It is cold, the house is empty and the heating is off. Although it is winter, during the day there is PV production and, without consumption, a surplus is generated.
The house loses heat throughout the day. Cold accumulates not only in the air but also in the structure.
When the evening comes, people go home and as it is very cold, the radiators have to be turned on to the maximum. There is no more PV production and energy is consumed from the grid (which is more expensive than the surplus payment). It’s dinner time, but with the radiators at maximum, you can’t turn on the vitroceramic hob or the oven at the same time because the power limiter goes off.
The radiators are switched on during the day to a greater or lesser extent depending on the available PV surplus. Warm air does not allow “structural cold” to build up.
When the evening comes, people go home and it is not necessary to run all the radiators at maximum power because the house is already warm. In any case, if it is necessary to use other appliances, the system selectively switches off the non-priority loads (radiators), avoiding a power cut due to excess power.