Design of thermal energy storage systems and experimental and numerical investigation of its working parameters

Sustainability of energy is one of the most important problems for using renewable energy resource in our country and also in the World. Energy storage systems are investigated by many researchers as a solution for sustainability of renewable energy resources such as wind and solar. Charging the energy while the energy sources are widely available and then discharging the stored energy when the sources are limited will substantially provide sustainable energy usage. As well as for sustainability of renewable energy resources, energy storage is also important for using current energy systems sustainable, efficient, economical and environmental friendly. In concerning with the air conditioning systems, the load intensity of day time could be reduce with making cool storage at night time. In comparison with the day time, at night time, energy costs and condensation temperature of cooling systems are very low, so cooling systems can be operated more efficiently and economical.In this study, charging and discharging periods of latent energy storage systems are investigated parametrically. The experimental studies are divided into two group as; Shell-and-tube Latent Energy Storage System (Shell-and tube LESS) and Ice-on-coil Latent Energy Storage System (Shell-and tube LESS). At first, phase change process is investigated in a relatively small volume, as shell-and tube LESS, to designate the design and operating parameters of ice-on-coil LESS. Parametric experiments are performed for three different pipe materials, two different shell diameters and for various inlet temperatures and flow rates of heat transfer fluid. Besides, special measurement cards are used to investigate the temperature variations, ice formations and natural convection interactions inside the system. The validation of ice thickness measurement method is performed by comprising the results of present method with photographs and thermocouple measurements. Furthermore, in shell-and tube LESS, calculation of stored (or rejected) energy, unlikely from the literature, a control volume approach is applied with using temperature and ice radius variations.With the aid of the parametric results of shell-and tube LESS experiments, an ice-on-coil LESS is designed and constructed. Ice-on-coil LESS is designed as spiral form, counter flow and staggered arrangement to obtain a homogenous phase change process inside the tank. For ice-on-coil LESS, besides the charging experiments, internal and external melting experiments are also performed for several flow rates, inlet temperatures and heat loads.