SOLAR ELECTRIC GENERATION

University of Palermo – Palermo (Italy)

Abstract

A Rank® HT1 has been installed in the Campus of the University of Palermo, Italy. The machine is integrated in the trigeneration installation developed in the framework of the European project STS-Med (Small scale Thermal Solar units for Mediterranean communities).

The project

The Arca Consortium has relied on the Rank® machines a trigeneration installation in the Campus of the University of Palermo (Italy). They have developed it for the Italian pilot plant of the STS-Med European project, in which they also included a concentrated solar power (CSP) plant, biomass boiler, thermal storage tank, and absorption chiller.

The STS-Med project (Small scale thermal solar units for Mediterranean communities) focuses on the development, implementation and dissemination of cutting-edge technologies to improve the energy efficiency of public buildings and has four demonstration plants. STS-Med is composed by 14 organizations from 6 countries (Italy, France, Cyprus, Egypt, Greece and Jordan).

Technological innovation

The most imporant innovation lies in using a CSP system in small plants, providing electricity, hot water and air conditioning to 20 thousand users of public buildings in the Mediterranean area. The pilot system shows a valid combination of technologies capable of covering the total demand of towns and urban districts.

The installation consists of 21 fresnel linear concentrators modules with a surface of 470 m2. It will produce a maximum power of 220 kW and an annual thermal energy above 310 MWh. The high performance energy storage tank allows to provide energy without depending of the effective solar radiation and is composed of a 8 m3 molten salt tank with a thermal capacity of 400 kWh that operates between 160 and 260 °C. A 23 kW LiBr absorption chiller (COP of 1.1) is integrated to the HVAC system of the ARCA offices, and the 10 kW Rank® ORC unit with a net electrical efficiency of 10%. Both systems share a common cooling tower connected to their respective condensers.

The solution

The Rank® HT1 system installed has an electric power of 10 kW with a nominal net electrical efficiency of 10%. A 3.5m3/h pump transfers the heat transfer oil, which enters to the evaporator at 200 °C and transfer heat until diminishing its temperature to 165 °C. A secondary water circuit connects the ORC condenser to a cooling tower of 100 kWt capacity. The electricity produced by the ORC system covers 19% of the actual consumption of the ARCA Consortium offices. Therefore, it is a solution with a high revenue, since the ORC system represents only 18% of the initial cost of the project.