• Energy Research
• Closed Access close
• Restricted close
• UA close
• EC close

Abstract The moving boundary method is an appealing approach for the design, testing and validation of advanced control schemes for evaporators and condensers. When it comes to advanced control strategies, not only accurate but fast dynamic models are required. Moving boundary models are fast low-order dynamic models, and they can describe the dynamic behavior with high accuracy. This paper presents a mathematical formulation based on physical principles for two-phase flow moving boundary evaporator and condenser models which support dynamic switching between all possible flow configurations. The models were implemented in a library using the equation-based object-oriented Modelica language. Several integrity tests in steady-state and transient predictions together with stability tests verified the models. Experimental data from a direct steam generation parabolic-trough solar thermal power plant is used to validate and compare the developed moving boundary models against finite volume models.

Abstract Critical Infrastructure Protection is a relatively new scientific domain stemming from an American Presidential directive PDD-63 of May 1998. Critical Infrastructure (CI) performance and protection are national priorities for all European Union (EU) countries following the introduction of the EU Directive 2008/114/EC, which takes an all hazards approach. This paper has an international focus. At the global and European level, the interest in identifying the impacts of climate change on CIs and extreme weather events (EWE) has increased in the last decades, following several high-profile so-called natural disasters. Concern is evidenced by the UN Sendai Framework for Disaster Risk Reduction and the EU Commission’s Staff Working Document on Risk Assessment and Mapping; Guidelines for Disaster Management, SEC (2010) 1626. This paper presents and discusses scientific work which has been published in this area, with a focus on energy CI. The impacts of climate change and extreme weather events on energy CI are initially identified. Important aspects in CI protection such as risk assessment, interdependencies with other sectors, and adaptation/resilience options are subsequently presented and discussed.

The effects of clinostating on physiological processes and biochemical characteristics of wheat plants (Triticum aestivum L.) both healthy and infected by the wheat streak mosaic virus (WSMV) were studied. In six experiments, each lasting over 30 days, healthy and infected plants of the dwarf Apogee variety were grown under conditions of continuous horizontal and vertical clinostating with 2 rpm at 21 +/- 2 degrees C and 6000 1x (the optimal moisture of a substrate being maintained). The control variants (healthy and infected) were simultaneously grown under the same conditions of temperature and illumination in stationary containers and in open pots. During the experiment, visual observations were carried out over the state of tested plants. After completing the experiment, biometric indices, pigment, carbohydrate and dry matter contents were determined in all the plants. It was shown that clinostating sharply reduced the reproductive function of healthy plants and considerably affected their biomass (productivity) and concentration of chlorophylls and sugars. The viral infection resulted in further reduction of these characteristics. In control variants the viral effect was more significant. We speculate that clinostating reduced the rate of reproduction and spread of the virus.

Abstract Five different models for calculating solar module temperature, output power and efficiency for sunny days with different solar radiation intensities and ambient temperatures are assessed in this paper. Thereafter, modeled values are compared to the experimentally obtained values for the horizontal solar module in Nis, Serbia. The criterion for determining the best model was based on the statistical analysis and the agreement between the calculated and the experimental values. The calculated values of solar module temperature are in good agreement with the experimentally obtained ones, with some variations over and under the measured values. The best agreement between calculated and experimentally obtained values was for summer months with high solar radiation intensity. The nonlinear model for calculating the output power is much better than the linear model and at the same time predicts better the total electrical energy generated by the solar module during the day. The nonlinear model for calculating the solar module efficiency predicts the efficiency higher than the STC (Standard Test Conditions) value of solar module efficiency for all conditions, while the linear model predicts the solar module efficiency very well. This paper provides a simple and efficient guideline to estimate relevant parameters of a monocrystalline silicon solar module under the moderate-continental climate conditions.

The objective of the paper is to present a -t stability index that can be used for the security assessment of electric power systems. This index provides an evaluation of the system securitylevel by considering t he values of the accelerations and kinetic energies of the generators, after the occurrence of a large disturbance. The derivation of the index is based on the pattern recognition principles and the fuzzy sets theory. The results that are o btained f rom the application of the i ndex are illustrated by the stability analysis of two power systems. The first is the CIGRE test system, while the second is the Hellenic Interconnected System.

This deliverable focuses on ASTEP’s informed consent procedures for research actions involving human participants, in regard to the collection, storage, and protection of personal data. The explicit confirmation that the data used in the project are publicly available and can be freely used for the purposes of the project is also given.

We investigate low-cycle and high-cycle fatigue of 04Kh16N11M3T and 03Kh20N45M4BCh austenitic alloys under rigid loading by pure bending in air, hydrogen, and lithium-lead eutectic at 80, 250, and 350°C. The amplitude of deformation did not exceed ±3%. We discovered a decrease in durability at 250 and 350°C in the presence of lithium-lead eutectic under low-cycle loading and under high-cycle loading in the stage of limited endurance. The greater the amplitude of loading, the sharper the decrease in durability, and this effect is more pronounced at 250°C than at 350°C. Under the action of gaseous hydrogen, the durability of 04Kh16N11M3T alloy increases under low-cycle loading as compared to that in air. In the same situation, the durability of 03Kh20N45M4BCh alloy decreases. Under high-cycle loading, no influence of hydrogen on the limited endurance of these alloys was detected. Both in hydrogen and in lithium-lead eutectic, we observed a decrease in the amplitude of deformation at the fatigue limit on a base of 107 cycles.

Abstract Pillow-Plate Heat Exchangers (PPHEs) represent an innovative equipment type, with space-effective, light and pressure-resistant construction. In this work, an experimental study of air cooling by water in small-scale PPHEs was carried out and an analysis of the hydraulic resistance and heat transfer was performed based on the experimental data. A semi-empirical correlation for friction factor inside pillow-plate panels which is based on main geometric parameters is proposed. This correlation is reliable in a wide range of Reynolds numbers, both for laminar and turbulent flow regime. For the external channel between pillow-plate panels, the correlations for pressure drop and heat transfer were obtained based on experimental data. The CFD simulations were carried out to investigate heat transfer in the external channel of the PPHE. The deviation between the experimental and simulated values of heat transfer coefficient is maximum 17%. The received correlations enable to calculate the overall heat transfer and pressure drop in small-scale PPHEs and can be applied for preliminary design of PPHEs. The case study of the PPHE application for water heating is considered. The designed heat exchanger with minimal heat transfer area has 30% less surface area then chevron-type plate heat exchangers traditionally used for such application.

Abstract The objective of the paper is to describe an expert system methodology which has been developed for determining the most likely nature, cause and expected duration of failures occurring in power system components. The inference engine task is based on Bayes' theorem and the knowledge acquired during the study of the historical outage records of the power system. This study allows the expected values of outage rates and durations to be evaluated for all component categories and groups. This expert system methodology can be a very useful tool with which to determine the most likely expected duration of a failure and to select the most appropriate operational actions to be performed. An example of application of this methodology to failures occurring in power transformers is also included.