Organic Positive Temperature PCMs
As mentioned on the first page, a number of organic materials have been identified as potential PCMs, including waxes, oils, fatty acids and polyglycols.
There are several factors to consider when developing organic PCMs, but the most important are usually cost, latent heat, and freezing/melting range.
All the above materials comprise of long chain molecules, usually with a carbon backbone, and the freezing/melting point is dependent on the number of carbon molecules in the backbone, i.e. longer chain equals higher melting point.
The prefix "A" in the product range stands for "Aliphatic" which is a general term for these sorts of long chain molecules.
PlusICE Organic PCM Solutions
The materials from this group that have the highest latent heat and the most precise freezing/melting point are pure, single chain length compounds, such as pure linear hydrocarbons. Unfortunately, these materials can only be produced by extensive processing and purification and so for almost all applications are prohibitively expensive. At the other end of the scale are naturally occurring blends such as vegetable oils and animal by-products, such as fats. These materials are very attractive economically, but they contain a wide range of molecules with different chain lengths. Each of these has its own freezing/melting point, so the resulting product changes phase gradually over a wide temperature range. Since most PCM energy storage applications are required to operate within a narrow phase change temperature, these materials are generally unsuitable. Additionally, materials such as fats and fatty acids are prone to oxidation over time and must be treated with anti-oxidants to prevent this.
Over the years PCM Products has developed a wide range of phase change materials that have good latent heats, narrow phase change temperature ranges, and are economical. All the components are non-toxic and non-hazardous. They are non-flammable, although some of the lower temperature PCMs are classed as combustible. They are all positive temperature PCMs - there are many organic materials that could be used in sub-zero applications, but these tend to be extremely flammable at ambient temperatures
The organic PCMs are extremely easy to handle in their solid and liquid states, and unlike the water based PCMs do not require encapsulation to protect them from the atmosphere. They can also be modified in a number of ways, such as thickening, incorporation into a solid polymer, or adsorption onto a dry free flowing powder. Further details of this can be found in our Products section.