S. Castello

Modeling of array performance degradation including single-module failure

A model for the performance degradation of a series-parallel array is presented, which includes single-module failure as an independent parameter. The model is checked by using data relevant to two arrays located at the ENEA Casaccia research center near Rome (Italy). By using the model, a first assessing of the influence of single-module failure on array degradation is performed. As a result, it is found that module replacement is not always necessary.

Preliminary Operation Data of the Improved Pilot Plant “Isola del Giglio”

The 45 kW pilot plant “Isola del Giglio” has been running since June 1985. The plant was built to evaluate technical and economical problems related to the use of photovoltaics for food refrigeration and water sterilization. Recently, in order to better meet local requirements, the PV plant has been modified and substantially improved. Technical activities were mainly aimed at making the cold storage system more reliable and cutting down the energy supply from the local grid. Since April 1990 the plant has been running in the new configuration: two independent cooling sections are automatically managed by dedicated control units and maintain the temperature of the 300 m3 refrigerator at the preselected value. Both thermal and electrochemical energy storage are available, for a total autonomy of about eleven days. The paper illustrates the improvements carried out and describes the new plant architecture and its operation logic. Besides, the most important results so far obtained, in terms of component performance, system availability and energy balance, are discussed.