<p>Evaporative cooling is a highly energy efficient alternative
to conventional vapor compression cooling system. The sensible cooling effect
of evaporative cooling systems is well documented in the literature. Direct
evaporative cooling however increases the relative humidity of the air as it
cools it. This has made it unsuitable for data centers and other applications
where humidity control is important. Desiccant-based dehumidifiers (liquid,
solid or composites) absorb moisture from the cooled air to control humidity
and is regenerated using waste heat from the data center. This work is an
experimental and theoretical investigation of the use of desiccant assisted
evaporative cooling for data center cooling according to ASHRAE thermal
guidelines, TC 9.9. The thickness (depth) of the cooling pad was varied to
study its effect on sensible heat loss and latent heat gain. The velocity of
air through the pad was measured to determine its effect on sensible cooling.
The flow rate of water over the pad was also varied to find the optimal flow
for rate for dry bulb depression. The configuration was such that the rotary
desiccant wheel (impregnated with silica gel) comes after the direct evaporative
cooler. The rotary desiccant wheel was split in a 1:1 ratio for cooling and
reactivation at lower temperatures. The dehumidification effectiveness of a
fixed bed desiccant dehumidifier was compared with that of a rotary desiccant
wheel and a thermoelectric dehumidifier. A novel condensate recovery system
using the Peltier effect was proposed to recover moisture from the return air stream,
(by cooling the return air stream below its dew point temperature) thereby
optimizing the water consumption of evaporative cooling technology and
providing suitable air quality for data center cooling. The moisture recovery
unit was found to reduce the mass of water lost through evaporation by an
average of fifty percent irrespective of the pad depth.</p>
<p> </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12311654 |
| Date | 15 May 2020 |
| Creators | David Okposio (8844806) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/NET_ZERO_DESICCANT_ASSISTED_EVAPORATIVE_COOLING_FOR_DATA_CENTERS/12311654 |
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