Kristina Berzina

Optimal PV electrical energy storage of office building's communal space lighting

Due to the advances in photovoltaic material research and solar panel price reduction over last years, the usage of this alternative energy source in northern countries seems more attractive. Usage of energy storage devices can help use the solar power more efficiently and smarter. This paper deals with the optimization of proposed solar panel array of renovated office buildings communal lighting in Riga, using storage devices and demand side management of the produced power.

Flexible approach to course testing for the improvement of its effectiveness in engineering education

The paper is devoted to the question of the course quality testing and analysis in the field of engineering higher education. The opportunity to develop a testing approach and method for further lifelong improvement of the courses, its activities and its teaching/learning methodologies is considered on the basis of well-known taxonomy of educational objectives. The idea is that the objectives could be applied both to the course as a whole, either it is bachelor, master or doctor level of education, as well as to the separate activities of the learning process. Further testing of the course is based on the achievement of these objectives at the end of the course or completing the activities applying both quantitative and qualitative approach to the testing process. The process of course planning, evaluation and improvement is analysed from its infinitive character point of view.

Self-assessment as a key criterion for increase of quality of higher education in modern conditions

The process of globalization poses new challenges for the government in the field of education system regulation. The growing importance of the need for a qualitative assessment of the state of the educational process contributed to the development of one of the new scientific directions — the issue of quality management of higher education. Despite the fact that a lot of publications have appeared recently on improving the quality of education and the need to introduce its objective assessments, the discussion is mainly about assessing the individual achievements of students and about licensing, certification and accreditation of educational institutions, while the problem of assessing the quality of higher education is much deeper and more serious. The article is devoted to the problem of improving the quality of modern higher education in the context of the need for self-assessment, criteria for assessing quality are proposed.

Latvian electrical power system stability's analysis taking into account new development strategy until 2025

Energy is one of the sectors directly affecting the economic growth and forming a significant part of overall expenses in several industry branches, especially in manufacturing. The development of the energy sector requires significant investments which can only be attracted in a stable and predictable investment environment. Therefore, Latvian energy sector is being planned in a long-term both globally and at the European Union (EU) level. During the last two decades, increase in electricity demand and environmental concern resulted in fast growth of power production from renewable sources, where wind energy is one of the most efficient alternatives. The second important moment is the Baltic power systems development strategy, with the breakdown of continental Europe from the energy circle of BRELL until 2025. The purpose of this paper is devoted to the evaluation sufficiency of the taken measures, taking into account the integration of a large wind farm in the Latvian Electric Power System (EPS) in terms of stability. The methodology proposed in the paper can be applied for the detection of network parameters that are most vulnerable to perturbations such as a voltage drop, as well as defining the relations of said parameters with the EPS parameters, and using this information for the consequent improvement of behavioral EPS properties in general. Thus, knowing the location of sensors, it is possible to determine and control the nodes that undergo the biggest fluctuations of operational parameters during the disturbances.

Effective and optimal simulation of light design in Riga Technical university's lighting laboratory from the point of view of energy efficiency

Considering that there is a demand to increase the efficiency of indoor lighting power consumption, an effective light design must be developed that can be applied as well as in old buildings as in new projects. To achieve a lower total building energy consumption without sacrificing lighting quality, there is a need for effective lighting modeling, which gives reliable, in real life prospective results. These models in combination with energy-efficient lighting fixtures, as well as the integration of daylight reduces energy consumption and maintenance costs of the premises.

Determination of Synchronous Reactive Frequency Doublers EMFs Using Magnetic Field's Mathematical Simulation

In many spheres of human activities devices that work on increased frequency current are widely applied. 50 Hz current can be converted into increased frequency (100-400 Hz) current using synchronous reactive converters, which are based on exude and usage of higher harmonics.