Under what conditions does a heat engine work as a refrigerator?
Heat pump and refrigerator are devices which transfer the heat from colder region to hotter region. And you need some kind of work input to do that as it is not a spontaneous process (2nd law of thermodynamics).
They both work on the same thermodynamic cycle. The difference in heat pump and the refrigerator is that when it comes to heat pump, we are concerned with the hotter region and when it comes to refrigerator, we are concerned with the colder region. Consider an air conditioned room in summer. The temperature of the room is lesser than that of the surrounding. The heat is being extracted from the room (colder region) and rejected to the surrounding (hotter region). Here, the AC will act as refrigerator. During winters, the air conditioned room is hotter than that of the surrounding. The heat in this case will be extracted from the surrounding (the colder region) and rejected to the room (hotter region). Here, the AC will act as heat pump.
Heat engines and refrigerators are having actually opposite processes.The only way one can turn heat engine to refrigerator is by reversing the processes under required conditions.
Heat pump and refrigerator are devices which transfer the heat from colder region to hotter region. And you need some kind of work input to do that as it is not a spontaneous process (2nd law of thermodynamics).
They both work on the same thermodynamic cycle. The difference in heat pump and the refrigerator is that when it comes to heat pump, we are concerned with the hotter region and when it comes to refrigerator, we are concerned with the colder region. Consider an air conditioned room in summer. The temperature of the room is lesser than that of the surrounding. The heat is being extracted from the room (colder region) and rejected to the surrounding (hotter region). Here, the AC will act as refrigerator. During winters, the air conditioned room is hotter than that of the surrounding. The heat in this case will be extracted from the surrounding (the colder region) and rejected to the room (hotter region). Here, the AC will act as heat pump.
Heat engines and refrigerators are having actually opposite processes.The only way one can turn heat engine to refrigerator is by reversing the processes under required conditions.
