Advances in sorption systems for energy efficient heating and cooling

At present there is important R&D in the field of sorption heating, cooling and thermal energy storage systems going on worldwide. Sorption systems can enable a more efficient use of renewable energies (solar, geothermal, etc.) both for domestic and industrial applications. This special issue presents the recent advances in the following key-sorption technologies: • Ad-sorption and ab-sorption closed- cycle heat pumps and chillers. • Ad-sorption and ab-sorption open-cycle systems for air conditioning, dehumidification, solar cooling, etc. • Sorption and thermochemical systems for thermal energy storage

Sistema de registro e análise com base na falha humana

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de ProduçãoFalhas Humanas em empresas podem ser responsáveis por queda na produtividade, retrabalhos, acidentes de trabalhos, além de danos materiais e pessoais irrecuperáveis. As agroindústrias por absorverem mão de obra local, quando na zona rural, necessitam investir na prevenção das falhas humanas pois seus funcionários não possuem experiência e nem tão pouco afinidade com a cultura organizacional. O objetivo geral deste trabalho é levantar, analisar, classificar e registrar as causas das falhas humanas involuntárias no sistema produtivo de uma indústria de couro. Baseado na bibliografia pesquisada é descrito conceitos, análises e classificação das causas das falhas humanas, além de outros temas relacionados. Mediante a análise de relatórios de acidentes de trabalho de um curtume em um período de 1 ano e meio, baseado na bibliografia foi possível realizar um diagnóstico com a classificação das causas mais comuns das falhas humanas encontradas no sistema produtivo. Com este diagnóstico foi possível sugerir ações preventivas que possam minimizar as falhas humanas involuntárias no sistema produtivo desta agroindústri

Tests of prototype PCM 'sails' for office cooling

This is the post-print version of the final paper published in Applied Thermal Engineering. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.PCM modules, constructed from a paraffin/LDPE composite, were tested in an occupied London office, in summer. Design variations tested the effect on heat transfer of a black paint or aluminium surface, the effect of different phase transition zones and the effect of discharging heat inside or outside. The modules’ temperatures were monitored along with airflow rate, air temperature and globe temperature. Their small size meant any effect on room temperature was negligible. Using DSC measurements of the PCMs’ thermophysical properties, in conjunction with the environmental measurements, a semi-empirical model of the modules was constructed in FLUENT using an enthalpy-porosity formulation to model phase change. Good validation was obtained for all modules using the temperature measurements with notable divergence when maximum liquid fraction was reached. The model was validated by the temperature measurements and used to generate mean liquid fraction and surface heat transfer rate profiles for performance comparisons. The broad phase transition zones of the PCMs results in wasted latent heat capacity. Black modules transfer heat and exhaust latent storage capacity significantly quicker than aluminium modules, due to radiant exchange. Discharging heat outside leads to an increase in thermal storage capacity and a higher rate of heat absorption.Buro Happold Engineers and the EPSRC

Life cycle assessment of innovative materials for thermal energy storage in buildings

The politically endorsed reduction of greenhouse gas emissions entails the transformation of thermal energy systems towards renewable energies, especially in the building sector. This comes along with a demand in energy storage, as there is a time offset between energy availability and demand. As sensible heat storages induce major losses and have limited energy density, current water-based solutions are only partially sufficient to meet these demands. Within the project “Speicher-LCA” the environmental performance of a variety of innovative materials available for energy storage in buildings is assessed. The project provides the first extensive comparison of environmental profiles of various thermal energy storage materials, including phase change, thermochemical and sorption materials. The specific performances in the storage cycle are taken into account. All results will be publically accessible through a spreadsheet tool including a comprehensive set of materials, components as well as their integration into different building types. This paper discusses the methodological framework of the study and presents the environmental assessment results for selected materials. It highlights the main challenges in the assessment of innovative storage materials on different system levels which require specific definition of functional units accordingly. The first assessment results on material level for selected phase change (PCM) and thermo-chemical materials (TCM) allow an environmental characterization regarding their potential application in thermal storages. In addition, ranges of required numbers of storage cycles for amortization have been calculated for the non-renewable primary energy demand. For PCMs amortization cycles range between ∼20 to 150 cycles for salt hydrates and up to ∼280 cycles for paraffins. Regarding TCM, energetic amortization of silica gel and zeolite 13x is reached after ∼60 and ∼260 cycles respectively. Since the realization of storage components and systems which can actually be used in real applications will further increase the cycle number required for amortization, these storage materials may thus not be suitable for applications with a low number of cycles over lifetime, such as seasonal storage

Influence of the type of phase change materials microcapsules on the properties of lime-gypsum thermal mortars

In a society with a high growth rate and increased standards of comfort arises the need to minimize the currently high energy consumption by taking advantage of renewable energy sources. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction of the use of heating and cooling equipment, using only the energy supplied by the sun. However, the incorporation of phase change materials in mortars modifies its characteristics. The main purpose of this study was the production and characterization of mortars with incorporation of two different phase change materials. Specific properties of two phase change materials, such as particle size, shape and enthalpy, were determined, as well as the properties of the fresh and hardened state of the mortars. The proportion of PCM was 0%, 10%, 20% and 30% of the total mass of the solid particles. In order to minimize some problems associated with shrinkage and consequent cracking of the mortars, the incorporation of polyamide fibers and superplasticizer was tested. It was possible to observe that the incorporation of phase change materials in mortars caused differences in properties such as compressive strength, flexural strength and shrinkage. Even though the incorporation of PCM microcapsules resulted in an increase in the shrinkage, it was possible observe a significant improvement in mechanical properties.The authors wish to express their thanks to the Portuguese Foundation for Science and Technology, for funding the project PTDC/ECM/102154/2008, Contribution of Thermal Active Mortars for Building Energy Efficiency

The crystal structure of human Rogdi provides insight into the causes of Kohlschutter-Tonz Syndrome

Kohlschutter-Tönz syndrome (KTS) is a rare autosomal-recessive disorder of childhood onset characterized by global developmental delay, spasticity, epilepsy, and amelogenesis imperfecta. Rogdi, an essential protein, is highly conserved across metazoans, and mutations in Rogdi are linked to KTS. However, how certain mutations in Rogdi abolish its physiological functions and cause KTS is not known. In this study, we determined the crystal structure of human Rogdi protein at atomic resolution. Rogdi forms a novel elongated curved structure comprising the ?? domain, a leucine-zipper-like four-helix bundle, and a characteristic ??-sheet domain. Within the ?? domain, the N-terminal H1 helix (residues 19-45) pairs with the C-terminal H6 helix (residues 252-287) in an antiparallel manner, indicating that the integrity of the four-helix bundle requires both N- and C-terminal residues. The crystal structure, in conjunction with biochemical data, indicates that the ?? domain might undergo a conformational change and provide a structural platform for protein-protein interactions. Disruption of the four-helix bundle by mutation results in significant destabilization of the structure. This study provides structural insights into how certain mutations in Rogdi affect its structure and cause KTS, which has important implications for the development of pharmaceutical agents against this debilitating neurological disease