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Hot water heat stores with stratification are a common technology used in solar energy systems and reuse of waste heat. Adding a PCM module at the top of the water tank would give the system higher storage density, and compensate heat loss in the top layer. The work presented here includes experimental results and numerical simulation of the system using an explicit finite-difference method. Experiments and simulations were carried out using different cylindrical PCM modules. With only 1/16 of the volume of the store being PCM, 3/16 of water at the top of the store was held warm for 50% to 200% longer and the average energy density was increased by 20% to 45%. Furthermore, these 3/16 of water were reheated by the heat from the module after being cooled down in only 20 min.

Activity pacing (AP) is a concept that is central to many chronic pain theories and treatments, yet there remains confusion regarding its definition and effects.To review the current knowledge concerning AP and integrate this knowledge in a manner that allows for a clear definition and useful directions for future research.A narrative review of the major theoretical approaches to AP and of the empirical evidence regarding the effects of AP interventions, followed by an integrative discussion.The concept of AP is derived from 2 main traditions: operant and energy conservation. Although there are common elements across these traditions, significant conceptual and practical differences exist, which has led to confusion. Little empirical evidence exists concerning the efficacy of AP as a treatment for chronic pain.Future research on AP should be based on a clear theoretical foundation, consider the context in which the AP behavior occurs and the type of pacing problem ("underactivity" vs. "overactivity"), and should examine the impact of AP treatment on multiple clinical outcomes. We provide a provisional definition of AP and specific recommendations that we believe will move the field forward.

Abstract In recent years, the overall energy consumption is increasing significantly and the energy consumption in the building sector represents over 30% of the global ones in developed countries. Thermal energy storage (TES) using phase change materials (PCM), which are materials able to store high amounts of energy as latent heat, is suggested as a possible solution to decrease the energy consumption. The authors of this paper developed materials able to encapsulate/stabilize PCM in addition to isolate an industrial residue from the steel recycling process: electrical arc furnace dust (EAFD). This waste is a hazardous dust, and when it is combined with a polymeric matrix produce dense sheet materials suitable for multilayered constructive systems. In this paper the physical, mechanical, thermal and acoustical characterization of two new materials with EAFD and PCM in a polymeric matrix for constructive system is presented. The results are compared with those obtained for one commercial dense sheet material available in the market, Texsound commercialized by TEXSA (Spain). The new dense sheet materials developed in this paper have similar acoustic properties compared to the results obtained for the commercial material and are competitive with it, even better because the new material incorporates PCM which increases the thermal inertia of final constructive system.

Abstract Thermal energy storage systems for both heat and cold are necessary for many industrial processes. High energy density and high power capacity are desirable properties of the storage. The use of latent heat increases the energy density of the storage tank with high temperature control close to the melting point. Tube in PCM tank is a very promising system that provides high packing factor. This work presents an experimental study of a PCM tank for cold storage applications. Two different configurations and different flow rates of the heat transfer fluid were studied. The effectiveness of the PCM storage system was defined as that of a heat exchanger. The results showed that the heat exchange effectiveness of the system did not vary with time, decreased with increasing flow rate and increased with increasing heat transfer area. The effectiveness was experimentally determined to only be a function of the ratio m ˙ /A. This equation was found to be adequately be used to design a PCM storage system, and a case study is presented. It was shown that the tube in tank design together with a low temperature PCM is suitable as a thermal storage facility for cold storage.

Using recycled rubber crumbs as drainage layer in extensive green roofs have high potential to reduce the heating and cooling loads in buildings over traditional materials used as drainage layer, such as pozzolana gravel. However, the environmental impact due to the life cycle should be analyzed to assess its environmental benefit. This paper evaluates the environmental performance of green roofs in which the drainage layer is made of rubber crumbs, a recycled material the use of which is still experimental for this purpose. In this paper Life Cycle Assessment (LCA) is applied to compare the environmental impact of four constructive systems, two extensive green roofs without insulation layer and with different drainage materials, e a recycled material, rubber crumbs, and a conventional one, pozzolana gravel -, in front of two conventional flat roofs, with and without thermal insulation (polyurethane), built in an experimental set-up consisting of four monitored house-like cubicles, located in Mediterranean continental climate (Lleida, Spain). The LCA considered the production, construction, operational, and disposal phases of the roofs, according to UNE-EN 15643-2. The operational phase was carried out using data measured in the experimental set-up, considering heating and cooling energy consumptions in the winter and summer period, respectively.

The Authors tested a complete new system for recovering wood fuel from the termination of depleted orchards. This operation can generate between 25 and 80 fresh t ha?¹, that can be directed to the growing bioenergy sector. The new system is based on highly-mobile low-investment general-purpose equipment, which allows containing operational cost and speeding relocation between work sites. The new residue collection system is quite flexible, and achieves cost-effective recovery on relatively small fields, often smaller than 1 ha. Under the conditions of the study, trees are cut, chipped and delivered at a cost between 35 and 40 EUR t?¹ (40% water mass fraction), provided that fields are within a 20 km distance from the biomass plant. Use of a standard drum chipper results in a better product quality than if a grinders is used, as is the case for conventional orchard removal operations. Feeding the chipper with a separate loader allows a significant cost reduction, provided that the field offers at least 25 t of fresh wood. In the future, use of remote controls and electronic tethers may allow a further cost reduction, which is estimated at 15%.

Abstract An exergy analysis, which only considers the unavoidable exergy destruction, is conducted for single, double, triple and half effect Water–Lithium bromide absorption cycles. Thus, the obtained performances represent the maximum achievable performance under the given operation conditions. The coefficient of performance (COP), the exergetic efficiencies and the exergy destruction rates are determined and the effect of the heat source temperature is evaluated. As expected, the COP increases significantly from double lift to triple effect cycles. The exergetic efficiency varies less among the different configurations. In all cycles the effect of the heat source temperature on the exergy destruction rates is similar for the same type of components, while the quantitative contributions depend on cycle type and flow configuration. Largest exergy destruction occurs in the absorbers and generators, especially at higher heat source temperatures.