This paper describes experiments on finned tube heat exchangers, focusing on reducing the thermal contact resistance at the contact between the pipe and the lamella. Various contact materials, such as solders and adhesives, were investigated. Several methods of establishing contact were tested, including blowtorch soldering, brazing, and furnace soldering. Thermal camera measurements were carried out to assess the performance of the contact materials. Moreover, finite element analysis was performed to evaluate the contact materials and establish guidelines in the fin–tube connection modeling by comparing simplified models with the realistic model. Blowtorch brazing tests were successful while soldering attempts failed. During the thermographic measurements, reflective surfaces could be measured after applying a thin layer of paint with high emissivity. These measurements did not provide valuable results; thus, the contact materials were assessed using a finite element analysis. The results from the finite element analysis showed that all the inspected contact materials provided better heat transfer than not using a contact material. The heat transfer rate of the tight-fit realistic model was found to be 33.65 for air and 34.9 for the Zn-22Al contact material. This finding could be utilized in developing heat exchangers with higher heat transfer with the same size.

Researchers have increasingly focused on thermal comfort, examining both individuals’ thermal sensations and the percentage of people dissatisfied with the thermal environment. Most studies rely on the widely used PMV (Predicted Mean Vote) model and the PPD (Predicted Percentage of Dissatisfied) value derived from it, both defined by the ISO 7730:2005 standard. However, previous studies have shown that this standardized method only applies under steady-state conditions, which do not reflect the dynamic nature of everyday environments. As closed-loop control technologies gain prominence in building services, the need to evaluate thermal comfort under time-varying conditions has grown. The standard method does not account for the thermal inertia of the human body, which limits its applicability in such dynamic contexts. In this study, we develop a method to estimate instantaneous thermal sensation under non-stationary conditions by incorporating thermal inertia through signal processing techniques. This approach addresses a well-recognized limitation of the standard PMV–PPD model and provides a way to assess thermal comfort in real time. We collected experimental data using a thermal comfort measurement station, a thermal manikin, and human subjects in a controlled climate chamber. The proposed method enables real-time evaluation of thermal comfort in dynamic environments and offers a foundation for integration into HVAC control and comfort optimization systems.

A zöldtető szerepe a csapadékvíz-gazdálkodásban Bevezetés A vízellátás feladatainak megoldási lehetőségei közül nem hagyható el a csapadékvíz mint alternatív vízforrás figyelembevétele. Akár egy családi házról, akár településről, akár országos méretben gondolkodunk, a csapadékra mint hasznosítandó vízre kell tekintenünk, az esővíz minél gyorsabb, teljesebb elvezetése nem minősíthető fenntarthatónak. A fenntartható csapadékvízgazdálkodás fő elve, hogy a lehulló csapadékot helyben tartsuk, "hasznát vegyük" épületen belül vagy kívül, és csak a felesleges mennyiséget vezessük el. A csapadékvíz hasznosítása, elvezetése során figyelembe kell vennünk az utóbbi évek szélsőséges csapadékeseményeit. Ezeknek a vízhozamai az eddig elégségesnek mutatkozó, statisztikai adatokon alapuló biztonsági túlméretezéssel készült csapadékvíz-elvezető rendszert olyan mértékben terhelik túl, hogy a vízelvezetés üzembiztonsága sérül. Emiatt egyre inkább előtérbe kerül a csapadékvíz csillapított elvezetésének igénye, ami a vízelvezető infrastruktúra egyidejű terhelésének csökkentésén túl egyúttal a csapadékvíz hasznosításának is teret adhat. Ennek a csillapításnak-és egyéb vízgazdálkodási, energetikai célkitűzéseknek-egyik, egyre terjedőben levő eszköze a zöldtető, amelynek több szempontú kutatására a PTE MIK épületén mintarendszert építettünk ki.

Thermal sensation of the human body and cognitive performance are closely related. Extreme temperature conditions can significantly impair concentration, memory and mental state, leading to reduced productivity. It is therefore important to ensure appropriate climatic conditions to maintain productivity. This is particularly important in modern buildings, where thermal comfort can be ensured and guaranteed through building services engineering. It is uncertain, however, what the exact thermal satisfaction value is for people in terms of mental performance. There is both consensus and unresolved matters in the literature on the subject. The aim of this research is to investigate the optimal thermal comfort level with live subjects and by measuring thermal comfort parameters. It also aims to confirm or refute the results presented in the literature.