Search Results

1 - 5 of 5 items

  • Author: Grzegorz Majewski x
Clear All Modify Search

Abstract

This study determines the approximate duration of the thermal seasons in Warsaw, and investigates their long-term variability. The measurement data come from the Ursynów meteorological station at the Warsaw University of Life Sciences (WULS) (λE 21°02’52’’, φN 52°09’38’’, 102.5 m a.s.l.), situated in the south of Warsaw, and comprise mean diurnal air temperatures for the years 1961-2013. In order to identify thermal seasons, the method of five-day rolling averages was applied, which revealed a substantial year-by-year variability. The achieved results were close to those found by other methods for stations situated within the same climatic region. Over the analysed period, winters and springs have become shorter, whereas the other two seasons have become longer. Nevertheless, the positive trend was only statistically significant for thermal summers. The increasing length of the thermal summer in Warsaw Ursynów may be due to the influence of urban heat islands in built-up areas.

Abstract

Analysis of thermal comfort in the ENERGIS Building, an intelligent building in the campus of the Kielce University of Technology, Poland is the focus of this paper. For this purpose, air temperature, air relative humidity, air flow rate and carbon dioxide concentration were measured and the mean radiant temperature was determined. Thermal sensations of the students occupying the rooms of the building were evaluated with the use of a questionnaire. The students used a seven-point scale of thermal comfort. The microclimate measurement results were used to determine the Predicted Mean Vote and the Predicted Percentage Dissatisfied indices.

Abstract

The use of quantitative methods, including stochastic and exploratory techniques in environmental studies does not seem to be sufficient in practical aspects. There is no comprehensive analytical system dedicated to this issue, as well as research regarding this subject. The aim of this study is to present the Eco Data Miner system, its idea, construction and implementation possibility to the existing environmental information systems. The methodological emphasis was placed on the one-dimensional data quality assessment issue in terms of using the proposed QAAH1 method - using harmonic model and robust estimators beside the classical tests of outlier values with their iterative expansions. The results received demonstrate both the complementarity of proposed classical methods solution as well as the fact that they allow for extending the range of applications significantly. The practical usefulness is also highly significant due to the high effectiveness and numerical efficiency as well as simplicity of using this new tool.

Abstract

The paper discusses the issue of using microstructures as the heat enhancement technique that can be applied in ventilation and heating systems. The possibilities of usage are given and the experimental test results are presented. They prove that the application of microstructures may significantly improve the heat flux value exchanged during boiling of distilled water.

Abstract

Knowledge on soil moisture is indispensable for a range of hydrological models, since it exerts a considerable influence on runoff conditions. Proper tools are nowadays applied in order to gain in-sight into soil moisture status, especially of uppermost soil layers, which are prone to weather changes and land use practices. In order to establish relationships between meteorological conditions and topsoil moisture, a simple model would be required, characterized by low computational effort, simple structure and low number of identified and calibrated parameters. We demonstrated, that existing model for shallow soils, considering mass exchange between two layers (the upper and the lower), as well as with the atmosphere and subsoil, worked well for sandy loam with deep ground water table in Warsaw conurbation. GLUE (Generalized Likelihood Uncertainty Estimation) linked with GSA (Global Sensitivity Analysis) provided for final determination of parameter values and model confidence ranges. Including the uncertainty in a model structure, caused that the median soil moisture solution of the GLUE was shifted from the one optimal in deterministic sense. From the point of view of practical model application, the main shortcoming were the underestimated water exchange rates between the lower soil layer (ranging from the depth of 0.1 to 0.2 m below ground level) and subsoil. General model quality was found to be satisfactory and promising for its utilization for establishing measures to regain retention in urbanized conditions.