Thesis (MEng)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: In the present study, research was conducted to determine the
feasibility of water energy storage through which the output of
heated air by an upward facing solar air heater could be prolonged.
Following a systematic approach, a number of experimental test
swere initially performed on an upward facing solar air heater in
order to obtain a benchmark that could be used to evaluate the
influence of water storage during the day-time performance of a
solar air heater. As expected, an increase in the air mass flow rate
not only led to an increase in the collector efficiency but also to a
decrease in the temperature gain across the collector. In addition,
a number of day- and night-time experiments were executed on a
plastic covered water tank in order to evaluate it's ability to store
and discharge thermal energy. Results clearly indicated that the
plastic covered water tank was both an ideal collector and storage
medium of solar energy. Experimental results also revealed that
the plastic covered water tank was an ideal source of thermal
energy for a solar air heater during night-time operation.
Subsequently, both day- and night-time experiments were
performed on an upward facing solar air heater in which plastic
covered water tanks were installed. Day-time experimental results
revealed that the modified solar air heater still had the same
collector efficiency tendency, as observed in the initial solar air
heater experiments, but that the water energy storage led to a
dramatic decrease in the absorber plate temperature and in the
corresponding temperature gain experienced across the collector.
In contrast, the night-time operation results clearly indicated that
the water energy storage was not only able to prolong the output of
heated air by the solar air heater, but was further able to increase
the air temperature by between 7.5 and 1.5 °e, depending on the
air mass flow rate. It was furthermore shown in the study that
available theory is able to accurately predict the performance of an
upward facing solar air heater, either with or without water energy
storage, as long as the equations are employed within their range
of validity / AFRIKAANSE OPSOMMING:In die hierdie studie is daar ondersoek ingestel na die
lewensvatbaarhied van son-energiestoring in water ten einde die
tydperk van lugverhitting deur 'n son-Iugverwarmer te verleng. 'n
Sistematiese prasedure is gevolg waardeur daar aanvanklik 'n
aantal eksperimente op 'n son-Iugverwarmer uitgevoer is am
sodoende die eienskappe van so 'n lugverhiUingstelsel, sander
energie storing, te vekry. Die resultate het getoon dat 'n toename
in die massavloei tempo van die lug lei tot 'n toename in die
kollektor effektiwiteit van die stelsel, maar terselfdetyd lei tot 'n
afname in die temperatuur styging in die kollektor. Met die
eienskappe van die lugverwarmingstelsel bekend, is daar voorts 'n
aantal dag- en nag-eksperimente uitgevoer op 'n plastiek bedekte
watertenk am die storing en vryselling van termiese energie deur
die watertenk te kwantifiseer. Die resultate het daarap gedui dat
die plastiek bedekte watertenk nie net beide 'n goeie kollektor en
stoor medium vir son-energie is nie, maar oak dat dit 'n ideale bran
van termiese energie vir 'n lugverwarmingstelsel tydens die nag is.
Met inagname van die vorige resultate, is daar dan 'n aantal
plastiek bedekte watertenks in die apparaat geinstalleer, en 'n
aantal dag- en nag-eksperimente is uitgevoer. Die dageksperimente
het getoon dat die die nuwe lugverwarmer met water
energie storing dieselfde eienskappe toon ten opsigte van die
kollektor effektiwiteit as die oorspronkilke son-Iugverwarmer. Tog,
as gevolg van die laer absoberende plaat temperature was die
temperatuur toename in die kollektor heelwat laer. In kontras
hiermee dui die nagresultate aan dat die plastiek bedekte
watertenks nie net die vermoe het am die tydperk van
lugverwarming te verleng nie, maar oak dat die lug tempertuur,
afhangende van die massavloei tempo van die lug, met tussen 1.5
en 7.5 °C verhoog kan word. Die studie het laastens oak getoon
dat dit moontlik is am met behulp van beskikbare teorie die
temperatuur toename in die kollektor van 'n son-Iugverwarmer met
of sander water energie storing, akkuraat te voorspel, mits die
vergelykings binne hul geldige gebiede gebruik word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52993 |
| Date | 12 1900 |
| Creators | Lombaard, Francois |
| Contributors | Kroger, D. G., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 1 v. (various foliations) : ill. |
| Rights | Stellenbosch University |
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