News – PiM

First Schematics of the Stirling engine used for DIGESPO

25 May 11

The stirling engine power conversion device operates by extracting work from a temperature differential between the hot heat exchangers in the engine and the cold heat exchangers in the engine. This temperature differential is effected by circulating a heated fluid (water, steam, heat transfer fluid, or other) into and out of the hot fluid ports of the engine, while simultaneously circulating a cooler fluid (water, glycol, or other) into and out of the cold fluid ports of the engine. The pumps to create this liquid circulation are external to the engine and provided by the system integrator. The other connections on the P3 engine are electrical sensor leads for monitoring internal temperatures and pressures, and the three electrical leads connected to the internal motor/generator integrated into the driveline of the engine. This motor/generator is used to spin up the engine on start-up, and then to produce electrical energy when the engine is running on the temperature differential. The P3 SolarHeart Engine is expected to produce a 3kWe maximum output at 300°C hot fluid temperatures and 20°C cold fluid temperatures.

First prototype of the solar array used by DIGESPO

25 May 11

The solar collectors are made up of four modules of four parabolic mirror troughs each. The floor area of each module is 2.5 x 2.4 metres squared. The total actual active area of the collectors is 13.4 metres squared. At the focal point of each mirror a specially designed heat pipe will be used to collect the energy focused along the length of the mirror. The heat pipe (and the closed hydraulic circuit linking the modules to the Stirling engine) will be filled with special oil which will be the energy carrier. This oil will be heated to a temperature of 350 degrees C. The modules will be tracking the sun on an East West Axis. The angle of the collectors to the Vertical will be fixed.