Characterising the discharge cycle of CaCl 2 and LiNO 3 hydrated salts within a vermiculite composite scaffold for thermochemical storage

Transpired solar collectors (TSC) are an efficient means of building heating but due to the demand/use mismatch their capabilities are maximised when paired with a suitable storage technology. The Hydration and/dehydration of inorganic salts provides an appropriate energy storage medium which is compatible with the air temperature provided by a conventional TSC (<70 °C). The study reports on technical appraisal of materials which are compatible with building scale energy storage installations. Two salts (CaCl2, and LiNO3) were impregnated into porous vermiculite to form a salt in matrix (SIM). Their performance during the discharge portion of the cycle at high packing density was examined using a laboratory scale reactor. Reactor and exit temperature increases were considerably lower than those predicted from first principles. Peak reactor temperature rises of only 14 °C were observed with a reduction in temperature output from this initial peak over 60 hours. Poor salt utilization resulting from deliquescence near the reactor inlet was identified as being the source of the reduced performance. Changes in reactor size, orientation and cycling between input periods of moist and dry air did not improve reactor performance. The investigation has identified that moist air transit through the packed SIM reactor column is limited to approximately 100 mm from the air inlet. This has implications for reactor design and the operation of any practical building scale installation. Predictions of building scale energy storage capabilities based on simple scaling of laboratory test considerably under estimate the volume and complexity of equipment required

IEA SHC Task 42 / ECES Annex 29 WG A1: Engineering and Processing of PCMs, TCMs and Sorption Materials

An overview on the recent results on the engineering and characterization of sorption materials, PCMs and TCMs investigated in the working group WG A1 "Engineering and processing of TES materials" of IEA SHC Task 42 / ECES Annex 29 (Task 4229) entitled "Compact Thermal Energy Storage" is presented

Recent Mars: A Habitable Planet? – Results from Investigations in Space, in Mars Analogue Habitats and from Laboratory and Theoretical Studies

Mars is a frozen desert planet. Considerable intense UV radiation fluxes reach its surface and with its thin and 95 % CO2 rich atmosphere and an atmospheric pressure of approximately 6 mbar this planet is not supposed to be habitable. But according to a variety of different experiments during the last decade where microorganisms were investigated under Mars-like environmental conditions there is evidence that even recent Mars appears to be a habitable planet. The habitability of the surface and upper subsurface of Mars depends on one hand on the viability and adaptation capacity of microorganisms under Mars-like environments and on the other hand on the planet's energy resources and liquid water availability. Besides chemical, inorganic energy sources in the soil intense solar radiation is available as additional energy source on the surface of Mars but might be harmful for most of known terrestrial life forms. However, previous studies on extremophilic microorganisms which were performed on space exposure platforms (e.g. BIOPAN on the satellite FOTON and EXPOSE on ISS) show the high resistance of tested bacteria, archaea and lichens to space radiation and desiccation caused by vacuum. During Mars simulation experiments photosynthesizing microorganisms are even able to do photosynthesis periodically. The periodicity of the photosynthetic activity depends on the diurnal cycle with its varying temperatures and relative humidity. It is important to emphasize that the aforementioned space resistant microorganisms are mainly collected in polar and alpine habitats. They are living in permafrost regions with high UV radiation income and extreme dryness provoking high adaptation strategies. Because of these environmental parameters the alpine, desert and polar habitats were characterized as Mars analogue. The Mars analogy of these regions can also be justified by comparing the colonized alpine and polar field profiles with surface structures on Mars. Numerous investigations were done during field campaigns in the Alps, the Arctic (Svalbard) and in Antarctica. Based on these field investigations it becomes obvious that gullies, polygon rich regions and micro caves, fissures and cracks in rocks can be seen as suitable candidates for habitable areas on the surface of Mars in addition to the supposed ice rich environment in the subsurface. As mentioned above, the habitability of Mars depends also on the availability of liquid water. Due to the presence of salts and perchlorate rich soils on Mars water can for sufficient relative humidity remain in a liquid phase, forming at least temporary liquid cryobrines far below the freezing point, which e.g. might be useful for some halophilic microorganisms. This may be in favour of the habitability of the Martian surface. In addition the habitability can also be influenced by the sorption and desorption capacity of other soil particles. These particles and salty solutions could avoid or enhance the liquid phase of water. Processes enhancing the liquefaction of water might explain the recently observed rheological events provoking e.g. the formation of gullies on the surface of Mars which are known as real habitats for a diversity of microorganisms on terrestrial martian analogue environments mostly present in the polar regions. All presently enumerated factors are positively emphasizing that habitability of recent Mars is particularly probable for some of terrestrial life forms

-Decane adsorption on SiO-adsorbents

The equilibrium of n -decane adsorption on microporous and mesoporous SiO 2 -adsorbents (silicalite, SiO 2 -faujasite US-Ex, aerosil 200) was investigated using isoteric measurements. Following the comparison of the dispersion energy for porous and non-porous adsorbents carried out by Barrer (1966) and theoretical investigations of de Boer & Custers (1934) experimental data were analysed. A simple empirical correlation between the pore diameter of the adsorbents and the initial isosteric adsorption heat was found. The equation parameters are the condensation heat of the adsorbate, the diameter of the adsorbate molecule and an empirical constant

Natural zeolites in thermal adsorption storage and building materials for solar energy utilization in houses

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Two natural zeolitic tuffs of different European origin were studied for thermal adsorption storage application and as possible additives in plaster. The water adsorption behavior and the thermal adsorption storage properties were checked by thermoanalysis and in a lab-scaled storage of 1.5 L volume. The storage capacities achieve about half of the capacities of synthetic zeolites. The mixing properties in standard plaster showed to be very suitable for use. From our thermoanalytical results we estimated for an additive content of 20 wt.% thermal effects of 30-50 kJ/kg plaster. The thermal effect of Micronal® in plaster amounts to 20 kJ/kg plaster if the possible concentration of 10 wt.% is taken into account. Thus, the zeolitic tuff have a better thermal effect than the BASF product Micronal® containing an organic phase change material (PCM) as active component.cf201

Impact of UV C exposure on the water retention of the lichen Buellia frigida

New results on extremophiles and observations of Mars missions regarding the detailed mineralogy, the occurrence of water in the equatorial region of Mars [1-3], new announcements of MSL findings and their implications for the surface condi-tions at Gale crater [4, 5] as well as measurements of the Mars surface radiation environment [6] fuel the debate about possible developments of life on Mars. Based on previous studies [7-8] we examined water vapor interaction and water-bearing properties of B. frigida before and after UVC irradiation. The meas-urements have been partially conducted after simula-tion of environmental conditions which are supposed to be Mars-like. Lichens are symbiotic organisms that are able to colonize a broad range of extreme habitats and, therefore, represent useful model systems in as-trobiological research. Our aim is to contribute to an improved under-standing of extremophiles under exobiological aspects within the frame of BIOMEX (Biology and Mars Ex-periment) at the ISS, in respect to irradiation effects on water retention properties. The results may also sup-port data evaluation of in-situ missions such as MSL and ExoMars. References: [1] Feldmann W.C. et al. (2004) JGR 109 E 09006. [2] Bibring, J.-P. et al. Science 307, 1576-1581. [3] Poulet F. et al. (2005) Nature 438, 623- 627. [4] Vaniman D.T. et al. (2013) Science DOI: 10.1126/science.1243480. [5] Ming D.W. et al. (2013) Science DOI: 10.1126/science.1245267 [6] Hassler D.M. et al. (2013) Science DOI: 10.1126/science. 1244797.[7] Jänchen J. et al. (2006) Icarus, 180, 353- 358. [8] Jänchen J. et al. (2013) 44th LPSC Abstract No. 1504