4 ms·

That would seem inevitable, so the only real question was how much (+2C.) So, how much cooler does the city with many heat pumps get in the winter then?

stephen_g 3y ago
The opposite effect I expect should be less for heating, since the heat is constantly leaking out of buildings at some rate back into the environment (insulation, double glazing etc. reduces this but all the added heat eventually leaks out), and additional energy is being put in which turns into heat too (e.g. COP 4 means 1 unit heat from electricity and 3 units shifted from the outside environment). So whether there is temporary localised cooling depends on the quality of the insulation but overall and over time there is no cooling due to the additional input.
- guerrilla 3y ago
  The heat is constantly leaking into the buildings too. I'd be more concerned with differences in efficiency with direction that you mention at the end. In any case, the net result is still negative, so how much negative is still the question that stands.
Ozzie_osman 3y ago
Effect must be less. For AC, you're transferring indoor heat outdoor AND generating excess heat from running the AC itself. For heating, the excess heat generation presumably works counter to the heat transfer.
raverbashing 3y ago
Good question, some aspects make it different: - you're always getting some "free warmth" through the sun, so on average you need to pump less energy to heat than to cool (for same temp difference) - Hot air rises, cold air sinks, not sure how that works in a city environment, probably concentrates the cold more
- superq 3y ago
  Temp differentials are still differentials, though, so sun warmth would be already accounted for.
  - raverbashing 3y ago
    Kind of, because your house will always be warmer than the outside at thermal equilibrium, both in summer and winter (with heating/ac off) So, yes if you consider the differential in-house current-target temperature yes, but difference of outside/inside temperature no.

stephen_g 3y ago

The opposite effect I expect should be less for heating, since the heat is constantly leaking out of buildings at some rate back into the environment (insulation, double glazing etc. reduces this but all the added heat eventually leaks out), and additional energy is being put in which turns into heat too (e.g. COP 4 means 1 unit heat from electricity and 3 units shifted from the outside environment). So whether there is temporary localised cooling depends on the quality of the insulation but overall and over time there is no cooling due to the additional input.

guerrilla 3y ago
The heat is constantly leaking into the buildings too. I'd be more concerned with differences in efficiency with direction that you mention at the end. In any case, the net result is still negative, so how much negative is still the question that stands.

Ozzie_osman 3y ago

Effect must be less. For AC, you're transferring indoor heat outdoor AND generating excess heat from running the AC itself. For heating, the excess heat generation presumably works counter to the heat transfer.

raverbashing 3y ago

Good question, some aspects make it different: - you're always getting some "free warmth" through the sun, so on average you need to pump less energy to heat than to cool (for same temp difference) - Hot air rises, cold air sinks, not sure how that works in a city environment, probably concentrates the cold more

superq 3y ago
Temp differentials are still differentials, though, so sun warmth would be already accounted for.
- raverbashing 3y ago
  Kind of, because your house will always be warmer than the outside at thermal equilibrium, both in summer and winter (with heating/ac off) So, yes if you consider the differential in-house current-target temperature yes, but difference of outside/inside temperature no.