Now here's an article about an interesting invention. From National Geographic:
Posted on October 26, 2004 09:38 PM. Filed under: environment.A decade ago Rod Sprules was designing a heated suit for search-and-rescue technicians. He was flipping through a reference book to look up the energy content of propane when he came across an interesting tidbit about coffee.
It said coffee grounds release more heat than wood when they're burned. Sprules, a mechanical engineer by training and an entrepreneur by heart, wrote down the fact in a book of ideas that he keeps and went back to work.
A few years later, while Sprules and his wife, Joanne Johnson, were living in Paris, he scoured his notebook for promising business ideas and rediscovered the coffee entry.
He went down from his apartment to a small café to ask the perplexed proprietor for some coffee grounds. Back upstairs, he dried the coffee grounds in the oven, stuffed them into an old cigar tube, added some candle wax, and set it on fire.
"It burned really well," Sprules recalled. [continue]