In a vapor compression refrigeration system, the coefficient of performance is observed as 10. If the enthalpy after compression is 1368.28 kJ/kg and after condensation is 598.58 kJ/kg. If the system works on 50% of the C.O.P., then what is the value of enthalpy after evaporation? a. 1220 b. 1210 c. 1240 d. 1280
Question
In a vapor compression refrigeration system, the coefficient of performance is observed as 10. If the enthalpy after compression is 1368.28 kJ/kg and after condensation is 598.58 kJ/kg. If the system works on 50% of the C.O.P., then what is the value of enthalpy after evaporation? a. 1220 b. 1210 c. 1240 d. 1280
Solution
The coefficient of performance (COP) of a refrigeration system is defined as the ratio of the heat removed from the system (Q_in) to the work done on the system (W).
Given that the COP is 10 and the system works at 50% of the COP, the effective COP is 10 * 0.5 = 5.
The enthalpy after compression (H2) is given as 1368.28 kJ/kg and after condensation (H3) is 598.58 kJ/kg.
The work done on the system (W) is the difference in enthalpy after compression and after condensation, i.e., W = H2 - H3 = 1368.28 kJ/kg - 598.58 kJ/kg = 769.7 kJ/kg.
Since COP = Q_in / W, we can solve for Q_in (the heat removed from the system or the enthalpy after evaporation, H1) as follows:
Q_in = COP * W = 5 * 769.7 kJ/kg = 3848.5 kJ/kg.
Therefore, the value of enthalpy after evaporation (H1) is 3848.5 kJ/kg. However, this value does not match any of the options provided (a. 1220, b. 1210, c. 1240, d. 1280). There might be a mistake in the question or the provided options.
Similar Questions
An ideal gas has a gas constant R = 0.3 kJ/kg-K and a constant-volume specific heat Cv = 0.7 kJ/kg-K. If the gas has a temperature change of 100 degrees C, what is the change in enthalpy?Question 2Select one:a.30 kJ/kgb.70 kJ/kgc.100 kJ/kgd.insufficient information to determine
The vapour pressure of a certain liquid is 30 kPa at 25oC and 60 kPa at 38oC. What is the enthalpy of vaporisation? (kJ mol-1)
Measurements show that the enthalpy of a mixture of gaseous reactants decreases by 217.kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 151.kJ of work is done on the mixture during the reaction.Calculate the change in energy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. kJIs the reaction exothermic or endothermic? exothermicendothermic
4.Question 4What is the change in specific enthalpy if water vapor at 80 bar and a quality of 0 is expanded to a saturated vapor at 100 bar? 1 point1317 kJ/kg-1409 kJ/kg1409 kJ/kg2726 kJ/kg
A 1000W heater is placed in an insulated beaker containing 750g of water at 100 ∘ C. The water vapour is allowed to escape. Assume that there is no loss to the surroundings via conduction, convection or radiation. The specific latent heat of vaporisation of water is 2260kJ/kg.Part AWater leftAll questions in this part are answered correctlyHow much water is left after 5.0minutes?Value?UnitskgCorrect!Hint 1Hint 2Hint 3Part BHalf evaporatedHow long will it take for half of the water to have evaporated? Give your answer to the nearest second.
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.