Performance evaluation of latent heat TES system-case study:Dimensions improvements of annular fins exchanger

Thermal Energy Storage (TES) is an important challenge for the development and implementation of Concentrated Solar Power (CSP) plants. The heat can be stored in a sensible, thermochemical or latent form. Recently, the latent heat thermal energy storage (LHTES) kind has gained the most of research interest as it has the advantage of increasing the energy density of the current commercial TES systems through the use of a Phase Change Materials (PCM). However, the main limitation of PCMs technology is the low thermal conductivity, which affects the system performances and lead to significant energy losses. In this sense, a good container design can impact positively the system performances. For that sake, several designs have been proposed to overcome the decreasing heat transfer rate. For this purpose, this study propose many enhancements and improvements of the fins method based on the integration of PCM in an exchanger with annular fins. The main objective of this paper is to study the impact of finned exchangers on the total flow transferred and also on the height of these annular fins. Finally, the physical model describing the thermal behavior of the studied system is developed and simulated after 80 min of charging process.</p

Experimental and numerical investigation of potential filler materials for thermal oil thermocline storage

A thermal energy storage system (TES) is a key technology to ensure continuous power supply from solar thermal power plants. Choosing the appropriate storage method and the suitable material for energy storage remains a major challenge in research and development in the solar power field. The sensible heat storage in solid media using thermocline system is a significant cost-effective option when compared to liquid storage material in two tank system. An incorporation of this potential concept is the oil/rock thermocline system which is based on the direct contact between natural rocks chosen as filler material and thermal oil as the heat transfer fluid (HTF), and it is used in the Concentrated Solar Power (CSP) plants. The present paper highlights the thermal energy storage potential of six rocks (quartzite, basalt, granite, hornfels, cipolin and marble) proposed as filler material for thermal oil thermocline storage concept. These rocks were chosen according to their abundance in Morocco. Different technical methods were performed in order to assess the rocks properties (physical, chemical and thermal) at temperatures up to 350 °C (temperature operating conditions using linear Fresnel reflectors or parabolic trough). The thermal performances of the studied rocks inside a thermocline storage system were evaluated using a validated numerical model. Based on the experimental investigation two rocks (Quartzite and Cipolin) were identified as the most suitable filler materials to be used in direct contact with the studied HTF (synthetic oil). While, the numerical analysis revealed that Basalt rock has the best thermal performances inside the studied thermocline storage system concept, but it isn't chemically compatible with synthetic oil. Hence, it can be used advantageously with other heat transfer medium (e.g. Air).</p

Performance evaluation of latent heat TES system-case study:Dimensions improvements of annular fins exchanger

Thermal Energy Storage (TES) is an important challenge for the development and implementation of Concentrated Solar Power (CSP) plants. The heat can be stored in a sensible, thermochemical or latent form. Recently, the latent heat thermal energy storage (LHTES) kind has gained the most of research interest as it has the advantage of increasing the energy density of the current commercial TES systems through the use of a Phase Change Materials (PCM). However, the main limitation of PCMs technology is the low thermal conductivity, which affects the system performances and lead to significant energy losses. In this sense, a good container design can impact positively the system performances. For that sake, several designs have been proposed to overcome the decreasing heat transfer rate. For this purpose, this study propose many enhancements and improvements of the fins method based on the integration of PCM in an exchanger with annular fins. The main objective of this paper is to study the impact of finned exchangers on the total flow transferred and also on the height of these annular fins. Finally, the physical model describing the thermal behavior of the studied system is developed and simulated after 80 min of charging process.</p