So 40-50 degrees is better than 20 below, thats true. But its still not enough for living decently and heat pumps wont replace natural gas for cooking or hot water.. And they wont have jobs to pay the natural gas bill in advance.
Of course you can't use heatpumps for cooking. Cooking fundamentally is controlled removal of water from the ingredients. This requires at least 100degC, and usually you want to fry something, so even with good contact to the frying pan, you need at least 150-200 degC. But energy used for cooking is totally negligible in grand scheme of things.
Domestic hot water is already different: heatpumps are definitely able to harvest the free energy. Yearly COP for making DHW, in medium climate like middle Europe, would be something like 2.5, without taking any legionella risk. Investing in a heatpump just to produce DHW and nothing else is unlikely to be financially viable, but nobody's doing that. DHW comes as a side effect when you have a heatpump that heats water (primarily for room heating).
Room heating tends to dominate over DHW, in total energy cost. For room heating, low distribution temperature is the key. COP in excess of 4 is well possible. In pathological cases, the COP might be even lower than what you get for DHW - i.e., something like 1.5 which was mentioned above. But tihs is some kind of absolute worst-case. I don't know if it is relevant at all, probably not.
High distribution temperature is a problem in very poorly insulated houses, because they require
high power density - i.e., a lot of heating power
per room volume. Assuming we don't want to improve the insulation, this is still totally fixable with large standard radiators, but they would be so big they'd look misproportioned in those small rooms; originally, they used underdimensioned radiators at very high temperatures, which is not suitable for heatpumps. Ignoring retrofit in-floor heating system (assuming people do not want to spend on such "large" renovation) for the sake of the argument, this leaves either accepting the visual change of large radiators, or using fan coil units, either using water as the medium, or not forgetting the trivial case of just installing bog standard split type heatpump (or two). And thus, we have arrived at a solution which just works. If the reason not to do it is aesthetical, then I say, grow up. If it is financial, then increasing energy cost is going to do the trick.
No one ever said a heatpump is just a plug in device which requires no planning and no changes at all. It will require some compromises. But the amount of free, renewable (originally solar) energy harvested is well worth some compromises, IMHO, especially if it is something trivial like needing to have a box in a room which makes a tiny bit of noise.
The strengths of a heatpump are:
* simplicity, small amount of materials needed to build it, no significant amounts of special conflict minerals or similar (maybe the compressor uses rare earth magnets and inverter PCB uses one tantalum cap or whatever)
* the fact it harvests renewable (solar) energy
* the fact that it taps into
natural overnight and even seasonal energy storage systemIf you only abstract the heatpump as a miracle which multiplies the input power by 3-4, you easily forget where this is coming from, and the seasonal storage point alone is
huge. In other words, the Space around us is at -273degC. When the sun shines during day, we do get a lot of solar power, with PV, for example. But when the sun sets, PV production is suddenly zero. But our atmosphere does not suddenly cool to -273degC. No, maybe if it was +10degC during the day, maybe it will be -5degC during the night, thanks to the Earth storing that solar energy. And
that stored solar energy, at -5degC, during night, can be tapped into by a heatpump. And this extends into seasonal scale. Even during cold, dark winter days, our Earth still stores the solar energy, providing us with conditions where heatpumps can pump; from air, or in the coldest areas (with <1% World's population), from the ground.
It is not the only significant piece of technology, but it probably has most bang for the buck. Even here in Finland, in cold and dark conditions, a simple 700EUR (2000EUR installed, thanks to the cartel, but still) split type unit can harvest 5000kWh of free energy per year, and most of this during times when it's completely dark, and cold as ****. Compare this to a 5kWp PV installation producing approximately the same amount of energy (5000kWh per year), costing 5000EUR, and producing most of that energy during times when it is least needed. And yet, you should
still install PV. You should just install heatpumps even more eagerly.
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