, it is just a different application of a heat pumping system. Take the heat from point A and move it to point B. A fridge still heats.

3.

sun is not warming the ground then the heat / energy must be coming from below,

yep, the point i keep making over and over again.

Snow is insulating the ground and so the heat is not escaping into the atmosphere.
This is a very different situation from clear ground such as in the uk so I don’t see any relevance to our discussion.

The snow does not “insulate” the ground.
In your model if all the heat came from the sun and the If the snow on the ground insulated the ground from getting warm then there would be no heat in the ground at all ever.
So that cannot be the case.

If the snow insulated the ground keeping the ground heat in, then the snow would melt rapidly and not settle as the ground would always be significantly above the freezing point of water. What actually happens and your graph proves this is that the cold athmospthere and the snow does cause the ground to get cold, leading to permafrost. The point that the temperatures start to tip above 0’C can be a couple of feet down In very cold regions well below the “insulating” snow.

The other misconceptions are caused by the way we measure temperature, we say -40’C and we think thats really cold it’s a negative number and therefore it must be taking energy away.
When we start using more scientific ways of measuring temperature -40’c is 313Kelvin which now suddenly seems quite warm compared with zero Kelvin So there is a lot more energy in 313Kelvin than there is in Zero kelvin? same as there is a lot more energy in -40’c than their is in -273.15’C

So once again a ground source as well as any other heat pump does rely on heat from the sun, recharging the ground, the ground is always warm/contains energy (especially if you consider kelvin measurements) even where the sun don’t shine and the ground surface is always frozen.

If the pipes are near the surface and its the middle of summer heating the surface… sure the ground source heat pump will work better and more efficiently than in the winter, but who is running their heat in the summer?

 

[AndyRKett]

ONE thing I don't understand is;
They say you shouldn't install a chest freezer in an outside garage, as it be LESS efficient....?

really what ultimately makes a heat pump work is the changes in pressure.
Compression makes things hot and expansion makes things cold and if you’re already close to the temperature you want to reach there is less change in pressure and therefore less expansion in the refrigerant, the less the refrigerant expands the less it will cool down. A fridge or freezer will be designed to work at normal room temperature best, so rely on the compressed refrigerant being at about 20°C as it enters the expansion valve. if this is colder than the gas will not expand so dramatically, and you’ll get less of a cooling effect.

the compressor is also designed to pump a gas so if it’s already very cold then the gas becomes more dense and harder to compress so this adds further inefficiency into the system.

 

[Cornish Ian]

As i expected you’re twisting things to suite your narrative.

1. If air is being warmed by the condenser is rising that is convection (warm ait rising) I have no idea what you mean by “replaced by convection” but the only thing being “charged’ is the air, as it is being charged with heat from the condenser, there is no “charge’ going into the heat pump system in this case the fridge

2. but its not going in a different direction, it is just a different application of a heat pumping system. Take the heat from point A and move it to point B. A fridge still heats.

3.

yep, the point i keep making over and over again.

The snow does not “insulate” the ground.
In your model if all the heat came from the sun and the If the snow on the ground insulated the ground from getting warm then there would be no heat in the ground at all ever.
So that cannot be the case.

If the snow insulated the ground keeping the ground heat in, then the snow would melt rapidly and not settle as the ground would always be significantly above the freezing point of water. What actually happens and your graph proves this is that the cold athmospthere and the snow does cause the ground to get cold, leading to permafrost. The point that the temperatures start to tip above 0’C can be a couple of feet down In very cold regions well below the “insulating” snow.

The other misconceptions are caused by the way we measure temperature, we say -40’C and we think thats really cold it’s a negative number and therefore it must be taking energy away.
When we start using more scientific ways of measuring temperature -40’c is 313Kelvin which now suddenly seems quite warm compared with zero Kelvin So there is a lot more energy in 313Kelvin than there is in Zero kelvin? same as there is a lot more energy in -40’c than their is in -273.15’C

So once again a ground source as well as any other heat pump does rely on heat from the sun, recharging the ground, the ground is always warm/contains energy (especially if you consider kelvin measurements) even where the sun don’t shine and the ground surface is always frozen.

If the pipes are near the surface and its the middle of summer heating the surface… sure the ground source heat pump will work better and more efficiently than in the winter, but who is running their heat in the summer?

You were up late Andy.
On points 1 and 2 I was just explaining what I believe vexorg meant by his comments. Nothing to do with my narrative.
Perhaps if he sees this he could clarify what he meant.