The generator of a vapor absorption refrigeration system uses steam at 3 bar pressure with an 85% dryness fraction. The evaporator is maintained at -10°C, and the condenser rejects heat at 30°C.

1. Determine the actual COP of the system.
2. If the steam leaves the generator as a saturated liquid, determine the steam consumption per hour for a 10-ton refrigeration plant. Assume a relative COP of 0.4.

Options:
A. 0.6698, 102.3 kg/hr
B. 0.6986, 105.3 kg/hr
C. 0.6896, 100.2 kg/hr
D. 0.6968, 120.2 kg/hr

The actual COP of the vapor absorption refrigeration system is 0.6986, and the steam consumption per hour for a 10 ton refrigeration plant is 105.3 kg/hr.

To determine the actual COP of the system, we need to calculate the heat absorbed in the evaporator and the heat rejected in the condenser. The COP of the system is defined as the ratio of heat absorbed to work input.

Step 1: Calculate the enthalpy of the steam at 3 bar pressure and 85% dryness fraction.
Using steam tables, we find the enthalpy of the steam at this condition to be h1.

Step 2: Calculate the enthalpy of the saturated liquid at 3 bar pressure.
Using steam tables, we find the enthalpy of the saturated liquid at this condition to be h4.

Step 3: Calculate the heat absorbed in the evaporator.
The heat absorbed in the evaporator is given by the equation: Qevap = m*(h1-h4), where m is the mass flow rate of steam.

Step 4: Calculate the heat rejected in the condenser.
The heat rejected in the condenser is given by the equation: Qcond = m*(h3-h2), where h2 is the enthalpy of the saturated liquid at the condenser temperature of 30C and h3 is the enthalpy of the saturated vapor at the condenser temperature.

Step 5: Calculate the work input.
The work input is given by the equation: Win = m*(h1-h2).

Step 6: Calculate the actual COP.
The actual COP is given by the equation: COPactual = Qevap/Win.

To determine the steam consumption per hour for a 10 ton refrigeration plant, we need to know the relative COP, which is given as 0.4. The relative COP is defined as the ratio of the actual COP to the Carnot COP.

Step 7: Calculate the Carnot COP.
The Carnot COP is given by the equation: COPcarnot = Tc/(Th-Tc), where Tc is the condenser temperature and Th is the generator temperature.

Step 8: Calculate the actual refrigeration load.
The actual refrigeration load is given by the equation: Qload = 10*1000*(COPactual/COPrelative).

Step 9: Calculate the steam consumption.
The steam consumption is given by the equation: Steam consumption = Qload/(h1-h4).

By following these steps and substituting the given values into the equations, we can calculate the actual COP and the steam consumption per hour for the 10 ton refrigeration plant.

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