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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of PMV Fuzzy Control Algorithm in Pursuing Optimum Thermal Comfort

Fang, Wen-Hong 19 June 2012 (has links)
The exhausting fossil fuels have stimulated heating researches on alternative renewable energy, as well as energy friendly studies. In a country like Taiwan, with high density on population and buildings, fresh cold air are supplied by either fan-coil units or air-condition units. However, with the lack of intelligent control and poor justification on thermal comfort, these machines failed to provide optimal thermal comfort, a situation that always leads to "excessive control" and energy waste as a consequence. Optimal thermal comfort is pursued by using PMV fuzzy control theory, along with thermal comfort monitoring system derived from LabView icon-control software. Thermal Comfort indices such as Predicted Mean Vote (PMV) and Predicted Percent of Dissatisfied (PPD) according to the ISO 7730 are used as indicators of thermal comfort.Sensors, conscious of variations in humidity and temperatures, can figure out PMV and PPD via LabView Online Real Time calculation, and then we can control the environment comfort around PMV=1 next by using fuzzy control theory as well as energy efficient equipment such as AC stepless fans and AC stepless heaters. Many comfort simulation cases, comfort simulation with random humidity and temperatures, and a 12-hour automatic control, were presented as three testing items to check whether PMV FUZZY algorithm is competitive in fixing the environment thermal comfort around PMV=1. The confirmation of this question can be proved by this empirical study.
2

Indoor climate : A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting

Abreu Saraiva Freitas, Iuri January 2018 (has links)
This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.
3

Investigating The Relationship Between Mean Radiant Temperature (MRT) And Predicted Mean Vote (PMV) : A case study in a University building

Godbole, Swapnil January 2018 (has links)
Thermal comfort in an indoor environment is largely dependent on the four environmental and two personal parameters which is most commonly measured by the Predicted Mean Vote (PMV) model developed by Fanger. It has been studied that variations in these parameters beyond a range could lead to discomfort complaints. However, little research has been done on the effect of mean radiant temperature variations and its influence on predicted mean vote and thermal comfort specially in an actual building environment. This study aims to investigate the relationship between mean radiant temperature and predicted mean vote in indoor environment. Using the methods of on-site measurement of indoor environmental parameters and subjective votes on thermal sensation in an educational building; it was found that rise in mean radiant temperature lead to rise in PMV value and discomfort vote amongst occupants seated near glazed façade. A very strong positive correlation was found between mean radiant temperature and PMV near the window side of the room under warm and sunny weather conditions. Analysis of indoor environmental data from the several measurement sessions concluded that rise in mean radiant temperature and PMV was not noticed until there was a direct solar transmission through the window. It is advisable to use solar shading on windows, but special consideration should be given to the trade-offs between energy consumption (heating or cooling) and lighting energy consumption. No conclusions could be made in terms of ankle draft discomfort due to experimental limitations and more research would be required to investigate this phenomenon. / Termisk komfort inomhusmiljö är till stor del beroende av de fyra miljö och två personlig parametrar som oftast mäts av Predicted Mean Vote (PMV) modell som utvecklats av Fanger. Det har studerats att variationer i dessa parametrar utanför en limit kan leda till missnöjeklagomål. Däremot har lite forskning gjorts på effekten av mean radiant tempratur och dess inverkan på predicted mean vote och termisk komfort speciellt i en verklig byggnadsmiljö. Syftet med denna studie är att undersöka sambandet mellan mean radiant tempratur och predicted mean vote i inomhusmiljö. Användning mätmetoderna av inomhusmiljöparametrar och subjektiva röster av termisk komfort uppfattning i en byggnad för utbildning; det konstaterades att stiga i medel leda mean radiant tempratur att stiga i predicted mean vote värde och missnöje rösta bland byggnad brukarna sitter nära glasfasaden. En väldigt positiv korrelation mellan men radiant tempratur och predicted mean vote nära en fönstersida under varma och soliga väder var noterat. Genom att analysera data av inomhusmiljön från de multipla mätningssessionerna konkluderat att ökningen i mean radiant tempratur och predicted mean vote inte märktes tills det fanns en direkt soltransmission genom fönstret. Det är rekommenderar att använda solskydd på fönster, men med tanke på kompromisser mellan energiförbrukning (värme eller kyla) och ljussättning konsumtion.   Inga slutsatser kan göras om luftdrag på fotled grund av experimentella begränsningar och mer forskning skulle krävas för att undersöka detta fenomen.

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