Phase Change Material

Phase Change Material. Phase change materials (PCMs) store thermal energy via the latent heat of phase transitions PCMs can be used to provide district cooling (subambient transition temperatures) to buffer thermal swings in buildings (near ambient transition temperatures) and to store solar thermal energy for shortterm or seasonal applications (higher transition temperatures).

What Is Meant by Phase Changing Material?Characteristics and Classification of Phase Change MaterialsWhat Are The Best Phase Change Materials?Applications of Phase Change MaterialsFire and Safety IssuesWhen substances change phase thermal energy is absorbed and released (known as latent heat) When a solid material melts it transforms into a liquid Many materials have the ability to absorb a large quantity of heat energy during the phase transition When a substance freezes and solidifies the heat it received while melting is released At different temperatures different materials melt and solidify and they may absorb varying amounts of heat energy Because phase change materials melt and solidify at precise specified temperatures they can be used to control the temperature in a wide range of applications When compared to sensible heat energy materials materials that melt to absorb heat are substantially more efficient at absorbing heat energy This indicates that storing heat energy in a phase change material requires a significantly less amount of material than storing heat energy in a nonphase change substance In what follows we are going to describe essential term Variations in the state of matter from liquid to solid solid to liquid solid to gas and liquid to gas can all be used to store latent heat PCMs on the other hand can only go from solid to liquid or liquid to solid Despite the fact that liquid–gas transitions have a higher heat of transformation than solidliquid transitions liquid to gas phase conversion is impractical for thermal storage because it requires huge volumes or high pressures to keep materials in their gas phase Solid–solid phase transitions are usually extremely slow and have a low heat of transformation Solidliquid PCMs initially behave like sensible heat storage (SHS) materials with their temperature rising as heat is absorbed When PCMs reach their phase transition temperature (melting point) unlike typical SHS materials they absorb a huge amount of heat at a nearly constant temperature until the entire material is melted When the temperature around a liquid substance drops the PCM hardens releasing Phase transition materials are divided into various categories Paraffin waxes are the most used PCM for electronics thermal control because they have a high heat of fusion per unit weight a wide melting point range dependable cycling a noncorrosive feature and are chemically inert Due to the volume transition from solid to liquid void management is critical when designing with paraffin PCM Because paraffin PCMs have a low heat conductivity creating enough conduction routes is another important design consideration Another type of salt is hydrated salts These PCMs have a high fusion heat per unit weight and volume a high thermal conductivity for nonmetals and minor volume fluctuations between solid and liquid phases Because they are corrosive and have low longterm durability (thousands of cycles) they are not typically used for electronic heat sinks The most prevalent application is for very large thermal storage applications (for example solar heating) where a r Phase change materials are used in a variety of applications including but not limited to 1 Storage of thermal energy 2 Heat dissipation and electrical engines 3 Use of power during offpeak hours 4 Cooking with the sun 5 Food beverages coffee wine milk products and greenhouses that require cooling 6 Delaying the production of ice and frost on surfaces 7 Recovery of waste heat 8 Batteryfor Cold Energy 9 Building conditioning 10 Under heavy garments the human body cools down 11 In bioclimatic construction passive storage is used 12 Spacecraft thermodynamic systems 13 Textiles that are used to make apparel 14 Blood transfer operating tables hotcold therapies and the treatment of birth asphyxia are all examples of medical applications 15 Exothermic temperature peaks in chemical processes are smoothed 16 Electronic device thermal protection 17 Food thermal protection transportation the hotel trade ice cream and so on 18 Chilling of the turbine in Some phase change materials are harmless and can be suspended in water Others are poisonous or include hydrocarbons or other combustible elements As a result PCMs must be carefully chosen and applied in line with fire and building rules as well as sound engineering techniques Because of the increased fire danger flame propagation smoke possibility for the explosion in containers and liability flammable PCMs should not be used in residential or other regularly used structures Electronics use phase change materials for temperature regulation as well.

Phase Change Materials: Thermal Management Solutions

An introduction to Phase Change Materials Phase Change Materials (PCMs) are ideal products for thermal management solutions This is because they store and release thermal energy during the process of melting & freezing (changing from one phase to another) When such a material freezes it releases large amounts of energy in the form of latent heat of fusion or energy of crystallisation.

Phase Change Material an overview ScienceDirect Topics

Phase change materials work by absorbing and releasing large amounts of latent heat depending upon their state When they reach a freezing point they turn into a solid and release stored heat at a consistent temperature This allows for better control As phase change materials reach their melting point they turn into liquids.

Phasechange material Wikipedia

Phase change materials (PCMs) are substances which absorb or release large amounts of socalled LayerContentThickness (mm)Density (kg M − 3)Thermal Conductivity (w M − 1Cotton fabric0823615200612Nonwoven polyester with PCM4521462901073Heating fabric0704813200734Nonwoven polyester165514720086.