If you simulate, you will see that the „high“-signal only reaches the output Q2 if the output of the analog threshold trigger is “low”.

If the value of the analog input is > 279, the output of the analog threshold trigger is “high”. From this time the refrigerator is activated. At the same time the heating is turned off (because the “high”-signal of the analog threshold trigger is connected with a negatived input of the “AND”). That means: If the analog value >279 ->> Q1 is active, for so long until the analog value <251, then Q2 is active. So only one output is activated at the same time.

Is that you thought about?

Greetings
Fux