In automotive industry plants, which use injection molding machines for rubber processing, tar contaminates air to such an extent that air fails to enter standard heat recovery systems. Accumulated tar clogs ventilation heat recovery exchangers in just a few days. In the plant in which the research was conducted, tar contamination causes blockage of ventilation ducts. The effect of this phenomenon was that every half year channels had to be replaced with new ones, since the economic analysis has shown that cleaning them is not cost-efficient. Air temperature inside such plants is often, even in winter, higher than 30°C. The air, without any means of heat recovery, is discharged outside the buildings. The analyzed plant uses three types of media for production: hot water, cold water at 14°C (produced in a water chiller), and compressed air, generated in a unit with a rated power consumption of 180 kW. The aim of the study is to determine the energy efficiency improvement of this type of manufacturing plant. The main problem to solve is to provide an air purification process so that air can be used in heat recovery devices. The next problem to solve is to recover heat at such a temperature level that it would be possible to produce cold for technological purposes without air purification. Experimental studies have shown that air purification is feasible. By using one microjet head, a total of 75% of tar particles was removed from the air; by using 4 heads, a purification efficiency of 93% was obtained. This method of air purification causes air temperature to decrease from 35°C to 20°C, which significantly reduces the potential for heat recovery. The next step of the research was designing a cassette-plate heat exchanger to exchange heat without air purification. The economic analysis of such a solution revealed that replacing the heat exchanger with a new one even once a year was not cost-efficient. Another issue examined in the context of energy efficiency was the use of waste heat from the air compressor. Before any changes, the heat was picked up by a chilled water system. The idea was to use the heat for cold generation. Temperature of oil and air in the compressor exceeds 65°C, which makes it a perfect heat source for an adsorption refrigeration device. This solution reduced the cooling demand by 147 kW, thus reducing power consumption by 36.75 kW. This study shows that even in factories where air is heavily polluted with tar, there are huge potentials for energy recovery using existing technical solutions. It is important to note that problems of this kind should always be approached individually.
MicroRNAs (miRNAs) are short, noncoding RNA transcripts. Mammalian miRNA coding sequences are located in introns and exons of genes encoding various proteins. As the central nervous system is the largest source of miRNA transcripts in living organisms, miRNA molecules are an integral part of the regulation of epigenetic activity in physiological and pathological processes. Their activity depends on many proteins that act as processors, transporters, and chaperones. Many variants of Parkinson’s disease have been directly linked to specific gene mutations which in pathological conditions are cumulated resulting in the progression of neurogenerative changes. These mutations can often coexist with specific miRNA dysregulation. Dysregulation of different extracellular miRNAs has been confirmed in many studies on the PD patients. It seems reasonable to conduct further research on the role of miRNAs in the pathogenesis of Parkinson’s disease and their potential use in future therapies and diagnosis of the disease. This review presents the current state of knowledge about the biogenesis and functionality of miRNAs in the human genome and their role in the neuropathogenesis of Parkinson’s disease (PD)—one of the most common neurodegenerative disorders. The article also describes the process of miRNA formation which can occur in two ways—the canonical and noncanonical one. However, the main focus was on miRNA’s use in in vitro and in vivo studies in the context of pathophysiology, diagnosis, and treatment of PD. Some issues, especially those regarding the usefulness of miRNAs in PD’s diagnostics and especially its treatment, require further research. More standardization efforts and clinical trials on miRNAs are needed.
Didactic classes are conducted in lecture halls usually adapted from the technical side to present content. Audiovisual and sound systems are installed. Unfortunately, in many cases, classrooms are designed from the point of view of air conditioning and ventilation, just like office rooms. As a result, during classes, even in rooms where air conditioning occurs, the conditions change so unfavourably that both teacher and students experience discomfort. The work analyzes the change in temperature, CO2 concentration, PM2.5 concentration and relative humidity in the room, where heat gains from people and equipment as well as moisture gains exceed design values. The work uses a channel-free Respireco recuperator with cyclic operation. First, the thermodynamic properties of the recuperator itself were checked, and then it was tested in a selected Polish primary school. The results show that this type of recuperators are able to provide correct indoor climatic conditions in lecture halls. The use of mechanical ventilation using a recuperator with a ceramic heat recovery caused the CO2 concentration in the room to drop by 50% during classes. However, PM2.5 concentration was maintained at a level three times lower than in a room without mechanical ventilation. It should therefore be concluded that the use of mechanical ventilation with recuperation not only reduces heating costs but also significantly improves air quality.
Abstract. Adsorption refrigeration systems, as opposed to absorption type operate in a cyclic manner. The result is that at the beginning of each process must be fed into the adsorber state in which they will adsorb or desorb a refrigerant. In the case of two adsorbers at the start of a cycle, the one of the adsorber must be refrigerated while the second has to be heated. These processes are causing unnecessary energy loss. The aim of the work is to show how these processes can be connected and the heat received from one adsorber is transported to another adsorber. As part of the study, the heat and mass recovery processes will be considered. It turns out that in the thermal wave type systems, it is possible to recover more than 25% of the energy lost to bring the adsorber to the states in which they will operate efficiently to desorb and adsorb refrigerant. That is, it is possible to improve the efficiency of the adsorption refrigeration unit using the proposed improvements.
1 KLIMATYZACJA Z WYKORZYSTANIEM SORPCYJNO-WYPARNYCH SYSTEMÓW CHŁODZENIASorpcyjno-wyparne systemy chłodzenia DEC (ang. desiccant evaporation cooling) stanowią alternatywę dla klasycznych systemów klimatyzacji wykorzystujących sprężarkowe urządzenia chłodnicze. Stosowanie systemów DEC pozwala na obniże-nie zużycia energii elektrycznej przez systemy klimatyzacyjne nie pogorszając przy tym jakości powietrza dostarczanego do pomieszczeń. Nie wykorzystują przy tym "freonowych" czynników chłodniczych, dzięki czemu nie mają negatywnego wpły-wu na środowisko. W technologii DEC powietrze chłodzone jest poprzez odparowanie wody, aby zwiększyć efekt chłodzenia powietrze wstępnie jest osuszone przy zastosowaniu stałych, bądź ciekłych sorbentów. Do regeneracji sorbentów, wymagają dostarczenia ciepła o temperaturze w zakresie 50 -100˚C. Ze względu na możliwość wykorzystania odpadowych i odnawialnych źródeł ciepła technologia DEC stanowi interesujące rozwiązanie. W artykule opisano zasadę działania systemu DEC, oraz przedstawiono wyniki obliczeń dla systemu pracującego w warunkach letnich w klimacie umiarkowanym. Obliczenia wykonane zostały przy założeniu temperatury powietrza zewnętrznego równej 27˚C, wilgotność względną przyjmowano z przedziału 45 -80% zmieniając tę wartość co 5%. Do analizy przyjęto stałe zyski ciepła jawnego i utajonego wewnątrz przestrzeni klimatyzowanej, które wynoszą odpowiednio 15 kW i 3 kW. Strumień powietrza wentylacyjnego przyjęto na poziomie 1000 ℎ ⁄ . Wyniki obliczeń pokazują, że w zakresie wilgotności względnej powietrza zewnętrznego poniżej 60 % systemy DEC są w stanie zapewnić odpowiednią jakość powietrza wentylacyjnego, oraz odebrać zyski ciepła i wilgoci z pomieszczeń klimatyzowanych. Wybrany sorbent, do regeneracji wymaga dostarczenia strumienia ciepła o temperaturze około 70˚C, w ilości trzykrotnie większej w stosunku do strumienia ciepła jaki jest do odebrania z pomieszczeń.
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