Will the COP of a refrigeration unit likely be larger when it chills room-temperature air to 3°C (as in your kitchen’s refrigerator) or when it chills room-temperature air to -18°C (as in your kitchen’s freezer)

The operating condition for the single compressor in a household refrigerator is the lowest box temperature, which is typically A. 0F B. -20F C. 20F D. 40F

Welded ______sealed compressors are normally used in household refrigerators.

SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C dut 246.36 kJ/kg OF P 0.8 MPa h2 = 286.69 kJ/kg P 0.72 MPa T= 26 C h3 = 87.83 kJ/kg h3 = h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS SAMARRA RING

SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C 212 h 246.36 kJ/kg da OF SAMARRA P 0.8 MPa VER h2 = 286.69 kJ/kg O P 0.72 MPa T= 26 C hg = 87.83 kJ/kg h3 =h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 50°C 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBIECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS RING

5. A refrigerator with tetrafluoroethane as refrigerant operates with an evaporation temperature of 247.15 K (-26°C) and a condensation temperature of 300.15 K (27°C). Saturated liquid refrigerant from the condenser flows through an expansion valve into the evaporator, from which it emerges as saturated vapor. (a) For a cooling rate of 5.275 kW, what is the circulation rate of the refrigerant? (b) By how much would the circulation rate be reduced if the throttle valve were replaced by a turbine in which the refrigerant expands isentropically? (c) Suppose the cycle of (a) is modified by the inclusion of a countercurrent heat exchanger between the condenser and the throttle valve in which heat is transferred to vapor returning from the evaporator. If liquid from the condenser enters the exchanger at 300.15 K (27°C) and if vapor from the evaporator enters the exchanger at 247.15 K (-26°C) and leaves at 294.15 K (21°C), what is the circulation rate of the refrigerant?

please provide full calculations thank you

Thermodynamics: A refrigeration unit using Refrigerant-134a is used to maintain a certain space at –15°C.  The condenser rejects heat (?H) to cooling water that enters the condenser at 15°C at a rate of 0.2 kg/s and leaves at 35°C (all as saturated liquid water). The superheated refrigerant enters the condenser at 0.8 MPa and 40°C and leaves as a saturated liquid at the same temperature. If the compressor consumes 4.5 kW of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load (?̇L), (c) the COP.

A certain refrigerator has a COP of 5.00. When the refrigerator is running, its power input is 500 W. A sample of water of mass 500 g and temperature 20.0°C is placed in the freezer compartment. Assume all other parts of the refrigerator stay at the same temperature and there is no leakage of energy from the exterior, so the operation of the refrigerator results only in energy being extracted from the water. -->Compare the cost to make 44 kg of ice using two different refrigerators; one has a COP of 5.00 and the other has a COP of 6.00. Electricity costs $0.10 per kWh. Using the same assumptions given in the example, find the cost difference (in dollars) between the refrigerators to freeze the water.

Thermodynamics May you please explain the steps as if I was in 9th grade. I have tried this problem five times, and it has not worked out.