Performance Improvement of the Solar Heat Pump Using Carbon Nanotubes in the Refrigerant and its Condenser Structure

Document Type : Propulsion and Heat Transfer

Authors

1 Mechanical Engineering, Islamic Azad University, East Tehran Branch

2 Faculty of Aerospace Engineering, Urmia University of Technology, Urmia, Iran.

Abstract

Improving the performance of solar heat pumps has always been of interest to researchers. The purpose of this study has been to find the optimal state of carbon nanotube (CNT) concentration in the refrigerants and condenser copper tubes as well as the total tube length and the diameter of the condenser helical coil, in order to maximize the exergy and heat transfer. The investigation has been carried out by the numerical method using finite volume, unsteady and laminar flow. The genetic algorithm has been used to obtain the optimum choice for the condenser in two states of constant and variable diameter. Three concentrations of 0, 0.5 and 1 percent for the carbon nanotubes in the refrigerant, three concentrations of 0, 1 and 3 percent for the carbon nanotubes in the copper tube, three different values for the condenser diameter in each of the two states of constant and variable diameter, and three different condenser tube lengths have been investigated. The results show that the use of CNT in the refrigerant, always increases the Nusselt number and the exergy while, the use of CNT in the wall structure of the condenser copper tube reduces them. The results also show that the use of carbon nanotubes in the refrigerant increases the Nusselt number by 16% to 21%, and the exergy by 9% to 13%. However, using carbon nanotubes in the condenser copper tube wall reduces the Nusselt number and the exergy up to 9.5% and 18% respectively.

Keywords

References

1. Sporn, P., Ambrose, E., “The Heat Pump and Solar Energy”, Proc of the World Symp. on Applied Solar Energy Phoenix, US, 1955.##
2. Morrison, G., “Simulation of Packaged Solar Heat-Pump Water Heaters”, J. Sol. Energy, Vol. 53, No. 3, pp. 249-257, 1994.##
3. Azarkish, H., Behzadmehr, A., Hosseini Soruri, S., “Investigation on The Use of Different Refrigerant in the Solar Heat Pump to Warm a Residential House”, 18th annual Conf. Mech. Eng. Sharif University of Technology, 1389. [In Persian]##
4. Mesgari, S., Hjerrild, N., Arandiyan, H., Taylor, P.A., “Carbon nanotube heat transfer fluid for solar radiant heating of buildings”, J of Energy and Building, Vol. 175, No. 15, pp. 11-16, 2018.##
5. Cervantes, J. G., Torres Reyes, E., “Experiments on a Solar-Assisted Heat Pump and an Exergy Analysis of the System”, J. Appl. Therm. Eng., Vol. 22, No. 12, pp. 1289-1297, 2002.##
6. Badescu, V., “First and Second Law Analysis of a Solar Assisted Heat Pump Based Heating System”, J. Energ Convers Manage., Vol. 43, No. 18, pp. 2539-2552, 2002.##
7. Dikici, A., Akbulut, A., “Performance Characteristics and Energy–Exergy Analysis of Solar-Assisted Heat Pump System”, J. Build Environ., Vol. 43, No. 11, pp. 1961-1972, 2008.##
8. Stritih, U., Zavrl, E., Paksoy, H.O., “Energy analysis and carbon saving potential of a complex heating system with solar assisted heat pump and phase change matrial (PCM) thermal storage in different climatic condition”, Euro. J. Sustain. Dev. Res., Vol. 3, o. 1, pp. 1/17-17/17, 2019.##
9. Moreno Rodriguez, A., Garcia Hernando, N., González-Gil, A. and Izquierdo, M., “Experimental Validation of a Theoretical Model for a Direct-Expansion Solar-Assisted Heat Pump Applied to Heating”, Energ J., Vol. 60, No. 1, pp. 242-253, 2013.##
10. Zhang, D., Wu, Q., Li, J. and Kong, X., “Effects of Refrigerant Charge and Structural Parameters on the Performance of a Direct-Expansion Solar-Assisted Heat Pump System”, J. Appl. Therm. Eng., Vol. 73, No. 1, pp. 522-528, 2014.##
11. Mastronardo, E., Milone, C., “Thermochemical performance of carbon nanotubes based hybrid materials for MgO/H2O/Mg(OH)2 chemical heat pumps”, J. Appl. Energy, Vol. 181, No. 1, pp. 232-243, 2016.##
12. Palanisamy, K., Kumar, P.C.M., “Experimental investigation on convective heat transfer and pressure drop of cone helically coiled tube heat exchanger using carbon nanotubes/water nanofluids”, J. Helion, Vol. 5, No. 5, e1707, 2019. ##
13. Vahdat Azad, A., Vahdat Azad, N., “Application of nanofluids for the optimal design of shell and tube heat exchangers using generic algorithm”, J. Case Studies in Thermal Engineering, Vol. 8, pp. 198-206, 2016.##
14. Dai, N., Li, S., “Simulation and performance analysis on condenser coil in household heat pump water heater”, J. Sustain. Cities Soc., Vol. 36, pp. 176-184, 2018.##
15. Dai, N., Li, S., “Coupling Model of Heat Pump System and Water Tank with Immersed Condenser Coil in HPWH”, 4th Inter. Conf. On Build. Energy, Environ.; Melborne, Australia, pp. 671-676, 2018.##
16. Prabhanjan, D. G., Rennie, T. J. and Raghavan, G. V., “Natural Convection Heat Transfers from Helical Coiled Tubes”, Int. J. Therm. Sci., Vol. 43, No. 4, pp. 359-365, 2004.##
17. Jegadheeswaran, S., Pohekar, S., “Exergy Analysis of Particle Dispersed Latent Heat Thermal Storage System for Solar Water Heaters”, J. Renew. Sust. Energ. Rev., Vol. 2, No. 2, pp. 023105-1-17, 2010.##
18. Park, K. J., Jung, D., “Boiling Heat Transfer Enhancement with Carbon Nanotubes for Refrigerants Used in Building Air-Conditioning”, J. Energ. Buildings., Vol. 39, No. 9, pp. 1061-1064, 2007.##
19. Vallet, G. M., Dunand, M. and Silvain, J. F., “Influence of Carbon Nanotubes Dispersion on Thermal Properties of Copper-Carbon Nanotubes (CNTs) Composite Materials”, Univers. J. Mater. Sci., Vol. 3, No. 4, pp. 55-61, 2015.##

Files

History

  • Receive Date: 11 August 2019
  • Revise Date: 24 November 2019
  • Accept Date: 25 August 2020
  • Publish Date: 22 October 2020

Share

How to cite

Statistics