Heat transfer and heat exchangers
Heat transfer is involved in all thermal processes and the efficiency of the heat transfer is of utmost importance for the efficiency of the process as a whole.
Energy transfer over a temperature difference always constitutes a thermodynamic loss, and the larger the difference, the larger the loss. For this reason, methods of enhancing heat transfer, i.e. reducing the temperature difference, are important to reach high thermal efficiency of the system.
Research at the Division of Applied thermodynamics and refrigeration started from design of heat pumping equipment involving heat exchange with the ambient and with the fluids or bodies to be cooled or heated. Within the systems, a refrigerant is circulating, changing phase from liquid to gas in the evaporator and back to liquid in the condenser. It is thus natural that the heat transfer research at the division has a focus on two-phase flow, but that enhanced heat transfer in single phase flow is also important.
The research conducted in this area covers:
- Compact heat exchangers
- Enhanced heat transfer
- Cooling of electronics
- Industrial processes, pinch
Projects related to heat transfer during the last ten years have for example been investigating:
- Flow boiling in small channels
- Condensation in vertical rectangular channels
- Heat transfer of nanofluids
- Porous surfaces for enhanced boiling heat transfer
- 3D-printing of heat exchangers