The paper analyses thermal comfort in intelligent and traditional buildings in Poland. It provides a comprehensive study on the subjective assessment of indoor environment conditions as well as on parameters that influence human thermal sensations and preferences. Direct measurements of physical parameters (e.g., air and globe temperature, relative humidity) as well as simultaneously conducted anonymous questionnaire studies were used to provide the necessary data. The study covered all seasons and a large number of participants representing various age groups and body build types, who completed a total of 1778 questionnaires. The results indicate that typically smart buildings offer higher levels of thermal comfort than the traditional ones and that people tend to prefer warmer environments. Moreover, it has been observed that the BMI index, air movement and the number of people per surface area can have an impact on the perceived thermal sensations.

The paper analyses the indoor environment in two modern intelligent buildings located in Poland. Measurements of air and globe temperatures, relative humidity and carbon dioxide concentration in 117 rooms carried out in the space of 1.5 years were presented. Thermal comfort of the occupants has been investigated using a questionnaire survey. Based on 1369 questionnaires, thermal sensation, acceptability and preference votes were analysed in view of their interdependency as well as their dependency on operative temperature, which proved to be very strong. It has been found that the respondents did not completely rate thermal comfort and indoor environment quality as very high, although the overwhelming sensations were positive. Apart from the operation of heating, ventilation and air conditioning (HVAC) systems, this might have also been the cause of individual human factors, such as body mass index, as tested in the study, or the finding that people were generally in favour of a warmer environment. Moreover, thermal environment proved to be the most important element for ensuring the well-being of the occupants.

The work presents the use of laser texturing of DLC coatings to improve tribological properties. The coatings were applied by the PVD method to the rings made of 4H13 steel. The surface texturing was performed with the TruMICRO 5325c picosecond laser with the radiation wavelength λ = 343 nm. The surface microstructure analysis, surface microgeometry and microhardness measurements and tribological tests were carried out. The problem presented in the paper can be used to extend the knowledge of the areas of application of DLC coatings, especially in sliding friction pairs.

Enhancement of pool boiling heat transfer can be attained with a number of passive and active techniques. The paper experimentally analyses the impact of laser treatment of the copper surfaces on pool boiling heat transfer of distilled water and ethyl alcohol. The samples were modified with a laser beam to produce longitudinal grooves of highly developed microstructures in the laser textured area. Specimens of different groove depths, groove widths and micro-fin widths were produced. The results indicate a significant influence of laser processing on heat flux dissipated from the surfaces and heat transfer enhancement for all the samples tested. The experimental results have been generalized in the form of a heat flux correlation based on a modified model of enhanced pool boiling heat transfer.

The laser treatment of surfaces enables the alteration of their morphology and makes them suitable for various applications. This paper discusses the use of a laser beam to develop surface features that enhance pool boiling heat transfer. Two types of structures (in the ‘macro’ and ‘micro’ scale) were created on the samples: microfins (grooves) and surface roughness. The impact of the pulse duration and scanning velocity on the height of the microfins and surface roughness at the bottom of the grooves was analyzed with a high precision optical profilometer and microscope. The results indicated that the highest microfins and surface roughness were obtained with a pulse duration of 250 ns and scanning velocity of 200 mm/s. In addition, the influence of the ‘macro’ and ‘micro’ scale modifications on the boiling heat transfer of distilled water and ethyl alcohol was studied on horizontal samples heated with an electric heater. The largest enhancement was obtained for the highest microfins and roughest surfaces, especially at small superheats. Heat flux dissipated from the samples containing microfins of 0.4 mm height was, maximally, over three times (for water) and two times (for ethanol) higher than for the samples with smaller microfins (0.2 mm high). Thus, a modification of a selected model of boiling heat transfer was developed so that it would be applicable to laser-processed surfaces. The correlation proved to be quite successful, with almost all experimental data falling within the ±100% agreement bands.