Abstract
As
global warming and water scarcity issues continue to grow, it is essential to
increase resources efficiency for air conditioners and power plants. In order
to increase the efficiency, the systems need to be modified to take the
advantages of the low night temperature and thermal storage tanks. In this
study, the low night temperature and thermal storage tanks effects on the
cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to
16:00 as a case study, hot water from the condenser is partially stored on
daytime and cooled slowly during the night. The storage tank volume is
optimized by considering two big tanks and five small tanks. The results show
that night cooling reduces cooling water temperature by 5.8 °C or 21.8% while
the cooling efficiency is increased by 36%. The thermal storage tanks enable to
have the low continuous flow rate and help to reduce the fan power by 67.1%. On
the storage side, compared to two tanks system, the tanks volume is reduced by
16.5% when 5 tanks are used. In theory this reduction can go up to 50% by
increasing the number of tanks and reducing their individual size.
Keywords
References
- Isaac M., and van Vuuren D. P., “Modeling Global Residential Sector Energy Demand for Heating and Air Conditioning in the Context of Climate Change”, Energy Policy, 37(2): 507–521, (2009).
- Ghani S., Bakochristou F., ElBialy E. M. A. A., Gamaledin S. M. A., Rashwan M. M., Abdelhalim A. M., and Ismail S. M., “Design Challenges of Agricultural Greenhouses in Hot and Arid Environments – A Review”, Eng. Agric. Environ. Food, 12(1): 48–70, (2018).
- Xu J., and Li Y., “Experimental Performance of Evaporative Cooling Pad Systems in Greenhouses in Humid Subtropical Climates”, Appl. Energy, 138: 291–301, (2015).
- Abu-Hamdeh N. H. and Almitani K. H., “Solar Liquid Desiccant Regeneration and Nanofluids in Evaporative Cooling for Greenhouse Food Production in Saudi Arabia”, Sol. Energy, 134: 202–210, (2016).
- M. R. Susta, “Condensers and Coolings Systems”, (2004).
- TRNSYS, “Mathematical Reference Volume 5”, (2006).
- Kumar P., “Cooling Tower”, Energy Efficiency in Electrical Utilities Guide Book, (2005).
- Liu N., Zhang L., and Jia X., “The Effect of the Air Water Ratio on Counter Flow Cooling Tower”, Procedia Eng., 205: 3550–3556, (2017).
- Abdel-Ghaffar Y. E., “Effect of Operating Parameters on the Performance of Counter Flow Type Cooling Towers”, Industry Education, DepL, Mansoura Univ, New Damietta, Egypt, (2004).
- Ayoub A., and Gjorgiev B., “Cooling Towers Performance in a Changing Climate: Techno-Economic Modeling and Design Optimization”, Energy, 160: 1133–1143, (2018).
- Cengel Y., and Boles M., Thermodynamics: An Engineering Approach, (2006).
- Lança M., Coelho P. J., and Viegas J., “Enhancement of Heat Transfer in Office Buildings during Night Cooling − Reduced Scale Experimentation”, Build. Environ., 148: 653–667, (2019).
- Jiang L., and Tang M., “Thermal Analysis of Extensive Green Roofs Combined with Night Ventilation for Space Cooling”, Energy Build., 156, 238–249, (2017).
- Ali A. H. H., “Passive Cooling of Water at Night in Uninsulated Open Tank in Hot Arid Areas”, Energy Convers. Manag., 48(1), 93–100, (2007).
- Dyreson A., and Miller F., “Night Sky Cooling for Concentrating Solar Power Plants”, Appl. Energy, 180, 276–286, (2016).
- Taghian Dehaghani S., and Ahmadikia H., “Retrofit of a Wet Cooling Tower in Order to Reduce Water and Fan Power Consumption Using a Wet/Dry Approach”, Appl. Therm. Eng., 125: 1002–1014, (2017).
- Naik B. K., Choudhary V., Muthukumar P., and Somayaji C., “Performance Assessment of a Counter Flow Cooling Tower – Unique Approach”, Energy Procedia, 109: 243–252, (2017).
- Belmonte J. F., Izquierdo-Barrientos M. A., Eguía P., Molina A. E., and Almendros-Ibáñez J. A., “PCM in the Heat Rejection Loops of Absorption Chillers. A Feasibility Study for the Residential Sector in Spain”, Energy Build., 80: 331–351, (2014).
- Kasumu A. S., Nassar N. N., and Mehrotra A. K., “A Heat-Transfer Laboratory Experiment with Shell-and-Tube Condenser”, Educ. Chem. Eng., 19: 38–47, (2017).
- Vera-García F., García-Cascales J. R., Gonzálvez-Maciá J., Cabello R., Llopis R., Sanchez D., and Torrella E., “A Simplified Model for Shell-and-Tubes Heat Exchangers: Practical Application”, Appl. Therm. Eng., 30(10): 1231–1241, (2010).
- Spxcooling.com. Application of Cooling Towers for Free Cooling. [online] Available at: https://spxcooling.com/library/detail/the-application-of-cooling-towers-for-free-cooling [Accessed 24 Jan. 2019].
- Fantech.com.au. Fan Laws, (2016). [online] Available at: https://www.fantech.com.au/images/PDF/Catalogue/fanlaws.pdf [Accessed 24 Jan. 2019].
Abstract
As
global warming and water scarcity issues continue to grow, it is essential to
increase resources efficiency for air conditioners and power plants. In order
to increase the efficiency, the systems need to be modified to take the
advantages of the low night temperature and thermal storage tanks. In this
study, the low night temperature and thermal storage tanks effects on the
cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to
16:00 as a case study, hot water from the condenser is partially stored on
daytime and cooled slowly during the night. The storage tank volume is
optimized by considering two big tanks and five small tanks. The results show
that night cooling reduces cooling water temperature by 5.8 °C or 21.8% while
the cooling efficiency is increased by 36%. The thermal storage tanks enable to
have the low continuous flow rate and help to reduce the fan power by 67.1%. On
the storage side, compared to two tanks system, the tanks volume is reduced by
16.5% when 5 tanks are used. In theory this reduction can go up to 50% by
increasing the number of tanks and reducing their individual size.
Keywords
References
- Isaac M., and van Vuuren D. P., “Modeling Global Residential Sector Energy Demand for Heating and Air Conditioning in the Context of Climate Change”, Energy Policy, 37(2): 507–521, (2009).
- Ghani S., Bakochristou F., ElBialy E. M. A. A., Gamaledin S. M. A., Rashwan M. M., Abdelhalim A. M., and Ismail S. M., “Design Challenges of Agricultural Greenhouses in Hot and Arid Environments – A Review”, Eng. Agric. Environ. Food, 12(1): 48–70, (2018).
- Xu J., and Li Y., “Experimental Performance of Evaporative Cooling Pad Systems in Greenhouses in Humid Subtropical Climates”, Appl. Energy, 138: 291–301, (2015).
- Abu-Hamdeh N. H. and Almitani K. H., “Solar Liquid Desiccant Regeneration and Nanofluids in Evaporative Cooling for Greenhouse Food Production in Saudi Arabia”, Sol. Energy, 134: 202–210, (2016).
- M. R. Susta, “Condensers and Coolings Systems”, (2004).
- TRNSYS, “Mathematical Reference Volume 5”, (2006).
- Kumar P., “Cooling Tower”, Energy Efficiency in Electrical Utilities Guide Book, (2005).
- Liu N., Zhang L., and Jia X., “The Effect of the Air Water Ratio on Counter Flow Cooling Tower”, Procedia Eng., 205: 3550–3556, (2017).
- Abdel-Ghaffar Y. E., “Effect of Operating Parameters on the Performance of Counter Flow Type Cooling Towers”, Industry Education, DepL, Mansoura Univ, New Damietta, Egypt, (2004).
- Ayoub A., and Gjorgiev B., “Cooling Towers Performance in a Changing Climate: Techno-Economic Modeling and Design Optimization”, Energy, 160: 1133–1143, (2018).
- Cengel Y., and Boles M., Thermodynamics: An Engineering Approach, (2006).
- Lança M., Coelho P. J., and Viegas J., “Enhancement of Heat Transfer in Office Buildings during Night Cooling − Reduced Scale Experimentation”, Build. Environ., 148: 653–667, (2019).
- Jiang L., and Tang M., “Thermal Analysis of Extensive Green Roofs Combined with Night Ventilation for Space Cooling”, Energy Build., 156, 238–249, (2017).
- Ali A. H. H., “Passive Cooling of Water at Night in Uninsulated Open Tank in Hot Arid Areas”, Energy Convers. Manag., 48(1), 93–100, (2007).
- Dyreson A., and Miller F., “Night Sky Cooling for Concentrating Solar Power Plants”, Appl. Energy, 180, 276–286, (2016).
- Taghian Dehaghani S., and Ahmadikia H., “Retrofit of a Wet Cooling Tower in Order to Reduce Water and Fan Power Consumption Using a Wet/Dry Approach”, Appl. Therm. Eng., 125: 1002–1014, (2017).
- Naik B. K., Choudhary V., Muthukumar P., and Somayaji C., “Performance Assessment of a Counter Flow Cooling Tower – Unique Approach”, Energy Procedia, 109: 243–252, (2017).
- Belmonte J. F., Izquierdo-Barrientos M. A., Eguía P., Molina A. E., and Almendros-Ibáñez J. A., “PCM in the Heat Rejection Loops of Absorption Chillers. A Feasibility Study for the Residential Sector in Spain”, Energy Build., 80: 331–351, (2014).
- Kasumu A. S., Nassar N. N., and Mehrotra A. K., “A Heat-Transfer Laboratory Experiment with Shell-and-Tube Condenser”, Educ. Chem. Eng., 19: 38–47, (2017).
- Vera-García F., García-Cascales J. R., Gonzálvez-Maciá J., Cabello R., Llopis R., Sanchez D., and Torrella E., “A Simplified Model for Shell-and-Tubes Heat Exchangers: Practical Application”, Appl. Therm. Eng., 30(10): 1231–1241, (2010).
- Spxcooling.com. Application of Cooling Towers for Free Cooling. [online] Available at: https://spxcooling.com/library/detail/the-application-of-cooling-towers-for-free-cooling [Accessed 24 Jan. 2019].
- Fantech.com.au. Fan Laws, (2016). [online] Available at: https://www.fantech.com.au/images/PDF/Catalogue/fanlaws.pdf [Accessed 24 Jan. 2019].
Details
| Primary Language | English |
|---|---|
| Subjects | Engineering |
| Journal Section | Research Article |
| Authors | |
| Publication Date | December 1, 2020 |
| Submission Date | January 25, 2019 |
| Published in Issue | Year 2020 Volume: 23 Issue: 4 |
Cite
This work is licensed under Creative Commons Attribution-ShareAlike 4.0 International.