Effective heat utilization for energy saving in food and beverage thermal isolated containers

The purpose of this paper is to create a rapid temperature balancing container which can firstly absorb heat from the stored thing to change its temperature within minutes into a desired value set by the melting temperature and type of the used phase change materials (PCMs), and then keep that temperature last longer as the absorbed heat is later released. Models in different geometrical shapes using a commercial PCM, called PW-70, with melting temperature of 70°C have been made and tested carefully in laboratory. The best results of the four tested models, derived from the multi-layer model, have shown that average temperature of the boiled water which was acting as the stored substance reached the desired range of 55 ~ 65°C within only about 15 minutes and this temperature range lasted within nearly 5 hours. It is also shown that this period is even much longer if the desired temperature value is lower. This is a big advantage compared with the vacuum container without PCM in which the desired range was reached after about 4 hours but lasted for only more than 2 hours. With this good performance, the new design has shown much more effective utilization of heat energy in food or beverage preservation purpose.