Heat Pumps, the great deception?

[porta]

If that was true then countrys with long snow cover would get almost no heat into the soil through the winter as the snow would reflect most of the sunlight

Snow is a good insulator, a bit like an oxymoron, it’s certainly counterintuitive

 

[Cornish Ian]

Think about going to the beech on a hot summer's day. Yes the sand will be hot on the surface but dig less than a foot down and sand quickly becomes cold. Soil is the same, dig down a foot or two and you'll find the temperature is much colder. This soil temperature a few feet down doesn't change much, in the height of summer or the middle of winter the temperature of the soil only a short distance from the surface remains largely the same temperature.

If the Sun warming the soil was how these system's worked then they would be terrible in the winter when you want them to work and brilliant at heating your house in the summer when you don't want them. Also these systems can work in reverse to cool your house in the summer, so you don't want to be trying to expel heat energy from the house into hot earth on warm summer's days.

These systems work like air-conditioning. They use a compressor to compress a liquid or gas, when you compress liquids and gasses they get hotter and increase in pressure. When you drop the pressure, you loose heat. So the compressor pushed the compressed hot fluid into the house. It then radiates the thermal energy into the house and looses pressure. The now cold fluid runs into the ground, heated buy ground temperature, to return to a normal temp, then the compressor warms it up again.

In a car air conditioning system the "house" would be the condenser under the bonnet, and the ground outside would be the evaporator in the cabin. condenser gets hot, cabin gets cold.

It doesn't matter how deep you go with the pipes because its the constant temperature you want. If the system was reliant in anyway from the heat of the sun then it wouldn't work at all on an over cast day or in the middle of the winter when the ground is frozen or covered in snow.
The pipes laid out across the garden is "easier" because you don't need a hole boring machine and ground survey to install the system, just bury the pipes a few feet down and be done with it. But it takes up far less space to just drill a vertical hole into the ground and fit all your pipes in a small patch of ground which is much better for modern houses with small gardens.

Looking at research papers the average 1m temperature for soil is 8.8'C in the north of Scotland and 12.7'c in the south of England.

Now answer this. If there is snow on the ground and puddles are literally frozen over with an air temperature of say -3'C then how can the sun be heating the earth below that to 12'C ?


This has nothing to do with Geothermal energy in terms of extreme depth and pressures leading to "geothermal energy" we're not dealing with Magma, but the earth is hot and it does not need the sun to stay hot. stick a temperature probe into the ground in a densely covered forest on a cold day and you'll still find a meter or two down that ~10'c temperature. In fact you have literally confirmed exactly my point in your post !!

So sorry but the sun has nothing to do with how a ground source heat pump works. Air source heat pumps as per the name suggests are much more susceptible to changes in the heat of the air caused by the heat of the sun and for that very reason, they are horribly inefficient and expensive to run.
Think driving around in your car with your windows open in the winter and running the aircon, that will give you some idea of how efficient an air source heat pump is.

Have a look at any ground temperature graph relative to depth and seasons. You will see a significant rise in ground temperature of the first few metres during the months that have the higher solar radiation and air temperature. Even at depths of 5 metres you will see a temperature rise in the summer. It will lag the solar and air temperature inputs due to the huge mass of ground absorbing the energy so the peak will be a little later than at shallower depths but it is a definite peak.
Think of the first 10 metres of ground as a giant heat sink that is constantly being fed from the sun, it heats up in summer and slowly releases that energy which can be taken by ground source heat systems in winter.

 

[PuntoHowTo]

Have a look at any ground temperature graph relative to depth and seasons. You will see a significant rise in ground temperature of the first few metres during the months that have the higher solar radiation and air temperature. Even at depths of 5 metres you will see a temperature rise in the summer. It will lag the solar and air temperature inputs due to the huge mass of ground absorbing the energy so the peak will be a little later than at shallower depths but it is a definite peak.
Think of the first 10 metres of ground as a giant heat sink that is constantly being fed from the sun, it heats up in summer and slowly releases that energy which can be taken by ground source heat systems in winter.

The whole planet maintains its temperature, and there are studies of the ground under the Antarctic where the weather is in double digit minus figures and a couple of meters down its still a toasty 15°C where the sun isn’t shining for 6 months a year.

Yes heat does come from the sun and it would be stupid to argue otherwise but there is also a lot of heat permeating up as well. A ground source heat pump does not need sun heated ground to work, it just needs the ground and pipes can be laid out across a large area or sunk horizontally into the ground without any effect on how the system functions

 

[Cornish Ian]

The whole planet maintains its temperature, and there are studies of the ground under the Antarctic where the weather is in double digit minus figures and a couple of meters down its still a toasty 15°C where the sun isn’t shining for 6 months a year.

Yes heat does come from the sun and it would be stupid to argue otherwise but there is also a lot of heat permeating up as well. A ground source heat pump does not need sun heated ground to work, it just needs the ground and pipes can be laid out across a large area or sunk horizontally into the ground without any effect on how the system functions

 

[PuntoHowTo]

What your graph shows is that the deeper you go the less impact the seasons have on the ground temperature, almost like there might be heat coming from somewhere else ?

But weather you’re at ground level of 12 feet deep there is this average trend throughout the year of about 62F about 15-16C

In the Antarctic where the sun doesn’t shine for 6 months of the year and the air temperature is -40C and the ground is burried under feet of freezing cold snow, you dip a little below the surface and the temperature is 15C !

No ground source heat pumps do not rely on the sun to work, they rely on inherent heat that is in the ground that is not just from the sun but is there all the time no matter where you are in the world.

Even at the bottom of the deepest parts of the sea 30,000+ feet away from the surface and the sun, the temperature is still above freezing.

I will say it again heat pumps do not work by pumping the heat of the sun.
They will work even in the coldest parts of the world, they will work were the sun is unable to get to the ground, and as per the comment that started this conversation, they do not need the sun to “recharge” the heat of the ground in order to continue working.

 

[Cornish Ian]

What your graph shows is that the deeper you go the less impact the seasons have on the ground temperature, almost like there might be heat coming from somewhere else ?

But weather you’re at ground level of 12 feet deep there is this average trend throughout the year of about 62F about 15-16C

In the Antarctic where the sun doesn’t shine for 6 months of the year and the air temperature is -40C and the ground is burried under feet of freezing cold snow, you dip a little below the surface and the temperature is 15C !

No ground source heat pumps do not rely on the sun to work, they rely on inherent heat that is in the ground that is not just from the sun but is there all the time no matter where you are in the world.

Even at the bottom of the deepest parts of the sea 30,000+ feet away from the surface and the sun, the temperature is still above freezing.

I will say it again heat pumps do not work by pumping the heat of the sun.
They will work even in the coldest parts of the world, they will work were the sun is unable to get to the ground, and as per the comment that started this conversation, they do not need the sun to “recharge” the heat of the ground in order to continue working.

You seem to be missing the fact that the ground is acting as an accumulator for the solar energy.
Perhaps this will help. Note key words like solar energy

 

[Cornish Ian]

What your graph shows is that the deeper you go the less impact the seasons have on the ground temperature, almost like there might be heat coming from somewhere else ?

But weather you’re at ground level of 12 feet deep there is this average trend throughout the year of about 62F about 15-16C

In the Antarctic where the sun doesn’t shine for 6 months of the year and the air temperature is -40C and the ground is burried under feet of freezing cold snow, you dip a little below the surface and the temperature is 15C !

No ground source heat pumps do not rely on the sun to work, they rely on inherent heat that is in the ground that is not just from the sun but is there all the time no matter where you are in the world.

Even at the bottom of the deepest parts of the sea 30,000+ feet away from the surface and the sun, the temperature is still above freezing.

I will say it again heat pumps do not work by pumping the heat of the sun.
They will work even in the coldest parts of the world, they will work were the sun is unable to get to the ground, and as per the comment that started this conversation, they do not need the sun to “recharge” the heat of the ground in order to continue working.

You seem to be missing the fact that the ground is acting as an accumulator for the solar energy.
Perhaps this will help. Note key words like solar energy.
Sorry double post. It seemed to have disappeared for a while

 

[timmycm850]

Ventilated soffits can be achieved by drilling and fitting the round soffit vents every 600m, quite easy to do.

The battery powered thermostat/ hygrometers are great. They give a great indication of moisture level just perfect information to know you have to open a window, great stuff.

I have a method when it comes to showers.
Shower then turn off the shower, squegy down about 75% of the walls/door while still in there, squegy the shower tray while still in there. All this time I'm gradually draining myself, then dry myself with a towel while still stood in the shower, then get out of the shower clean and dry, the shower is also nearly dry( only 25% wet). The advantages of this are, I'm not soaking the bathroom floor , my towel is not as wet because I dripped most of the water off myself before towelling, 75% of the water in the shower has been squegied down the drain, only 25% of the water dries itself into the room(hopefully with the bathroom window open) KEEP THE BATHROOM DOOR SHUT, so all the moisture goes out of the property. Simple really. Ie don't let the water into the house, changing to this procedure adds about 20 seconds to by bathroom time but moisture content in the bathroom doesn't get over 75%.
Sorry to put all this info on a car based forum.

Tim

 

[PuntoHowTo]

You seem to be missing the fact that the ground is acting as an accumulator for the solar energy.
Perhaps this will help. Note key words like solar energy

I’m not going to keep repeating myself so just to make this point one last time. your argument is floored ! again, In the antartic ground, where the sun doesn’t shine for 6 months of the year the air temperature is -40C and the ground is covered in a thick layer of snow and ice there is still a temperature constant a few feet down, when the temperature of the soil above it is at a constantly lower temperature.

Again WITHOUT THE SUN THE GROUND STILL MAINTAINS A CONSTANT TEMPERATURE.

You found one website trying to flog these systems that supports your claim, but this does not account for the fact that they install these systems in vertical bore holes which at 100m deep are not subject to any variability in ground temperature.

This deeper temperature is ~10 - 15C and is constant the world over.

Yes the closer to the surface you are the ground is obviously going to be subject so some variability but when you actually want a heating system to work, the ground temperature effects of the sun are at their lowest. But it is not reliant on pumping the suns heat.
As highlight by many of the comments on here (I think maybe including your own) the temperature only goes up the deeper and further away from the sun you go.

 

[chris3234]

Snow is a good insulator, a bit like an oxymoron, it’s certainly counterintuitive

But if the soil heat was coming from the sun and needed to be replenished it would make the heat pump useless as the snow would stop any more heat getting into the soil as snow is great at reflecting solar rays being white
Is the point I was making



So there for soil heat must be coming up from deeper below

 

[Cornish Ian]

I’m not going to keep repeating myself so just to make this point one last time. your argument is floored ! again, In the antartic ground, where the sun doesn’t shine for 6 months of the year the air temperature is -40C and the ground is covered in a thick layer of snow and ice there is still a temperature constant a few feet down, when the temperature of the soil above it is at a constantly lower temperature.

Again WITHOUT THE SUN THE GROUND STILL MAINTAINS A CONSTANT TEMPERATURE.

You found one website trying to flog these systems that supports your claim, but this does not account for the fact that they install these systems in vertical bore holes which at 100m deep are not subject to any variability in ground temperature.

This deeper temperature is ~10 - 15C and is constant the world over.

Yes the closer to the surface you are the ground is obviously going to be subject so some variability but when you actually want a heating system to work, the ground temperature effects of the sun are at their lowest. But it is not reliant on pumping the suns heat.
As highlight by many of the comments on here (I think maybe including your own) the temperature only goes up the deeper and further away from the sun you go.

Kensa supply both borehole and surface systems and their buried pipework mentioned would be the latter.
Three more articles explaining where the energy comes from.
I believe you should be able to see the sources at the top.

 

[Cornish Ian]

But if the soil heat was coming from the sun and needed to be replenished it would make the heat pump useless as the snow would stop any more heat getting into the soil as snow is great at reflecting solar rays being white
Is the point I was making



So there for soil heat must be coming up from deeper below

Think of the top 10 metres of ground as a huge heat sink or accumulator which is warmed by the sun, mainly in the summer.
The ground source system which is a metre or so down, draws on this accumulated heat throughout the winter so yes the heat is coming from deeper below. If you consider 10 metres depth of ground stores a massive amount of heat energy it is not surprising that temperatures remain fairly stable at a depth of 10 metres.
There will be a small amount of heat coming from much deeper (which Andy refers to ) but if you look at my previous graph of seasonal ground temperatures relative to depth, you should be able to see that in the periods of high solar radiation / summer the temperature of this upper layer rises dramatically whereas if the heat was mainly coming from the earths core then it would be almost constant.

 

[PuntoHowTo]

Kensa supply both borehole and surface systems and their buried pipework mentioned would be the latter.
Three more articles explaining where the energy comes from.
I believe you should be able to see the sources at the top.

I’ll keep referring you to my previous post.

I will also point out that you’re being very selective in what you are choosing to post pictures of, as there are plenty of things contained within the articles you post that also contradict what you’re repeatedly saying. I guess that’s why you’re posting pictures and not links so you can control what is seen by anyone reading this.
A heat pump is a heat pump it just needs a source of heat to work, not specifically the sun.
If you wanted to make a system specifically to extract the heat from the sun then you’d be laying the pipes out on a black painted roof facing south.

Ground source heat pumps gain their heat from the ground, they work best when they extract heat from way below the level of any seasonal fluctuations in temperature caused by the sun.

And as I keep saying and you keep ignoring, even where there is no sun, and no heat to be conducted into the ground from the air, the ground still has a constant temperature that heat pumps can use.

The ground doesn’t need to be “recharged” by the sun as that constant temperature is there the world over.

 

[PuntoHowTo]

There will be a small amount of heat coming from much deeper (which Andy refers to ) but if you look at my previous graph of seasonal ground temperatures relative to depth, you should be able to see that in the periods of high solar radiation / summer the temperature of this upper layer rises dramatically whereas if the heat was mainly coming from the earths core then it would be almost constant.

There is a lot of heat coming from below, about 50% of the energy that heats the earth and atmosphere comes from the sun, the other 50% comes from the earth itself.

Your graph shows exactly what I keep pointing out, the sun has a dramatic effect on the few feet at the surface but that effect drastically drops off the deeper you go. Once you get down a few meters the suns effect is not noticeable the ground level temperatures remain constant, go down further still and the temperature isn’t getting colder the further away you move from the effects of the sun. It’s getting hotter.

You keep saying the ground is a heat sink but if I heat one end of an aluminium bar to 100°C the middle of that bar measures 60°C as some of the heat is conducted along its length, you don’t then have the other side end of the bar measuring 80°C

Equally if you cook a rotisserie chicken or a slab of kebab meat the middle of the meat will never be hotter than the surface of the meat which. Geothermal energy from deep in the ground permeates all the way to the surface hence the ground temperature constant the world over.

 

[vexorg]

Think about going to the beech on a hot summer's day. Yes the sand will be hot on the surface but dig less than a foot down and sand quickly becomes cold. Soil is the same, dig down a foot or two and you'll find the temperature is much colder. This soil temperature a few feet down doesn't change much, in the height of summer or the middle of winter the temperature of the soil only a short distance from the surface remains largely the same temperature.

If the Sun warming the soil was how these system's worked then they would be terrible in the winter when you want them to work and brilliant at heating your house in the summer when you don't want them. Also these systems can work in reverse to cool your house in the summer, so you don't want to be trying to expel heat energy from the house into hot earth on warm summer's days.

So, where does the energy come from? If you take the heat out of the soil, day after day around the pipes, then the soil will get colder and colder, the heat energy has to come back into the system from somewhere. I dont believe there is enough to say from below, as that would be effectively geothermal.

These system as fitted near the surface, and that would imply that the energy comes from above. On a cold day then it can only be solar since the air temp may be very cold.

 

[eeeno]

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.

 

[vexorg]

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

Yes, if designed that way. But many homes in the UK and 50 to 100 years old or more. Poorly insulated, and require ventillation to prevent dampness

 

[bugsymike]

As I understand it Finland generally has dry cold where we in Britain have the wet kind, so as we warm up the wet comes out.

 

[PuntoHowTo]

So, where does the energy come from? If you take the heat out of the soil, day after day around the pipes, then the soil will get colder and colder, the heat energy has to come back into the system from somewhere. I dont believe there is enough to say from below, as that would be effectively geothermal.

These system as fitted near the surface, and that would imply that the energy comes from above. On a cold day then it can only be solar since the air temp may be very cold.

We literally live on a ball filled with liquid hot rock. So yes 50% of the heat energy we get here at the surface comes from the ground.

Ironically its that moving mass of liquid hot rock that generates the magnetic field needed to keep an atmosphere in place and lock in the other 50% of the heat that's coming in from the sun.

 

[chris3234]

So, where does the energy come from? If you take the heat out of the soil, day after day around the pipes, then the soil will get colder and colder, the heat energy has to come back into the system from somewhere. I dont believe there is enough to say from below, as that would be effectively geothermal.

These system as fitted near the surface, and that would imply that the energy comes from above. On a cold day then it can only be solar since the air temp may be very cold.

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