Search results for "pcm"
showing 10 items of 13 documents
Analyses of phase change materials’ efficiency in warm-summer humid continental climate conditions
2017
The usage of phase change materials (PCMs) is a way to store excess energy pro- duced during the hot time of the day and release it during the night thereby reducing the overheating problem. While, in Latvian climate conditions overheating is not a big issue in traditional buildings since it happens only a couple of weeks per year air conditioners must still be installed to maintain thermal comfort. The need for cooling in recently built office buildings with large window area can increase signi cantly. It is therefore of great interest if the ther- mal comfort conditions can be maintained by PCMs alone or with reduced maximum power of installed cooling systems. Our initial studies show tha…
State of the art thermal energy storage solutions for high performance buildings
2010
In this thesis, the general thermal energy storage solutions for high performance buildings have been comprehensively reviewed. Based on the properties of storage material, the thermal storage solutions can be classified into sensible, latent and thermochemical heat storages. Their categories, characteristics and certain applications have been systematically introduced. Special emphases are put on the latent thermal storage technologies. Different classifications of phase change materials (PCMs), i.e. organic-, inorganic-, and eutectic- PCMs, have been carefully presented with their particular features and material candidates. PCM applications can cover almost every part of the building env…
Methods for Determining the Thermal Transfer in Phase-Changing Materials (PCMs).
2020
A very important issue that needs to be solved as simply and correctly as possible is how to establish the thermal performance of phase-changing materials (PCM). The undertaken researches have analyzed the values of the thermal performances of the PCM taking into account the method of finite elements and the experimental research, respectively, based on a modern measurement system that was designed and implemented. Butyl stearate which has been encapsulated through complex coacervation in polymethyl methacrylate has been used as a PCM. Samples were made containing 10%, 20%, 30% and 40% PCM, respectively, within their structure. The research has established that at both the hot plate and the…
UN MODELLO ALLE DIFFERENZE FINITE DI UN PANNELLO FOTOVOLTAICO ACCOPPIATO A MATERIALE A CAMBIAMENTO DI FASE
2010
La diffusione commerciale dei dispositivi fotovoltaici presenta negli ultimi anni un trend di crescita significativa a livello internazionale. Numerose ricerche sono state svolte al fine di incrementare l’efficienza di conversione elettrica dei pannelli fotovoltaici e tra le soluzioni indagate è stato sperimentato l’impiego di materiali a cambiamento di fase (MCF) per ridurre i picchi di temperatura di funzionamento. Nel lavoro è stato sviluppato un algoritmo di calcolo in grado di fornire l’andamento temporale della temperatura di un pannello fotovoltaico accoppiato a materiale a cambiamento di fase (Sistema PV-MCF). La determinazione della distribuzione di temperature che interessano un s…
PCM thermal storage design in buildings: Experimental studies and applications to solaria in cold climates
2017
Abstract As energy availability and demand often do not match, thermal energy storage plays a crucial role to take advantage of solar radiation in buildings: in particular, latent heat storage via phase-change material is particularly attractive due to its ability to provide high energy storage density. This paper analyzes the performance of a building-integrated thermal storage system to increase the energy performances of solaria in a cold climate. A wall opposing a highly glazed facade (south oriented) is used as thermal storage with phase change materials embedded in the wall. The study is based on both experimental and simulation studies. The concept considered is particularly suited t…
Zastosowanie magazynów ciepła do celów grzewczych i c.w.u
2018
Magazynowanie energii jest kluczowym zagadnieniem dla rozwoju energetyki odnawialnej. W obszarze budownictwa i inżynierii komunalnej, poza innymi formami, zachodzi konieczność magazynowania energii w postaci termicznej, rozumianej jako zwiększenie energii wewnętrznej układu magazynującego lub wykorzystanie przemian fazowych. Technologie wykorzystujące procesy sorpcyjne, lub efekty termiczne reakcji chemicznych są tu raczej mniejsze zastosowanie. Energię termiczną w najmniejszej skali magazynujemy w zasobnikach ciepłej wody użytkowej, w zbiornikach buforowych instalacji grzewczych. Większe instalacje realizowane są dla obiektów użyteczności publicznej, takich jak szpitale, biurowce. Duże mag…
Finite difference thermal model of a latent heat storage system coupled with a photovoltaic device: Description and experimental validation
2014
Abstract The use of photovoltaic (PV) systems has been showing a significant growth trend but for a more effective development of this technology it is essential to have higher energy conversion performances. Producers of PV often declare an higher efficiency respect to real conditions and this deviation is mainly due to the difference between nominal and real temperature conditions of the PV. To improve the solar cell energy conversion efficiency many authors have proposed a methodology to keep lower the temperature of a PV system: a modified PV system built with a normal PV panel coupled with a Phase Change Material (PCM) heat storage device. In this paper is described a thermal model ana…
Nestriktas klasterizācijas metodes un to salīdzināšana
2022
Šis darbs ir veltīts piecām klasterizācijas metodēm: K-vidējo klasterizācijas algoritms, C-vidējo nestriktas klasterizācijas algoritms, iespējamību C-vidējo klasterizācijas algoritms, nestrikto iespējamību C-vidējo klasterizācijas algoritms un iespējamību C-vidējo nestriktas klasterizācijas algoritms. Darbs satur šo algoritmu aprakstu un salīdzināšanu, ņemot par pamatu datu klasterizācijas rezultātus. Ir aprakstīta pieeja iespējamību nestriktas klasterizācijas algoritma vispārinājumam.
Reciprocal influence of B cells and tumor macro and microenvironments in the ApcMin/+ model of colorectal cancer
2017
One of the most fascinating aspects of the immune system is its dynamism, meant as the ability to change and readapt according to the organism needs. Following an insult, we assist to the spontaneous organization of different immune cells which cooperate, locally and at distance, to build up an appropriate response. Throughout tumor progression, adaptations within the systemic tumor environment, or macroenvironment, result in the promotion of tumor growth, tumor invasion and metastasis to distal organs, but also to dramatic changes in the activity and composition of the immune system. In this work, we show the changes of the B-cell arm of the immune system following tumor progression in the…
A photovoltaic panel coupled with a Phase Changing Material heat storage system in hot climates
2008
Nowadays, there is a great impulse in the field of photovoltaic cell systems (PV) to develop new devices with better energy conversion performances and higher cost effectiveness. This paper is focused on the design and development of a modified PV system, consisting of a normal PV panel coupled with a Phase Change Material (PCM). PCMs are "latent" energy storage materials, using chemical bonds to store and release heat. The system is based on the idea that decreasing the operating temperature of the panel causes an increase in its energy conversion efficiency. A theoretical analysis of the system was accomplished by using COMSOL MULTIPHYSICS, a partial differential equations (PDEs) solver. …