Residential sized heat pumps can do '400-500%' efficiency (i.e. 4-5kWh of heat for every kWh of electricity), so electrical heating at 100% efficiency is indeed inefficient. If the calculations are really valuable it could still be worth it though.
Miniscule % of people have heat-pumps. In UK most people use either a gas boiler or a dumb electric heater. And you can't even install heatpump in an an apartment building without re-constructing half of it.
Today that is true, but I think the trend will move towards a larger share in the future. Relevant anecdotes:
- All newly build housing in the Netherlands must be without natural gas, thus either lower heat-grid or heat pump heating
- People that use airconditioning for heating have a heat pump without being aware of it (if configured that way)
Finally, for any technology early in the adoption curve, the market share - or even the growth rate (%) - today shouldn't be taken as good indicators for future development. E.g. McKinsey famously underestimated the mobile phone market by 100x that way [1] and the energy predictions on the adoption of solar manage to underestimate installed solar power _every_ year. Instead, also consider growth-of-growth and network effects as adoption grows.
They are slowly becoming more common here in Germany. I'd say about half of the houses in the newly developed part of town have one and a few older ones are retrofitting them as well here.
No, heat pumps don't have over 100% efficiency the same way hot water pumps that pump from municipal source don't have >100% efficiency in heating home (it uses hot water available from somewhere else).
Heat pumps engage some other source of energy so if you want to measure efficiency you now need to include that other source into account.
Since you are engaging natural source of energy you can measure how effective (not efficient in thermodynamical terms) your heat pump system is, by calculating how much energy it can transfer for energy put into the pump. But this has nothing to do with efficiency, which in case of devices used to convert one type of energy into another or moving energy from place to place is typically meant in its strict thermodynamical sense.
The efficiency calculation here measures only electrical power in vs heat energy out. Heat pumps are always listed with greater than 100% efficiency. There is no problem with the laws of thermodynamics of doing this and it’s even listed in text books with the explanation of how it is possible.
The work of the heat pump is to move heat from one location to another, it does so with the byproduct of producing more heat, therefore it produces more heat energy than the electrical energy put in.
You’re right that conservation of energy says that the heat in being moved did come from somewhere but that’s outside the system, and you will always find heat anywhere but absolute zero. Calculations for turbines or engines don’t make any efficiency allotments for heat already in the air, which is also necessary for them to run.
Heat pump is not just the pump mechanism, but the entire system which includes mass of rock that is heat reservoir.
What typically happens is you drill deep in the ground or rock and circulate air, water or some other refrigerant underground. During summer you pump hot refrigerant to heat up the mass of rock. This can be for example water that has been made hot by the sun. During winter you push water through that warm rock to recover the heat to warm your home.
No, it is not thermodynamically possible to recover more than 100% of stored energy.
Electrical heating is as close to 100% efficient as you can get. Every watt your computer uses ends up as heat.
Generating those watts from non-renewable sources is much less efficient though.
I wonder if it's possible to calculate when the benefit of contributing to BOINC projects outweighs the CO2 generated.