1. A heat engine is operating on a Carnot cycle and has a thermal efficiency of 75percent. The waste heat from this engine is rejected to a nearby lake at 15°C at arate of 800 kJ/min. Determine the power output of the engine and the temperatureof the source.II. A double-pipe heat exchanger is utilized to cool oil (cp= 2.20 kJ/kg.k) initiallyat 150 °C at a rate of 2 kg/s by water (ep- 4.18 kJ/kg.k) that enters at 20°C andleaves at 45 °C at a rate of 1.2 kg/s. Determine the rate of heat transfer in the heatexchanger and the exit temperature of the oil.

Answered: Image /qna-images/answer/688b8330-6e77-4d9f-9a09-9bac0f2dfba0.jpg

Answered: 1. A heat engine is operating on a…

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

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Energy Flux Malaysia has just launched a new type of house refrigerator system using R-134a as a working fluid. It is claimed that the refrigerator can maintain the temperature of the refrigerated space at -35°C by rejecting heat to the surrounding air that enters a well-insulated condenser at 17°C and leaves at 27°C. The refrigerant enters the well-insulated condenser at 1.2 MPa and 60°C at a rate of X kg/s and leaves at the same pressure at 44°C. In an effort to attract consumers, silence mode feature is introduced where noise generated from the compressor unit is significantly reduced. Due to this new feature, the refrigerator is believed to consume 50% more actual power input when operated at Y kW. As an intern hired by the manufacturer, you have been tasked to perform the followings: a. Illustrate the above cycle with appropriate labels. Based on the information in TABLE Q1, calculate the mass flowrate of the surrounding air entering the heat exchanger in kg/s and determine the…
A heat pump operates on the ideal vapor compression refrigeration cycle with R-134a as the working fluid between the pressure limits of 120 and 800 kPa If the rate mass flow rate of the refrigerant is 0.4 kg/s, the rate of heat supply by the heat pump to the heated space is
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NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -30°C by rejecting its waste heat to cooling water that enters the condenser at 18°C at a rate of 0.28 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and -34°C and the compressor is estimated to gain a net heat of 420 W from the surroundings. The heat exchanger loses no heat to the environment. 26°C 42°C Condenser Expansion valve Evaporator OL Water 18°C 1.2 MPa 65°C Oin W in Compressor 60 kPa -34°C Determine the COP of the refrigerator. (You must provide an answer before moving on to the next part.) The COP of the refrigerator is 1.824 >
In a processing plant, waste heat is to be recovered from a hot oil stream into a cold water stream using a parallel-flow heat exchanger with 0.75 effectiveness. The hot oil enters the heat exchanger at 285 °C with a mass flow rate of 25.0 kg/min while the cold water flows into the heat exchanger at 35 °C with a mass flow rate of 48 kg/min. The specific heat capacities of the oil and the water are 2.2 kJ/kg.K and 4.2 kl/kg.K, respectively. The convective heat transfer coefficient on the oil side of the heat exchanger is 58 W/m?.K and that on the water side is 102 w/m².K. Neglect any thermal resistance at the heat transfer wall separating the oil and water streams in the heat exchanger. (a) Calculate the outlet temperatures of the oil and cold water streams in the heat exchanger. (b) Find the number of transfer units (N) of the heat exchanger. (c) Determine the heat transfer area required for the heat exchanger. It is given that for a parallel flow heat exchanger, the effectiveness (e)…
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Q14//A surface condenser receives exhaust steam at 0.14 bar from an engine developing 180 kW. The circulating water enters the condenser at 15°C and leaves at 40°C. The final temperature of the condenser steam is 50°C. If the engine consumes 9 kg of steam per kW per hour, determine the quality of the steam entering the condenser, if the weight of circulating water per hour is 31600 kg. (Answer: x=0.85) ****
A gas refrigeration system utilizing air as the working fluid possesses a pressure ratio of 3. The air is directed into the compressor at 5°C. The high- pressure air is then cooled down to 40°C by rejecting heat to the ambient environment. The refrigerant exits the turbine at -85°C and subsequently absorbs heat from the cooling area prior to its entry into the regenerator. The mass flow rate of air is 0.45 kg/s. Given that the isentropic efficiencies are 82 percent for the compressor and 87 percent for the turbine, and using constant specific heats at ambient temperature, find: (a) The effectiveness of the regenerator. (b) The rate at which heat is extracted from the cooling area. (c) The Coefficient of Performance (COP) of the cycle.
The engine of a Diesel power plant uses 0.0236m^3/s of bunker oil whose specific gravity is 0.8 as fuel. This fuel undergoes pre-heating before being supplied to the engine using an oil heater. The heating medium used in this parallel flow heat exchanger is the engine's exhaust gas. Oil enters the HX at 10C and leaves at 100C while the exhaust gas enters at 370C and leaves at 175C. Specific heat of oil and gas are 2.5 and 1.09kJ/kg-K respectively. A. Draw the figure, sketch the t-L diagram, then, compute the heat transfer in MW. B. Determine the amount of exhaust gas in kg/s C. What is the LMTD of the heat exchanger? Express the answer in Kelvin. D. What is the overall heat transfer coefficient of the heat exchanger? express in Watts/m^2-K?

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