UPDATE: GoSun has cancelled production the Thermal Battery due to complications in commercializing this technology. While initial test in 2014-15 yielded great results, further testing showed too much degradation of the PCM material.
Future back-up heating for the GoSun Grill will be done via a small electric heating element. GoSun's design team is working on this solution with plans to release in 2017.
The following webpage remains as an inspiration of the Thermal Battery for those interested in learning about this concept.
The GoSun Grill's Thermal Battery is a break-through innovation for both the consumer solar energy and the culinary industry.
It's a smart way to capture heat before rain, night, clouds or while you’re out and about.
How does it work?
The simple four pound (1.8kg) module is placed inside the GoSun Grill to preheat for a couple hours before cooking. Using the latent-heat capacity of our proprietary PCM (short for Phase Change Material) encapsulated within an aluminum extrusion, the Thermal Battery is able to store much more energy than a material with only sensible heat (such as concrete or sand). Through the process of melting the PCM at roughly 310°F or 155°C, the Sun’s energy is stored for use later in the day. Capable of reaching temperatures over 400°F or 205°C, this heat is fully insulated while left inside the evacuated tube chamber.
When the Cooking Pans are placed on top of the Thermal Battery, the reverse of the melting cycle begins where the PCM begins to transfer its stored heat into the cool, uncooked food. Conduction between the hot Thermal Battery and the food is very strong since they are virtually in contact with one another, separated by two layers of metal. The food cooks quickly as heat rises from the Battery and the PCM slowly cools (actually changes phases, aka freezes) back to its solid state.
Is it safe?
This is not an electric battery. It is not acid based and it is a not corrosive. It is a safe, non-toxic organic wax that is encased in an aluminum vessel. When used to cook food inside the GoSun Grill, the Thermal Battery Module is located underneath the Cooking Pans. There is no risk for cross contamination since the Thermal Battery is hermetically sealed.
How do you use the Thermal Battery?
The Thermal Battery is first placed inside the GoSun Grill, on top of the Tray, about two hours before preparing a meal to allow ample time for it to heat up. Once preheated, the Tray is carefully opened so the Cooking Pans can be placed on top of the Battery. The Tray is then pushed back into the tube so the meal can cook inside the highly insulated chamber.
Will it last?
The PCM is capable of a high number of completely reversible freeze/melt cycles so it is designed to last for years. After extensive testing performed by our parnters, we have found no noticeable degradation in the non-flammable, non-toxic PCM.
How long does it take?
The Thermal Battery takes roughly two hours to heat up to maximum temperature in full sun. Once preheated, cooking times are significantly reduced since the food is in direct contact with the heat when placed on top of the Battery.
How much energy is available?
The Thermal Battery has been designed with enough capacity to autonomously cook a meal for eight people without any outside help. For example, this could be four pounds of chicken or four loaves of bread. When fully charged with heat, there's an estimated 300WH (watt-hours) of energy. If heat energy and electrical energy were the same, that converts to the same energy of about 55 iPhones.