https://orcid.org/0000-0001-5383-7216
![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
ABSTRACT
Theoretical and experimental investigations were performed to study the impact of four pads in series on the thermal performance of an economical evaporative air cooler that works at a low voltage (12 Volts). Straw and cardboard pads were studied. The studied parameters were dry bulb temperature, the dry bulb temperature difference between inlet and outlet air, cooling efficiency, and the total heat transfer rate. Three draft fan speeds were considered, i.e. 2.8, 3.5, and 4.7 m/s. The results showed that adding multiple pads in series had an insignificant impact on the evaporative cooler thermal performance compared to one pad. The straw pads’ cooling efficiency at 2.8 m/s was lower than that of the cardboard, i.e. 91.4% and 93.1%, respectively. Also, it was found that the velocity of the air passing through the cooler significantly impacted the cooling efficiency. The theoretical results for the lowest speed of 2.8 m/s showed an increase in the cooling efficiency of the cardboard pad by 46.6% compared to the speed of 4.7 m/s due to a long time for heat transfer. Therefore, the best air velocity entering the cooled space was 2.8 m/s.
Nomenclature
| AC | = | Constant (6.66 × 10−4 C−1) |
| C | = | Velocity, (m. s−1) |
| Cp | = | Specific heat of air at constant pressure, (J.kg−1. °C−1) |
| D | = | Diameter, (m) |
| ṁ | = | Mass flow rate, (kg. hr−1) |
| P | = | Partial pressure, (kPa) |
| PB | = | Total pressure, (kPa) |
| Pws | = | Saturated water vapor pressure, (kPa) |
| q | = | Heat transfer rate, (W) |
| = | Volume flow rate, (m3. hr−1) | |
| R | = | Experimental result |
| T | = | Bulb temperature, (°C) |
| Vr | = | Independent variable |
| W | = | moisture content, (kgw. kgda) |
| W | = | Uncertainty |
| Greek symbols | = |
|
| = | Cooler efficiency, (%) | |
| ρ | = | Density, (kg. m−3) |
| = | Relative humidity, (%) | |
| Subscripts | = |
|
| a | = | Air |
| d | = | Dry |
| i | = | Inlet |
| o | = | Outlet |
| w | = | Wet |
Acknowledgements
The authors thank the Engineering College at Tikrit University for supporting us in completing this work.
Disclosure statement
No potential conflict of interest was reported by the authors.
Additional information
Notes on contributors
Thamer Khalif Salem
Assist. Prof. Dr. Thamer Khalif Salem received his B.Sc. degree in mechanical engineering from the College of Military Engineering, Baghdad, Iraq, in 1996. He was awarded his M.Sc. degree in Mechanical Engineering / Refrigeration and air-conditioning at the University of Technology, Baghdad, Iraq, in 2003. In 2004, he has joined Tikrit University in Salahuddin, Iraq. He completed Ph.D. degree in the Mechanical Engineering Department at the University of Özyeğin, Istanbul, Turkey. His research areas of interest are in cooling technologies in electronics (Heat pipe), heat transfer on micro-structured surfaces, CFD analysis and experimental studies for two Phase Forced Convection of condensation process, Exergy analysis and Refrigeration cycles.
Samer M. Khalaf
Dr. Samer M. Khalaf is currently a lecturer at Mechanical Department, College of Engineering, Tikrit University- Iraq. He received his BSc and MSc from Tikrit University-Iraq and his PhD. degree from Al-Nahrain University-Iraq. He published a number of papers in prestigious journals and conferences. His areas of interest are thermal power energy ,nanofluids, and refrigeration and air conditioning.
Nassir Dhamin Mokhlif
Dr. Nassir Dhamin Mokhlif is an assistant professor at department of petroleum and gas Refining Engineering, college of petroleum processes engineering, Tikrit University, Tikrit, Iraq. He received his PhD from Universiti Teknologi Petronas, Malaysia in 2014, MSc in Tikrit University, Iraq in 2003, and BSc in University of Baghdad, Iraq in 1991. He has a professional expertise in modeling the thermo-fluid heat exchangers, solar energy, and refrigeration system analysis.
Manar S.M. Al-Jethelah
Dr. Manar S.M Al-Jethelah is currently an Assistant Professor at Mechanical Engineering Department, College of Engineering, Tikrit University- Iraq. She received her BSC and MSc from Tikrit University- Iraq and her PhD degree from University of Guelph- Canada. She published a number of papers in prestigious journals and conferences. Her areas of interest are thermal solar energy, thermal storage, nanofluids, and phase change materials.