Phase change materials offer innovative solutions for saving energy
Phase change materials, which can be used in a wide range of applications, enable low cost thermal energy storage solutions for countries such as India, thus reducing energy consumption
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Phase change materials (PCMs) are suitable for storing thermal energy in the form of latent heat and release when required by changing its phase from solid to liquid and vice versa. They absorb or release large quantities of heat at a constant temperature thereby maintaining desirable ambient conditions. Studies conducted to compare phase change (latent heat) and sensible heat storages have shown that a significant reduction in storage volume can be achieved by using PCM as compared to sensible heat storage. Phase change materials find their application in cold storage, temperature controlled food transportation, pharmaceutical transportation, air conditioning, solar applications, thermal wear, building cooling and heating and in fact any industry looking to exploit off peak electricity tariffs for heating or cooling or capturing freely available energy (and we have lots of it – cold nights for warm days and warm days for cold nights!)
Form stable PCM
These materials are nontoxic in nature, flexible, have high latent heat (above 200 kJ/kg, and is the most desirable property for any PCM in any application), high tensile or tearing strength both above and below the melting point of the PCM. Further, it is so stable that it can easily be heated and cooled without leaking out its phase change material. The form stable PCM provide stored heat that has improved safety and handling ability.
These materials are now being tried in jackets for human comfort. People and in particular the country’s defense forces, living in remote areas suffer harsh weather conditions. Form stable PCMs provide the optimum temperature to the body. Any raw PCM when in solid state causes discomfort to the user while working. Using form stable PCM enables the user to bend and do any kind of work with complete flexibility. Moreover, the user always remains protected from any kind of leakage as it is the polymer which is in contact with the body and the chemical is entrapped in the polymer matrix.
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The next question is fast charging in a microwave oven! Poor thermal conductivity limits effective charging in microwave oven. Several technological issues such as sparking or hot spots have been effectively addressed too. With the thermally conductive materials, the heat instantly gets transmitted to adjacent particles. Moreover, the thermally conductive material removes sparking or over heating during microwaving and provides uniform heating and uniform discharging of the said material.
One application is to use these materials as portable ‘ovens’ for keeping food warm over long duration. The product is a simple, low cost, safe and easy to use. These have been incorporated into lunch boxes to keep their contents hot for long duration. It is an effective and efficient method of keeping food hot during long office hours or journeys for users. Elements accessories has launched a lunch box in US called ‘Lava Lunch’ using the same form stable phase change materials. It keeps the food warm for a period of six hours and won the Baby + Child Best New products award presented at NY NOW.
These materials enable low cost thermal energy storage solutions for the developing world. The materials can be transformed into a variety of shapes, sizes and forms; find applications in jackets, apparel, thermal seat cushions, table ware items, hot plates, food warmers, medical wraps, cooling lithium ion batteries, tea coasters or covers for tea cups, seat covers in cars, solar heating application, dining mats, liner of helmet, cold chain transportations, and any heating and cooling applications where leakage is to be avoided. There are immense possibilities for entrepreneurs and companies alike to create a variety of products using these materials!
Samit Jain is the Managing Director of Pluss Polymers Pvt Ltd
Nidhi Agrawal is the Associate – R&D at Pluss Polymers Pvt Ltd
First Published: May 29 2014 | 3:38 PM IST