Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2020Dynamic thermal modelling of PV performance and effect of heat capacity on the module temperature
Tuncel, B.; Ozden, T.; Balog, R. S.; Akinoglu, B. G.
One of the main weaknesses of Si-based Photovoltaic (PV) solar modules is the sensitivity of their efficiency to module (cell) temperature. Especially in locations with long hot seasons, the efficiency loss of PVs due to high temperatures should be considered carefully. Thermal modelling is a method to predict the performance of a PV module using essentially the 1st law of thermodynamics and available data. In this paper, a transient thermal model is described, which considers hourly meteorological data, including wind speed and direction, module parameters, and locational information. In transient analysis, the heat capacity value of PV panel is required, but it is not a parameter specified in the manufacturer's datasheet. Experiments on the heat capacity of PV modules are missing in the literature. The thermal model provides verified performance analysis for a poly-c-Si PV module installed in Ankara, Turkey, with a calculated heat capacity value. And a sensitivity analysis for the heat capacity of the transient thermal model is performed. It is found that the model results are almost invariant under changing module heat capacity values.
- MakaleYalnız künye2019A fuzzy logic embedded energy management software with multi-agent system for a stand-alone PV power plant
Ozden, T.; Kesler, S.; Okumus, H.I.
The worst scenario projected for an off-grid photovoltaic power system is the time interval that the solar irradiation amount is in short to supply the load throughout the day, and this situation is resulted in energy deficiency. Nowadays, an off-grid power generating system, which is designed to consider the worst scenario encountered only during a certain period of time, brings through big financial problems in terms of the initial installation costs. This study proposes a smart software to perform energy management considering users’ comfort and their criteria, which are taking some information from the agents communicating with the consumption units wirelessly and the battery agent. All loads and agents in this system are initially defined by the user according to the importance of the consumption loads such as critical, essential, significant, lesser, and insignificant loads. The proposed energy management software includes fuzzy logic-based decision maker to manage load suspension or put the suspended load into effect again according to the state of the sources. The total amount of consumption is kept less than the total existing energy so that the energy to be consumed by the critical loads is always provided. Considering the existing amount of energy and consumer preferences, the total amount of load units is maximized at each sampling step. The proposed system, which is attained without compromising the user comfort, enables more efficient energy consumption. Also, for supplying the critical loads in case of lack of energy is possible.
- MakaleAçık Erişim2019Preliminary investigations on two different procedures to calculate the efficiency and performance ratio of PV modules
Ozden, T.; Akinoglu, B.G.
Short- and long-term outdoor performances of the photovoltaic (PV) modules are extremely important in reaching their economic viabilities. Such information is very valuable for the investors, customers and researchers of PV technologies. Two different procedures are possible, and both are used by many researchers. However, to the best of our knowledge, there is no comparative investigation to evaluate these two procedures. One of the methods uses instantaneous I–V curves of PV modules taken in a specified instant of time, while the others simply use the integrated energy values of the input and the yield of PV modules. In fact, both have advantages and disadvantages. In the present work, we outlined the advantages and disadvantages of both methods and compared them using the data of two different cell-type modules which are installed at GÜNAM’s outdoor test facility. In the analysis, the data that we used are taken under the same outdoor test conditions and ambient weather conditions. The outcomes of these preliminary analyses can be summarized as follows: (1) The procedure that uses instantaneous I–V curves seems dependent on the specified time intervals and ambient weather conditions at that instant; (2) accordingly, we will propose how to determine an optimal time interval to reach better performance results; (3) using the integrated values, we achieved the variations in performances with different integration time periods; (4) preliminary comparisons of these two procedures resulted in key conclusions on performance and degradation calculations of PV modules.