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1
Content available Application of laser treatment technology for boiling heat transfer augmentation
Orman Łukasz J., Radek Norbert, Honus Stanislav, Pietraszek Jacek
Production Engineering Archives
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2024
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Vol. 30, Iss. 2
259--265
EN
Boiling heat transfer can be enhanced when the heater’s surface morphology is altered. The paper discusses the use of the laser beam to produce efficient heat exchangers. Two types of samples were investigated with distilled water and ethyl alcohol as boiling agents. The specimens differed with the height of the microfins: 0.19 mm and 0.89 mm. It was observed that both of them enhanced boiling heat transfer in comparison to the smooth reference surface. However, the sample with higher micro-fins performed better, especially in the region of low temperature differences, where the heat flux was about three times higher than in the case of the smaller microfins. The comparison of the experimental data with selected models of boiling heat transfer revealed significant differences with regard to the heat flux. The laser-made samples dissipated larger heat fluxes than it could be anticipated according to the models. It might be linked with high surface roughness of the area between the microfins, generated as a result of the laser beam interaction with the surface.
2
Content available Critical analysis of pool boiling correlations
Radek Norbert, Orman Łukasz J., Honus Stanislav, Pietraszek Jacek
System Safety : Human - Technical Facility - Environment
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2023
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Vol. 5, iss. 1
258--265
EN
The manuscript describes the problem of boiling heat flux determination with the focus on nucleate boiling mode. It presents the boiling phenomenon on the bare surface and provides a review of the correlations that can be used for modelling purposes. Two most commonly applied correlations were validated against the experimental results. One of them showed significant discrepancies, which might be attributed to the conditions of the research and possible variations in the morphology of the heater. The other correlation proved to be successful in determining heat flux.
3
Content available Validation of the Fanger Model and Assessment of SBS Symptoms in the Lecture Room
Krawczyk Natalia, Dębska Luiza, Piotrowski Jerzy Z., Honus Stanislav, Majewski Grzegorz
Rocznik Ochrona Środowiska
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2023
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Tom 25
68--76
EN
The indoor environment of buildings significantly affects the well-being and health of room users. Experiencing thermal discomfort reduces concentration and productivity during study or work, causing drowsiness, fatigue or deterioration in general well-being. The study focuses on presenting the results of the questionnaire study on the symptoms of sick building syndromes (SBS), namely: dizziness, nausea, eye pain and nasal mucosa, experienced by 69 students during a lecture in a large and modern auditorium of Kielce University of Technology. The results show that many students experienced SBS symptoms, which seem to have affected their concentration during the class. The article also discusses the thermal sensations of the students with a focus on comparing the obtained results with the Fanger model of thermal comfort. The discrepancy between the model calculation results and the experimental data has been observed and discussed.
4
Content available Thermal Comfort Analysis in the Smart Sustainable Building with Correlation Development
Dębska Luiza, Honus Stanislav, Krawczyk Natalia, Orman Łukasz J., Piotrowski Jerzy Z.
Rocznik Ochrona Środowiska
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2023
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Tom 25
116--127
EN
The paper presents the results of the experimental study of thermal comfort in the smart building of Kielce University of Technology (Poland). The experiments were conducted throughout four seasons of the year and focused on developing a modified thermal comfort correlation that could determine the thermal sensations of room users more accurately than the standard methodology. Twelve groups of volunteers participated in the study, and thermal sensations were analysed for both genders separately. Even though the thermal environment was not considered overwhelmingly favourable (with 75% of men and 60% of women providing positive assessment), thermal acceptability was high. It amounted to 90% (the same for both genders). The air temperature of 22°C proved to be most preferable. The BMI index and CO2 concentration were found to influence thermal sensations and were incorporated into a modified correlation, which provided more accurate results than the original Fanger model of thermal comfort.
5
Content available Investigation of Thermal Comfort in the Intelligent Building in Winter Conditions
Orman Łukasz J., Honus Stanislav, Jastrzębska Paulina
Rocznik Ochrona Środowiska
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2023
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Tom 25
45--54
EN
The paper analyses thermal sensations, preferences and acceptability as well as humidity sensations of students in the intelligent building "Energis" of the Kielce University of Technology (Poland). The tests were performed in 8 lecture rooms, during which the volunteers filled in the anonymous questionnaires (with 3 to 7 possible answers for each question) and – simultaneously – physical air parameters were measured with Testo 400 microclimate meter. The study aimed to determine if the intelligent building provides proper indoor environment conditions during the heating season and to assess the accuracy of the standard methodology for thermal comfort determination. Experimental analysis of thermal and humidity sensations revealed that a share of the respondents critically assessed the indoor environment: 17% regarding temperature and 30% regarding humidity. Moreover, the standard methodology for thermal comfort calculations proved overwhelmingly inaccurate compared to the experimental data (with the results for 6 rooms being beyond the 50% error range). Since smart buildings are still not very common in Central Europe, the experimental data obtained in the study can be valuable both from the scientific but also practical point of view – providing useful data for building engineers and designers.
6
Content available remote Thermal comfort testing in the smart sustainable building
Krawczyk Natalia, Dębska Luiza, Honus Stanislav, Zegarek Marta, Kiniorski Mateusz, Orman Łukasz J.
Journal of New Technologies in Environmental Science
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2023
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Vol. 7, nr 2
37--45
EN
Today, more and more buildings are being built based on the idea of sustainable development. This mainly concerns the creation of such microclimate conditions in the rooms that a person feels comfortable inside. Therefore, the article presents tests of thermal comfort for three teaching rooms in an intelligent building. The research was carried out using two methods, a microclimate meter measurements and questionnaires. The survey provided research results on thermal sensation vote, thermal preference vote and humidity assessment. Moreover, the results of Predicted Percentage of Dissatisfied and Predicted Mean Vote were presented in the paper. Students between the age of 21 and 25 and one female in her 30s participated in the survey. Through the results of the questionnaires and the microclimate meter, significant differences were shown between the Fanger model and the questionnaires in terms of PMV and PPD.
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