Flat plate aluminum heat pipe collector with inherently limited stagnation temperature

Abstract

This paper presents a new flat plate collector technology based on heat pipes. The use of heat pipes can lead to several advantages over direct flow collectors: A simple hydraulic interconnection, an inherently limited stagnation temperature and substitution of copper. This flat plate collector prototype with aluminum heat pipes features all three aspects in one collector. The paper outlines the theoretical modeling approaches and presents the construction of the collector as well as detailed results of measurements of the collector performance. By use of specially designed heat pipes the heat transfer is limited at higher temperatures, which leads to a maximum stagnation temperature of 140°C at the manifold of the collector, thus preventing damages to the solar circuit fluid and solar components. Therefore, cost savings regarding the collector by substituting copper with aluminum and cost savings regarding the solar system due to lowered stagnation temperatures can be achieved.