ABSTRACT
In this study, an innovative heat and mass transfer core is proposed to provide thermal comfort and humidity control using a hollow fiber contactor with multiple bundles of micro-porous hollow fibers. The hollow fiber-based core utilizes 12 bundles aligned vertically, each with 1,000 packed polypropylene hollow fibers. The proposed core was developed and tested under various operating and ambient conditions as a cooling core for a compact evaporative cooling unit and a dehumidification core for a liquid desiccant dehumidification unit. As a cooling core, the fiber-based evaporative cooler provides a maximum cooling capacity of 502 W with a wet bulb effectiveness of 85%. As a dehumidification core and employing potassium formate as a liquid desiccant, the dehumidifier is capable of reducing the air relative humidity by 17% with an overall dehumidification capacity of 733 W and humidity effectiveness of 47%. Being cheap and simple to design with their attractive heat and mass transfer characteristics and the corresponding large surface area-to-volume ratio, hollow fiber membrane contactors provide a promising alternative for cooling and dehumidification applications.
Acknowledgment
The authors gratefully acknowledge the special support of the “Dean of Engineering Research Scholarship for International Excellence” Award 2011 from the Faculty of Engineering at the University of Nottingham.
Nomenclature
AC | = | alternating current |
COP | = | coefficient of performance |
EER | = | energy efficiency ratio (Btu/Wh) |
h | = | enthalpy (J/kg) |
HCOOK | = | Potassium Formate |
LiBr | = | Lithium Bromide |
LiCl | = | Lithium Chloride |
= | mass flow rate (kg/s) | |
Pv | = | vapor pressure (mbar) |
PE | = | polyethylene |
PEI | = | polyetherimide |
PP | = | polypropylene |
PTFE | = | polytetrafluoroethylene |
PVC | = | polyvinyl chloride |
PVDF | = | polyvinylidene fluoride |
RH | = | relative humidity (%) |
LiCl | = | Lithium Chloride |
= | cooling capacity (W) | |
T | = | temperature (°C) |
w | = | humidity ratio (kgH2O/kgair) |
= | electric power (W) |
Greek
ε | = | effectiveness |
Subscripts
a | = | air |
db | = | dry bulb |
Deh | = | dehumidification |
dp | = | dew point |
ele | = | electric |
eq | = | equilibrium |
in | = | input |
out | = | output |
su | = | supply |
wb | = | wet bulb |