BRE Global technical author Corinne Williams answers 5 questions about her new publication Assessing the performance of Phase Change Materials in buildings.
Question 1: Did you have to test several cocktails during the writing of this publication?
No! The ice cube example is a simple way to explain how PCMs work. Ice is a commonly used and well known PCM. An ice cube absorbs heat from a drink. When the ice cube reaches its melting temperature, it changes phase – from a solid to a liquid – and it absorbs large amounts of energy (at constant temperature) and cools the drink in the process.
Question 2: So what are PCMs?
A PCM is a material or substance which when changing its state – for example, from solid to liquid or liquid to solid – is capable of storing or releasing large amounts of energy at a constant temperature (the transition temperature). PCMs are referred to as latent heat storage materials.
Question 3: How are PCMs used in construction?
PCM construction products need to be considered as part of the overall package of temperature control measures in a building and early specialist advice is desirable to ensure they are applied correctly and appropriately.
They can be used to provide thermal mass to buildings with low thermal mass to improve the thermal performance and indoor comfort.
PCMs incorporated into different construction products are available. Most of their applications are for inside buildings, such as ceilings and walls. PCM construction products come in various physical forms such as panels, plaster, boards and tiles and are available for different operating (or transition) temperatures.
PCMs in construction products simply absorb latent heat energy from the indoor environment when they change from solid to liquid when the indoor air temperature reaches the transition temperature, during the day. This process needs to reverse when the temperature drops during the night so the cycle can restart the next day.
Question 4: Where are PCMs being used?
There are a number of demonstration and exemplar buildings where PCMs have been installed. Three examples are:
- the east wing of Somerset House, London, using clay boards containing PCM
- the visitor centre at the BRE Innovation Park, Ravenscraig, Lanarkshire, incorporating a PCM ceiling panel system
- the BASF Research House at the University of Nottingham, using PCM wall boards.
Question 5: What is your favourite cocktail?
I’m not an expert on cocktails but my favourite would be something non-alcoholic, involving strawberries!