1,721,167 research outputs found
Recent Advances in Green Hydrogen Technology
No full textDuring the 20th century, the global energy system was mainly based on the use of fossil fuels, such as oil, natural gas, and coal [...
Economic assessment of renewable energy systems integrating PhotoVoltaic panels, seawater desalination and water storage
No full textSplenic hepatocyte autotrasplantation in pigs: new technical aspects and preliminary results of survival and proliferation.
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Splenic hepatocyte autotrasplantation in pigs: new technical aspects and preliminary results of survival and proliferation.
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Parabolic trough photovoltaic/thermal collectors. Part II: Dynamic simulation of a solar trigeneration system
No full textSolar heating and cooling systems by absorption and adsorption chillers driven by stationary and concentrating photovoltaic/thermal solar collectors: Modelling and simulation
No full textSolar heating and cooling systems are a promising technology which may significantly contribute to the reduction of greenhouse gas emissions, the enhancement of energy efficiency, and the increase of renewables share in the building sector. The available literature show a high number of papers aiming at investigating solar heating and cooling systems based on heat driven and solar technologies, configurations, operating strategies, and financing issues. Nevertheless, none of the papers available in literature investigates the possibility to replace conventional solar thermal collectors by flat plat and concentrating photovoltaic/thermal systems, also producing renewable electricity. To cover this lack of knowledge, in this paper a dynamic simulation model of novel solar polygeneration heating and cooling systems is presented. Such dynamic simulation model is developed and implemented in a computer code, written in MatLab, and allows investigating the energy, economic and environmental performance of such novel solar polygeneration systems, based on both adsorption and absorption chiller technologies fed by dish-shaped concentrating and flat photovoltaic/thermal collectors. In order to show the potentiality of the presented tool, a comprehensive parametric case study is carried out to find out the optimal system configurations, as a function of crucial design and operating parameters and of weather conditions. The presented case study analysis refers to a small cluster of four buildings, including office and residential spaces, located in different European weather zones. The modelled solar polygeneration systems simultaneously produce electricity, space heating and cooling, and domestic hot water; electricity is self-consumed or delivered to the electrical grid. For comparative purposes, two different back-up system configurations, based on an electric chiller and a condensing gas-fired heater are also taken into account as conventional reference building-plant systems. By means of this systematic parametric analysis, comprehensive guidelines for system designers, practitioners and/or researchers focused on the development and use of solar heating and cooling systems are provided
Design and comparative techno-economic analysis of two solar polygeneration systems applied for electricity, cooling and fresh water production
No full textTwo solar polygeneration systems were investigated for electricity, cooling and fresh water production. In the first scenario (LFPS), the linear Fresnel (LF) solar field was used as thermal source of the Organic Rankine Cycle (ORC), absorption chiller (ACH) and multi-effect desalination (MED) unit. In the second scenario (PVPS), photovoltaic (PV) panels were considered as the electricity source to supply the electricity load that is required for lighting, electrical devices, compression chiller (CCH) and reverse osmosis (RO) units. A techno-economic comparison was made between two scenarios based on the land use factor (F), capacity utilization factor (CUF), payback period, levelized cost of electricity (LCE), levelized cost of cooling energy (LCC) and levelized cost of water (LCW). The calculations were conducted for four different locations in order to determine the effect of solar radiation level on the LCE, LCC and LCW of systems in both scenarios. The results showed that the LCE and LCW of PVPS is lower than that of LFPS and the LCC of LFPS is lower than that of PVPS. Also, the payback period of LFPS and PVPS systems are obtained as 13.97 years and 13.54 years, respectively, if no incentive is considered for the electricity sale
A novel solar trigeneration system integrating Photovoltaic/Thermal collectors and seawater desalination: dynamic simulation and economic assessment
No full textThis paper investigates the integration of renewable energy sources and water systems, presenting a novel solar system producing simultaneously: electrical energy, thermal energy, cooling energy and domestic water. The polygeneration system under analysis includes photovoltaic/thermal solar collectors (PVT), a multi-effect distillation (MED) system for seawater desalination, a single-stage LiBr-H2O absorption chiller and additional components, such as storage tanks, auxiliary heaters and balance of plant devices. The PVT produces simultaneously electrical energy and thermal energy, at a maximum temperature of about 100 °C. The electrical energy is delivered to the grid, whereas the thermal energy may be used for different scopes. First, the thermal energy may be used for heating purposes and/or domestic hot water production. As an alternative, the solar thermal energy can be used to drive an absorption chiller, producing chilled water for space cooling. Finally, the solar energy, in combination with the thermal energy produced by an auxiliary biomass-fired heater, may be used by the MED system to convert seawater into domestic water. The system is dynamically simulated by means of a zero-dimensional transient simulation model. The simulation model also includes detailed control strategies, for the management of the solar thermal energy and for the control of the whole system. Results show an excellent energetic performance of the system under investigation whereas the economic profitability is good only in case of public funding
Design and dynamic simulation of a novel polygeneration system fed by vegetable oil and by solar energy
No full textIn this paper the integration of vegetable oil-fed reciprocating engines with solar thermal collector is
investigated, seeking to design a novel polygeneration system producing: electricity, space heating and
cooling and domestic hot water, for a university building located in Naples (Italy), assumed as case study.
The polygeneration system is based on the following main components: concentrating parabolic trough
solar collector, double-stage LiBr–H2O absorption chiller and a reciprocating engine fed by vegetable oil.
The engine operates at full load producing electrical energy which is in part consumed by the building
lights and equipments, in part used by the system passive loads and the rest is eventually sold to the grid.
In fact, the engine is grid connected in order to perform a convenient net metering. The system was
designed and then simulated by means of a zero-dimensional transient simulation model, developed
using the TRNSYS software. The simulation tool developed by the authors allows one to analyze the
results for different time basis (minutes, days, weeks, months and years), from both energetic and economic
points of view. The economic results show that the system under investigation is profitable, especially
if properly funded
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