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Background Very few studies have reported updated data on the incidence, clinical evolution and treatment of inflammatory bowel disease (IBD) in Europe. Aims i) To assess the incidence of IBD in Spain; ii) to describe the main epidemiological and clinical characteristics of patients at diagnosis and the evolution of the disease; and iii) to explore the use of drug treatments in the biological era. Methods Prospective and population-based nationwide registry. Adult patients diagnosed with IBD -Crohn’s disease (CD), ulcerative colitis (UC) or IBD unclassified (IBD-U)- during 2017 in all the 17 Spanish administrative regions were included and will be followed-up for 5 years after diagnosis. Treatment was grouped into 5 categories: mesalazine (oral or topical), steroids (intravenous, oral or topical), immunomodulators (thiopurines, methotrexate or cyclosporine), biologics (anti-TNF, vedolizumab or ustekinumab) and surgery. Results 3627 incident cases of IBD diagnosed during 2017 in 108 hospitals covering over 22 millions of adult inhabitants (about 50% of the Spanish population) comprise the study cohort (Table 1). The overall incidence (cases/100.000 person-years) was 16 for IBD, 7.5 for CD, 8 for UC, and 0.5 for IBD-U. Incidence of CD was somewhat higher in Central Spain, while that of UC was higher in Northern Spain (Asturias and Navarra) (Figure 1). About 46% of patients had CD and 50% UC. Diagnosis delay was longer in CD than in UC (5 vs. 2 months, p < 0.01). The proportion of patients with symptoms at diagnosis was higher in UC than CD (94 vs. 89%, p < 0.01). By contrast, those with CD vs. UC had higher frequency of family history of the disease (18 vs. 13%, p < 0.01), tobacco smoking (38 vs. 12%, p < 0.01) and extraintestinal manifestations (12 vs. 6%, p < 0.01). At diagnosis, 18% of CD patients had structuring or fistulising behaviour, and 69% of UC patients had extensive colitis or left-sided colitis. During a median of 12-month of follow-up, 28% of patients were hospitalised (35% of CD and 22% of UC patients, p < 0.01). A total of 2.6% CD patients progressed to a more severe phenotype, and 2% UC patients developed a more extensive involvement. The cumulative exposure to different treatments is shown in Figure 2. Conclusion The incidence of IBD in Spain is quite high and similar to that reported in Northern Europe. IBD patients require the use of substantial therapeutic resources, which are greater in CD than in UC, and much greater than previously reported. One third of patients are hospitalised in the first year after diagnosis and over 5% undergo surgery. These results highlight the high burden of IBD as well as some of the important challenges faced by clinicians and healthcare systems to manage this costly and complex disease.

[EN] In this work the possibilities of enhancing the energy performance of CO2 transcritical refrigeration systems using a dedicated mechanical subcooling cycle are analysed theoretically. Using simplified models of the cycles, the modification of the optimum operating conditions of the CO2 transcritical cycle by the use of the mechanical subcooling are analysed and discussed. Next, for the optimum conditions, the possibilities of improving the energy performance of the transcritical cycle with the mechanical subcooling are evaluated for three evaporating levels (5, 5 and 30 C) for environment temperatures from 20 to 35 C using propane as refrigerant for the subcooling cycle. It has been observed that the cycle combination will allow increasing the COP up to a maximum of 20% and the cooling capacity up to a maximum of 28.8%, being both increments higher at high evaporating levels. Furthermore, the results indicate that this cycle is more convenient for environment temperatures above 25 C. Finally, the results using different refrigerants for the mechanical subcooling cycle are presented, where no important differences are observed., The authors gratefully acknowledge Jaume I University of Spain, who financed the present study through the research project P1.B2013-10.

An experimental comparison has been performed of a cascade refrigeration facility working with the refrigerant pairs R134a/R744 and R152a/R744. This kind of facility is suitable for industrial and commercial refrigeration applications. The high GWP refrigerant R134a has been substituted with the low GWP refrigerant R152a, in accordance with the new environmental regulations aimed at mitigating the Greenhouse effect. As both refrigerants belong to the family of HFC fluids, the replacement has been carried out as a drop-in. Apart from safety considerations, as R152a is included in the A2 group, the results of the wide range of tests conducted show that no special energy improvement or worsening is achieved, and that the replacement of R134a with R152a is technically and energetically feasible. The authors gratefully acknowledge the financial support for the present work provided by the Spanish Ministry of Economy and Competitiveness (research project ENE2014-53760-R).

We present the experimental evaluation of a R134a/CO2 cascade refrigeration plant designed for low evaporation temperature in commercial refrigeration applications. The test bench incorporates two single-stage vapour compression cycles driven by semi hermetic compressors coupled thermally through two brazed plate cascade heat exchangers working in parallel and controlled by electronic expansion valves. The experimental evaluation (45 steady-states) covers evaporating temperatures from 40 to 30 C and condensing from 30 to 50 C. In each steady-state, we conducted a sweep of the condensing temperature of the low temperature cycle with speed variation of the high temperature compressor. Here, the energy performance of the plant is analysed, focussing on the compressors' performance, temperature difference in the cascade heat exchanger, cooling capacity, COP and compressors discharge temperatures., The authors gratefully acknowledge Jaume I University of Spain, who financed the present study through the research project P1.B2013-10.

IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The classical position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gascooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed. From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time., The authors are indebted to the Spanish Ministry of Education and Science (IESCO2) and to the Spanish Ministry of the Environment and Rural and Marine Affairs (ENE2011-22968) for the economic support given to the present work.

The aim of the present paper is to describe a general methodology suitable for analysing any intermediate configuration considered in staged vapour compression refrigeration cycles. This general methodology only depends on two basic parameters related to the subcooling and desuperheating obtained in the inter-stage system. A COP expression based on the two basic parameters was obtained from the general configuration. By means of its particularization to seven common configurations, it was then possible to make an energy comparison of the various configurations working with two fluids appropriated for the low temperature domain such as ammonia and R-404A., 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 this work.

[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.

[EN] The aim of the present paper is to detail an analysis, based on experimental data, of the inter-stage working conditions of a two-stage vapour compression facility equipped with a compound compressor, which operates with the most usual inter-stage configurations (two-stage with direct liquid injection and two-stage with subcooler) in medium- and low-capacity commercial refrigeration applications. The experimental analysis is performed in an evaporating temperature range between -36 and -20 degrees C, and in a condensing temperature range between 30 and 47 degrees C, using one of the fluids most widely-used in Europe for low-temperature applications, the R-404a. The inter-stage working temperature/pressure obtained in the tests has been contrasted with the two usual criterion of the optimum working conditions definition: the arithmetical mean of the refrigerant condensing and evaporating temperatures and the criterion of equal pressure ratios in both stages. This paper presents the differences and affinities with the criterion and analyses the influence of the intermediate systems (direct liquid injection and subcooler) on the inter-stage operating conditions., The authors are indebted to the Generalitat Valenciana for partial support under project GV05/091.

International agreements will restrict in the near future the use of high-GWP refrigerants in Europe. These restrictions will favour the implantation of refrigeration systems with low-GWP fluids, especially in applications with high leakage rate. To clarify possible solutions that accomplish the forthcoming F-Gas Regulation, we present simplified models of five two-stage vapour compression refrigeration systems and evaluate them with low-GWP refrigerants (HFC, HFO and naturals). We analyse the energy performance over a wide range of evaporating and environment temperatures and present the TEWI analysis under a same scenario, typical of a centralized commercial refrigeration application. We conclude that, for high-GWP refrigerants, direct emissions have greater weight in TEWI than the indirect ones, so future solutions might be based on low-GWP fluids, in some cases with risk of toxicity or flammability. We observe the indirect two-stage systems (cascades) with CO2 as low temperature fluid are promising solutions, especially for warm regions., The authors gratefully acknowledge Jaume I University of Spain, who financed the present study through the research project P1.B2013-10.

[EN] The EU Regulation 517/2014 has recently been approved in a further attempt to curb the effects of GlobalWarming. As a consequence, the refrigeration sector is moving towards refrigerants with a low GlobalWarming Potential (GWP100) in accordance with the limit fixed by these regulations (150). In this regard, the old refrigerant R152a attracts renewed interest due to its low GWP (138) and its similarity to R134a. The present work shows the results of using R152a in a vapour compression plant equipped with a hermetic compressor and an IHX designed for R134a. The refrigerant was replaced by a conventional drop-in process in order to carry out an energy comparison. The results have revealed an improvement in the COP with R152a up to 13% despite a reduction in the cooling capacity of about 10%. During the test campaign, R134a hermetic compressors have been shown to be capable of operating with R152a., The authors acknowledge Jaume I University of Spain, who financed partially the present study through the research project P1.B2013-10.

The present paper presents experimental results obtained from a refrigerating vapour-compression plant’s shell-and-tube (1–2) evaporator working with R407C. Several tests have been carried out to study the influence of the evaporating pressure and the refrigerant’s mass flow rate on the refrigerant’s boiling heat-transfer coefficient inside horizontal tubes. This work has been performed by analyzing the variations of the evaporator’s overall thermal-resistance, computed using the effectiveness-NTU method, considering the influence of pressure drops and glide at the evaporator, and finally transferring the results and conclusions to the boiling heat-transfer coefficient. It has been observed that the variations of the boiling heat-transfer coefficient show a dependence on the evaporating temperature and the refrigerant’s mass-flow rate, which has been analyzed in the test range.

This paper proposes a simplified steady-state model of a single stage vapour compression plant. The developed model is mainly based on well known physical equations and partially based on empirical and parametrical correlations. As input data uses only the main operating variables: evaporating and condensing refrigerant temperatures and refrigerant total superheating degree, and returns as main values: refrigerant mass flow rate, cooling capacity, compression power consumption and COP. In this way the model allows to analyze easily the influence of the main operating variables on the energy performance. Furthermore, the model results are validated using experimental data taken from a test bench in a wide range of operating conditions and working with three refrigerants (R134a, R407C and R22). The agreement between the model predictions and the actual values is found to be within ±5% for mass flow rate and specific refrigerating effect and ±10% for the rest energy parameters.

Internal or liquid-suction heat exchangers are used in many refrigeration and air conditioning systems based on the vapour compression cycle, with the basic objective of assuring the entrance of refrigerant in liquid phase to the expansion device. This purpose is achieved by exchanging energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These devices can have positive or negative influences on the plant overall energy efficiency, depending on the working fluid and the operating conditions. In this paper the experimental results obtained from a refrigeration test facility with and without the presence of an internal heat exchanger, using R22, R134a and R407C as working fluids, are presented and analyzed, including the impact of pressure drops and variations of refrigerant mass flow rate. A comparison between experimental and theoretical results is also enclosed.

In this paper, the predicted performance of a shell-and-tube (1-2) evaporator installed in a vapour compression liquid chiller is analysed. The classical thermal design methods are applied to the evaporator performance with two HFC refrigerants, a pure fluid (R134a) and a zeotropic blend with an appreciable glide (R407C). From the experimental results obtained it is possible to discuss the validation of the simplificatory assumptions usually taken, evaluating the resulting error introduced due to the no consideration of pressure drops and temperature glide (in the case of zeotropic blends) at the evaporator. Concluding that is not possible to consider the behaviour of a zeotropic refrigerant as a pure refrigerant, rejecting the glide. Whereas the assumption of no pressure drops in evaporator, leads to an error of about 5% in cooling capacity calculation. Copyright © 2004 John Wiley & Sons, Ltd.

In this paper, the influence of the main operating variables on the energetic characteristics of a vapour compression plant, based on experimental results, is addressed. The experimental tests are performed on a single-stage vapour compression plant using three different working fluids, R134a, R407C and R22. The operating variables considered are the evaporating pressure, the condensing pressure and the superheating degree at the compressor inlet. The performance characteristics followed to analyse the energetic performance are the refrigerating capacity and the power requirements of the reciprocating compressor, presenting and discussing in this work the main experimental results obtained.

Unlike other refrigerants, R744 (or carbon dioxide) has a very low critical temperature (30.98 C) which hampers working in subcritical conditions especially when the environment is used as a heat rejection sink. Accordingly, CO2 refrigeration plants are designed to work in supercritical conditions. Notwithstanding, the heat rejection temperature may decrease below the critical one during long periods of time (for example in winter or autumn), thereby offering the possibility of operating in subcritical conditions. According with this and in order to give useful information for related system design and operation, the aim of this paper is to analyse the behaviour of a CO2 refrigeration plant designed for supercritical conditions when it works in subcritical conditions. To achieve this objective a series of experimental assays has been performed. The results obtained shown a decrease in the coefficient of performance (COP) and cooling capacity ðQ_ evÞ if the heat exchanger designed as a gas-cooler operates as a condenser in some cases. To avoid this, a possible solution is proposed consists on using an inverter drive to reduce the refrigerant mass flow rate in order to enhance the gas-cooler/condenser thermal effectiveness. From the experimental results obtained, it could be remarked that if the heat exchanger is designed as a condenser and operates as a gas-cooler, the energy performance of the refrigeration plant could improve under certain subcritical and supercritical conditions., The authors are indebted to the Spanish Ministry of Education and Science (IESCO2) and to the Spanish Ministry of the Environment and Rural and Marine Affairs (ENE2011-22968) for the economic support given to the present work.

Background and purpose Information received by IBD patients about their disease is of particular importance. The objective of the study was to determine the information resources these patients used, together with their perceived information gaps and expected preferences. Patients and methods A prospective, observational, cross-sectional study conducted on IBD patients attending 13 Spanish hospitals during 2008. Patients completed a semi-structured 52-question survey. Results Survey was adequately completed by 379 of 385 patients (98%), of whom 57% had Crohn's disease and 43% ulcerative colitis. Mean patient age was 37.9 years (range, 16–76 years). Gastroenterologists were the most commonly used resource (98%), followed by the Internet (60%), and general practitioners (50%). More than 90% reported good to excellent satisfaction with gastroenterologists, nurses, and patients’ associations. Only 56% considered their information needs to be covered. The Internet was mostly used by young patients and those with a high education level. In the future, 85% of the patients would like to receive information from the gastroenterologists, and 92% by face-to-face interviews. Patients mainly want additional information on treatment (medical and surgical), clinical manifestations, cancer, and mortality risks. They also think that they are poorly informed about their social and work rights, risks of cancer and death, and research trials. Conclusions Patients with IBD use and prefer gastroenterologists as the main source of information, but only half of them consider their information needs to be covered.

This work analyses and compares two approaches to evaluate the boiling heat transfer of CO2 in a real evaporation process: classical empirical correlations and flow pattern maps. We develop a finite-volume mathematical model of an evaporator to contrast both approaches and simulate it with four empirical correlations, not developed for CO2 but tested successfully with it, and a flow pattern map specific for CO2. We contrast the results of the simulation with 73 experimental steady-states performed with a transcritical CO2 refrigeration plant that incorporates a concentric counter current evaporator. We observe that both approaches can predict the evaporation process of CO2, nonetheless, in spite of the more complex mathematical formulation, the considered flow pattern map allows to obtain more precision., The authors are indebted to the Spanish Ministry of Education and Science (CTM2008-06468-C02-02/TECNO) for the economic support given to the present work.

This work focuses on the investigation of new drop-in or long-term refrigerants for low evaporating temperatures that can be used as substitutes for HCFC-22, which is gradually being phased-out. This process is already in progress in European countries (Regulation CE-1005/2009) and has been accelerated in Article 5 Countries of the Montreal Protocol. Specifically, in this work the energy influence of the suction line/liquid line heat exchanger on the new substitute fluids is addressed from an experimental approach. The study has been based on experimental measurements in a single-stage vapour compression refrigeration plant, which has been tested in the same external conditions operating with and without an Internal Heat Exchanger (IHX). The energy influence of the IHX working with R22 and three potential substitutes for low temperature applications, the chlorine-free drop-in fluids R417B and R422A and the chlorine-free long-term substitute R404A has been analysed. From the experimental results, reductions in capacity and COP have been observed when R22 is replaced by the drop-in fluids, although the presence of an IHX can help to lessen these reductions. Furthermore, the criteria that are usually employed to determine the energy advantage or disadvantage of the use of the IHX with the new refrigerants have been tested, the results confirming that they remain valid for them.

he paper presents the analysis of the energy performance of an air vortex cooling tube under variations of the air inlet properties, with t hree independent experimental tests validated through the energy balance in the device. The experimental analysis includes the following variations of the input conditions: First, the effect of the air inlet pressure to the vortex tube, focused on the analysis of temperature variations in the output cold stream and in the cooling capacity when the cold flow fraction varies. Second, we studied air inlet temperature variations to the vortex tub e under different cold flow fractions, which is an analysis not found in the literature. And finally, is studied the performance of the vortex tube when the insulation is provided or in absence of insulation.

The gas-cooler heat exchanger is a characteristic device of the refrigeration plants that use CO2 as the working fluid in transcritical conditions. The proper gas-cooler sizing, allows getting the maximum effectiveness in the heat exchange, thus permitting to reduce the temperature approach and improving the heat recovered in the coolant (secondary) fluid and the COP of this kind of systems. This work deals with the development of a steady-state coaxial gas-cooler model that uses water as coolant fluid. The model is based on the finite-volume methodology and is validated with experimental data. An uncertainty lower than ±10% was obtained in the calculation of the heat transfer rates and an uncertainty lower than ±3 °C in the outlet temperatures of both fluids. Several correlations for estimating the CO2 heat convection coefficient have been studied to select the one that best fits the model. Using the model, the influence of different parameters on the gas-cooler thermal effectiveness has been analyzed and presented in this work. Finally, a comparison between the traditional ε-NTU method and the developed model has been done., 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 the economic support given to the present work.

[EN] The world community has committed to eliminate the HCFC-22 refrigerant to a series of deadlines according to the agreements taken during the 19th Montreal Protocol meeting in September 2007. This phase-out, which is already in progress in European Countries, has been accelerated in Article 5 countries. Refrigerant manufactures offer different drop-in refrigerants to replace R22 in existing equipment by non-ozone depleting substances in order to be able to make full use of the remaining life of the plants or different retrofit refrigerants, the use of which implies modifications to the existing systems. This work aims to contribute to the understanding of the implications of the process of R22 substitution, either with drop-in or retrofitting processes, by presenting a theoretical and experimental analysis of the performance of R22, of two drop-in fluids (R422A, R417B) and a retrofit refrigerant (R404A), in a two-stage vapour compression plant over a wide range of evaporating temperatures for a fixed condensing temperature of 40 C. In this communication the main energy parameters, such as cooling capacity and COP are analysed and discussed., The authors are indebted to the Spanish Ministry of Education and Science (CTM2008-06468-CO2-02/TECNO) and to the Spanish Ministry of the Environment and Rural and Marine Affairs (200800050084716) for their economic support for the present work.

This work presents the experimental evaluation of the energy performance of a modified single-stage CO2 transcritical refrigeration plant with an internal heat exchanger (IHX) based on vapour injection in suction line. This modification, which is only applicable to refrigeration plants with an expansion process divided in two stages with a liquid receiver between them, consists of extracting saturated vapour from the liquid receiver in order to: decrease the vapour quality at the evaporator inlet, and reduce the superheating degree at the compressor suction by means of the expansion and following injection of the extracted refrigerant. Three different injection points have been evaluated experimentally: before the IHX, after the IHX and just before the suction chamber of the compressor. The experimental measurements show that the cooling capacity and COP can be enhanced in 9.81% and 7.01%, respectively. Furthermore, a reduction in the discharge temperature of the compressor up to 14.7 C has been measured inside the evaluation range., 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 the economic support given to the present work.

[EN] This work presents an experimental evaluation, from an energy analysis point of view, for two of the most used inter-stage systems in two-stage vapour compression cycles driven by compound compressors: the direct liquid injection and subcooler systems. The evaluation, considers the two-stage cycle with no intermediate systems as reference cycle and was performed on a plant, driven by a compound compressor using the refrigerant R404A for an evaporating temperature range of -36 to -20 degrees C and for a condensing temperature range of 30-47 degrees C. The analysis of the results shows that the inter-stage systems determine the performance of the energy parameters, which are discussed in the paper. The configuration yielding the best results was the two-stage compression cycle with subcooler, since the cooling capacity and COP values for this configuration were the highest. Conversely, the two-stage compression cycle working with direct liquid injection showed lower performance from an energy point of view, though this configuration allows a substantial reduction of the discharge temperature., The authors would like to thank BANCAJA for its partial support to the project P1-1B2008-12.

[EN] In this paper, a simplified model for the study of shell-and-tubes heat exchangers (HXs) is proposed. The model aims to agree with the HXs when they are working as condensers or evaporators. Despite its simplicity, the model proves to be useful to the pre-designment and correct selection of shell-and-tubes HXs working at full and complex refrigeration systems. The heat transfer coefficient and pressure drop correlations are specially selected and treated to implement them into the shell-and-tubes HXs presented. The model is implemented and tested in the modellization of a general refrigeration cycle and the results are compared with data obtained from a specific test bench for the analysis of shell-and-tubes HXs., This research has been partially financed by Spanish Ministry of Education and Culture (MEC), under the Project DPI2005-09262-C02-01/02 and by Fundacion Seneca (CARM) with the research project with Reference Number 088766/PI/08.

[EN] As a result of the ban of the CFC fluids in 2000 and the future limitation of HCFC fluids, which manufacture limit is the year 2010, refrigerant producers have been working to develop different mixtures, mainly based on HFC fluids, which emulate the properties of the former refrigerants used in refrigeration plants. At the moment, the HFC-404A and the HFC-507A are the more widely used fluids in Europe as replacement of the CFC-502 in plants operating at low temperatures. This work presents the experimental evaluation, from an energy point of view, of both refrigerants in the same refrigeration plant, which corresponds to a double-stage vapour compression plant driven by a compound compressor. The characterization was made for an evaporating temperature range between ¿36 and ¿20 °C for a constant condensing temperature of 40 °C., The authors are indebted to 'Fundacion Caixa Castello-Bancaixa' (P1.1B2008-12) and to the 'Ministerio de Medioambiente y Medio Rural y Marino' (200800050084716) for the support given to the present study.

[EN] This work presents a procedure for calculating the COP and heat transfer rates, based on on-site experimental temperature measurements, of a lithium¿bromide/water direct-fired double-effect absorption chiller in reverse parallel flow configuration, running on natural gas. The chiller was equipped with a set of thermocouples which allowed measuring its working temperature levels through all its operating stages. The chiller analysed in this work is the central cooling system of the air-conditioning installation of the Principe Felipe Science Museum, located at the Valencia¿s City of Arts and Sciences (Spain). This installation is capable of providing a cooling capacity of 4.5 millions of kcal/h (5.2 MW), by means of three direct-fired double-effect absorption chillers. From the experimental measurements a calculation procedure, based on energy and mass balances, has been developed, which allows estimating the specific powers by unit of mass flow rate through the evaporator. From these power values the instantaneous COP of the chiller could be obtained. Additionally, the paper analyzes different aspects that were not possible to be considered and details the actions taken in order to take them into account., The authors would like to thank the company C.A.C. S.A for its partial support to the project 'Auditoria energetica de la instalacion de climatizacion del Museo Principe Felipe'.

[EN] This paper presents a detailed experimental analysis of the energetic effects of using a subcooler system in a two-stage refrigeration facility driven by a compound compressor. The analysis is carried out by comparing the experimental performance of the two-stage cycle working with the subcooler system to the experimental performance of the two-state cycle working without the subcooler system in an evaporating temperature range between -36 degrees C and -21 degrees C and in a condensing temperature range between 31 degrees C and 49 degrees C using R-404A as the working fluid. Experimental results show that the amount of refrigerant used to obtain the subcooling, which is injected between the compression stages, causes an increment in the interstage working pressure, in power consumption, and in the cooling capacity of the cycle. This paper discusses and analyzes these modifications.

Presentamos el caso de una paciente mujer de 34 anos de edad, intervenida hace 8 anos mediante bypass gastrico con exclusion antropilorica, sin complicaciones inmediatas en el postoperatorio, que se remite a nuestra unidad para estudio de anemia ferropenica severa con requerimientos transfusionales y gastroscopia y colonoscopia normales. La EDB mostro mucosa normal de intestino delgado hasta la anastomosis, continuando de forma retrograda hasta piloro sin detectar lesiones, pudiendo sobrepasarse este (Fig. 1) hasta el munon gastrico, donde se aprecio una lesion ulcerosa origen de la hemorragia digestiva, se pudo objetivar con mayor precision haciendo retroversion en la misma cavidad (Fig. 2). Se objetivo la papila de aspecto normal in situ.

[EN] This work presents a mathematical model of a shell-and-tube condenser based on mass continuity, energy conservation and heat transfer physical fundamentals, whose methodology can be easily adapted for modelling any type of condenser. The model is formulated as a combination of control volumes that represents all the refrigerant states in the condenser and the liquid receiver function, which is carried out by the condenser of the experimental plant. Model validation is performed by using steady-state data and transient tests from an experimental vapour compression plant; the prediction error of the model is lower than 5% and a good representation of the dynamic performance of the condenser is achieved. A theoretical comparison involving the importance of the dynamic responses of the evaporator and the condenser at the plant is also presented., The authors are indebted to the Generalitat Valenciana for partial support under programme Formación de Personal Investigador (FPI) CTBPRB/2005/105 and project GV05/091.

[EN] This work presents the experimental evaluation of the energy efficiency and optimal gas-cooler pressures of a single-stage refrigerating plant working with carbon dioxide as refrigerant in transcritical conditions. The performance of the plant was tested at three different evaporating temperatures (-0.9, -10.1 and -18.1 degrees C), for three gas-cooler refrigerant outlet temperatures (31.2, 33.6 and 40.0 degrees C) at each evaporating temperature and in a wide range of gas-cooler pressures (74.4-104.7 bar). The experimental tests enabled us to calculate accurately the optimal gas-cooler pressures and compare them with the most commonly used relations to define this value in single-stage refrigerating cycles operating with carbon dioxide in transcritical conditions. Furthermore, an analysis of the reduction in energy efficiency produced in the plant if the optimum pressure is not well defined is also presented., The authors are indebted to Frost-Trol S.A. (www.frosttrol.com) and the Spanish Ministry of Education and Science (ENE2006-09972/CON) for the economical support given to the present work and for the Grant BES-2007-16820 linked to the Ministry project

This work presents a mathematical model of a shell-and-tube evaporator based on mass continuity, energy conservation and heat transfer physical fundamentals. The model is formulated as a control volume combination that represents the different refrigerant states along the evaporator. Since the model is based on refrigerant and secondary fluid states prediction, it can be easily adapted for modelling any type of evaporator. The strategy of working with physical fundamentals allows the steady- and dynamic-state analysis of any of its performance variables. The paper presents a steady-state validation made with two pure refrigerants (HCFC-22, HFC-134a) and with a zeotropic blend (HFC-407C), and a dynamic validation with transient experimental tests using HCFC-22. The model prediction error is lower than 5% and it is well in accordance with actual dynamic behaviour. Copyright © 2006 John Wiley & Sons, Ltd.

[EN] Based on a previously developed and validated steady-state model of a single-stage vapour compression plant, the present paper describes an in-depth study directed to examine the consequences of changes in the operating conditions in such a plant. These include modifications of condensing and evaporating temperatures and the total superheating degree at compressor suction, which are the main energy parameters in a refrigeration plant. The aim of this work is not to determine the final energy state when the operating conditions are modified, which could be achieved using the steady-state model, but to study the mechanism that explains the variation. The pursuit of this goal implies conducting a detailed analysis of the performance and influence of several intermediate variables, the evolution of which has a direct effect on the final cooling capacity, compression power and COP values. The results obtained show the significant influence of the suction pressure (through the specific suction volume) on the compression power and cooling capacity, while the condensing and evaporating temperatures have a similar influence on the COP., The authors are indebted to the Generalitat Valenciana for partial support under project GV05/091

Aim: to evaluate the utility of double-balloon enteroscopy for small-bowel disease. Design: a prospective study of 50 consecutive enteroscopies performed from December 2004 to July 2005 to analyze diag- noses and treatments. Patients: 44 patients (33 had undergone a previous capsule endoscopy) with indications for obscure digestive hemorrhage, an- giodysplasia, Peutz-Jeghers syndrome, ulcer, suspected Crohns disease, tumors, and refractory celiac disease. Results: we carried out enteroscopy studies in 44 patients by the oral route and, in 6 additional patients, by both the oral and anal routes. We reached the ileon with the oral route in all cases but one (jejunal stenosis), and in 4 cases out of 7 with the anal route, with an average duration of 73 minutes. We found an- giodysplasia in 19 cases, as well as NSAID-related enteropathy, Crohn's disease, diverticulosis, and Waldenstrom's disease. We performed biopsies in 31% of cases with diagnoses of adenocarci- noma, lymphangiectasia secondary to tumor in celiac disease, and Whipple's disease. We treated 19 patients with angiodysplasia (1 to 20 synchronous lesions) with argon, and 4 patients with polyps using polipectomy (sporadic polyps or Peutz-Jeghers syndrome). A retained capsule in one patient with stenosis was removed. Conclusions: double-balloon enteroscopy is a useful and ef- fective technique in the diagnosis and treatment of small intestine diseases, thus complementing capsule endoscopy. More studies are needed to analyze its impact on the management of this con- dition.

Introduccion y objetivo La Region de Murcia realizo en el bienio 2006–2007 un estudio piloto para evaluar eficacia, coste y aplicabilidad de un programa de Cribado de Cancer Colorrectal que fuera extensible en el futuro al resto de la Region. Metodo El estudio se aplico a la totalidad de la poblacion de entre 50 y 69 anos (riesgo medio) del area sanitaria dependiente del Hospital Morales Meseguer (29726 personas) a las que se invito a la realizacion de un test de SOHi cuantitativo y posterior colonoscopia como prueba de confirmacion diagnostica. Se definieron diferentes parametros de control de calidad para la colonoscopia: porcentaje de intubaciones a ciego, tiempos de endoscopia, polipos recuperados, cumplimiento en sedoanalgesia y grado de satisfaccion. Resultados Se realizo el test de SOHi el 42,3% de la poblacion diana. Fueron positivos el 9,47%. La tasa de aceptacion de la colonoscopia fue del 93,3%. Se realizaron 1369 colonoscopias con los siguientes resultados en (%): Lesiones 80,9, adenomas 61,1, Adenomas de alto riesgo 38,4, Pacientes de alto riesgo por adenomas: 22,7, Carcinoma in situ o intramucoso 8,1, Carcinoma infiltrante 4,67. Valor predictivo positivo del test de SOHi fue: Adenoma alto riesgo: 46,5%; Adenoma bajo riesgo: 21,5%; Carcinoma: 3,6%. 159 (11,5%) pacientes precisaron sucesivas colonoscopias (224 pruebas) por los siguientes motivos: dolor 35 (2,52%), mala preparacion limpieza 13 (0,94%), anticoagulacion-antiagregacion 12 (0,87%), complicaciones 8 (0,58%), control endoscopico de carcinoma invasivo 18 (1,31%), polipos multiples 16 (1,16%), lesiones complejas 58 (4,23%). 59 del total precisaron 72 colonoscopia bajo sedacion profunda para su resolucion. Se predijeron 15 (1,09%) complicaciones (12 hemorragias, 1 perforacion y 3 serositis); 8 de ellas requirieron ingreso hospitalario para tratamiento. 90 pacientes fueron derivados a una Consulta de Alto Riesgo por presencia de lesiones multiples (> 10). 58 pacientes estan en seguimiento por polipos adenomatosos multiples en sus distintas calificaciones y han sido detectadas 5 PAF atenuadas. Conclusiones El metodo ha demostrado su eficacia para la deteccion y tratamiento de lesiones si bien al coste por colonoscopia hay que sumar las cargas de trabajo derivado de la necesidad de tratamiento de los problemas hallados en dichos pacientes. La aplicabilidad del programa dependera de la capacidad de las unidades para dimensionar adecuadamente su actividad.

The case of a 42-years-old male with acute pancreatitis of ethanol origin and formation of pseudocysts in the tail of the pancreas is presented. The patient suddenly presented a picture of hypovolemic shock caused by rupture of the spleen. Emergency splenectomy with resection of necrotic tissue was performed and thrombosis of the splenic vein was observed. The patient evolved satisfactorily following surgery.