Plastic Heat Exchangers (PHX) have been introduced into the industry around 40 years ago, for their low cost, high corrosion resistance, low density and ease of manufacture. DuPont was the first company overcoming the design difficulties related to the reduced strength at higher temperatures and the poor thermal conductivities compared to metals, adopting a tube bundle design made of polytetrafluoroethylene (Teflon). At the current state-of-the-art of the technology, different configuration of PHX are commercially available. The operability range in terms of temperature lies within -40° and 120°C. One main issue remains the decreasing mechanical strength of plastic materials with increasing temperature. Waste heat recovery represents one of the primary application categories for PHX, due to the highly corrosive environment for conventional metallic heat exchangers.
In this context, we propose a student project with the aim of designing plastic heat exchangers as evaporators and condensers for organic Rankine cycles for waste heat recovery applications, where corrosive environment is present and HEXs are subjected to high degrees of fouling.
The focus will be the integrated study of the component with the thermodynamic cycles to assess the techno-economic feasibility of ORCs with plastic components. The starting point will be given by a previously conducted Master thesis (http://findit.dtu.dk/en/catalog/2386036882
), where different configurations of HEXs were proposed as evaporator and jacket water heat exchangers, and different materials were found suitable from both a thermodynamic and mechanical stand-point.
A starting point for the work is described by the following:
- Heat exchanger modelling accounting for plastic behavior (both in terms of mechanical and thermal performance)
- Component integration into the thermodynamic cycle (possibly techno-economic analysis, exergy analysis, comparison between different cycle layouts)
- Assessment of the economic benefit of using plastic material during the entire lifetime of operation of the plant
The aforementioned points/tasks are open for further discussion and the work can be extended or adjusted according to the students’ preferences.
We look for master students with a background in thermodynamics and heat transfer, and possibly a basic knowledge of materials engineering and solid mechanics.
Numerical work should be carried by using Matlab, for easier integration with previous work. Therefore, a basic knowledge of Matlab programming is preferred.
If you are interested or need further information, please contact Roberta Mancini (firstname.lastname@example.org).
Material for further reading
- Cevallos, J. G., Bergles, A. E., Bar-Cohen, A., Rodgers, P., & Gupta, S. K. (2012). Polymer Heat Exchangers—History, Opportunities, and Challenges. Heat Transfer Engineering, 33(13), 1075–1093
- Gómez Aláez, S. L., Bombarda, P., Invernizzi, C. M., Iora, P., & Silva, P. (2015). Evaluation of ORC modules performance adopting commercial plastic heat exchangers. Applied Energy, 154, 882–890.
Knowledge of thermodynamics and heat transfer. Programming skills, preferably using Matlab