Abstract: A thermal energy storage system is provided that includes a container for containing a phase change material, a jacket connected to the exterior of the container. A compartment is formed between the jacket and the container, the jacket having an inlet for receiving a heat transfer fluid into the compartment and an outlet for discharging heat transfer fluid from the compartment. Thermal energy is transferred from the heat transfer fluid present in the compartment to the phase change material, and a flow guide provided in the compartment for guiding and distributing the heat transfer fluid that enters through the inlet. At least one side of the flow guide is welded to the jacket. The flow guide includes a concealing portion which extends from the at least one side. The concealing portion extends across the inlet and is spaced apart from the inlet.

Abstract: A thermal energy storage is provided that includes a first container for a phase change material and a jacket connected to the first container. A space is formed between the jacket and the first container, a heating chamber is provided that includes a heating device, the heating chamber being in fluid communication with the jacket, a second container for a heat transfer fluid, a pump arrangement for pumping the heat transfer fluid from the second container, via the heating chamber, and to the said space formed between the jacket and the first container, in order to cause thermal energy to be transferred between the heat transfer fluid and the phase change material. The heating chamber has a projecting portion that extends through a wall of the second container such that a connecting interface between the pump arrangement and the heating chamber is located inside the second container. If any heat transfer fluid leaks through the connecting interface it remains in the second container.