The Challenge
Cooling towers for power stations and large air condition plants are among the largest industrial consumers of fresh water in Australia. In these processes waste heat is conveyed by warm water which is evaporated and mixed with cooler air inside cooling towers and then released to the atmosphere. In Victoria, estimates of water consumption for these two purposes total almost 100 gigalitres per annum. Cooling towers around Melbourne not only lose fresh water, but are known sources for outbreaks of Legionnaires’ disease.
A highly compact polymer heat exchanger has been developed with the objective of replacing cooling towers currently used in power stations and large air conditioning systems. This heat exchanger is a closed system and is designed not to lose water while transferring waste heat. Industry wide adoption of this heat exchanger technology would result in significant conservation of water and contribute to a reduction in the occurrence of Legionnaire’s disease associated with air conditioning cooling towers.
The Project
This project developed the concept of constructing heat exchangers using polymer materials in place of metals. The advantages of polymer materials include their low cost, corrosion resistance and easy fabrication in comparison with aluminium and copper which are the main materials used in heat exchangers for industrial applications.
The first steps were the design and construction of a compact polymer heat exchanger for testing in an experimental laboratory setup at Victoria University. This allowed experiments under various controlled conditions and access to precision instrumentation to gather performance data. The flow and heat transfer data collected were used in computational fluid dynamics (CFD) simulations to further investigate design and performance parameters.
The stability of the polymer in the heat exchanger is essential to success of this technology and a detailed study of the material’s suitability was undertaken to test its performance under simulated operating conditions.
Field experiments were conducted at Yallourn power station for simple air-cooling and for hybrid cooling configurations to test the performance of the polymer heat exchanger in actual operating conditions.
The Outcome
New technologies for waste heat management can significantly reduce water consumption and with further development, offer major benefits to the community.
This project demonstrated that compact polymer heat exchangers can be used to replace the cooling towers used in power stations and large air-conditioning systems. This finding opens the path to major water savings. Polymer heat exchangers can also be successfully used to replace metal heat exchangers currently used in air-handling units of air-conditioning systems and air coolers. The main advantages of polymer heat exchangers are low cost, corrosion resistance, and ease of maintenance.
Development of commercially viable products requires further work on fabrication techniques for ensuring reliable water tightness in polymer heat exchangers.
Further participation of industry partners to test and develop the performance of the polymer heat exchangers in field applications is needed to gain market acceptance for the wide spread adoption of polymer heat exchangers.
