Copper oxide-titanium dioxide (TiO 2) p–n junctions are promising materials for photovoltaic devices and may reduce production costs due to their low cost and inexpensive production methods compared with silicon solar cells. The present review compares solar cells made with copper oxides combined with TiO 2–TiO 2/Cu 2O and TiO 2/CuO heterojunctions, and “cascade heterojunction systems.” First, we describe the main properties of titanium (iv) dioxide (TiO 2), cuprous oxide (Cu 2O), and cupric oxide (CuO), and their potential applications. Next, we explain the concept of copper oxide and TiO 2 heterojunctions. We summarize and present the photovoltaic characteristics (efficiency, fill factor, circuit current density, and open circuit voltage), thickness, preparation method, and electrode type for solar cells comprising copper oxide and TiO 2. The efficiency of the solar cells ranged from 0.0005% to 1.62%. The thickness of the TiO 2 and cupric oxide layers ranged from 0.06 to 16 µm, and from 0.18 to 1.5 µm, respectively, depending on the fabrication method. Additionally, we review and discuss the available combinations of copper oxide with other materials (Cu 2O with ZnO, CuO with ZnO, and CuO with Si), as well as the effect of the thickness of the copper (i) oxide and copper (ii) oxide on the solar cell performance. Finally, we present aspects to improve the conversion efficiency of heterojunction solar cells with copper oxides combined with TiO 2. This review will be useful for the construction and further development of thin-film solar cells.

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Here, we evaluated the efficiency of a solar domestic hot water system in a dormitory in Rzeszow. Radiance exposure was analyzed based on information obtained from an online database (the meteorological station in Rzeszow-Jasionka). The mean seasonal and annual solar irradiation of a flat surface and surfaces inclined at 30°, 45°, and 60° from the horizontal plane in Rzeszow were determined. The mean monthly irradiation was compared with that in selected European cities based on the Photovoltaic Geographical Information System meteorological database. The thermal solar panel area and final consumption of solar energy in Poland from 2005 to 2014 are also presented. The characteristics of the analyzed building, distribution of the inhabitants, and consumption of hot water from 2009 to 2014 are described. The heat demand was determined by hot water consumption per day per person based on hot water consumption metering and heat metering. The solar energy conversion efficiency was determined after the solar thermal collectors were installed in the building. The relation of the heat demand calculated based on the thermal energy utilized to heat water per person and heat metering for heating water was also analyzed. We also present a method of calculating the annual (stratified by month) ratio of solar energy utilization. Energy savings for the building were calculated. Improvements that could further increase the solar energy efficiency and shorten the investment payback period are proposed.

Nowadays, much attention is paid to the elimination of heat sources poisoning our environment. The air pollution is the most dangerous form of pollution of the environment, due to its direct impact on all living organisms, coverage of large areas and easy movement of pollutants. Therefore, air protection is one of the priority directions of each voivodeship. Hence, many programmes are being developed to promote the replacement of the old heating devices with the new ones and the installation of renewable energy conversion devices. There is no doubt that the equipment which emits the most harmful compounds into the atmosphere includes the old boilers fired with coal, wood or wood chips. In winter, chimneys with black circular smoke are a frequent sight. This problem can only be solved by connecting houses to the public heating network or by removing the old stoves. In this publication, an analysis of the profitability of boiler replacement with coal was carried out in terms of the material and environmental benefits. It is proposed to replace this boiler with a pellet boiler, an eco-pea boiler and a gas condensing boiler. The boilers were selected on the basis of the calculated thermal output, which is equal to 18.56 kW.

Abstract. In the first part of this paper we present an overview of photovoltaic devices installed in Poland in the years 1960-2015. In the years 2009-2016, approximately 199 MW in total power of photovoltaic devices were installed. The second part of the paper we focus on presenting the research results on the usage of tracking photovoltaic installations in 2010-2016 collected in various periods of their work. PV panels were installed on the building of the Institute of Electrical Power Engineering of the Lodz University of Technology. In this paper we considered PV installations as an additional source of energy improving the total energetic efficiency of the building via the reduction of energy consumed from public electric and power networks. The installation satisfies up to 30% of annual energy demand of laboratories. However, the break-even period of the system was estimated to be about 30 years because of the high cost of installation.