In this paper the technical and economic feasibility of the installation of an innovative thermal concentrating solar system (TCSS) for high pressure steam production in a dairy is discussed. The production of soft cheese takes place thanks to the injection of saturated steam into washtubs that are filled with semi-finished materials. The steam is produced in natural gas fired tube boilers and is evidently lost and make-up fresh treated water at atmospheric conditions is required. In this context, the installation of a TCSS based on the technology of the linear Fresnel concentrating systems is proposed to provide part of the required steam and, consequently, to reduce the consumption of the fossil fuel improving the process environmental performances. To this purpose, the piping integration of the new system in the original one has been analyzed in detail respecting the essential safety requirements in accordance with the guidelines of the Pressurized Equipment Directive (PED) and maintaining the required service level to the thermal end-user. In order to assure a satisfying exploitation of the solar power source, the adoption of a storage system based on a pressurized vessel containing a mixture of water and steam has been considered and optimized from a technical and economic point of view. Indeed, the dairy production is scheduled only during six hours in the morning per day. This particular thermal load profile makes difficult the integration with the not programmable solar power source with peaks during the median hours of the day. Particular attention has been dedicated to the operative behavior of the integrated system defining suitable control rules thanks to the installation of valves and sensors. Beside the technical analysis, an economic assessment has demonstrated the profitability of the thermal plant modification, that assures a substantial improvement of the overall energy efficiency of the production process.
Improvement of the energy efficiency of a dairy using the thermal concentrating solar system technology
GABBRIELLI, ROBERTO;DEL MEDICO, FRANCESCO
2014-01-01
Abstract
In this paper the technical and economic feasibility of the installation of an innovative thermal concentrating solar system (TCSS) for high pressure steam production in a dairy is discussed. The production of soft cheese takes place thanks to the injection of saturated steam into washtubs that are filled with semi-finished materials. The steam is produced in natural gas fired tube boilers and is evidently lost and make-up fresh treated water at atmospheric conditions is required. In this context, the installation of a TCSS based on the technology of the linear Fresnel concentrating systems is proposed to provide part of the required steam and, consequently, to reduce the consumption of the fossil fuel improving the process environmental performances. To this purpose, the piping integration of the new system in the original one has been analyzed in detail respecting the essential safety requirements in accordance with the guidelines of the Pressurized Equipment Directive (PED) and maintaining the required service level to the thermal end-user. In order to assure a satisfying exploitation of the solar power source, the adoption of a storage system based on a pressurized vessel containing a mixture of water and steam has been considered and optimized from a technical and economic point of view. Indeed, the dairy production is scheduled only during six hours in the morning per day. This particular thermal load profile makes difficult the integration with the not programmable solar power source with peaks during the median hours of the day. Particular attention has been dedicated to the operative behavior of the integrated system defining suitable control rules thanks to the installation of valves and sensors. Beside the technical analysis, an economic assessment has demonstrated the profitability of the thermal plant modification, that assures a substantial improvement of the overall energy efficiency of the production process.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
