NAERINGSPH-Nærings-phd

The present project aims at a synthetic design of cooling system, in which the power consumption, e.g. for pumping the coolant fluid, and the cooling efficiency are taken into consideration in a synchronic manner. The constructual law, which writes "For a finite-size system to persist in time (to live), it must evolve in such a way that it provides easier access to the imposed currents that flow through it", will be applied to the design procedure. It is note worthy that the "flow" in the quoted statement refers to both the actual fluid flow and the hypothesized "heat flow". The constructual law applied in the design process of the present project, mimicking the naturally evolved flow systems, e.g. river basins, circulatory systems, tree-branch architectures, etc., is serving as a guideline for achieving a better configuration that possess higher cooling efficiency while the flow friction loss (or equivalently the pumping power required) is kept as low as possible. The implementation of the present project is aligned with the long term development strategy of Trilobite AS, which is developing water purification systems employing high power LED and ultrasonic devices where a significant amount of heat is to be removed to ensure a stable performance. Given a limited space with complex constraints for deployment, the cooling systems that are currently available in the market usually suffer from the difficulties encountered in their integration with the rest of the system. Thus, it becomes one of our prior concerns seeking for an appropriate solution that incorporates the integrability and feasibility in practice. Moreover, since the thermal management of increasingly miniaturized system with tremendous cooling requirement itself is a potential market of billions of US dollars, Trilobite AS is in the meanwhile premeditating its development on an individual track.

We hoped for the development of a new technology for heat disipation. This was fulfilled and the outcome of the project and impacts are the following: - Patent Filed -New business area is forming - Additional technology for main area in Trilobite - Possible side-tracks with analytical technology started - Further continuation of the project into a product started

The primary focus of this project is to carry out an insightful investigation on the heat transfer enhancement of high flux applications with limited packaging space, i.e. Integrated Circuits (IC) cooling, solar energy harvesting, spacecraft thermal control, etc., in which the impact of micro/ nanostructure might be significant. In general, heat transfer enhancement technologies fall into two major categories referred to as active or passive type. The active type usually introduces the forced convective flow driven by an external propeller i.e. a fan or a pump, or a system rotation/vibration to increase the thermal energy exchange rate between the bulk flow and the thermal boundary layer adjacent to the heated surface. Not to mention the miniaturization of the cooling system, more specifically the thermal resistance between the device enclosure and the ambient which is dominated by natural convection and radiation heat transfer, both are of passive type and little improvement can be achieved due to their physical mechanism. On the other hand, cooling methods for high power density devices are always expected to have steady operation condition and low power consumption levels. Active cooling technologies, like conventional fin-fan units or even the more advanced solutions e.g. electrostatic fluid accelerator and hybrid jets, are either lack of competence or not realistic to implement on portable devices regarding the aforementioned constraints. In the present project, a novel passive heat dissipation design procedure based on constructal law, which utilizes the thermal boundary layer intervention by optimized structure/layout design will be proposed with least presence of all deficits previously encountered.