Abstract
When a heated solid body temperature reaches the melting point, temperature stops increasing and remains constant until the whole body is completely molten. The heat input during this melting is spent on freeing the body molecules. This latent heat of melting remains inside the body and may be released when the body is cooled and solidifies. This heat was suggested, already several decades ago, for storing thermal energy. The advantage it offers is avoiding high temperature differences - which otherwise decrease effectiveness of storage (by inevitable heat escape by conduction). Also the mass of the body needed to store a given amount of heat is much smaller. For investigations of the melting and solidification processes a special wind tunnel has been designed and is being built in this study. The tested sample of phase change material, encapsulated in a spherical shell, will be exposed in the tunnel to recirculating hot air flow in a 140 mm x 140 mm test section. Sudden decrease in air flow temperature is made by shifting away the whole closed-circuit part of the tunnel and exposing the test section to flow of cold (room temperature) air.
Highlights
One of the main problems with energy – perhaps the crucial one - is mismatch between availability and demand
High temperature differences suffice with a small storage body but may cause problems – such as too much heat escaping through inevitably imperfect insulation by conduction
The advantages obtainable from the isothermal energy storage were soon recognised as attractive possibility – apparent by comparing in Fig. 3 the difference between the final state 2* without the phase change and 2 with the latent heat
Summary
One of the main problems with energy – perhaps the crucial one - is mismatch between availability and demand. The advantages obtainable from the (very nearly – note the differences needed at the process beginning and end) isothermal energy storage were soon recognised as attractive possibility – apparent by comparing in Fig. 3 the difference between the final state 2* without the phase change and 2 with the latent heat. Promising is the current development of “smart” textiles, containing tiny encapsulated volumes of the phase change material among the fibres of the woven yarn With this textile material, typically for use in battle-dress uniforms in desert combat areas, the latent-heat beads can cool the soldier during the hot desert day (while being charged by the solar heat) – and heating him in the cold desert night (discharging the accumulated heat) [3]. Dependence between variations of temperature and internal thermal energy of a substance with and without phase change between the input state 1 and final states 2 or 2*
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
