
(a)
The mass flow rate of the refrigerant through the upper cycle.
(a)

Answer to Problem 59P
The mass flow rate of the refrigerant through the upper cycle is
Explanation of Solution
Express the specific enthalpy at state 2 using Carnot efficiency.
Here, specific enthalpy at state 1, 2 and 2s is
Express specific enthalpy at state 3.
Here, specific enthalpy at saturated liquid and pressure of
Write the specific enthalpy at state 3 is equal to state 4 due to throttling process.
Here, specific enthalpy at state 3 and 4 is
Express specific enthalpy at state 5.
Here, specific enthalpy at saturated vapor and pressure of
Express specific entropy at state 5.
Here, specific entropy at saturated vapor and pressure of
Express the specific enthalpy at state 6 using Carnot efficiency.
Here, specific enthalpy at state 5, 6 and 6s is
Express specific enthalpy at state 7.
Here, specific enthalpy at saturated liquid and pressure of
Write the specific enthalpy at state 7 is equal to state 8 due to throttling process.
Here, specific enthalpy at state 7 and 8 is
Express the mass flow rate of the refrigerant through the upper cycle.
Here, mass flow rate of the refrigerant through the lower cycle is
Conclusion:
Refer Table A-12, “saturated refrigerant-134a-pressure table”, and write the properties corresponding to pressure of
Here, specific entropy and enthalpy at state 1 is
Refer Table A-13, “superheated refrigerant 134a”, and write the specific enthalpy at state 2s corresponding to pressure at state 2 of
Write the formula of interpolation method of two variables.
Here, the variables denote by x and y is specific entropy at state 2 and specific enthalpy at state 2s respectively.
Show the specific enthalpy at state 2s corresponding to specific entropy as in Table (1).
Specific entropy at state 2 |
Specific enthalpy at state 2s |
0.9384 | 263.48 |
0.9420 | |
0.9704 | 273.03 |
Substitute
Thus, the specific enthalpy at state 2s is,
Substitute
Perform unit conversion of pressure at state 3 and 5 from
Refer Table A-12, “saturated refrigerant-134a-pressure table”, and write the property corresponding to pressure at state 3
Substitute
Substitute
Refer Table A-12, “saturated refrigerant-134a-pressure table”, and write the properties corresponding to pressure of
Substitute
Substitute
Perform unit conversion of pressure at state 6 from
Refer Table A-13, “superheated refrigerant 134a”, and write the specific enthalpy at state 6s corresponding to pressure at state 6 of
Show the specific enthalpy at state 6s corresponding to specific entropy as in Table (2).
Specific entropy at state 2 |
Specific enthalpy at state 6s |
0.9107 | 276.17 |
0.9271 | |
0.9389 | 285.47 |
Use excels and tabulates the values from Table (2) in Equation (X) to get,
Substitute
Refer Table A-12, “saturated refrigerant-134a-pressure table”, and write the property corresponding to pressure at state 7
Substitute
Substitute
Substitute
Hence, the mass flow rate of the refrigerant through the upper cycle is
(b)
The rate of heat removal from the refrigerated space.
(b)

Answer to Problem 59P
The rate of heat removal from the refrigerated space is
Explanation of Solution
Express the rate of heat removal from the refrigerated space.
Conclusion:
Substitute
Hence, the rate of heat removal from the refrigerated space is
(c)
The COP of the refrigerator.
(c)

Answer to Problem 59P
The COP of the refrigerator is
Explanation of Solution
Express the power input.
Express the COP of the refrigerator.
Conclusion:
Substitute
Substitute
Hence, the COP of the refrigerator is
Want to see more full solutions like this?
Chapter 11 Solutions
Thermodynamics: An Engineering Approach ( 9th International Edition ) ISBN:9781260092684
- Consider 0.65 kg of N2 at 300 K, 1 bar contained in a rigid tank connected by a valve to another rigid tank holding 0.3 kg of CO2 at 300 K, 1 bar. The valve is opened and gases are allowed to mix, achieving an equilibrium state at 290 K. Determine: (a) the volume of each tank, in m³. (b) the final pressure, in bar. (c) the magnitude of the heat transfer to or from the gases during the process, in kJ. (d) the entropy change of each gas and of the overall system, in kJ/K.arrow_forwardBài 1. Cho cơ hệ như hình 1. Hình biểu diễn lược đổ cơ hệ tại vị trí cân bằng tĩnh. Trục tọa độ Oy hướng theo phương chuyển động của vật 1, gốc O đặt tại vị trí cân bằng của vật 1(tức khi lò xo biến dạng tĩnh). Bỏ qua khối lượng của thanh số 3. Vật rắn 2 là pulley 2 tầng đồng chất có bán kính ngoài 21, bán kính trong I, bán kính quán tính đối với trục qua tâm P-1.5, khối lượng m:. Vật rắn 4 là thanh thắng đồng chất có khối lượng m, chiều dài 1. Cho các số liệu: m = 2kg, m= = 5kg, m = 4kg, k=40(N/cm), ! – 0.8(m),r=0.1(m). Điều kiện đầu y; =0.5 cm );j = 10 cm/s) . Giả sử hệ dao động bé, Vật rắn 2 chuyển động lăn không trượt trên mặt phẳng ngang. 1. Viết phương trình chuyển động của hệ. 2. Xác định tần số dao động tự do của hệ. 3. Xác định đáp ứng dao động tự do của hệ. dây dây 1 2r Hình 1 y 3 -2 I k www. -2arrow_forwardHints: Find the closed loop transfer function and then plot the step response for diFerentvalues of K in MATLAB. Show step response plot for different values of K. Auto Controls Show solutions and provide matlab code NO COPIED ANSWERS OR WILL REPORTarrow_forward
- Obtain the response of the system shown below for a parabolic or acceleration input r(t);where Auto Controls Show full solutionarrow_forwardProblem Statement A large plate of insulating material 8 cm thick has in it a 3 cm-diam hole, with axis normal to the surface. The temperature of the surroundings are 1800 K at one side of the plate and 400 K on the other side. Insulating plate D= 3 cm H= 8 cm Considering the sides of the hole to be black, (a) Draw a system of resistors that can be used to solve for the various heat transfer rates. For full credit you must label all "voltages", "currents," and resistances present. (b) Estimate the radiative heat transfer through the hole.arrow_forwardUsing MATLAB, plot the unit-step response curve for the following transfer function and Using MATLAB, obtain the rise time, peak time, maximum overshoot, and settling time. Auto Controls Provide codesarrow_forward
- Use Routh's stability criterion to determine how many roots with positive real partsthe following equations have Auto Controls Show full solutionsarrow_forwardPlot the unit step and unit ramp response curve for the following closed loop transferfunction using MATLAB. Indicate clearly the input and output in your plot Auto Controls provide matlab codearrow_forwardUsing a "for loop" in MATLAB program to obtain the unit-step response of thissystem for the following four cases in a single plot What can you observe from the plot? Auto Controls Provide matlab codearrow_forward
- Problem 2 (40 Points) A particle of mass m is embedded at a distance a from the center of a massless circular disk of radius r. The disk rolls without slipping down a plane inclined at an angle a with the horizontal. A horizontal force of Ễ = −Fxî + Fyĵ resists motion of the disk down the plane by pushing on the disk at the axle that runs through the center of the disk. a) Find the kinetic energy T. (10 points) b) Find the potential energy V. (10 points) c) Write a position vector to the axle at the center of the wheel in terms of x and y. (10 points) d) Using virtual work, find the applied force Q₁ that would go in Lagrange's Equations. DO NOT WRITE OUT OR SOLVE LAGRANGES'S EQUATIONS. (10 points) x r m e 10 g F α HINTS 1) Consider using the STATIONARY red xy frame a reference frame from which to draw vectors 2) The red xy system DOES NOT move. It is stationary. 3) Consider that the disk rolls a distance of re down the ramparrow_forwardDraw a counter balance circuit of a vertical cylinder. using counter balance valve and external load.arrow_forwardplease sketch a stress-strain diagram for a typical structural steel in tension and display all of the important features.arrow_forward
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
