Innovative concept of vortex generator-equipped multi-drain heat recovery systems–Numerical study and energetic analysis

In light of the environmental concerns associated with the misuse of fossil fuels and the increasing consumption of energy, heat recovery systems have become an essential option for conserving energy. In this study, an innovative design that couples a highly efficient vortex generator-based heat exchanger with a new multi-drain water application for 48 accommodations is suggested. A numerical study is done by varying the flow rate and investigating the effect on the heat transfer, overall heat transfer, and thermal enhancement factor. Besides, the economic and environmental impacts of the system are studied to investigate its sustainability. Four types of input energy are studied: coal, diesel, gas, and electricity. Results show that the design provides a temperature increase of 3.5 to 7.5 °C of cold water, consequently, the daily environmental savings are up to 0.87 € (for gas), 1.74 € (for diesel), 4.63 € (for coal), 17.63 € (for electricity US) and 2.26 € (for electricity FR). Besides, the daily economical savings are up to 7.54 $, 8.63 $, 4.63 $, and 15.07 $ respectively with a payback period of around 0.61, 1.2, 1.42, and 2.89 years for gas, diesel, coal, and electricity respectively.