Refrigerator Prototypes Ranking Task Six new refrigerator prototypes are tested

Question

Refrigerator Prototypes Ranking Task

Six new refrigerator prototypes are tested in the laboratory. For each refrigerator, the electrical power P needed for it to operate and the maximum heat energy that can be removed per second QC,max/t from its interior are given.

Part A

Rank these refrigerators on the basis of their performance coefficient.

Rank from largest to smallest. To rank items as equivalent, overlap them.

Part B

Thsee six refrigerators are placed in six identical sealed rooms. Rank the refrigerators on the basis of the rate at which they raise the temperature of the room.

Rank from largest to smallest. To rank items as equivalent, overlap them.

1) P= 750 W, Qc,max/deltaT= 1500 J/s

2) P= 400 W, Qc,max/deltaT= 1200 J/s

3) P= 500 W, Qc,max/deltaT= 2000 J/s

4) P= 250 W, Qc,max/deltaT= 1000 J/s

5) P= 500 W, Qc,max/deltaT= 1500 J/s

6) P= 1000 W, Qc,max/deltaT= 3000 J/s

Explanation / Answer

(a)

coefficient of performance is,

cop = Q / W = Q / p*dT

(1)

cop = 1500 / 750 = 2

(2)

cop = 1200 / 400 = 3

(3)

cop = 2000 / 500 = 4

(4)

cop = 1000 / 250 = 4

(5)

cop = 1500 / 500 = 3

(6)

cop = 3000 / 1000 = 3

ranking of refrigerators-

3 = 4 > 2 = 5 = 6 >1

(b)

rate at which they raise the temperature of the room is,

H1 = P + Qc / dt = 750 + 1500 = 2250

H2 = 400 + 1200 = 1600

H3 = 500 + 2000 = 2500

H4 = 250 + 1000 = 1250

H5 = 500 + 1500 = 2000

H6 = 1000 + 3000 = 4000

ranking-

6 > 3 > 5 > 1 > 2 > 4

answer

Related Questions

Navigate

• Browse (All)
• Browse R
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.