Operation analysis of photovoltaic panels loaded under constant electric load
2020
Ziemelis, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Kancevica, L., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Pelece, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Putans, H., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Rucins, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Usually additional devices are used to connect the consumers to solar panels, which can be quite complex and expensive, such as solar inverters, electric batteries, battery charge/discharge controllers and others. Therefore, the aim of this work is to look for possibilities for direct connection of solar panels to the electricity consumers with active load resistance (electric heaters) and, at the same time, to ensure maximum capacity of the electricity produced by the solar panels by adjusting for this purpose the voltage (number of panels) of the solar panels to the value of the load resistance of the consumer, so that during the season the solar panels will operate longer (more) in the peak power point area of the solar panels. An experiment was conducted between February 1 and October 31, 2018 and 2019, during which the daily amounts of the energy generated by four solar panels SoletP6.60-WF-250 (273 days in total) were loaded with 3.5; 4.5; 6.5 and 8.4 Ω electrical resistance. Processing the recorded data showed that most energy – 212.4 kWh – was generated by a 4.5 Ω loaded solar panel, which on a clear day (04/29/2019) had the power and energy transfer rates of 15.6 % and 14.22 %, respectively. Least energy – 180.3 kWh was produced by an 8.4 Ω loaded solar panel. All the four panels together produced 788.6 kWh. It has been found that, at a loss of 2 % of the produced power, the load resistance of the solar panel SoletP6.60-WF-250 could be within the range of 4 to 5.5 Ω. By using the statistical frequency function in the data processing the power and energy production characteristics of differently loaded solar panels are explained. By a calculation example there is shown the principle of direct connection of the standard 2 and 4 kW electric heaters to the solar panels.
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