Example 2 A plant using R134a refrigerant has a cooling capacity of 352 kW of refrigeration. It evaporates at 0 C and condenses at 35 C, with the 5 K of superheat at the evaporator outlet and 5 K of sub-cooling at the condenser outlet. Assuming isentropic compression and ignoring pressure drops in the piping, the evaporator and condenser, determine the following; a) The refrigeration effect b) The mass flow rate of refrigerant c) The compressor power d) The rate of heat rejection at the condenser e) The COP f) The corresponding Carnot COP g) The percentage Carnot efficiency

Example 2 A plant using R134a refrigerant has a cooling capacity of 352 kW of refrigeration. It evaporates at 0 C and condenses at 35 C, with the 5 K of superheat at the evaporator outlet and 5 K of sub-cooling at the condenser outlet. Assuming isentropic compression and ignoring pressure drops in the piping, the evaporator and condenser, determine the following; a) The refrigeration effect b) The mass flow rate of refrigerant c) The compressor power d) The rate of heat rejection at the condenser e) The COP f) The corresponding Carnot COP g) The percentage Carnot efficiency

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A Single Stage Vapor Compression (SSVC) refrigeration system has a cooling capacity of 7.5 tons. The following are the actual conditions: discharge of the evaporator is at -30°C & 0.2 MPa, discharge of the condenser is at 30°C & 2.0 MPa, discharge of the compressor is at 130°C & 2.5 MPa. Determine the COP of the system.
A cooling system with a capacity of 10 tons of refrigeration operates at 210 KPA in the evaporator while in the condenser it is 850 KPA if the R-134a refrigerant is in a saturated state calculate the theoretical power required to operate the compressor.
A medium size power station is used to produce 30 MW net power for a refinery. The station uses steam as the operating fluid and operates according to the Carnot cycle between the pressure limits of 0.4 bar and 35 bar. Steam enters the boiler as a saturated liquid and leaves it as a dry saturated vapour. ist t Reneric o "nd h Ts diaar ntion of s) (ii) Determine the dryness fraction of the steam that is fed to the condenser. (4 marks) (iv) Determine the specific enthalpy values at the four key points of the cycle. (6 marks) Calculat "Fic of the cycle (5 Ma, KS) (vi) Determine the thermal efficiency of the cycle. (1 mark) (vii) Using the highest and lowest temperature values in the cycle, re- calculate the efficiency of the cycle and show that it is equivalent to the result in part (vi). (2 marks) arks). 2.
The evaporator and condenser is isobaric with a net heat transfer 250 W in a vapor-compression refrigeration cycle. The cycle operates with R-134a working fluid at a steady state. The compressor's isentropic efficiency is at 60% with a high pressure of 16 bar and low pressure of 1 bar during the cycle. Solve for the mass flow rate, coefficient of performance, and draw the T-s diagram.
Condenser a steam power plant that operates on a simple ideal ranking cycle and has a net power output of 22MW. Steam enters the turbine at 7Mpa and 450.05°C and is cooled in the condenser at a pressure of 10kpa by running cooling water from a lake through the tubes of the condenser at rate of 1750 kg/s. Determine the mess flow rates of steam through the steam turbine assuming that the cp of superheated steam is 2.9593kJ/kg.K.
Superheated steam at 18 MPa, 560 °C enters the steam turbine. The pressure at the exit of the turbine is 0.06 MPa and saturated liquid water leaves the condenser at 0.06 MPa. Pressure is increased to 18 MPa again after the pump. Find: (a) Sketch the process on a T-s diagram. (b) The net work per unit of steam flow in kJ/kg. (c) Heat transfer to steam passing through the boiler, in kJ/kg.
A 540,000 kJ/h capacity refrigeration system using Refrigerant 22 and served by a single compressor unit operates at an evaporator temperature of -23 oC and a condensing saturation temperature 40oC. To get rid of the single compressor load, a modification is proposed to use two stage of compression with refrigerant intercooling. (a) Determine the power required in the original system. (b) Determind the power required for the proposed modified system.
A vapor-compression refrigeration machine uses refrigerant-134a as much as 2 kg/min with operating conditions leaving the evaporator at a temperature of -14°C and a condenser pressure of 0.8 Mpa. Determine the COP value and cooling load of the machine.
1. A refrigerant system using refrigerant 22 is to have a refrigerating capacity of 60 kW. The evaporating temperature is -10°C and the condensing temperature is 42°C. Determine the: • Enthalpy at each point of the cycle in kJ/kg • Refrigerating Effect in kJ/kg Compressor work in kJ/kg • Energy rejected in kJ/kg • Mass flow rate of refrigerant in kg/s • Compressor power in kW • Heat rejected in kW • Coefficient of Performance Note: Draw the P-h Diagram with labels. Show your system balancing for checking.
Question 3 In a vapour-compression refrigeration system, refrigerant - 134a enters the compressor superheated at 200 kPa and - 5 °C. The refrigerant enters the condenser at 1.4 MPa and 75 °C, and exits at 1.4 MPa as a saturated liquid. There is no significant heat transfer between the compressor and its surroundings, and the refrigerant passes through the evaporator with a negligible change in pressure. If the refrigerating capacity is 105 kW, represent the cycle on a T-s diagram and determine: a) the mass flow rate of the refrigerant in kg/s, b) the power input to the compressor in kW, c) the coefficient of performance, and (2) d) the isentropic compressor efficiency
Steam is supplied to a two-stage turbine at 40 bar and 350°C. It expands in the first turbine until it is just dry saturated, then it is re-heated to 350°C and expanded through the second-stage turbine. The condenser pressure is 0.035 bar. Calculate the work output and the heat supplied per kilogram of steam for the plant, assuming ideal processes and neglecting the feed-pump term. Calculate also the specific steam consumption and the cycle efficiency
11. A vapour compression refrigeration plant uses ammonia. The compressor takes vapour from the evaporator at 207.7kPa and -8°C and delivers to the condenser at 1470kPa and 113°C. The temperature of the liquid leaving the condenser at a rate of 12kg/min is 38°C. Calculate: (a). the dryness of the refrigerant entering the evaporator (b). the cooling load (c). the power to the compressor (d). coefficient of performance (e). plant capacity