The development of a portable vessel for the collection, storage, and utilization of solar thermal energy for household use

Solar;Thermal Energy Storage;Latent Heat;Renewable Cooking Fuels

Alonso, Matthew Paul

关键词: Solar;    Thermal Energy Storage;    Latent Heat;    Renewable Cooking Fuels;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/101168/ALONSO-DISSERTATION-2018.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The purpose of this work is to address the global need for a cooking system without fuel, fire, or emissions and that respects cultural norms and cooking traditions. 3 billion people cook on wood, animal dung, and charcoal. The emissions from burning these fuels cause over 4 million premature deaths a year and negatively impact our environment. In addition, the energy impoverished spend 25% of their income on household fuels. Solar energy can provide a solution and do so in a culturally appropriate manner. Stored solar thermal energy can provide an option to: cook at any time or place; replace the fuel and the fire in most cooking systems; and perform similar to fire cooking. This dissertation documents the first sealed portable solar thermal energy storage vessel that operates in the 300 - 400 C range. This is quantified by measuring the performance of a field tested solar thermal energy system and through laboratory testing of the thermal energy storage vessel.Field tests measured the temperature - time relationship during solar heating of storage vessels to 340 C and the recovery of energy from these vessels using a water heating test. Each vessel contained 5 kg of potassium nitrate and were composed of 1.7 kg of aluminum. They were heated with low cost, commercially available and unmodified, 1.5 m^2 parabolic solar cookers. The energy storage vessels were heated in an average time of 2 hours and 21 minutes. During energy recovery testing, the solar charged vessels heated an average of 7 L of water, totaling about 2.3 MJ of useful cooking energy. The first liter of water reached “boiling” temperature (95 C) in an average of 3 minutes and 40 seconds.The portable thermal energy storage vessel was used as a platform to test additional energy storage materials. The thermal energy recovery performance capabilities of aluminum, potassium nitrate, sodium nitrate, and a 60/40 mol\% mixture of sodium nitrate and potassium nitrate were experimentally measured. Between 2.2 - 2.9 MJ of energy were recovered from these vessels. They boiled 6 - 9 L of water. The initial power output of the vessels ranged from 1000 - 2000 W. In addition, a discussion on evaluating the performance of stored solar thermal energy systems was initiated. Future work can compare the documented performance of these materials with the local cooking requirements to select an appropriate thermal storage solution for the community. The results are promising for the development of stored solar thermal energy systems for cooking and other small-scale uses of thermal energy including space heating, food processing, device charging and lighting.