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A new TRNSYS type for thermosiphon flat-plate solar thermal collectors: validation and optimization procedure
摘要： This paper presents a new TRNSYS Type (called Type 99) which can be used for the energy assessment of thermosiphon Flat-Plate solar thermal Collectors (FPCs) for water heating. The accuracy of this new type is higher than the standard type (Type 45a) available in TRNSYS library, since the density and specific heat of water are estimated according to the operating fluid temperature. The results of a suitable experimental campaign are also presented for different commercial FPCs system layouts. The developed Type 99 is successfully validated, proven by the very good agreement achieved between the simulation and experimental results. By the new Type 99 a suitable Design of Experiment (DoE) analysis is carried out with the aim to assess the design and operating parameters mostly affecting the energy and economic performance of two types of FPCs. Specifically, collector pipe diameters, slope, storage tank volume, and thermal insulation thickness are investigated. The analysis is carried out for three case studies which refer to residential Domestic Hot Water (DHW) production applications and to three different European weather zones (Freiburg, Naples and Larnaca). For these case studies an optimization procedure is also carried out by varying the same design and operating parameters for two different objective functions: best energy behaviour [maximum Primary Energy Saving (PES)] and best economic performance [minimum Simple Pay Back (SPB)]. Interesting novel design criteria and encouraging economic results are obtained.
关键词： economic assessment,DoE analysis,Building solar thermal systems,dynamic energy performance analysis,experimental validation
更新于2025-09-23 15:22:29
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A Techno-economic Approach for Increasing the Connectivity of Photovoltaic Distributed Generators
摘要： High penetration of distributed generation (DG) results in technical problems as voltage rise, voltage unbalance, substation reverse power, and transformer overloading. These problems adversely affect the connectivity of DGs either in the planning stage by decreasing the number of connected DGs, or in the operation stage by applying DGs’ active power curtailment (APC). This paper presents a techno-economic approach for the enhancement of photovoltaic (PV) DGs connectivity. The proposed approach firstly employs a probabilistic economic technique for determining the non-curtailable portion of the PV DG power that ensures profitable DG investment. This portion is integrated, as an economic constraint, in the planning phase of the proposed approach that aims to maximize the number of PV DGs connected to the system. In the operation phase, the proposed approach utilizes the capabilities of the existing equipment on the system; i.e. regulators, capacitors, DGs reactive power, and DGs APC to mitigate all technical problems. The overall objective of this stage is to minimize the total DGs APC while fulfilling all technical and economic constraints. The proposed approach is tested on the modified IEEE 123-bus feeder. The results clarify the efficiency of the proposed techniques in increasing the connectivity of PV DGs while maintaining profitable DG project.
关键词： Distributed generators,voltage control,economic assessment,Photovoltaic,power curtailment
更新于2025-09-19 17:13:59
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Energy assessment and economic sensitivity analysis of a grid-connected photovoltaic system
摘要： This paper presents techno-economic assessment results of a grid-connected photovoltaic (PV) system for domestic building application. The PV system electricity output, energy conversion ef?ciency and cell temperature are explored based on the local weather condition, the system life cycle cost is evaluated with full account of the life of assets, volatile economic ?uctuations, uncertainty in?uence factors, net present value (NPV) and discounted payback period (DPP) under Feed-in Tariff (FiT) scheme, the annual savings and payback time are compared for the FiT and new Smart Export Guarantee (SEG) schemes. Technical analysis results indicate that the system is capable of ful?lling the building electrical energy demand from April to October, and the extra electricity of 1530.23 kWh is exported to the grid in this period. The life cycle cost assessment results illustrate that the system achieves a NPV of ￡1335.32 and has a DPP of 9.34 years under the FiT scheme. Moreover, the sensitive analyses reveal that the high discount rate decreases the system NPV whereas the high initial cost leads to long payback period to realize the positive NPV. Furthermore, the FiT is the most cost-effective solution for PV system and has the shortest DPP compared with the SEG.
关键词： Techno-economic assessment,Photovoltaic system,Feed-in tariff,Smart export guarantee,Economic sensitivity analysis
更新于2025-09-16 10:30:52