Biomass water heater

A project submitted to the faculty of the California Maritime Academy in partial fulfillment of the requirements for the degree of Bachelors of Science in Mechanical Engineering.

For centuries, composting has played a large part in the agricultural industry as a natural fertilizer however, there is an underlying use for compost other than its nutrient rich properties. Using compost for heat generation is not a typical method of renewable energy however, this is an efficient one. Our project aims to optimize the heat recovery produced by the compost to heat water. This heat generation can have many applications from heating a swimming pool to acting as a pre-heater for a household. Our goal is to create an environment for our compost that will maximize the heat output and have the greatest coefficient of performance. We constructed a semi-closed system to hold our compost and recirculate air through compost and over the heat exchanger. We managed to achieve an average box temperature of about 120oF and an average air temperature of 110oF. With this air temperature, we managed raise the temperature of water approximately 4 degrees and a coefficient of performance of 2.9. Based on the properties of the air, water and from our results, we determined the effectiveness of our heat exchanger to be 10.3%.