Experimental investigation of the temperatures and performance of a commercial ice-storage tank

[EN] This paper presents the results of an experimental installation with an internal melt-ice-on-coil tank which has a total capacity of 172 kWh. The aim of this work is to analyse the freezing process in a tank with counter-current spiral-shaped coils immersed in around 1855l water. An experimental campaign has been performed with different inlet temperatures and mass flow rates of the heat transfer fluid. This study analyses (i) the chiller performance, (ii) the ice-formation process and (iii) the energy consumption of the installation. Supply temperatures between 2.5 C and 5.2 C have been sufficient to charge the tank without using any nucleating agents. The lowest energy consumption has been achieved for the fastest charging tests.The authors gratefully acknowledge ACCIONA Infraestructuras for the financing support and collaboration. Parts of the experimental results used in this work were collected at Federico II University during the project "Layout d'impianto e metodi di controllo innovativi per la refrigerazione domestica, commerciale e professionale". A.W. Mauro acknowledges the financial support provided by Regione Campania.López-Navarro, A.; Biosca Taronger, J.; Torregrosa-Jaime, B.; Martínez Galván, IO.; Corberán, JM.; Esteban-Matías, JC.; Payá-Herrero, J. (2012). Experimental investigation of the temperatures and performance of a commercial ice-storage tank. International Journal of Refrigeration. 36(4):1310-1318. doi:10.1016/j.ijrefrig.2012.09.008S1310131836

Ice formation modelling around the coils of an ice storage tank

This paper aims to develop a dynamic model of the charging process of a commercial ice-storage tank. Firstly, three different 1st order and 2nd order numerical schemes have been compared to solve the transport equation of the heat transfer fluid. Euler s method has finally been chosen as the mass flow rate can vary throughout the charging and it avoids the oscillations which are introduced by Lax-Wendroff s and MacCormack s method. Secondly, the heat transfer outside the coils is analyzed. The numerical complications involved in the creation of the first ice layer around the tubes are discussed and an electrical resistance model is introduced to avoid this problem. The model results have provided a very good agreement with experimental measurements of charging tests which have been performed on a CALMAC ICEBANK tank with a capacity of 172 kWh. The model helps to predict the final part of the latent heat transfer process, where the thermal power is decreased due to the contact between the ice layers around adjacent tubes of the tank.Biosca Taronger, J.; Payá Herrero, J.; López Navarro, A.; Corberán Salvador, JM. (2012). Ice formation modelling around the coils of an ice storage tank. Journal of Physics: Conference Series. 395:12133-12142. doi:10.1088/1742-6596/395/1/012133S1213312142395Zalba, B., Marı́n, J. M., Cabeza, L. F., & Mehling, H. (2003). Review on thermal energy storage with phase change: materials, heat transfer analysis and applications. Applied Thermal Engineering, 23(3), 251-283. doi:10.1016/s1359-4311(02)00192-8Gebhart, B., & Mollendorf, J. C. (1978). Buoyancy-induced flows in water under conditions in which density extrema may arise. Journal of Fluid Mechanics, 89(4), 673-707. doi:10.1017/s0022112078002803Chen, S.-L., & Lee, T.-S. (1998). A study of supercooling phenomenon and freezing probability of water inside horizontal cylinders. International Journal of Heat and Mass Transfer, 41(4-5), 769-783. doi:10.1016/s0017-9310(97)00134-

Performance characterization of a PCM storage tank

This paper presents the experimental results of a versatile latent heat storage tank capable of working with organic phase-change materials within a temperature range from -10 °C to 100 °C. The tank contains a paraffin with a phase-change temperature between 3 °C and 8 °C. Firstly, this study focuses on explaining the design criteria which were followed to build the tank. Secondly, a full experimental characterization of the performance has been carried out. The enthalpy temperature curve, the specific heat and density have been measured for the tested paraffin. The performance of the tank has been analyzed in terms of the vertical stratification within the PCM, the effectiveness, the reacted fraction and the total heat transfer of the tank. The results indicate that up to 78% of the maximum capacity is reached within 4 h. The performance is mainly controlled by the supply temperature and the effect of the mass flow rate is almost negligible given that all the tests are in laminar flow.The authors from the Polytechnic University of Valencia gratefully acknowledge ACCIONA Infraestructuras for the funding of the LHTS installation. The authors from University of Zaragoza would like to thank the Spanish Government for the partial funding of this work within the framework of research projects ENE2008-06687-C02-02 and ENE2011-28269-C03-01.López Navarro, A.; Biosca Taronger, J.; Corberán Salvador, JM.; Peñalosa, C.; Lázaro, A.; Dolado, P.; Payá Herrero, J. (2014). Performance characterization of a PCM storage tank. Applied Energy. 119:151-162. doi:10.1016/j.apenergy.2013.12.041S15116211