Dry air is cooled from 65 to 38?C, while flowing at the rate of 1.25 kg/s in a simple counterflow heat exchanger, by means of cold air which enters at 15?C and flows at a rate of 1.6 kg/s. It is planned to lengthen the heat exchanger so that 1.25 kg/s. of air can be cooled from 65 to 26?C with a counterflow current of air at 1.6 kg/s entering at 15?C. Assuming that the specific heat of the air is constant, calculate the ratio of the length of the new heat exchanger to the length of the original.GIVENA simple adiabatic air-to-air counter flow heat exchanger:Case 1Σ Warm air temperaturesTh,in = 65?CTh,out = 38?CΣ Air flow ratesmh = 1.25 kg/smc = 1.6 kg/sΣ Cold air inlet temperature (Tc,in) = 15?CAfter lengthening heat exchanger:Case 2Σ Warm air temperaturesTh,in = 65?CTh,out = 26?CAir flow ratesmh = 1.25 kg/smc = 1.6 kg/sΣ Cold air inlet temperature (Tc,in) = 15?CASSUMPTIONSThe specific heat of air is constantThe overall heat transfer coefficient (U) is the same in bothcases

Water Alr m, = 1.25 kg/s Trout - 38C or 26C Thin - 65C. Tam- 15C Cold Alr me- 1.6 kg/s