The number of installations with ground source heat pumps is steadily increasing. As they involve high investment costs, they require deliberate action and analysis. Research on the influence of design, materials and operating parameters on their coefficient of performance becomes of great importance. In this article the authors propose a new ground source heat pump system with horizontal ground heat exchanger and subsurface irrigation system. In order to examine the possibility of applying the system, the influence of soil moisture content on the heat pump coefficient of performance was investigated in this research. Conducting research on the real object is extremely expensive, so it was decided to conduct simulation studies using the finite element method. The presented results of research confirm that the soil moisture content has the greatest impact on the heat pump system coefficient of performance. The developed ground source heat pump system with subsurface irrigation system allow to reduce the length of ground heat exchanger loop.
There are typically two systems in use for sound reinforcement in open areas: the central, "wall of sound" system with speakers localized at the sides of the stage, and the zone system, in which additional speakers are introduced to obtain a uniform sound pressure level throughout the area of listening. In the past two decades the line array systems gained great popularity. The main purpose of their use is to obtain a uniformly distributed sound level throughout the listening area in order to achieve good speech intelligibility. The present paper aims to present an alternative and original method of sound reinforcement in open areas which is in contrast to the above solutions. This new method allows achieving a uniformly distributed sound pressure and good speech intelligibility in the area of interest, and also allows to gain spatial sound impression that accompanies sound reproduction in concert halls. Another advantage of the proposed system is the reduction of the sound level outside the area of interest, i.e. reduction of the noise level outside the area of listening.
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