The International Institute of Refrigeration has posted more than two dozen papers presented at the PCM 2016 conference in Karlsruhe, Germany, earlier this month. The downloads are available for 15 euros each. A few highlights:
• Passive cooling potential of two different PCM cooling ceilings in the energy efficiency center, (H. Weinlader, F. Klinker, M. Yasin)
"In the Energy Efficiency Center – the new R&D building of the ZAE Bayern - two different PCM cooling ceiling types are installed and monitored in two office rooms. The ceilings are connected to a water circuit and can be used for heating or cooling. The PCM ceilings are prototypes which differ in the positioning of the PCM layer: ceiling type 1 with the PCM on top of and ceiling type 2 with the PCM below the water pipes. It was found, that cooling ceiling type 2 had a better thermal connection between PCM and room, nevertheless, the passive cooling power of the two different system designs was quite similar when measured as a function of the room globe temperature."
• Experimental analysis on a novel air heat exchanger containing PCM in a cold room, (B. Copertaro, R. Fioretti, P. Principi)
"An air heat exchanger consisting of aluminium containers with finned surface filled with PCM (5 °C melting temperature) was located near the evaporator of a cold room. The aims are to reduce cooling energy consumption and improving the maintenance thermal conditions of stored products. For this purpose, an experimental campaign was carried out and a monitoring system was developed. The cold room thermal behaviour, with and without PCM, was studied under steady state operating conditions. As expected a reduced number of on/off compressor cycles (6 cycles instead 13 cycles) in the PCM added cold room was observed. Test results showed that by storing PCM in the air heat exchanger, up to 16% of energy saving can be achieved."
• Standardization of PCM characterization via DSC, (S. Gschwander, T. Haussmann, G. Hagelstein)
"This work investigates the influence of particle size on crystallization behaviour of microencapsulated and emulsified n-octadecane using differential scanning calorimetry (DSC) and laser diffraction. Analyses of microcapsules show a stepwise decrease of nucleation temperature (from 26 °C to 14 °C) with decreasing particle size (from 300 μm to 3 μm). Further reduction of particle size in emulsions (< 0.2 μm) results in a slight decrease of nucleation temperature (<2 °K)."
• Potential use of phase change materials in a display cabinet: development of a dynamic modeling approach, (H.M. Hoang, F. Raoult, D. Leducq)
"Different configurations (position of the PCM in the equipment) are simulated and discussed: after the evaporator and under shelf. At first, the modelling of a display cabinet in a transient state is developed based on a simplified heat transfer model using zonal approach. By combining it with a melting and freezing process of PCM units located inside the display cabinet, the effects of the PCM addition on air and food temperatures are simulated. Placing the PCM under shelves allows maintaining the product temperature during defrosting or electricity shortage."
• A case study on the application of phase-change materials in buildings, (A. Hantsch)
"Energy storages employing the phase-change enthalpy of some material yield much larger energy densities than specific-heat-based systems. This case study is about the effect of phase-change materials on the heat and cooling load and annual energy demand for various scenarios. By means of a TRNSYS model it is possible to carry out energetic annual simulations. The results of this contribution allow giving advice for the design of new systems."
• Experimentation for the evaluation of aluminum foams for improving heat transfer in PCM thermal storages, (R. Lazzarin, S. Mancin, M. Noro)
"This work investigates the use of Aluminum foams as heat transfer medium to improve the overall heat transfer of paraffin waxes that can be possible PCMs to be implemented in hybrid sensible-latent water TESs. The design of a new experimental testing rig is here presented together with some preliminary simulation results obtained during the phase change process of paraffin waxes with melting temperatures around 45 °C, with and without metal foams, in a water thermal storage unit."
• Latent heat storage with polyethylene enhanced with aluminum stripes, (T. Ozcan, E. Gukelberger, M. Kauffeld)
"Using a built prototype latent heat storage integrated into a solar air conditioning system at the Institute of Refrigeration, Air Conditioning, and Environmental Engineering’s test facility loading and discharging tests were conducted to investigate the use of PCM materials in a heat exchanger of a solar system to support steam production in cloudy periods. The latent heat storage concept is designed for the temperature range to 130 °C."
• Comparison of a single stage and a multistage latent heat storage for domestic hot water delivery, (J. Diriken, J. van Bael, F. Leemans)
"In this paper we assess the potential to use multiple PCM in combination with a compact heat exchanger for direct domestic hot water delivery purposes for e.g. district heating substations. The results of the measurements on a compact thermal energy storage device based on multiple phase change materials with different melting temperatures are compared to a geometrical identical system with a single PCM with one melting temperature."
For a full list of papers, go to http://www.iifiir.org/ClientBookline/toolkit/p_requests/formulaire.asp?GRILLE=IIFRRECHFRIDOC&PORTAL_ID=portal_model_instance__fridoc_search.xml. Type Karlsruhe in the first search box, check "Conference papers" and type 2016 in the box next to "Year."