Development and evaluation of a prototype concentrating solar collector with thermocline based thermal energy storage for residential thermal usage

A prototype of a concentrating solar collector (CSC) receiver was designed, built, and evaluated on-sun at the University of Texas at El Paso in El Paso, TX. This prototype receiver consists of two parabolic trough-reflectors but, in principle, the design can be efficiently extended to multiple units for achieving a higher temperature throughput. Each reflector has a vacuum tube collector at the focal point of the trough. The solar collector system was combined with a single-tank thermocline thermal energy storage (TES) for off-solar thermal usage. The main goal of this study is to develop an advanced solar hot water system for most residential applications. The focus of this study is to investigate the feasibility and performance of the solar thermal system by employing the recent advancement in the TES-a thermocline based TES-system for the concentrating solar power technologies developed by the Sandia National Laboratories and National Renewable Energy Laboratories for electricity production. A CSC when combined with TES has potential to provide uninterrupted thermal energy for most residential usages. This paper presents a detailed description of prototype design and materials required. The thermal energy storage tank utilizes an insulated 170 l (45 gal) galvanized steel tank. In order to maintain thermocline in the TES tank, with hot water on top and cold water at the bottom, two plate distributors are installed in the tank. The data showed a significant enhancement in thermal energy generation. This thermocline based single tank presented a thermal energy storage potential for at least three days (with diminishing storage capacity) that test were performed. The whole prototype was made for approximately USD 355 (excludes any labor costs) and hence also has strong potential for supplying clean thermal energy in most developing countries. Tests of the prototype were conducted in November 2011. (C) 2013 AIP Publishing LLC.