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Valter edited Aug 22, 2026, 6:07 PM

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		+	### Statement
		+
		+	$5.9.20.$ [Insert the problem statement]
		+
		+	### Solution
		+
		+	### Statement
		+
		+	$5.9.20.$ How will the temperature in the room change if the door of a working refrigerator is left open?
		+
		+	### Solution
		+
		+	The temperature in the room will <b>increase</b>.
		+
		+	A refrigerator operates on the principle of a heat pump. It absorbs an amount of heat $Q_1$ from the cooled volume and rejects an amount of heat $Q_2$ to the surroundings (via the radiator on the back).
		+	To accomplish this process, the refrigerator's compressor consumes electrical energy from the grid to perform mechanical work $A$. According to the law of conservation of energy, the heat rejected into the room is:
		+	$$Q_2 = Q_1 + A$$
		+
		+	If the refrigerator door is left open, it begins to absorb heat $Q_1$ directly from the room air and rejects heat $Q_2$ right back into the same room.
		+	The net amount of heat the room receives during each operating cycle of the refrigerator is:
		+	$$\Delta Q = Q_2 - Q_1 = A$$
		+
		+	Since the compressor consumes electrical energy and performs work ($A > 0$), this work is completely dissipated and converted into the internal energy of the air in the room. A refrigerator with an open door effectively acts as a standard electrical space heater with a power output equal to the power consumption of its compressor.
		+
		+	---
		+	P.S. However, all this only applies to boring factory models. I don't know about you, but I modified my fridge: all the exhaust heat from the compressor is dumped directly into the shower water tank. As a result, the water is always hot, no money is wasted on a water heater, and if you open the door, the fridge actually works like an air conditioner, pulling heat out of the room (it's a pity, of course, that all this is only in the palace of my dreams).
		+
		+	#### Answer
		+	The temperature in the room will increase.
		+
		+	#### Answer
		+
		+	[Insert a concise answer or boxed result]

	@@ -0,0 +1,33 @@
			### Statement

			$5.9.20.$ [Insert the problem statement]

			### Solution

			### Statement

			$5.9.20.$ How will the temperature in the room change if the door of a working refrigerator is left open?

			### Solution

			The temperature in the room will <b>increase</b>.

			A refrigerator operates on the principle of a heat pump. It absorbs an amount of heat $Q_1$ from the cooled volume and rejects an amount of heat $Q_2$ to the surroundings (via the radiator on the back).
			To accomplish this process, the refrigerator's compressor consumes electrical energy from the grid to perform mechanical work $A$. According to the law of conservation of energy, the heat rejected into the room is:
			$$Q_2 = Q_1 + A$$

			If the refrigerator door is left open, it begins to absorb heat $Q_1$ directly from the room air and rejects heat $Q_2$ right back into the same room.
			The net amount of heat the room receives during each operating cycle of the refrigerator is:
			$$\Delta Q = Q_2 - Q_1 = A$$

			Since the compressor consumes electrical energy and performs work ($A > 0$), this work is completely dissipated and converted into the internal energy of the air in the room. A refrigerator with an open door effectively acts as a standard electrical space heater with a power output equal to the power consumption of its compressor.

			---
			P.S. However, all this only applies to boring factory models. I don't know about you, but I modified my fridge: all the exhaust heat from the compressor is dumped directly into the shower water tank. As a result, the water is always hot, no money is wasted on a water heater, and if you open the door, the fridge actually works like an air conditioner, pulling heat out of the room (it's a pity, of course, that all this is only in the palace of my dreams).

			#### Answer
			The temperature in the room will increase.

			#### Answer

			[Insert a concise answer or boxed result]