Heat Pumps, the great deception?

[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?

I am familiar with the concept of absolute zero and there is no need to go into long explanations of basic engineering or science that I would have encountered many years ago.

Anyway I presume you are familiar with temperature gradients through solids. A simple yes or no will suffice.
Assuming you do understand that then I will explain how the heat from the earths core affects ground source heat systems.

 

[chris3234]

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!

The problem is with bricks houses like the UK air systems are very hard to Install as there no voids to install the ducts workhence why most people uses water radsa water pipe needs a lot lot space then duct work for direct air heating to every room


This is one of the main reasons most houses use that type of heating

 

[bugsymike]

The problem is with bricks houses like the UK air systems are very hard to Install as there no voids to install the ducts workhence why most people uses water radsa water pipe needs a lot lot space then duct work for direct air heating to every room


This is one of the main reasons most houses use that type of heating

As Chris says.
I had a customer whose brand new bungalow came with ducted electrically supplied hot air blown around. It proved very expensive to run and after a few years was causing breathing problems by blowing dust through the voids, so was replaced with gas central heating, much cleaner and more economical for the owner.

 

[vexorg]

Ok, "recharged" isn't the correct word, but in a fridge then the the air is "refreshed" by the cold air coming in and the hot air moving up and away on the kitchen (or wherever you keep it). Again, if there was no convection again and air trapped and sealed then it too would reach equilibrium and the fridge would not get cold.

Yes, you are right, it is energy flow, and and if the pipes are taking energy from the soil surrounding the pipe then that energy needs replaced to keep the soil warm (relative term) otherwise there's no energy transfer.

The point is, if you are saying that there's no solar effect (winter, snow, whatever) then these horizontal pipes can only get heat from below (relative again energy equals heat here), and all the energy is geothermal from below. And I have my doubt about how much geothermal energy you'd get from 1m down.

 

[Cornish Ian]

Ok, "recharged" isn't the correct word, but in a fridge then the the air is "refreshed" by the cold air coming in and the hot air moving up and away on the kitchen (or wherever you keep it). Again, if there was no convection again and air trapped and sealed then it too would reach equilibrium and the fridge would not get cold.

Yes, you are right, it is energy flow, and and if the pipes are taking energy from the soil surrounding the pipe then that energy needs replaced to keep the soil warm (relative term) otherwise there's no energy transfer.

The point is, if you are saying that there's no solar effect (winter, snow, whatever) then these horizontal pipes can only get heat from below (relative again energy equals heat here), and all the energy is geothermal from below. And I have my doubt about how much geothermal energy you'd get from 1m down.

I hope you didn’t mind me translating to Andy what I believe you meant. I got that you meant the air was heated by the condenser and moved away by convection. Same with the heat flow “direction “
I thought Andy misunderstood and his answering post was a bit uncalled for so that’s why I suggested he reread your post.

 

[AndyRKett]

Anyway I presume you are familiar with temperature gradients through solids. A simple yes or no will suffice.
Assuming you do understand that then I will explain how the heat from the earths core affects ground source heat systems.

Yep you go and explain how the heat from the earths core affects ground source heat systems and that will sum up nicely the argument ‘I have been making all along….

Again, they do not need or rely on the sun to “recharge’ the ground

 

[Cornish Ian]

Yep you go and explain how the heat from the earths core affects ground source heat systems and that will sum up nicely the argument ‘I have been making all along….

Again, they do not need or rely on the sun to “recharge’ the ground

Ok. I think we both agree that the bore hole systems are fed from geothermal.

Now the horizontal systems, no snow involved just bare ground as mainly in the uk
Temperature rise per depth is in the order of 2.5 to 3 deg C per 100 metres, this rise is fed from the core
So as a rough approximation the temperature of last 10 metres near the surface would be raised 10% of that. ie 0.25 deg by geo.
While I was searching for a better graph I found this on Wikipedia which makes it easier.
0.087W per sq metre from the core over a 600 square metre array (10KW system) works out to be about 52Watts from geothermal.
The graph is obviously taken from somewhere with a hot summer but it demonstrates how the sun heats the ground.

 

[AndyRKett]

Ok. I think we both agree that the bore hole systems are fed from geothermal.
Now the horizontal systems.
Temperature rise per depth is in the order of 2.5 to 3 deg C per 100 metres, this rise is fed from the core
So as a rough approximation the temperature of last 10 metres near the surface would be raised 10% of that. ie 0.25 deg

See all previous comments try to understand them, the scientific and engineering principles that you claim to have encountered years ago. This may help you understand.

Maybe go back and read the links you clipped your screen shots from as well, they explain what I am explaining if you don’t pick and choose what you want from them.

 

[Cornish Ian]

See all previous comments try to understand them, the scientific and engineering principles that you claim to have encountered years ago. This may help you understand.

Maybe go back and read the links you clipped your screen shots from as well, they explain what I am explaining if you don’t pick and choose what you want from them.

I touched the post button accidentally Andy so you obviously only replied to half my post, apologies for that.
Wikipedia does give the average geothermal energy reaching the surface 0.087 watts per square metre and that works out at 52Watts for a typical ground array size. 0.03 percent of solar power I believe it says.
Over the continental crust it’s 0.065 watts per square metre (65 mW) which is even less at around 40W

 

[chris3234]

Ok, "recharged" isn't the correct word, but in a fridge then the the air is "refreshed" by the cold air coming in and the hot air moving up and away on the kitchen (or wherever you keep it). Again, if there was no convection again and air trapped and sealed then it too would reach equilibrium and the fridge would not get cold.

Yes, you are right, it is energy flow, and and if the pipes are taking energy from the soil surrounding the pipe then that energy needs replaced to keep the soil warm (relative term) otherwise there's no energy transfer.

The point is, if you are saying that there's no solar effect (winter, snow, whatever) then these horizontal pipes can only get heat from below (relative again energy equals heat here), and all the energy is geothermal from below. And I have my doubt about how much geothermal energy you'd get from 1m down.

No just below all-around the area covers by a ground source system is tiny vs the total volume of soil

 

[AndyRKett]

I touched the post button accidentally Andy so you obviously only replied to half my post, apologies for that.
Wikipedia does give the average geothermal energy reaching the surface 0.087 watts per square metre and that works out at 52Watts for a typical ground array size. 0.03 percent of solar power I believe it says.
Over the continental crust it’s 0.065 watts per square metre (65 mW) which is even less at around 40W

[bangs head against wall because he still doesn’t get it]

 

[Cornish Ian]

[bangs head against wall because he still doesn’t get it]

I think I’ve explained it well enough. For the area of a 10 kw horizontal array 40W is provided by geothermal and the remainder by solar. The Geo and solar energy are both stored in the surrounding block of ground several metres deep and similar width to be used when needed. Should be simple enough.
Thats why the installers say it’s from solar.

 

[Cornish Ian]

Two sections from Wikipedia Ground source heat pumps that may be of interest to someone.

 

[chris3234]

No way the sun provided 9.6kw to the soil again how would this work with months of snow cover?



Now I'm sure some heat does come from the sun but 9.6kwh would be. A lot of heat to be taking out the soil through the winter and probably more then you'd get with the same size solar array in the uk

I think I’ve explained it well enough. For the area of a 10 kw horizontal array 40W is provided by geothermal and the remainder by solar. The Geo and solar energy are both stored in the surrounding block of ground several metres deep and similar width to be used when needed. Should be simple enough.
Thats why the installers say it’s from solar.

 

[Cornish Ian]

No way the sun provided 9.6kw to the soil again how would this work with months of snow cover?

Those figures are for open ground not for somewhere where there is months of snow cover.
I used the figures from Wikipedia 8 or so posts back. Have a look and check my calculations if you wish. I used 600 square metres for the array size.
It gets a bit more complicated with snow cover obviously but I expect the geo energy would be more significant in that case.

 

[AndyRKett]

No way the sun provided 9.6kw to the soil again how would this work with months of snow cover?



Now I'm sure some heat does come from the sun but 9.6kwh would be. A lot of heat to be taking out the soil through the winter and probably more then you'd get with the same size solar array in the uk

Because he literally has no comprehension of how these systems work.

For the area of a 10 kw horizontal array 40W is provided by geothermal and the remainder by solar.

We don't measure heat energy in KW.

Where are you getting the 10KW figure from?

Also how much heat energy is the sun depositing in the ground throughout the day in the middle of winter, versus how much energy the heat pump is extracting from the ground ?

 

[Cornish Ian]

Because he literally has no comprehension of how these systems work.


We don't measure heat energy in KW.

Where are you getting the 10KW figure from?

Also how much heat energy is the sun depositing in the ground throughout the day in the middle of winter, versus how much energy the heat pump is extracting from the ground ?

10kw is the output of a typical horizontal array 600 square metres surface area.
That’s the area I used to calculate the input from geo thermal.
The sun would normally deposit less in the winter than is being extracted but because there is a big block of ground storing heat deposited in the summer then there is plenty of energy available. Have a look back at the graph for the ground temperatures over a year, or read what Wikipedia mentions about it. There is a screen shot of the relevant information a few posts back.

 

[AndyRKett]

10kw is the output of a typical horizontal array 600 square metres surface area.

So are you saying that the Sun is putting 10KW of heat into the ground when the sun is shining for A 600sqM area?

Or have you just taken a 10KW system and somewhere it’s posted that it needs a 600sqM area for pipe work?

 

[AndyRKett]

https://www.vaillant.co.uk/downloads/aproducts/renewables-1/flexotherm/flexotherm-230-v-tech-spec-1-2-web-1057063.pdf

This is a data sheet for a valiant set of heat pumps

If you look at the 11Kw system you’ll see that it is made up of a compressor that uses a maximum of 4.1KW and an additional electric heater which is 5.5KW do a bit of maths around the current use, the rest of the electronics uses another ~2Kw That’s where the 11KW comes from it is the energy the actual heat pump uses, that is not the energy it is extracting from the ground

 

[Cornish Ian]

So are you saying that the Sun is putting 10KW of heat into the ground when the sun is shining for A 600sqM area?

Or have you just taken a 10KW system and somewhere it’s posted that it needs a 600sqM area for pipe work?

The second, a 10 kW system would need something like 600 square metres of collector depending on the ground.

Some years ago we installed a 11kW system on top of a big bank about 12 metres thick made of loose stone with lots of air gaps between the stones, so fairly well insulated from any solid ground.
We spread a layer of soil, some sand, then laid the pipes in about 1000 tonnes of waste peat followed by a decent layer of soil to make a lawn. Probably not much more than 2.5 metres perhaps 3 at most above the stone but there was a few thousand tonnes tonnes of soil and the peat so it had a decent sized accumulator. (Peat is ideal as it stays damp and so conducts heat well.)
The system definitely worked very well for 7 or so years and is still doing so as far as I know.