InterviewSolution
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InterviewSolution
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Calculate temperature change: 20 000 l/h cheese milk (V1) is to be heated from 4°C to 34°C by 30 000 l/h hot water (V2) at 50°C. Density (r) and specific heat (cp) for milk are about 1020 kg/m^3 and 3.95 kJ/kg, K and for water 990 (at 50°C) and 4.18.(a) 20.5℃(b) 21.5℃(c) 18.8℃(d) 19.5℃The question was posed to me at a job interview.This intriguing question comes from Heat Exchangers in portion Building Blocks of Dairy Processing of Dairy Engineering |
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Answer» RIGHT choice is (d) 19.5℃ To explain: The TEMPERATURE change for the hot water can then be calculated: 20 000 X 1 020 x 3.95 x (34 – 4) = 30 000 x 990 x 4.18 x Dt2 Dt2 = 19.5°C. The hot water temperature will DROP by 19.5 from 50 to 30.5°C. |
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