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Uncertainty analysis of energy and economic performances of hybrid solar photovoltaic and combined cooling, heating, and power (CCHP?+?PV) systems using a Monte-Carlo method
摘要： This study examines the impacts of uncertainties in energy demands and solar resources on the energy and economic performances of hybrid solar photovoltaic and combined cooling, heating and power (CCHP + PV) systems with variations in PV penetration levels. This study investigates two models: a deterministic and stochastic model. The deterministic model uses hourly demands of the U.S. Department of Energy (DOE) reference large office building in San Francisco, CA and solar irradiance profiles in the Typical Meteorological Year (TMY) data as the independent variables. The stochastic model accounts for uncertainties in these independent variables using a Monte-Carlo method. The results show that regardless of PV penetration levels, the uncertainties in building energy demands and solar irradiance marginally influence the energy performance of CCHP + PV systems; however, they can notably increase annual operating costs up to $75,000 per year (13%). The annual cost increase is mainly attributed to a significant increase in demand charges (up to $79,000 per year). The demand charges tend to increase with higher uncertainties in the peak demand. The results suggest that in cases of the demand charge being responsible for a large portion in electricity bills (i.e., demand tariffs), a deterministic model tends to underestimate operating costs of CCHP + PV systems or other analogous distributed energy systems compared to a stochastic model. The errors with the deterministic model can become more extreme when demand charges outweigh energy charges.
关键词： Demand charge,U.S. DOE reference building,Tariff structure,Energy demand,Internal combustion engine,Combined heat and power
更新于2025-09-16 10:30:52
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Technoeconomic assessments of hybrid photovoltaic-thermal vs. conventional solar-energy systems: Case studies in heat and power provision to sports centres
摘要： This paper presents a comprehensive analysis of the energetic, economic and environmental potentials of hybrid photovoltaic-thermal (PVT) and conventional solar energy systems for combined heat and power provision. A solar combined heat and power (S-CHP) system based on PVT collectors, a solar-power system based on PV panels, a solar-thermal system based on evacuated tube collectors (ETCs), and a S-CHP system based on a combination of side-by-side PV panels and ETCs (PV-ETC) are assessed and compared. A conventional CHP system based on a natural-gas-fired internal combustion engine (ICE) prime mover is also analysed as a competing fossil-fuel based solution. Annual simulations are conducted for the provision of electricity, along with space heating, swimming pool heating and hot water to the University Sports Centre of Bari, Italy. The results show that, based on a total installation area of 4000 m2 in all cases, the PVT S-CHP system outperforms the other systems in terms of total energy output, with annual electrical and thermal energy yields reaching 82.3% and 51.3% of the centre’s demands, respectively. The PV system is the most profitable solar solution, with the shortest payback time (9.4 years) and lowest levelised cost of energy (0.089 €/kWh). Conversely, the ETC solar-thermal system is not economically viable for the sports centre application, and increasing the ETC area share in the combined PV-ETC S-CHP system is unfavourable due to the low natural gas price. Although the PVT S-CHP system has the highest investment cost, the high annual revenue from the avoided energy bills elevates its economic performance to a level between those of the conventional PV and ETC-based S-CHP systems, with a payback time of 13.7 years and a levelised cost of energy of 0.109 €/kWh. However, at 445 tCO2/year, the CO2 emission reduction potential of the PVT S-CHP system is considerably higher (by 40–75%) than those of the all other solar systems (254–317 tCO2/year). Compared to the solar energy systems, the ICE-CHP system has the shortest payback time (6.2 years), but its CO2 emission reduction (25 tCO2/year) is significantly lower. A high carbon price is beneficial for improving the cost-competitiveness of the solar energy systems, boosting its market penetration and helping to meet any carbon emission targets.
关键词： Internal combustion engine,Cogeneration,Combined heat and power,Solar collector,CHP,PV-thermal
更新于2025-09-12 10:27:22