Heat pumps and climate?

[JohnW2]

A recent conversation I had reminded me of something I have always wondered ...

Given that the Laws of Physics are as they are, does anyone know whether if, hypothetically, the entire world changed to using (only) air-source heat pumps for space and water heating, that would result in a significant (or even 'measurable') degree of "global cooling" (which, of course, might be welcome)?

The calculations to answer that question ought to be straightforward enough, but I suspect that others have already done it, thereby avoiding the need for me to re-invent that particular wheel!

Kind Regards, John

 

[bernardgreen]

It would not cause global cooling.

The air that was cooled by the heat pump will eventually mix with and be warmed by air heated by the heat that was pumped and is now escaping from the heated buildings.

Overall there will be global warming from the electrical energy used to pump the heat.

 

[JohnW2]

It would not cause global cooling. ... The air that was cooled by the heat pump will eventually mix with and be warmed by air heated by the heat that was pumped and is now escaping from the heated buildings.

..... only if the temperature of all air in all buildings in the world were allowed to fall to 'ambient'. So long as the interior of buildings is maintained at a temp higher than that of the surroundings, there will be heat 'trapped' (albeit 'dynamically') within the buildings which would otherwise have been in the surrounding environment.

Overall there will be global warming from the electrical energy used to pump the heat.

That is certainly part of the overall equation but, as above, I do not think that, in the real world, the amount of heat 'removed from the atmosphere' on the other side of the equation will ever be 'zero'.

Kind Regards, John

 

[bernardgreen]

So long as the interior of buildings is maintained at a temp higher than that of the surroundings, there will be heat 'trapped'

Heat is trapped only when the building's thermal insulation is such that no heat can escape. That is possible but living and working in a giant Thermos Flask could be a bit restrictive.

 

[flameport]

Heat pumps just move heat energy from one place to another. There is no net cooling or heating from that, and never can be.

 

[JohnW2]

Heat is trapped only when the building's thermal insulation is such that no heat can escape. That is possible but living and working in a giant Thermos Flask could be a bit restrictive.

As I've said, it's a dynamic situation.

All the 'additional' heat in all the buildings in the world (additional to what it would be were their interiors all at 'outside temperature) at any particular instant in time is heat that would (had it not been 'moved into buildings') otherwise have been in the atmosphere - so I don't see how atmospheric temp can be totally unaffected by some of it having been moved 'out of the atmosphere'?

The total amount of heat in (atmosphere PLUS buildings) will obviously always be the same, but as far as climate is concerned, it is surely its distribution between those two places (hence the amount of heat in the atmosphere) which matters, isn't it?

Kind Regards, John

 

[JohnW2]

Heat pumps just move heat energy from one place to another. There is no net cooling or heating from that, and never can be.

See what I've just written to bernard. Yes, the total of heat within buildings and heat in the atmosphere will not be changed by heat pumps. However, what will be changed, to at least some extent, is the proportion of the total heat which is in each of those two places, hence the amount of heat in the atmosphere - which is surely what matters to climate?

As I said, what I don't know, without doing some sums, is whether the amount of atmospheric heat which could be 'lost' into the interior of buildings would be quantitatively significant.

Kind Regards, John

 

[flameport]

The volume of the interior of buildings is insignificant compared to the volume of the atmosphere.
There will be no measurable difference, just a throwing an ice cube into a swimming pool makes no difference.

 

[Harry Bloomfield]

The total amount of heat in (atmosphere PLUS buildings) will obviously always be the same, but as far as climate is concerned, it is surely its distribution between those two places (hence the amount of heat in the atmosphere) which matters, isn't it?

The heat is only moved into buildings, on a temporary basis. It will escape, so the net effect is no difference, apart from the energy used in moving the heat.

 

[JohnW2]

The volume of the interior of buildings is insignificant compared to the volume of the atmosphere. There will be no measurable difference, just a throwing an ice cube into a swimming pool makes no difference.

As I implied, that's rather what I suspected. Thanks for being the only person who has actually answered my question, rather than confusing it

My attempts to estimate the answer myself were frustrated by the fact that I really don't know how to estimate the volume of the interiors of 'all buildings in the world'!

Kind Regards, John

 

[JohnW2]

The heat is only moved into buildings, on a temporary basis. It will escape, so the net effect is no difference, apart from the energy used in moving the heat.

As I keep saying, it's a dynamic situation - heat is moving both in and out of the buildings all the time.

However, at any point in time there will be heat within buildings which would be in the atmosphere had it not been moved from there into buildings - although, as flameport seems to agree, that may not result in a 'measurable' change in atmospheric temp.

Kind Regards, John

 

[Why Not Indeed]

Waste heat is generated by the pump itself. So the entire world would be warmer for the pumps running that if they're not.

 

[JohnW2]

Waste heat is generated by the pump itself. So the entire world would be warmer for the pumps running that if they're not.

Yes, that has already been acknowledged - its's the difference between that heat generation and the (probably very small) amount of heat loss that matters.

Having said that, it';s obviously the case that any form of heating buildings and water is going to result in heat loss into the environment (and also, directly or indirectly, some 'emissions' into the atmosphere), and air pumps are probably better than most of the alternatives in that respect.

Kind Regards, John

 

[Harry Bloomfield]

Having said that, it';s obviously the case that any form of heating buildings and water is going to result in heat loss into the environment (and also, directly or indirectly, some 'emissions' into the atmosphere), and air pumps are probably better than most of the alternatives in that respect.

All dependent on the power source.

 

[JohnW2]

All dependent on the power source.

No matter what the power source, if buildings are heated, some of that heat will end up in the atmosphere.

Some sources of (electrical) energy (i.e. those usually described as 'renewable', whatever that is meant to mean) are fairly 'green', but none totally so - and, as above, all will end up heating the atmosphere to some extent if they are used to heat buildings.

Kind Regards, John