Our preliminary design consists of three main components: the compressor, heat exchanger, and expander. A two stage compressor that aligns with our constraints will cost around $750. To build our heat exchanger, we expect to need copper tubing, various fittings, insulation, and a water pump that can create consistent flow through the exchanger. We expect these materials to total around $220. The majority of our team’s expenses will be involved in the expansion process. Firstly, our 4 horsepower air motor will cost about $650. Along with that, we will need a $250 magnetic AC generator for electricity transduction, drive belts to connect the air motor and generator, and a pressure regulator to control the air pressure input to the motor. Aluminum pulleys will be needed to attach the belt to the shafts of our motor and generator, but these can be built in the shop, rather than being purchased. This brings the total for the expansion subsystem to about $1,110. Additionally, we will require nylon tubing/connectors for airflow between subsystems and an aluminum base with rubber feet to securely mount our system. In order to accurately measure inputs and outputs of our system, we will need a thermocouple for the compression subsystem, a voltage data logger to measure electrical power output, and an accelerometer. These three devices total $280. Altogether, we anticipate a preliminary budget of $2,700 and roughly three hours of manufacturing time in the shop. A more detailed chart of our budget for each subsystem is shown below.
