Assessment of the optimum operation conditions of a plate heat exchanger for waste heat recovery in textile industry

Textile industry plays an important role economically in Turkey. A great amount of hot waste liquids and gases are let out in many textile processes. These waste liquids and gases have crucial energy saving potential, especially for dyeing process. It could be possible to provide energy saving by employing a waste heat recovery system (WHRS). The optimum operation conditions were assessed by integrating the first and the second law of thermodynamics for a counter flow PHE employed for a dyeing process in textile industry. The WHRS has been established by a well-known blanket manufactory located in Usak Organized Industrial Zone (UOIZ), Turkey has been evaluated. While the waste water mass flow rate varies between 8 and 12 m3/h, exergy destruction rate, exergy efficiency and effectiveness of the PHE have the values from 5.55 to 13.68 kW; from 53.6% to 67.2% and from 0.996 to 0.810, respectively. Optimum waste water and cold water mass flow rate was found as 10.00 and 7.00 m3/h, respectively. While the cold water mass flow rate varies between 5 and 9 m3/h, exergy destruction rate, exergy efficiency and effectiveness of the PHE have the values from 8.05 to 10.89 kW; from %56.3% to %63.9% and from 0.868 to 0.991, respectively. While the waste water inlet temperatures vary between 52.4 and 59.5 °C, exergy destruction rate, exergy efficiency and effectiveness of the PHE have the values from 5.40 to 9.46 kW; from 68.7% to 61.6% and from 0.969 to 0.924, respectively at optimum mass flow rates. The present study has a great potential to serve applications of WHRS for textile application especially dyeing process. It is expected that the approach presented here would be beneficial to everyone involved in the design and performance evaluation of WHRS with PHE in many industrial sectors. It is clear that employing PHEs operating optimum conditions contribute energy savings, decrease energy cost, improve environmental impacts and shorten process period and supply economical benefits for textile industry as well as the other industrial sectors.