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Considering the relevance of the consumption of domestic refrigerators in the Brazilian residential sector, representing about 30% of the sectorial consumption, studies of factors that influence this consumption, such as ambient temperature, age of equipment and usage habits, are of great importance to a greater understanding of these effects and, thus, to promote better energy strategies for the country. In this sense, the present study evaluates the impacts of ambient temperature, age of the equipment and habits of use in the consumption of domestic refrigerators, based on theoretical models and laboratory tests. The laboratories assays, adhering to theoretical models, showed that the environment temperature can influence the consumption of refrigerators up to 50% less (taking into account the south region temperature), when comparing to the value that are labeled by PBE/INMETRO. When the usage habits are assayed, it was verified that the consumption of the refrigerator could be increased in up to 53%, depending the frequency of door opening. Considerando la relevancia del consumo de refrigeradores domésticos en el sector residencial brasileño, que representa cerca del 30% del consumo sectorial, los estudios de los factores que influyen en ese consumo, como la temperatura ambiente, la antigüedad de los equipos y los hábitos de uso, son de gran importancia para una una mayor comprensión de estos efectos y, con ello, promover mejores estrategias energéticas para el país. En ese sentido, el presente estudio evalúa los impactos de la temperatura ambiente, la antigüedad de los equipos y los hábitos de uso en el consumo de refrigeradores domésticos, a partir de modelos teóricos y pruebas de laboratorio. Los ensayos de laboratorio, apegados a modelos teóricos, demostraron que la temperatura ambiente puede influir en el consumo de los frigoríficos hasta en un 50% menos (considerando la temperatura de la región sur), al comparar con el valor que marca el PBE/INMETRO. Al ensayar los hábitos de uso, se verificó que el consumo de la heladera puede incrementarse hasta en un 53%, dependiendo de la frecuencia de apertura de la puerta. Considerando a relevância do consumo de geladeiras domésticas no setor residencial brasileiro, representando cerca de 30% do consumo setorial, estudos de fatores que influenciam esse consumo, como temperatura ambiente, idade dos equipamentos e hábitos de uso, são de grande importância para uma maior compreensão desses efeitos e, assim, promover melhores estratégias energéticas para o país. Nesse sentido, o presente estudo avalia os impactos da temperatura ambiente, idade dos equipamentos e hábitos de uso no consumo de refrigeradores domésticos, com base em modelos teóricos e testes laboratoriais. Os ensaios laboratoriais, aderindo a modelos teóricos, mostraram que a temperatura ambiente pode influenciar o consumo dos refrigeradores em até 50% menos (levando em consideração a temperatura da região sul), quando comparado ao valor que é rotulado pelo PBE/INMETRO. Quando analisados ​​os hábitos de uso, verificou-se que o consumo da geladeira pode ser aumentado em até 53%, dependendo da frequência de abertura da porta.

Refrigerators are widely used by consumers with access to the electricity grid but rarely used in off-grid settings where households rely on a limited supply of electricity such as that by a stand-alone solar home system, because refrigerators’ power consumption requires a solar system size that is unaffordable for most consumers. Reducing the power consumption of refrigerators by improving their efficiency is one solution to this issue. In this paper, we assess the technical potential and costs of using commercially available technology to reduce the energy consumption of small (50- and 100-L) refrigerators. Our analysis shows that refrigerator electricity consumption can be reduced by about 50% and 70% using commercially available energy-efficient components at an incremental cost of about $45–$60 and $100–$120 per unit, respectively. Further, we find that highly efficient small refrigerators can be potentially available less than $300 if they sold at scale unlike much higher prices seen in the market today. We also find that the total annualized cost of an off-grid solar home system (including the cost of the refrigerator) can be decreased by about 50% if the most efficient refrigerator we analyzed is used, compared with the same energy system with a standard refrigerator because the additional cost of the efficient refrigerator is significantly lower than the cost savings due to smaller capacity requirements for panels and batteries. We recommend that policies such as awards, procurement, and standards be considered to facilitate the adoption of energy-efficient refrigerators in off-grid and microgrid settings.

Orientador: Luiz Carlos Pereira da Silva Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Os sistemas elétricos vêm sendo alvo de estudos que buscam torná-los mais inteligentes e seguros. Um novo paradigma surge com o conceito das redes inteligentes (smart grids), as quais incluem como uma das suas características principais a integração de equipamentos dos consumidores de forma ativa à operação do sistema elétrico. Um exemplo é o gerenciamento da demanda no horário de pico, aliviando a carga e aumentando a segurança do sistema, com o objetivo de obter benefícios para o sistema elétrico e também para os consumidores. Para que isso seja possível, são necessários alguns requisitos e avanços tecnológicos: existência de um portal de comunicação para interface entre o consumidor e seus aparelhos e a concessionária; equipamentos que permitam tal gerenciamento sem prejudicar e interferir na rotina dos consumidores; e mecanismos de compensação financeira para incentivar a participação dos consumidores. Nesta dissertação se propõe um estudo sobre um aparelho que apresenta potencial para esse tipo de gerenciamento, o refrigerador doméstico. Devido a sua inércia térmica e isolamento o refrigerador pode ser ligado e desligado durante algum tempo sem prejuízos para sua função principal. Os objetivos deste trabalho são: desenvolver um modelo adequado para a simulação computacional de um grupo de refrigeradores; implementar esquemas de gerenciamento que visem a redução de consumo no horário de pico; bem como analisar o efeito que estes procedimentos acarretariam em uma rede de distribuição de energia elétrica, levando em conta a redução do consumo no período de pico, a redução de perdas e a melhoria do perfil de tensão Abstract: The electrical systems have been exposed to new researches and developments with the main objectives of a smarter and safer operation and planning. A new paradigm arises with the concept of smart grids, which include as one of its main characteristics the integration of consumer's appliances in the system operation in a more active way. An example is the demand-side management at peak time, relieving the load and increasing system security, in order to obtain benefits to the electrical system and also to consumers. In order to make this possible, some requirements and technological advances are necessary: the existence of a communication interface between the consumers and their appliances and the utility; smart appliances that allow such management without any damage or interference on the routine of the consumer; compensation mechanisms to encourage consumer participation. In this dissertation it is proposed a study about a device that has potential to this kind of management, the household refrigerator. Due to its thermal inertia and isolation, the refrigerator can be turned on and off for some time without degradation of its primary function. The objectives of this work are: development of an adequate model for the computational simulation of a group of refrigerators; implementation of management schemes to reduce the consumption at peak time; analysis of the impacts of such procedures to a distribution grid, taking into consideration the reduction of the consumption at the peak hours, reduction of losses and improvement on voltage profile Mestrado Energia Elétrica Mestre em Engenharia Elétrica

Appliance labels are a widely used policy instrument to increase the adoption of energy-efficient technologies. Most countries use categorical labels to facilitate comparison of appliances based on energy consumption. Studies have found that consumers respond positively to the labels, but the differentiated response to the categories on labels is not well understood in the literature. This study presents the results of a discrete choice experiment corroborated by an analysis of secondary market data to demonstrate that consumers differentiate between label categories; with a greater value being placed on appliances with higher levels of energy efficiency performance. We examine two appliances - air conditioners and refrigerators and observe that there are some differences in consumer response - likely due to the different usage patterns of the two appliances. Consumer responses were observed in hypothetical choice situations constructed ensuring statistical and design efficiency. In a mixed logit model specification with correlated random parameters, the magnitude and the distribution of consumer preference for the highest category of energy efficiency are estimated. The results are validated by estimating the incremental price of higher category of energy efficiency using market data for comparison. The sources of consumer heterogeneity for the highest category of energy efficiency are identified after controlling for other consumer variables. The findings presented in this paper are useful for improving the effectiveness of existing energy efficiency programs and designing new programs to accelerate adoption of energy efficient technologies.

Under the concept of the Internet of Things, was designed a PCB to monitor faults in refrigerators or freezers, which use conventional compressors or non-inverters. It should be emphasized that these equipment belong to a cold chain, where it is considered approximately 2000 refrigerators. This solution includes among its main requirements Sigfox wireless communication, to send data or alarms from refrigerators or end nodes to the server in the cloud. One of the attractions to choose SigFox technology is its low cost as a communication service. Other aspects of design are: control the compressor, alert operational failures, measure the temperature inside the freezer, measure power consumption, voltage and current. Another fundamental requirement of the design is to achieve a low cost in its production to be in the margin of the sale of conventional temperature controllers, perhaps not equal, but not be well above the commercial value. With these premises, the hardware architecture is basically composed by a Switched-Mode Power Supply (SMPS), a control unit with a PIC32, 5VDC relays to switch an output of 220V AC, NTC temperature sensor, Power meter IC, battery charger, Sigfox communication module and E-Paper Display. © 2019 IEEE. Fondo Nacional de Ciencia Tecnología e Innovación: FP44842-502-2015 Department of Science, Information Technology and Innovation, Queensland Government Universidad Tecnológica de Pereira: FI1607T2004 Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIAS: Colciencias Ministry of Information and Communications Technology, Iran The authors would like to acknowledge the cooperation of all partners within the Centro de Excelencia y Apropiación en Internet de las Cosas (CEA-IoT) project. The authors would also like to thank all the institutions that supported this work: the Colombian Ministry for the Information and Communications Technology (Ministerio de Tecnologías de la Información y las Comunicaciones - MinTIC) and the Colombian Administrative Department of Science, Technology and Innovation (Departamento Administrativo de Ciencia, Tecnología e Innovación - Colciencias) through the Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación Francisco José de Caldas (Project ID: FP44842-502-2015). The authors would also like to thank Universidad Tecnológica de Bolívar for partial financial support with the project Design and Implementation of an Application Prototype for Predictive Control of Temperature in Logistic Cold Chains (Project ID: FI1607T2004).

This project has been carried out in the agreement of internship inside an enterprise, in the process-engineering department of BSH Home Appliances (Navarre). The ESD (Electrostatic Discharge) damages the electronic components of the products manufactured (dishwashers and refrigerators) and implies additional costs for the company as well as a reduction in quality and product reliability, due to a failure in the home appliance. The objective is to improve the current ESD protection in the entire factory, during all the life cycle that the electronic components follow. To do that, a previous ESD study has been carried out making measurements and observations, and the consequent improvement proposals have been stated. With the implementation of these improvement proposals, that if not now they will be implemented in the future, BSH is aware that its protection against ESD will increase. Graduado o Graduada en Ingeniería en Tecnologías Industriales por la Universidad Pública de Navarra Industria Teknologietako Ingeniaritzan Graduatua Nafarroako Unibertsitate Publikoan

Classical and quantum electronic circuits provide ideal platforms to investigate stochastic thermodynamics and they have served as a stepping stone to realize Maxwell's demons with highly controllable protocols. In this article we first review the central thermal phenomena in quantum nanostructures. Thermometry and basic refrigeration methods will be described as enabling tools for thermodynamics experiments. Next we discuss the role of information in thermodynamics which leads to the concept of Maxwell's demon. Various Maxwell's demons realized in single-electron circuits over the past couple of years will be described. Currently true quantum thermodynamics in superconducting circuits is in focus of attention, and we end the review by discussing the ideas and first experiments in this exciting area of research., 21 pages, 6 figures + 5 pages, 2 figures

In recent years, sustainable development has acquired a relevant position in our society. In this context, the design of modern products must consider these issues when creating eco-friendly and socially acceptable solutions, seeing sustainability as a matter of optimization in the use of available resources along the entire product lifecycle. This research aims to propose a dedicated Environmental Assessment Framework, using LCA methodology allowing designers to make environmental sustainability as an achievable and measurable requirement for developing new products. The case study presented is adapting the Life Cycle Assessment framework in the household refrigerator sector, of comparison between conventional gas-compression refrigeration and magnetic cooling system. The critical point of magnetic refrigerator is the presence of rare earths, and for this reasons a Life Cycle Assessment toll is needed to investigate the whole lifecycle.

Generation of inverter-connected solar and wind power displaces kinetic energy in power systems, decreasing frequency quality and threatening the system security. As a solution, this paper investigates the potential of electricity consumption to increase the inertial response of the system so that the frequency quality is maintained. The study focuses on three types of consumption: Electric vehicle (EV) charging, direct electric space heating (DESH), and the consumption of refrigerators, which all have different characteristics in terms of their response to the power system frequency. We aim to assess their potential inertia contribution in a Finnish case study. Therefore, the study firstly introduces the consumption models with required load control strategies, after which the performance of the loads as a part of the Nordic power system frequency dynamics is simulated. The results indicate that the loads are able to contribute to the system inertia but their consumption may not coincide with the moments of low system kinetic energy.

Quantum thermodynamics addresses the emergence of thermodynamic laws from quantum mechanics. The viewpoint advocated is based on the intimate connection of quantum thermodynamics with the theory of open quantum systems. Quantum mechanics inserts dynamics into thermodynamics, giving a sound foundation to finite-time-thermodynamics. The emergence of the 0-law, I-law, II-law and III-law of thermodynamics from quantum considerations is presented. The emphasis is on consistency between the two theories, which address the same subject from different foundations. We claim that inconsistency is the result of faulty analysis, pointing to flaws in approximations.

In a previous study an experimental testing apparatus was constructed and used to measure the defrosting efficiency of different heaters working under different control strategies. Based on the results obtained two defrosting heaters (one calrod and one distributed) and two control strategies (constant power and steps mode) were selected for this study. In the original mode the power was held at 160 W for 17.0 and 19.3 min for the distributed and the calrod heaters, respectively. In the steps mode the power was gradually reduced from 160 to 20 W, and the defrost length was set to 28.5 and 22.3 min, respectively, for the distributed and calrod heaters. Energy consumption tests were carried out following the ISO and AHAM standards, using the same top-mount frost-free refrigerator. Changes were implemented in the electronic board in order to vary the power and length of the steps. A glass window was installed in the rear wall of the refrigerator to visually monitor the defrosting process. A 4.3% drop in the energy consumptions obtained applying the two standards was achieved by replacing the calrod heater and the constant power mode with the distributed heater and the steps mode. Clogging tests were also carried out, using an automatic door-opening device to check the robustness of the different defrosting systems.

Experimental investigations have been carried out to study heat and mass transfer during desorption of Tetrafluoro ethane (R134a) from R134a and Dimethyl formamide (DMF) solution in a tubular generator. Absorption refrigeration system has been built with brazed plate heat exchangers as condenser, absorber, evaporator and solution heat exchanger and with stainless steel concentric tubes as the generator. Effects of operational parameters viz., solution two phase Reynolds number, driving temperature ratio, driving pressure ratio, solution initial concentration on generator performance are analyzed. Desorption ratio, Sherwood number and Nusselt number increase as the solution Reynolds number, solution initial concentration, driving temperature ratio increase whereas these parameters decrease as the driving pressure ratio increases. Finally a correlation for Nusselt number and Sherwood number are proposed based on the experimental studies. Highlights: R134a desorption from R134a-DMF mixture is investigated experimentally. Stainless steel concentric tubes are used as generator of absorption system. Heat and mass transfer parameters are analyzed. Effect of non dimensional parameters on generator performance is examined. Empirical correlations for Nusselt and Sherwood numbers are proposed. � 2012 Elsevier Masson SAS. All rights reserved.

R134a (1, 1, 1, 2 tetrafluro ethane)-DMAC (N, N Dimethyl Acetamide) vapour absorption refrigeration system (VARS) can be used for sub-zero temperature applications and in industries where ammonia is forbidden. Because of the low boiling temperature difference between R134a and DMAC, a little amount of the latter also boils along with the former in the generator. Hence, this system needs a rectifier. Owing to incomplete rectification, a little amount of DMAC escapes to the condenser which ultimately results in residual liquid in the evaporator and cooling loss. This paper evaluates the performance of R134a-DMAC VARS with rectifier and liquid vapour heat exchanger (LVHX) at different operating conditions by simulation studies. The system performance becomes maximum at some optimum generator temperature which increases with sink temperature and decrease in cooling temperature. Owing to a large heat duty of solution heat exchanger (SHX), its efficiency is vital in increasing the system COP. Due to the presence of the residual liquid and low ratio of latent heat to specific heat of R134a vapour, LVHX plays an important role. Rectifier loses its importance when efficiency of LVHX is high. Significance of all the three components increases at low cooling and high sink temperatures. � 2012 Elsevier Masson SAS. All rights reserved.

[EN] The performance of an Internal Heat Exchanger (IHX) operating in a CO 2 transcritical refrigeration plant is analysed, from an energetic point of view, in this work. The evaluation is based on experimental data by contrasting the performance of the plant working with (44 tests) and without the IHX (46 tests) at the same operating conditions. The experimental evaluation covers three evaporating levels (-5, -10 and -15 °C), at two different gas-cooler outlet temperatures each (31, 34 °C), for a wide range of gas-cooler operating pressures (74.5-105.9 bar). The thermal effectiveness of the IHX is empirically analysed for the different operating conditions in the first part of the paper. Moreover, the relation of its effectiveness with the operating parameters is presented. The second part is devoted to analyse the modification of the energetic performance of the plant caused by the IHX. The results show a maximum increment on cooling capacity of 12%, an increment of the efficiency of the plant up to 12% and a maximum increase on discharge temperature of 10 °C at -15 °C of evaporating temperature. © 2010 Elsevier Ltd and IIR. All rights reserved., The authors are indebted to the Spanish Ministry of Education and Science (CTM2008-06468-C02-02/TECNO) and to the Spanish Ministry of the Environment and Rural and Marine Affairs (200800050084716) for their economic support to the present work.

Auto refrigerant cascade (ARC) refrigerators operating with zeotropic mixtures provide refrigeration at temperatures less than 173 K (-100 �C) using a single compressor. Different authors have suggested different cascade heat exchangers for ARC refrigerators. There is no study in literature that suggests at what temperature ranges one, two or three cascade heat exchangers are necessary. In this paper the performance of an ARC refrigerator operating in the liquid refrigerant supply mode and operating with optimized hydrocarbon mixtures and different cascade heat exchangers is studied. The optimum number of cascade heat exchangers (stages) to be used for different operating temperatures is suggested. � 2010 Elsevier Ltd. All rights reserved.

In this paper dynamical modelling of heat exchangers adopted in thermodynamic cycles, as Vapor Compression Cycles, is considered. A phase-independent nonlinear model is proposed to represent a volume where a fluid flows exchanging heat with the environment, and possibly changing its physical state. Differently from other approaches in the literature, explicit computation of the mass exchange rate between vapor and liquid is exploited to comply with the constraints on model evolutions, related to the particular phase condition. This leads to an effective and efficient dynamical modelling of single-phase conditions (subcooled liquid or superheated vapor), two-phase conditions (saturated vapor and liquid) and transitions among them which could take place in the considered volume.

In this paper, the heat and mass transfer characteristics of a horizontal tube absorber of a lithium bromide/water absorption chiller, which was manufactured according to industrial standards without additives are presented. It can be concluded that the heat transfer coefficient does not vary with the lithium bromide content but slightly with the film Reynolds number. On the other hand, it has turned out that the mass transfer coefficient changes with the lithium bromide mass fraction and the position in the absorber but not significantly with the film Reynolds number. The experimental data are discussed and an interpretation of the data is proposed. � 2008 Elsevier Ltd and IIR.

© 2015 IEEE; 2015 16th IEEE International Conference on Mobile Data Management, To promote energy-efficient operations in residential and office buildings, non-intrusive load monitoring (NILM) techniques have been proposed to infer the fine-grained power consumption and usage patterns of appliances from power-line measurement data. Fine-grained monitoring of everyday appliances (such as toasters and coffee makers) can not only promote energy-efficient building operations, but also provide unique insights into the context and activities of individuals. Current building-level NILM techniques are unable to identify the consumption characteristics of relatively low-load appliances, whereas smart-plug based solutions incur significant deployment and maintenance costs. In this paper, we investigate an intermediate architecture, where smart circuit breakers provide measurements of aggregate power consumption at room (or section) level granularity. We then investigate techniques to identify the usage and energy consumption of individual appliances from such measurements. We first develop a novel correlation-based approach called CBPA to identify individual appliances based on both their unique transient and steady-state power signatures. While promising, CBPA fails when the set of candidate appliances is too large. To further improve the accuracy of appliance level usage estimation, we then propose a hybrid system called AARPA, which uses mobile sensing to first infer high-level activities of daily living (ADLs), and then uses knowledge of such ADLs to effectively reduce the set of candidate appliances that potentially contribute to the aggregate readings at any point. We evaluate two variants of this algorithm, and show, using real-life data traces gathered from 10 domestic users, that our fusion of mobile and power-line sensing is very promising: it identified all devices that were used in each data trace, and it identified the usage duration and energy consumption of low-load consumer appliances with 87% accuracy.

The experimental investigation of the performance of a vapour ejector refrigeration system is described. The system uses R134a as working fluid and has a rated cooling capacity of 0.5 kW. The influence of generator, evaporator and condenser temperatures on the system performance is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste heat, etc. The operating conditions are chosen accordingly as, generator temperature between 338 K and 363 K, condenser temperature between 299 K and 310.5 K, and evaporator temperature between 275 K and 285.5 K. Six configurations of ejectors of different geometrical dimensions are selected for the parametric study. The performance of the refrigeration system at different operating temperatures is presented. � 2006 Elsevier Ltd and IIR.

Purpose of this experiment was to select the best material for the construction of thermal links aiming at cooling down sensitive masses of the order of 100–1000 kg for the detection of rare decays and gravitational waves. We report on the technique used to measure the thermal conductivity at very low temperatures (down to 30 mK) of three different types of copper, before and after a thermal treatment of the samples. The most conductive copper was used for the thermal link of the CUORICINO experiment, where a mass of about 60 kg needs to be cooled down to a few mK. The cool down time was reduced by at least one order of magnitude with respect to previous similar experiments. An important contribution to this successful result came also from an improved procedure for controlling the residual heating provided by the conversion from ortho- to para-hydrogen in copper.

A busca por padrões de desenvolvimento sustentável que permitam melhor qualidade de vida para a geração atual e para as futuras gerações traz à tona questões como as tendências de esgotamento dos recursos naturais, de aumento da geração de poluição, de escassez de energia, e de drásticas mudanças climáticas. Para dar-se resposta a essas questões e a outros desafios da esfera ambiental, torna-se cada vez mais necessário estudar a viabilidade de adoção de estratégias alternativas nos processos produtivos. A preocupação com os padrões de consumo, que vem atingindo níveis bastante elevados, em todo o mundo, é crescente. Entre os numerosos bens de consumo duráveis comercializados hoje, chama a atenção o caso, extremamente representativo, dos produtos eletroeletrônicos, cujas vendas vêm aumentando significativamente nos últimos anos, praticamente em todos os países, levando, por conseguinte, ao aumento proporcional do uso de recursos naturais e da quantidade de resíduos lesivos ao meio ambiente gerados pela produção e descarte futuro dos produtos. A adoção de estratégias de tratamentos de fim de vida que abordem sistemáticas de ciclo fechado apresenta-se como uma solução para a redução da geração de resíduos e do consumo de recursos naturais. Nesse sentido, a estratégia da remanufatura é considerada, quando possível, a melhor para o enfrentamento da questão. Este trabalho estuda a viabilidade técnica e econômica da adoção dessa estratégia, de forma abrangente e sistemática, na indústria brasileira de refrigeradores, como contribuição para o desenvolvimento sustentável.

Micro miniature refrigerators are employed to cool small infra-red sensors and other electronic devices in a number of applications. In a micro miniature refrigerator the heat exchanger, expansion valve and evaporator are all machined on a thin glass or stainless steel sheet (typically about 1 mm thick). Unlike normal heat exchangers, the volume of the flow channels of the heat exchanger is much smaller than that of the walls of the heat exchanger. Also, a large temperature gradient (up to 200 K) is sustained between the two ends of the exchanger which are typically 50–100 mm long. The performance of the heat exchanger is therefore largely controlled by the heat conduction that takes place through the walls of the heat exchanger. In this paper the governing equations of practical micro miniature refrigerator heat exchanger are solved numerically to understand the complex convection–conduction interactions. Some guidelines are presented for the design of these heat exchangers.

A closed-cycle helium refrigerator is utilized for the development of a facility for performing Mossbauer and electrical resistivity studies at low temperatures down to 18 K. This facility includes a vibration isolation assembly in order to isolate the sample holder from the vibrations arising from the cold head of the closed-cycle refrigerator. A top-loading chamber and a set of bellows are used for this purpose. The performance of the system was tested by recording the spectra of natural iron foil at 300 K when the closed-cycle refrigerator was on and when it was off. The typical width of the outer lines of the Fe spectra obtained was 0.26 mm s-1, which indicates the effective isolation of vibration. A facility for electrical resistivity measurements by a four-probe method was also developed for use in the same facility for Mossbauer studies.

The performance of flat-plate collectors serving as low- and high-pressure generators in a two-stage intermittent solar refrigeration system is predicted from transient heat-transfer analysis. Experimental results obtained with a laboratory, two-stage solar refrigerator are presented and compared with theoretical predictions. The agreement is found to be good.

In the next-generation home network systems (HNS), interoperability among multi-vendor appliances is a challenging issue to implement value-added integrated services. This paper presents a service-oriented framework to enable both evolution of HNS and the appliance interoperability. The key idea is to construct the integrated services by combining the existing services deployed by the appliances. This allows to eliminate the reference model, which had been an obstacle of the evolution of the HNS., IWPSE'05 : Eighth International Workshop on Principles of Software Evolution, 5-6 Sept. 2005, Lisbon, Portugal

A new refrigerator which uses resonant high amplitude sound in inert gases to pump heat is described and demonstrated. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). The thermoacoustic refrigerator has no sliding seals, requires no lubrication, uses only low-tolerance machine parts, and contains no expensive components. Because the compressor moving mass is typically small and the oscillation frequency is high, the small amount of vibration is very easily isolated. This low vibration and lack of sliding seals makes thermoacoustic refrigeration an excellent candidate for food refrigeration and commercial/residential air conditioning applications. The design, fabrication, and performance of the first practical, autonomous thermoacoustic refrigerator, which will be flown on the Space Shuttle (STS-42), are described, and designs for terrestrial applications are presented. Approved for public release; distribution is unlimited.

Miniaturization of the absorption refrigerator requires an air cooled absorber and condenser and replacement of the customary solution pump by a bubble pump. The operating pressures in the bubble pump operated two fluid vapour absorption refrigerator have to be very low (vacuum) so as to make use of the hydrostatic principle to maintain the required pressure difference between the condenser and evaporator. Hence, only water and alcohol based working fluid combinations are found suitable. Thermodynamic properties, such as specific heat and heat of mixing, and thermophysical properties, such as vapour pressure, density, viscosity, surface tension and solubility, are necessary for the overall performance evaluation of such a refrigerator. In this paper, sixteen water based working combinations have been analyzed and compared with reference to the solution density governing the hydrostatic height, viscosity and specific heat affecting the heat and mass transfer and solubility to avoid crystallization.

La empresa OT-Fred és dedica al disseny i producció de kits per adaptar unitats de fred a vehicles de transport de mercaderies. Observen que la fallida del compressor de la unitat de fred pot porta greus conseqüències pel bloc motor del vehicle, que poden anar des de la pèrdua de la pròpia unitat de fred fins a la parada involuntària del vehicle. Per aquest motiu, és proposen trobar una manera de detectar aquesta fallida del compressor i aïllar-la a temps per evitar totes les conseqüències negatives possibles al vehicle. Aquest projecte consisteix en trobar la millor manera de controla el sistema de fred, per detectar de una manera rapida i precisa el mal funcionament del compressor.