Consider a two-stage compression refrigeration system operating between the pressure limits of 1.4 and 0.12 MPa. The working fluid is refrigerant-134a. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.5 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure, and it cools the refrigerated space as it vaporizes in the evaporator. Assuming the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic, determine (a) the fraction of the refrigerant that evaporates as it is throttled to the flash chamber, (b) the amount of heat removed from the refrigerated space and the compressor work per unit mass of refrigerant flowing through the condenser, and (c) the coefficient of performance.
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
THERMODYNAMICS (LL)-W/ACCESS >CUSTOM<
- please solve the following problemarrow_forwardA 5 cm external diameter, 10 m long hot water pipe at 80 degrees C is losing heat to the surrounding air at 5 degrees C by natural convestion with a heat transfer coefficient of 25 W/m^2 K. Determine the rate of heat loss from the pipe by natural convection.arrow_forwardThe outer surface of a spacecraft in space has emissivity of 0.8 and a solar absorptivity of 0.3. If solar radiation in incident on the spacecraft at a rate of 950 W/m^2, determine the surface temp of the spacecraft when the radiation emitted equals the solar energy absorbed.arrow_forward
- Of the following pairs of material types, indicate whether any of them satisfy the condition that both elements of the pair are generically related to the property of ductility.(A). Yes, ceramics and polymers.(B). No, none of the pairs.(C). Yes, metals and ceramics.(D). Yes, polymers and metals.arrow_forwardBoth Fouriers law of heat conduction and ficks law of mass diffusion can be expressed as Q=-kA(dT/dx). What do the quantities Q, k, a and T represent in a) heat conduction b)mass diffusionarrow_forward(9) Figure Q9 shows a 2 m long symmetric I beam where the upper and lower sections are 2X wide and the middle section is X wide, where X is 31 mm. The I beam sections are all Y=33 mm in depth. The beam is loaded in the middle with a load of Z=39 kN causing reaction forces at either end of the beam's supports. What is the maximum (positive) bending stress experienced in the beam in terms of mega-Pascals? State your answer to the nearest whole number. Y mm Y mm Y mm Xmm 2X mm Figure Q9 Z KN 2 marrow_forward
- (5) Figure Q5 shows a beam which rests on two pivots at positions A and C (as illustrated below). The beam is loaded with a UDL of 100 kN/m spanning from position B and ending at position D (as illustrated). The start location of B is Y=1.2 m from A. The total span of the UDL is twice the length of Z, where Z=2.2 m. What is the bending moment value at position X=2.5 m, (using the convention given to you in the module's formula book). State your answer in terms of kilo-Newton-metres to 1 decimal place. Bending Moment Value? UDL = 100 kN/m A Ym X = ? B Zm Figure Q5 C * Zm Darrow_forwardYou are required to state your answer in millimetres to the nearest whole number. 30 mm 30 mm A. No Valid Answer B. 27 ○ C. 26 O D.33 ○ E. 34 30 mm 50 mm Figure Q14 1marrow_forwardA beam supports a uniform load and an axial load P = 30 kips. If the maximum allowable tensile stress in the beam is 24 ksi and a maximum allowable compressive stress is 20 ksi, what uniform load can the beam support? Assume P passes through the centroid of the section.arrow_forward
- Bending Moment Value? 40 kN 100 kN 100 kN 100 kN 40 kN A B C D E Ym Zm Zm Ym X = ?arrow_forward(4) Figure Q4 shows a symmetrically loaded beam. The beam is loaded at position A (x = 0 m) and the end of the beam at position E with 30 kN. There is an additional load of 101 kN both at position B (Y = 0.87 m), in the middle at C and at position D. The middle section is 2Z, where Z = 0.82 m). Given that the reaction forces at RB and RD both equal 180 kN, calculate the Bending Moment value (using the convention given to you in the module's formula book) at a position of x=2.30m. State your answer in terms of kilo-Newton-metres to one decimal place. Bending Moment Value? 40 kN 100 kN 100 kN 100 kN 40 kN B D E Ym Zm Zm Ym X = ? Figure Q4arrow_forward(8) Figure Q8 shows a T cross-section of a T beam which is constructed from three metal plates each having a width of 12 mm and sectional engths of X=72 mm, Y=65 mm and Z=88 mm, where the plates are used for the web section, and the two flange sections respectively, as llustrated in Figure Q8. Calculate the neutral axis of the T-beam cross-section (as measured from the base) in units of millimetres, stating your answer to the nearest 1 decimal place. Z mm Y mm 12 mm X mm Figure Q8 12 mm 12 mmarrow_forward
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning