Design, Construction and Analysis of a Flat Heat Pipe. A Trident Scholar Project Report, No. 261

摘要

Thermophotovoltaic (TPV) energy conversion utilizes photons from a thermal radiator to convert photonic energy to electrical energy. Due to the nature of the system, the thermal radiator must emit uniform radiation and therefore maintain a uniform temperature profile in order to achieve maximum efficiency. Heat pipe technology can effectively meet the demand for an isothermal emitter as it utilizes near isobaric phase changes to transfer heat at a uniform temperature. In this project, heat pipes are explored for use in TPV energy conversion systems. A flat heat pipe offers many advantages over the conventional cylindrical design. These include increased surface area to volume ratio in order to maximize power density, as well as the ability to stack or layer the system with photovoltaic (PV) cells on both sides of the flat heat pipe to utilize available energy. Not only do flat heat pipes present unique engineering demands inherent in their operation to counteract pressure differences across their vessel walls, but they are also difficult to construct. To date, only limited analyses of their thermal characteristics have been done for use in performance predictions. Therefore, it is necessary to conduct analyses to enable consideration of heat pipes for implementation into TPV systems. This report details the design and construction of a flat heat pipe analysed both in symmetric and asymmetric heating conditions, involving a low temperature version of future emitter designs due to safety considerations. Water was used as a working fluid instead of the liquid metal required to achieve the temperatures of a functional emitter. Despite this difference in working fluid, the data presented is valuable to both TPV and heat pipe research.