The article presents the results of research on the efficiency of photovoltaic (PV) modules cooled with water. The aim of the experiment was to improve the working conditions of solar modules. A temperature decrease was obtained for the PV module by pouring cool tap water onto the upper surface of the modules, either in imitation of rain or as a water film. The power of the cooled and non-cooled devices were then compared. The temperature of the cooled modules dropped to almost 25 °C, whilst the temperature of the non-cooled module was 45 °C. The best results were achieved by cooling modules with a water film, since there were no water splashes, and the continuous cooling of the surface leads to a 20% increase in power. During the test, the non-cooled module attained a maximum power of 105.3 W/m2, compared to 125.5 W/m2 for its cooled counterpart. Cooling the module, therefore, resulted in a power increase of 20.2 W/m2. The results of the work may be of particular interest for small installations, especially because it cleans the modules while providing an increase in power.
Although geothermal resources are practically independent of climate factors, those factors significantly condition the potential use of the Earth’s natural heat resources. Unlike all the other factors limiting or facilitating the use of geothermal heat (like receivers’ temperature expectation, financial issues or local regulations), climate factors remain immovable. Thus, climate remains the main factor influencing the effective use of geothermal resources. Volumes of sold energy, typical capacity factors and rapid changes in heat demand may all influence the financial and technological performance of an investment. In the current paper, climate factors are translated into heat demand based on historical data (meteorological and district heating logs) by means of a dedicated artificial neural network, and analysed in terms of possible constraints and facilitators that might affect the effective use of geothermal energy. The results of ANN simulation indicate that average and typical operation is expected without any turbulences, yet about 10% of operating hours may require additional technical measures, like peak source support, smart management and buffers in order to limit pumping ramp rate. With appropriate dimensioning and exploitation, capacity factors as high as 60% are available, proving the potential for financially and environmentally effective use of geothermal resources.
One of the most challenging aspects of a new district heating (DH) design is its general performance, which will determine the ecological and economic impacts of the investment. Choosing the lowest applicable temperatures which are distributed via ultra-low-temperature district heating (ULTDH) systems may yield the desired results. The article elaborates the economic and ecological aspects of the application of ULTDH. The results of the analysis indicate that the capacity factor may be significantly improved, while the overall ecological effects of the investment are strongly dependent on the previously used heat source and the source of electric power.
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