WASTE HEAT RECOVERY IN HEAT PUMP SYSTEMS: SOLUTION TO REDUCE GLOBAL WARMING
Energy conversion technologies, where waste heat recovery systems are included, have received significant attention in recent years due to reasons that include depletion of fossil fuel, increasing oil prices, changes in climatic conditions, and global warming. For low temperature applications, there are many sources of thermal waste heat, and several recovery systems and potential useful applications have been proposed by researchers [1-4]. In addition, many types of equipment are used to recover waste thermal energy from different systems at low, medium, and high temperature applications, such as heat exchangers, waste heat recovery boiler, thermo-electric generators, and recuperators. In this paper, the focus is on waste heat recovery from air conditioners, and an efficient application of these energy resources. Integration of solar energy with heat pump technologies and major factors that affect the feasibility of heat recovery systems have been studied and reviewed as well.
KEYWORDS: waste heat recovery; heat pump.
 Pathania A, Mahto D. (2012) Recovery of engine waste heat for reutilization in air conditioning system in an automobile: An investigation. Global Journal of Researches in Engineering, 12(1).
 International Energy Agency Heat Pump Program. (2012) Heat pump and heat recovery technology.www.heatpumpcentre.org/en/aboutheatpumps/Sidor/default.aspx
 Reay DA. (1979) Heat recovery systems, a directory of equipment and techniques. E. & F. N. Spon: London.
 US Department of Energy. (2008) Heat recovery: Technology and opportunities in US Industry.
 Bitschi A. (2009) Modelling of thermoelectric devices for electric power generation. Doctor of Sciences Dissertation, Swiss Federal Institute of Technology Zurich (ETH ZURICH).
 Momin G, Deshmukh SR, Deshmukh MT, Chavan PT, Choudhari PP. (2014) COP enhancement of domestic refrigerator by recovering heat from the condenser. International Journal of Research in Advent Technology, 2(5):2321-9637.
 Hawlader, MNA. (2013) Utilization of solar energy and waste heat for water heating, drying and desalination of seawater. Paper presented in (ICMIME2013), 1-3 November, 2013, RUET, Rajshahi, Bangladesh.
 Jarnagin RE. (2008) Heat recovery from air conditioning units. University of Florida; Florida Cooperation Extention Service. Fact Sheet EES-26. Retrived on 10 October 2015 from http://www.wec.ufl.edu/extension/gc/harmony/documents/eh126.pdf.
 Hawlader MNA. (2014) Water heating and drying using solar energy and waste heat from air conditioners. Keynote Paper presented in International Symposium on Green and Sustainable Technology ISGST 2014, UTAR Perak Campus, Malaysia, Sept. 30- Oct.3.
 Islam MR, Sumathy K. (2013) Carbon dioxide driven solar-assisted heat pump water heating System: A theoretical analysis. Int. Res. J. Env. Sciences, 2(10):77-92.
 Austin BT, Sumathy K. (2011) Transcritical carbon dioxide heat pump systems: A review. Renewable and Sustainable Energy Reviews, 15:4013-4029.
 Zakaria MA (2010) A solar assisted heat pump system for desalination. PhD thesis, National University of Singapore, Singapore.
 Maina P, Huan Z. (2013) Effect of refrigerant charge in the output of CO2 heat pump. African J. Sci. Tech. Innov. Dev., 5(4): 303-311
 Neksa P. (2004) CO2 as refrigerant for systems in transcritical operation principles and technology status. A paper presented in AIRAHâ€™s 2004 natural refrigerants conference, Museum of Sydney, July 28 â€“ 2004.
 Sakar J. (2005) Transcritical carbon dioxide heat pump for simultaneously cooling and heating. Ph. D. thesis, Indian Institute of Technology Kharagpur, India.
 Stene J. (2008) High efficiency CO2 heat pump water heater systems for residential and non-residential buildings. Retrieved on 20 October 2014 from http://www.r744.com/assets/link/R744com_CO2-HPWH_2008.pdf
 Laipradit P, Tiansuwan J, Kiatsiriroat T, Aye L. (2008) Theoretical performance analysis of heat pump water heaters using carbon dioxide as refrigerant. Int. J. Energy Research, 32:356-366.
The IIUM Engineering journal follows the open access policy.