Experimental study of phase change materials for thermal storage in the temperature range of 300–400°C

Phase change materials (PCM) based on inorganic salts having a temperature of fusion between 300 and 400°C, were investigated using a lab scale set-up dedicated for studying latent heat storage for concentrating solar thermal power (CSP) technology. This experimental system provides thermal measurements of PCM specimens of about 1000 g under the heating temperature up to 450°C and enables simultaneous investigation of calorimetric properties of the loaded materials and heat transfer effects developed in the thermal storage during the charge and discharge phases. The measurement technique comprised temperature and pressure sensors, a control and data acquisition system and a thermal analysis model used to evaluate the experimental data. Results of the thermochemical tests conducted with a thermal storage medium composed of the ternary eutectic mixture of carbonate salts (34.5% K2CO3–33.4% Na2CO3–32.1% Li2CO3) and Diphyl (synthetic thermal oil, max working temperature 400°C) used as the heat transfer fluid are presented and discussed in this paper

Evaluation of solar thermal storage for base load electricity generation

In order to stabilize solar electric power production during the day and prolong the daily operating cycle for several hours in the nighttime, solar thermal power plants have the options of using either or both solar thermal storage and fossil fuel hybridization. The share of solar energy in the annual electricity production capacity of hybrid solar-fossil power plants without energy storage is only about 20%. As it follows from the computer simulations performed for base load electricity demand, a solar annual capacity as high as 70% can be attained by use of a reasonably large thermal storage capacity of 22 full load operating hours. In this study, the overall power system performance is analyzed with emphasis on energy storage characteristics promoting a high level of sustainability for solar termal electricity production. The basic system parameters, including thermal storage capacity, solar collector size, and annual average daily discharge time, are presented and discussed

Experimental study of phase change materials for thermal storage in the temperature range of 300–400°C

Phase change materials (PCM) based on inorganic salts having a temperature of fusion between 300 and 400°C, were investigated using a lab scale set-up dedicated for studying latent heat storage for concentrating solar thermal power (CSP) technology. This experimental system provides thermal measurements of PCM specimens of about 1000 g under the heating temperature up to 450°C and enables simultaneous investigation of calorimetric properties of the loaded materials and heat transfer effects developed in the thermal storage during the charge and discharge phases. The measurement technique comprised temperature and pressure sensors, a control and data acquisition system and a thermal analysis model used to evaluate the experimental data. Results of the thermochemical tests conducted with a thermal storage medium composed of the ternary eutectic mixture of carbonate salts (34.5% K2CO3–33.4% Na2CO3–32.1% Li2CO3) and Diphyl (synthetic thermal oil, max working temperature 400°C) used as the heat transfer fluid are presented and discussed in this paper

Experimental study of phase change materials for thermal storage in the temperature range of 300–400°C

Phase change materials (PCM) based on inorganic salts having a temperature of fusion between 300 and 400°C, were investigated using a lab scale set-up dedicated for studying latent heat storage for concentrating solar thermal power (CSP) technology. This experimental system provides thermal measurements of PCM specimens of about 1000 g under the heating temperature up to 450°C and enables simultaneous investigation of calorimetric properties of the loaded materials and heat transfer effects developed in the thermal storage during the charge and discharge phases. The measurement technique comprised temperature and pressure sensors, a control and data acquisition system and a thermal analysis model used to evaluate the experimental data. Results of the thermochemical tests conducted with a thermal storage medium composed of the ternary eutectic mixture of carbonate salts (34.5% K2CO3–33.4% Na2CO3–32.1% Li2CO3) and Diphyl (synthetic thermal oil, max working temperature 400°C) used as the heat transfer fluid are presented and discussed in this paper

High temperature thermal energy storage an experimental study

This experimental study deals with the thermal energy storage based on phase change effects of melting and vaporization in the storage medium. The phase change materials considered are chloride and fluoride salts having a melting point within the 600-1300°C temperature range. These salts are known to have extremely low thermal conductivity resulting in a substantially large heat exchanger surface embedded in the storage medium. Thermal performance enhancements of the storage systems can be obtained, however, by introducing an intermediate medium of high thermal conductivity to transfer heat from the salt to the heat exchanger. Liquid sodium Na has been selected for this purpose, on the analogy of pool boilers. The experimental results of this work have successfully demonstrated the effect of reflux evaporation - condensation heat transfer employed. It was shown that a storage system containing NaCl-Na could be operated for a prolonged time at a stable outlet working gas temperature of 780°C while the storage temperature was as high as 800°C. The factor that controlled the process of heat discharge was heat and mass transfer occurring on the NaCl-Na interface