enCORE from OSU will exhibit at Solar Decathlon 2011a unique ability to store heat generated from the solar thermal hot air collectors for extended periods of time. The structures uses a thermal battery which stores 30 hours of hot air at 86 degrees F. The thermal battery is designed using savEnrg™ Phase Change Material (PCM-29P) panels. savEnrg™ Phase Change Materials (PCM) are inorganic salt hydrates with negligible super cooling and sharp phase temperatures that have a capacity to store large amounts of energy as latent heat during their process of phase change. Phase Change Materials are non-toxic, non-combustible and made out of 100% natural, eco-friendly products.
Engineering Spotlight from the enCORE OSU Solar Decathlon 2011 team commented that, "Phase change materials may sound exotic, but in fact we encounter them on a nearly daily basis. The next time you are enjoying a cold drink take some time to consider the functionality of the ice in it. As the ice melts (changes phase) it acts as to maintain the drink at approximately 32 degrees F. The functionality of the phase change material in enCORE is much the same except for one key difference, it changes states at 86 degrees F! "
|A rendering of the plenum (source enCORE)|
The team engineers further stated that 86 degree F is the same temperature which we wish to deliver heating supply air to the house. Having such a material allows the control system to open a series of dampers which send a stream of air heated using our collection system to the plenum. This air melts the phase change material which is now storing energy for later use. The thermal energy is stored as a combination of sensible heat and latent heat providing the a total heat storage capacity of over 190KJ/kg.
Why is this so useful? The OSU team engineers explain in they project blog - Consider a fall day, it is a pleasant 65 degrees outside at 4 PM, however, the weather forecast calls for a 45 degree night. Clearly the house may demand no space heating or cooling during the day but will almost certainly need some heating overnight. The built in intelligence of the control system in enCORE will react to these parameters by examining national weather service data and pre-charge the phase change material for use overnight.
|Team enCORE installing savEnrg™ PCM Panels (source enCORE)|