Pavel Neuberger

Analysis of Ground Massif Temperatures with Slinky Horizontal Heat Exchanger

The article is describing a ground massif with a Slinky heat exchanger as a heat source for a heat pump, which is used for cold water warming and a heating of an administration building. The object of the research is to analyse the influence of the heat exchanger on the ground massif temperature while extracting heat energy at the beginning and during the heating season 2012 - 2013, as well as beyond it. Based on executed measurements the process of the ground massif temperatures near the exchanger is described. Also described is temperature process of the ground massif on a reference lot in a burial depth of the heat exchanger, and also subsurface temperatures in a depth of 0.2 m. The energy potential of the ground massif was evaluated using the difference of temperatures of the ground massif in the area of the Slinky heat exchanger at the beginning and at the end of the heating season.

Thermal properties of historic rural building materials in Czechia

Due to the different natural conditions, various local natural building materials were used for the construction of rural residential and farm buildings in various locations in the Czech Republic. Currently, it is often a requirement for the modernization of relatively old buildings. The buildings were built with different technologies. Very often only locally available material was used. In many cases, the properties of old materials are not available in the literature. However, it is necessary to know the thermal properties of building materials for the preparation of a reconstruction design. Thermal properties of materials are the basis for determination of heat losses of buildings useful for design of heating systems. The aim of this paper is to compare the research results focused on the thermal conductivity of different old construction materials (stones and rocks) and to show examples of preserved historical agricultural buildings. The results presented in this paper are based on the measurements by the portable instrument Isomet 2104. Authors recognised significant differences between tested materials. The mean values of thermal conductivity m of tested materials: gaize 1.49 W m-1 K-1, artificial marble 1.80 W m-1 K-1, gneiss 2.36 W m-1 K-1, proterozoic shale 2.68 W m-1 K-1, granite 3.66 W m-1 K-1 and quartz sandstone 6.15 W m-1 K-1. Differences between thermal conductivity values of stones and rocks should be respected in calculation of heat balance of new or reconstructed buildings to avoid the problems of the formation of thermal bridges.