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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.

Wood biomass is turned into industrial fuel through chipping. The efficiency of chipping depends on many factors, including chipper knife wear. Chipper knife wear was determined through a long-term follow-up study, conducted at a waste wood recycling yard. Knife wear determined a sharp drop of productivity (>20%) and a severe decay in product quality. Dry sharpening with a grinder mitigated this effect, but it could not replace proper wet sharpening. Increasing the frequency of wet sharpening sessions determined a moderate increase of knife depreciation cost, but it could drastically enhance machine performance and reduce biomass processing cost. Since benefits largely exceed costs, increasing the frequency of wet sharpening sessions may be an effective measure for reducing overall chipping cost. If the main goal of a chipper operator is to increase productivity and/or decrease fuel consumption, then managing knife wear should be a primary target. (C) 2014 Elsevier Ltd. All rights reserved.

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.

The incorporation of recycled materials in concrete as a partial replacement of cement is becoming an alternative strategy for decreasing energy-intensive and CO2 emissions imputable to the cement manufacture, while investigating new potential uses of such multifunctional materials for environmental sustainability opportunities. Therefore, low-cost and worldwide availability of by-products materials is being assessed for sensible heat thermal energy storage applications based on cementitious materials. A greater concern is especially required focusing on the thermal stability of cement paste under high temperature cycled conditions. Moreover, compatibility between cement type and supplementary cementitious materials is determinant for the proper performance reliability. In this study, benchmark cement types were selected, i.e., ordinary Portland and calcium aluminate. Six supplementary cementitious materials were added to both types of cement in a content of 10 % and 25 %. Thermo-mechanical properties were studied before and after 10 thermal cycles from 290 to 650 ◦C. Results after thermal cycling showed that calcium aluminate cement paste mixtures maintained their integrity. However, most ordinary Portland cement paste mixtures were deteriorated: only mixtures with 25 % cement replacement with chamotte, flay ash, and ground granulated blast furnace slag remained without cracks. Calcium aluminate cement paste mixtures obtained the highest compressive strength, for partial replacement of cement with 10 % of chamotte, ground granulated blast furnace slag, and iron silicate. The incorporation of supplementary cementitious materials did not increase the thermal conductivity. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors at University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme and by the Italian project ‘SOS-CITTA’ supported by Fondazione Cassa di Risparmio di Perugia under grant agreement No 2018.0499.026. Laura Boquera acknowledgments are due to the PhD school in Energy and Sustainable Development from University of Perugia. Laura Boquera would like to acknowledge the financial support provided by UNIPG – CIRIAF InpathTES project. The authors also thank the companies that provided the material to make possible this experimental research: Arciresa, Abrasivos Mendiola EDERSA—Masaveu Industria, General Admixtures S.p.A, Mapei, Ciments Molins industrial, and Promsa for the material supplied in this research. Financial support of the UNIPG-CIRIAF team has been achieved from the Italian Ministry of University and Research (MUR) in the framework of the Project FISR 2019: “Eco Earth” (code 00245) and it is gratefully acknowledged.

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.

A commercial drum chipper was fed alternately and piecewise with poplar stems and poplar tops, in order to determine the effect of piece size and tree part on machine performance. Chipping stems required most of the available power (231 kW) delivered by the tractor, whereas chipping tops took about half that much. However, productivity was twice as high with stems, compared to tops (i.e. 25 and 11 t h-1 of oven dry wood, respectively). As a consequence, specific fuel consumption per unit product was 15% lower with stems, compared to tops - i.e. 0.61 and 0.72 L m-3, respectively. Mean feeding speed was 0.37 m s-1 for stems and 0.41 m s-1 for tops, but the difference was not significant (p = 0.1677). Productivity and fuel consumption were strongly related to piece size, but tree part had its own additional effect, independent from size and possibly related to form. When chipping tops it is advisable to feed more pieces at a time, in order to partly compensate for the effect of piece size. Operators expecting to chip primarily small-size materials may acquire special chipper versions with wider drums and additional side rollers, for smoother mass feeding. oThe same chipper was tested with poplar stems and tops.oChipping stems resulted in higher productivity and lower fuel consumption.oChipping stems required most of the available tractor power.oChip particle size distribution was about the same for both feedstocks. © 2013 Elsevier Ltd.

In Italy, olive tree groves may offer up to a million tonnes of dry biomass per year as pruning residue. Searching for a cost-effective way to tap this potential, the authors tested a new machine, capable of recovering pruning residue at the same time as pruning. The pre-commercial prototype was tested on four different plots and compared to a simpler tractorbase mechanical pruning unit. The authors conducted detailed time-studies in order to determine machine productivity and residue recovery cost. The integrated machine can treat between 0.2 and 0.6 ha h(-1), producing between 0.33 and 1.03 tonnes of fresh residue hour(-1). Its integrated residue recovery function does not slow the pruning, which actually proceeds faster than with the tractor-base unit, due to the more efficient multiple-disc cutting bar. The marginal cost of residue recovery hovers around 40-45 (sic) fresh tonne(-1). However, the new machine must not be considered just as a biomass harvester, but rather as a mechanical pruning unit with an integrated biomass recovery function. Its main benefit derives from the capacity of performing a very effective mechanical pruning, and the residue recovery function is a secondary benefit yet unavailable on standard pruning machines. Its deployment must be seen in the context of a general effort to modernize olive grove management and to develop an integrated biomass production system, rather than as a further attempt to build a specialised biomass supply chain.