Thermophysical Properties of Propylene Glycol-Water Solutions (IP Units) Conc Tfreeze T 'F Cp Btu/ lbm-R u lbm/ft-h k Btu/ h-ft-R V ft2/h a ft2/h T F lbm/ft3 mass % F Pr 10 26.84 40 40 60 60 80 80 0.30164 0.31074 0.31924 0.32714 0.33440 100 0.97019 0.97250 0.97541 0.97879 0.98253 0.98649 0.99057 5.6489 3.9391 2.9024 2.2407 1.7970 1.4845 1.2525 62.989 62.880 62.697 62.448 62.144 61.792 61.402 60.983 60.544 60.094 63.741 100 18.169 12.328 8.8681 6.7041 5.2800 4.2946 3.5763 120 120 140 160 0.089682 0.062645 0.046293 0.035880 0.028917 0.024024 0.020399 0.017549 0.015165 0.013051 140 0.34100 0.34692 0.35214 160 1.0702 180 180 200 0.91815 3.0227 2.5708 2.1810 49.518 200 220 220 0.78427 14.166 0.0049359 0.0050815 0.0052202 0.0053520 0.0054767 0.0055941 0.0057038 0.0058056 0.0058991 0.0059837 0.0044882 0.0045866 0.0046863 0.0047869 0.0048878 0.0049888 0.0050892 0.0051884 0.0052860 0.0053812 20 19.09 20 0.22225 20 40 0.99463 0.99854 1.0022 0.93695 0.94218 0.94760 0.95316 0.95878 0.96441 40 29.626 19.152 60 60 80 63.627 63.442 63.195 62.892 62.542 62.153 61.732 61.287 80 100 120 140 100 0.35663 0.36038 0.26805 0.27496 0.28173 0.28833 0.29473 0.30090 0.30681 0.31242 0.31770 0.32264 8.6458 5.6941 4.0069 2.9830 2.3262 1.8815 1.5627 1.3197 1.1221 0.13588 0.089752 0.063406 0.047431 0.037195 0.030272 0.025315 0.021534 0.018447 13.246 9.7039 7.4557 5.9483 120 0.96997 140 160 160 180 0.97541 0.98067 0.98568 4.8790 4.0737 3.4280 180 200 200 60.827 a 4. Distilled water is being cooled by a 20% propylene glycol solution in a 1-1/U counter flow plate and frame heat exchanger. The water enters the heat exchanger at 50F at a flow rate of 86,000 lbm/h. For safety reasons, the water outlet temperature should never be colder than 35F. The propylene glycol solution enters the heat exchanger at 28F with a flow rate of 73,000 lbm/h. The port distances on the heat exchanger are Lv = 35 in and Lh = 18 in. The plate width is Lw = 21.5 in. The plate thickness is 0.04 in with a plate pitch of 0.12 in. The chevron angle is 30 and the plate enlargement factor is 1.17. All ports have a 2 in diameter. The fouling factor of the propylene glycol solution can be estimated as 2 x105 h-ft2-F/Btu. = = a a. Determine the maximum number of plates the heat exchanger can have while ensuring that the water outlet temperature never drops below 35F. b. Determine the thermal and hydraulic performance of the heat exchanger with the specified number of plates. Summarize your findings in a table similar to Table 5.17. Thermophysical Properties of Propylene Glycol-Water Solutions (IP Units) Conc Tfreeze T 'F Cp Btu/ lbm-R u lbm/ft-h k Btu/ h-ft-R V ft2/h a ft2/h T F lbm/ft3 mass % F Pr 10 26.84 40 40 60 60 80 80 0.30164 0.31074 0.31924 0.32714 0.33440 100 0.97019 0.97250 0.97541 0.97879 0.98253 0.98649 0.99057 5.6489 3.9391 2.9024 2.2407 1.7970 1.4845 1.2525 62.989 62.880 62.697 62.448 62.144 61.792 61.402 60.983 60.544 60.094 63.741 100 18.169 12.328 8.8681 6.7041 5.2800 4.2946 3.5763 120 120 140 160 0.089682 0.062645 0.046293 0.035880 0.028917 0.024024 0.020399 0.017549 0.015165 0.013051 140 0.34100 0.34692 0.35214 160 1.0702 180 180 200 0.91815 3.0227 2.5708 2.1810 49.518 200 220 220 0.78427 14.166 0.0049359 0.0050815 0.0052202 0.0053520 0.0054767 0.0055941 0.0057038 0.0058056 0.0058991 0.0059837 0.0044882 0.0045866 0.0046863 0.0047869 0.0048878 0.0049888 0.0050892 0.0051884 0.0052860 0.0053812 20 19.09 20 0.22225 20 40 0.99463 0.99854 1.0022 0.93695 0.94218 0.94760 0.95316 0.95878 0.96441 40 29.626 19.152 60 60 80 63.627 63.442 63.195 62.892 62.542 62.153 61.732 61.287 80 100 120 140 100 0.35663 0.36038 0.26805 0.27496 0.28173 0.28833 0.29473 0.30090 0.30681 0.31242 0.31770 0.32264 8.6458 5.6941 4.0069 2.9830 2.3262 1.8815 1.5627 1.3197 1.1221 0.13588 0.089752 0.063406 0.047431 0.037195 0.030272 0.025315 0.021534 0.018447 13.246 9.7039 7.4557 5.9483 120 0.96997 140 160 160 180 0.97541 0.98067 0.98568 4.8790 4.0737 3.4280 180 200 200 60.827 a 4. Distilled water is being cooled by a 20% propylene glycol solution in a 1-1/U counter flow plate and frame heat exchanger. The water enters the heat exchanger at 50F at a flow rate of 86,000 lbm/h. For safety reasons, the water outlet temperature should never be colder than 35F. The propylene glycol solution enters the heat exchanger at 28F with a flow rate of 73,000 lbm/h. The port distances on the heat exchanger are Lv = 35 in and Lh = 18 in. The plate width is Lw = 21.5 in. The plate thickness is 0.04 in with a plate pitch of 0.12 in. The chevron angle is 30 and the plate enlargement factor is 1.17. All ports have a 2 in diameter. The fouling factor of the propylene glycol solution can be estimated as 2 x105 h-ft2-F/Btu. = = a a. Determine the maximum number of plates the heat exchanger can have while ensuring that the water outlet temperature never drops below 35F. b. Determine the thermal and hydraulic performance of the heat exchanger with the specified number of plates. Summarize your findings in a table similar to Table 5.17