Trends of European research and development in district heating technologies

There is a considerable diversity of district heating (DH) technologies, components and interaction in EU countries. The trends and developments of DH are investigated in this paper. Research of four areas related to DH systems and their interaction with: fossil fuels, renewable energy (RE) sources, energy efficiency of the systems and the impact on the environment and the human health are described in the following content. The key conclusion obtained from this review is that the DH development requires more flexible energy systems with building automations, more significant contribution of RE sources, more dynamic prosumers׳ participation, and integration with mix fuel energy systems, as part of smart energy sustainable systems in smart cities. These are the main issues that Europe has to address in order to establish sustainable DH systems across its countries.This research was conducted in collaboration between Wrocław University of Technology (Poland) and Brunel University London (UK). The support for the Polish team was by the Ministry of Science and HigherEducationunderGrantno.50532

Photonic applications of photochromic molecules

International audienc

Technical and environmental assessment of selected heat pump configurations. A case study

Two heat pump systems with the highest energy performance indicators were chosen for an analysis. Those most efficient systems for heating and cooling are ground source heat pumps (GSHP) and the exhaust air heat pumps (EAHP). Consequently, two cases (case A and case B) with different pump configurations were related to a reference case R represented by gas-fired boilers covering heating needs and compression refrigeration units ensuring cooling needs. Technical assessment in the form of coefficients of performance as well as primary energy ratings were completed. An environmental impact taking into account CO2, SO2 and NOx emissions of analysed heat pump systems was also evaluated

Phase transitions in ferroelectric nonachlorodiantimonate [(CH 3)3NH]3Sb2Cl9 studied by calorimetric and dielectric methods

Phase transitions occurring in a ferroelectric crystal tris(trimethylammonium)nonachlorodiantimonate (III) (TMACA) were studied by calorimetric, dielectric and pyroelectric methods. Anomalies of dielectric and thermal properties were found around 200 K and at ca. 364 K. The anomalies in the low-temperature region exhibit a pronounced relaxational character. A detailed study of the behaviour of TMACA around 364 K clearly indicates that in fact TMACA undergoes two closely lying phase transitions, one of them being probably of the first order and the other of the second order. The temperature of the second order transition was determined to amount to (364.0 ± 0.3) K irrespective of the method employed, whereas the first order transition temperatures are detected by the dielectric measurements ca. 1 K below those found from the calorimetric measurements. An unusual sequence of the phase transitions was observed in DSC measurements : both on cooling and on heating the samples through the transition region, the second order phase transition precedes the first order one. The onset to ferroelectricity was found to be associated with the first order phase transition.Nous avons étudié des transitions de phase dans les cristaux de tris (triméthylammonium) nonachlorodiantimonate (III) (TMACA) par microcalorimétrie différentielle (DSC), ainsi que par des mesures des propriétés diélectriques et pyroélectriques. A 364 K, TMACA présente une transition depuis une phase basse température ferroélectrique vers une phase haute température paraélectrique. Une anomalie a été aussi observée à environ 200 K, associée probablement à une relaxation. Les résultats obtenus montrent que la transition à 364 K présente en fait deux transitions très rapprochées, l'une étant probablement du premier ordre et l'autre du second ordre. La transition du deuxième ordre est observée à la même température (364.0 ± 0,3) K quelle que soit la méthode utilisée, alors que celle du premier ordre est décelée par mesure de la constante diélectrique un degré plus bas que par calorimétrie. Celle-ci montre de plus un phénomène inhabituel, qu'on opère en programmation de température croissante ou décroissante : dans les deux cas, la transition du second ordre précède la transition du premier ordre. L'étude de la réponse pyroélectrique du cristal montre que le passage à l'état polaire est gouverné par la transition du premier ordre