• Energy Research

This paper addresses the problem of the reduction in the huge energy demand of hospitals and health care facilities. The sharp increase in the natural gas price, due to the Ukrainian–Russian war, has significantly reduced economic savings achieved by combined heat and power (CHP) units, especially for hospitals. In this framework, this research proposes a novel system based on the integration of a reversible CHP solid oxide fuel cell (SOFC) and a photovoltaic field (PV). The PV power is mainly used for balancing the hospital load. The excess power production is exploited to produce renewable hydrogen. The SOFC operates in electrical tracking mode. The cogenerative heat produced by the SOFC is exploited to partially meet the thermal load of the hospital. The SOFC is driven by the renewable hydrogen produced by the plant. When this hydrogen is not available, the SOFC is driven by natural gas. In fact, the SOFC is coupled with an external reformer. The simulation model of the whole plant, including the reversible SOFC, PV, and hospital, is developed in the TRNSYS18 environment and MATLAB. The model of the hospital is calibrated by means of measured data. The proposed system achieves very interesting results, with a primary energy-saving index of 33% and a payback period of 6.7 years. Therefore, this energy measure results in a promising solution for reducing the environmental impact of hospital and health care facilities.

This paper addresses the problem of the reduction in the huge energy demand of hospitals and health care facilities. The sharp increase in the natural gas price, due to the Ukrainian–Russian war, has significantly reduced economic savings achieved by combined heat and power (CHP) units, especially for hospitals. In this framework, this research proposes a novel system based on the integration of a reversible CHP solid oxide fuel cell (SOFC) and a photovoltaic field (PV). The PV power is mainly used for balancing the hospital load. The excess power production is exploited to produce renewable hydrogen. The SOFC operates in electrical tracking mode. The cogenerative heat produced by the SOFC is exploited to partially meet the thermal load of the hospital. The SOFC is driven by the renewable hydrogen produced by the plant. When this hydrogen is not available, the SOFC is driven by natural gas. In fact, the SOFC is coupled with an external reformer. The simulation model of the whole plant, including the reversible SOFC, PV, and hospital, is developed in the TRNSYS18 environment and MATLAB. The model of the hospital is calibrated by means of measured data. The proposed system achieves very interesting results, with a primary energy-saving index of 33% and a payback period of 6.7 years. Therefore, this energy measure results in a promising solution for reducing the environmental impact of hospital and health care facilities.

Abstract A dynamic simulation study in TRNSYS environment has been carried out to evaluate energy and economic performance of a novel heating and cooling system based on the coupling between a low or medium-enthalpy geothermal source and an Air Handling Unit, including a Desiccant Wheel. During summer season, a Downhole Heat Exchanger supplies heat to regenerate the desiccant material, while a certain amount of geothermal fluid is continuously extracted by the well in order to maintain high operating temperatures. Simultaneously, the extracted geothermal fluid drives an absorption chiller, producing chilled water to the cooling coil of the Air Handling Unit. Conversely, during the winter season, geothermal energy is used to cover a certain amount of the space heating demand. In both summer and winter operation modes, a geothermal energy is also used to supply Domestic Hot Water. A case study was analyzed, in which an existing low-enthalpy geothermal well (96 °C), located in Ischia (an island close to Naples, Southern Italy), is used to drive the geothermal system. Results showed that the performance of the proposed system is significantly affected by the utilization factor of Domestic Hot Water. In fact, considering a range of variation of such parameter between 5% and 100%, Primary Energy Saving increase from 77% to 95% and Pay-Back Period decreases from 14 years to 1.2 years, respectively. The simulations proved the technical and economic viability of the proposed system. In fact, a comparison with similar systems available in literature pointed out that the layout proposed in this work is characterized by better energy and economic performance, especially in the best scenario. Finally, a sensitivity analysis showed that the system performance is mainly affected by the nominal geothermal flow rate and by natural gas cost.

Abstract A dynamic simulation study in TRNSYS environment has been carried out to evaluate energy and economic performance of a novel heating and cooling system based on the coupling between a low or medium-enthalpy geothermal source and an Air Handling Unit, including a Desiccant Wheel. During summer season, a Downhole Heat Exchanger supplies heat to regenerate the desiccant material, while a certain amount of geothermal fluid is continuously extracted by the well in order to maintain high operating temperatures. Simultaneously, the extracted geothermal fluid drives an absorption chiller, producing chilled water to the cooling coil of the Air Handling Unit. Conversely, during the winter season, geothermal energy is used to cover a certain amount of the space heating demand. In both summer and winter operation modes, a geothermal energy is also used to supply Domestic Hot Water. A case study was analyzed, in which an existing low-enthalpy geothermal well (96 °C), located in Ischia (an island close to Naples, Southern Italy), is used to drive the geothermal system. Results showed that the performance of the proposed system is significantly affected by the utilization factor of Domestic Hot Water. In fact, considering a range of variation of such parameter between 5% and 100%, Primary Energy Saving increase from 77% to 95% and Pay-Back Period decreases from 14 years to 1.2 years, respectively. The simulations proved the technical and economic viability of the proposed system. In fact, a comparison with similar systems available in literature pointed out that the layout proposed in this work is characterized by better energy and economic performance, especially in the best scenario. Finally, a sensitivity analysis showed that the system performance is mainly affected by the nominal geothermal flow rate and by natural gas cost.

In this study the model of a Solar Heating and Cooling (SHC) system and its experimental setup are presented. The SHC system under investigation is a demonstration plant installed in Naples, based on flat plate solar collectors and a single-stage LiBr-H2O absorption chiller. In addition, two vertical tanks are installed as storage system. The balance of system includes: A cooling tower, pumps, valves, safety devices and pipes. The absorption chiller is powered only by solar energy, since there are devices for auxiliary thermal energy. The experimental setup also includes a number of meters (temperature, pressure, flow rate and radiation) to measure, collect and control the prototypal system. The experimental plant is dynamically designed and simulated in order to calculate its energetic and economic performance parameters. This analysis is carried out by means of a zero-dimensional transient simulation model, developed by using the TRNSYS software. Furthermore, a parametric analysis is implemented, aiming at determining the set of the synthesis/design variables that maximize system performances. The model was validated by the first experimental results obtained by the operation of the solar cooling system. Results show that, although flat-plate solar collectors have been specially designed for this kind of application, their operating temperature is often too low to drive the absorption chiller. In addition, the system performance is not particularly sensitive to the storage volume whereas the thermal capacity of the solar field is lower than the absorption chiller demand, determining a very discontinuous operation of the chiller itself.