Among the numerous renewable energy resources, the main advantage of water energy is that it utilizes the current of the streams and rivers regardless of the given time of the day or season. The main purpose of this study was to create a low capacity, floating hydropower plant that is suitable for shallow and even narrow water bodies. The device was designed to create electric energy while floating on the water’s surface; therefore, it can be used not only in natural streams but also in drainage channels and wastewater treatment plants. The prototype was tested under real circumstances to identify the impacts of various settings on the energy efficiency. Measurements were conducted in Veszprém, Hungary on the Brook Séd. The average depth of the riverbed was 36 cm. Based on the field measurements, optimal efficiency was achieved by using six paddles. On the other hand, much lower efficiency was achieved when low (two or three) or high numbers (12 or 15) of paddles were used. A design framework was elaborated that can facilitate the construction of a floating water wheel for any watercourse. The sensitivity analysis of the sizing variables used in the estimation of performance is supported by network analysis techniques.

While the number of installed geothermal heat pump systems is rising legislation is not prepared to address the issues concerning thermal impact. The aim of this paper is to model the effects of geothermal heat pump systems installed to shallow geothermal reservoirs in sedimentary formation based on the results of a real system in order to show the magnitude of the thermal affected zone. The system examined is a standalone geothermal heat pump with a production and an injection well-being able to produce a maximum of 3.4 m³/h groundwater. The thermal impact determined by simulation was 35 m for the standalone system. Two scenarios were considered to define the impact of two neighboring open-loop systems on each other. The results show that if two systems are to be installed on the same reservoir the minimum distance should be 55 m. That indicates that in case of designing systems installed to similar hydrogeological environment should consider the change in the water table and increased thermally affected zone if other groundwater heat pumps are in the area.