About Our PureTemp™ PCMs back to top
Entropy Solutions has developed a range of phase change materials (PCMs) from vegetable-based fats and oils during a Phase 1 and 2 SBIR Program and has made these PCMs available for use in consumer products. While most traditional PCMs are derived from petroleum, our innovative, bio-based PCMs are 100% environment-friendly and renewable.
The term "phase change materials" is used to describe materials that use phase changes (e.g., melting or freezing) to absorb or release a significant amount of latent heat at relatively constant temperatures.
As indicated by Table 1, the amount of energy consumed in HVAC applications in a given year across the United States is about the same as the amount of energy burned in gasoline engines. The HVAC industry represents a market potential in excess of 10 billion pounds of PCMs per year.
| Table 1. Summary of largest energy applications in U.S. Numbers are energy in quadrillions BTU | |
| Amount of gasoline consumed | 15 |
| Electricity produced | 12 |
| Approximate energy expended on producing electricity | 34 |
| Energy consumed for HVAC (including water heaters) | 14 |
How PCMs Work back to top
Initially, PCMs behave like sensible heat storage (SHS) materials; their temperature rises as they absorb heat. Unlike conventional SHS, however, when PCMs reach the temperature at which they change phase (their melting temperature) they absorb large amounts of heat at an almost constant temperature. The PCMs continue to absorb heat without a significant rise in temperature until all the material is transformed to the liquid phase. When the ambient temperature around a liquid material falls, the PCMs solidify, releasing their stored latent heat. PCMs store up to 14 times more heat per unit volume than do conventional storage materials such as water, masonry or rock.
A Simple Illustration of PureTemp™ in Action back to top
Most coffee is brewed at 82°C. Optimal drinking temperature is around 57°C. As we all know, it takes a few minutes to cool coffee to an optimal drinking temperature. When PureTemp™ is used in the walls of the coffee cup, the cup will remove and store the heat from the coffee when it is too hot, and cool it to the 57°-60°C range. Once the coffee temperature starts to drop below 57°C, the cup will automatically begin to release the heat that it captured when the coffee was too hot, maintaining the optimal drinking temperature range for up to 60 minutes.
In this particular case, the PCM was created to melt and freeze at 57°C. When hot coffee at 82°C is added to the coffee cup, the heat from the coffee will cause the PCM to melt. This melting process causes a cooling effect. It is the same cooling effect that ice has when it melts at 0°C. When most pure materials melt and transform from a solid to a liquid there is a cooling effect.
Conversely, when the coffee starts to cool down and drops below 57°C the PCM, which was melted, will start to solidify. This solidifying process causes a heating effect. It is the same heating effect that hot liquid wax has when it solidifies (for instance, when dripped on a table). When most pure materials solidify and transform from a liquid to a solid there is a heating effect.
Note that this is a passive process that requires no batteries, electricity or extra handling. Entropy Solutions' PCMs are simple thermal storage mediums created from non-toxic, vegetable-based substances.
The coffee analogy is but one example of how a PCM can be used to keep an object cooled down at a specific temperature or heated to a specific temperature. PCMs are a highly efficient way to sustain specific temperatures for prolonged periods of time. At Entropy we are able to target any temperature range between -40°C and +151°C, and we can tailor our PCM technology to work in numerous other applications where temperature moderation is desired.
Phase Change Product Listing back to top
Please click on the links below to see the sample DSC curves
| PCM | Melting temp. C° | Latent heat (J/g) |
| PureTemp -40 | -40 | 170 |
| PureTemp -14 | -14 | 150 |
| PureTemp -12 | -12 | 170 |
| PureTemp 4 | 4 | 205 |
| PureTemp 7 | 7 | 170 |
| PureTemp 15 | 15 | 205 |
| PureTemp 18 | 18 | 195 |
| PureTemp 23 | 23 | 208 |
| PureTemp 27 | 27 | 200 |
| PureTemp 30 | 30 | 160 |
| PureTemp 37 | 37 | 235 |
| PureTemp 40 | 40 | 170 |
| PureTemp 43 | 43 | 180 |
| PureTemp 48 | 48 | 273 |
| PureTemp 50 | 50 | 205 |
| PureTemp 53 | 53 | 185 |
| PureTemp 55 | 55 | 193 |
| PureTemp 56 | 56 | 251 |
| PureTemp 61 | 61 | 205 |
| PureTemp 68 | 68 | 210 |
| PureTemp 103 | 103 | 160 |
| PureTemp 151 | 151 | 175 |
The temperatures shown above are within close proximities of the "true" melting temperatures. Due to the nature of PCMs, there is a narrow range in which the PCM melts.
If your specifications require a different temperature, you need to know if the melting range covers your specifications, or you would like to discuss a potential application, please call or email us.