Our technology has three main components: the parabolic troughs, the organic Rankine cycle (ORC) engine, and the electrical control system.
Four parabolic troughs form an array of solar collectors. Each parabolic trough focuses incoming sunlight onto a pipe located at the trough’s focal point. The pipes are linked together to form a continuous loop through which a thermal absorption fluid (like glycol, the anti-freeze fluid used in automotive radiators) circulates. As the thermal fluid is pumped through this array, it is heated by the sun's rays which are striking the pipe, reaching up to 150º C by the time it has circulated through all four troughs. The thermal fluid then passes through a heat exchanger where it transfers its heat to the working fluid (a refrigerant like those used in refrigerators or air conditioner units) of the ORC. The thermal fluid exits the heat exchanger at a much cooler temperature (around 100º C), ready to start another circuit through the troughs to absorb more of the sun's energy. These concentrators are constructed mainly using steel, copper piping, and aluminum reflective sheeting. Assembly is straight-forward, requiring welding, pipe joining, and simple fabrication and carpentry capabilities.
The heat that was transferred to the working fluid in the heat exchanger is then used to power the organic Rankine cycle (ORC) engine, a novel scaled-down version of the Rankine cycle historically used in Megawatt-scale coal or natural gas-fired power plants. This closed-cycle engine has four main stages. First as the working fluid is heated (in the heat exchanger, also called a "boiler"), it vaporizes to form a pressurized gas. This gas is expanded through a series of "turbines" (e.g. an automotive turbo charger), causing them to spin (like air that drives a pinwheel). These turbines are coupled to automotive alternators to create electricity that can be used to charge a bank of batteries. After the gas exits the turbines, the working fluid then enters a second heat exchanger. In this heat exchanger, the heat remaining in the working fluid is transferred to a cold water stream. This accomplishes two things: the working fluid is cooled, and the cold water is heated to produce hot water. Finally, the working fluid is run through a final condenser (e.g. an automotive radiator) to remove any remaining heat, and it is then returned to the boiler via an automotive power steering pump. In this configuration, the outputs of the ORC are electricity and a hot water supply, but additional components could provide refrigeration as well by way of an absorption-chiller design. The ORC engine is constructed using standard automotive parts (power steering pump, alternator, bearings, pulleys and motors) that are high volume, low cost and ubiquitous. This reduces cost of the system and increases availability of initial materials and replacement parts, making local manufacture and use of this system feasible. Also because the engine is designed on such a small scale, it has a much simplified design that can be easily replicated and serviced.
The optimization of the system is achieved through a unique control system that orchestrates the energy inputs and outputs to suit the customer's resources and needs while maximizing efficiency. Versatility, scalability, cost-effectiveness, and simplicity of design are unique attributes that distinguish this technology as a reliable, affordable, sustainable, distributed renewable energy system for developing countries.