Mert Gürtürk

Energy and exergy analysis of a heat storage tank with a novel eutectic phase change material layer of a solar heater system

ABSTRACT Solar energy is one of the most important renewable energy sources, but it is not available every time and every season. Thus, storing of solar energy is important. One of the popular methods of heat storage is use of phase change materials (PCMs) which have large thermal energy storage capacity. In this study, the heat storage tank in a domestic solar water heating system was chosen as control volume. The experiments were performed in the province of Elazıg, Turkey, in November when solar radiation was weak due to cloudy sky. The heat storage tank of the system was modified to fill PCM between insulation and hot water part. A few PCMs which are Potassium Fluoride, Lithium Metaborate Dihydrate, Strontium Hydroxide Octahydrate, Barium Hydroxide Octahydrate, Aluminum Ammonium Sulfate, and Sodium Hydrogen Phosphate were analyzed to proper operating conditions using a Differential Scanning Calorimeter (DSC) and the best PCM was obtained with the Aluminum Ammonium Sulfate and Sodium Hydrogen Phosphate mixture. Thus, eutectic PCM was obtained and used in a heat storage tank of the solar water heating system. Energy and exergy analysis of heat storage tank was performed with and without the PCM. Energy and exergy analysis has shown that the heat storage tank with the PCM is more efficient than without the PCM and the maximum exergy efficiency was obtained as 22% with the heat storage tank with the PCM.

Energy and Exergy Analysis of a Perlite Expansion Furnace

Utilization opportunities of perlite have made the product adaptable to numerous applications in the construction, industrial, chemical, horticultural and petrochemical industries. Applications of the perlite include filler, high and low temperature insulation, concrete aggregate, textured coatings, absorbent and carrier etc. Thus, perlite seems to be a very important material. In this paper, thermodynamics analysis of a perlite expansion furnace was performed. Both energy and exergy relations were derived for the considered system. Some parameters, such as losses, irreversibility and design etc., were used for determining the energy and exergy efficiencies. Based on the results of the analysis of the system, the energy and exergy efficiencies are calculated to be 66 and 26 %, respectively. Some recommendations were also made towards increasing the efficiency in the Turkish perlite industry.