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Thermal analysis of building roof assisted with water heater and insulation material

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Abstract

Traditional roof systems are constructed with concrete and weathering coarse layer and these roof systems absorb and reflect a certain amount of solar radiation. The absorbed solar energy is transferred into building indoor and causes significant discomfort to the occupants. Also, this solar energy gets dissipated without any useful energy conversion. Hence this paper is focused to use the available solar energy effectively through a novel solar water heating system and the transfer of heat in the building indoor is arrested by proper roof insulation material. The modified insulated roof with the solar water heater is designed and simulated numerically in commercial computational fluid dynamics code with validation. Through this study, the factors that affect the performance of solar water heating system and thermal insulation capacity are analysed and the best design of the modified roof system is identified. The modified roof system produces 25 L of hot water per day with a temperature raise of 60°C in the winter season. Also, the same roof system maintains the ceiling temperature at about 27°C for a complete day in a summer season.

Keywords

Thermal analysis building roof solar water heating system roof insulation numerical simulation 

List of symbols

d

pipe diameter

tp

polyurethane layer thickness

tw

wood wool layer thickness

tcb

refractory carborundum brick layer thickness

Ta

ambient temperature

α

absorvity

q

solar radiation

Tsolair

temperature of the combined effect of radiation and convection

Tin

indoor temperature

kc

thermal conductivity of ceiling

ho

convective heat transfer coefficient of the exterior surface of the roof

hin

convective heat transfer coefficient of indoor

Tw

water outlet temperature

Tc

ceiling temperature

m

mass flow rate

References

  1. 1.
    Suehrcke H, Peterson E L and Selby N 2008 Effect of roof solar reflectance on the building heat gain in a hot climate. Energy Build. 40(12): 2224–2235CrossRefGoogle Scholar
  2. 2.
    Dharuman C, Arakeri J H and Srinivasan K 2006 Performance evaluation of an integrated solar water heater as an option for building energy conservation. Energy Build. 38(3): 214–219CrossRefGoogle Scholar
  3. 3.
    Chow T T, Dong Z, Chan L S, Fong K F and Bai Y 2011 Performance evaluation of evacuated tube solar domestic hot water systems in Hong Kong. Energy Build. 43(12): 3467–3474CrossRefGoogle Scholar
  4. 4.
    Li C and Wang R Z 2012 Building integrated energy storage opportunities in China. Renew. Sustain. Energy Rev. 16(8): 6191–6211MathSciNetCrossRefGoogle Scholar
  5. 5.
    Boait P J, Dixon D, Fan D and Stafford A 2012 Production efficiency of hot water for domestic use. Energy Build. 54: 160–168CrossRefGoogle Scholar
  6. 6.
    Mohsen M S, Al-Ghandoor A and Al-Hinti I 2009 Thermal analysis of compact solar water heater under local climatic conditions. Int. Commun. Heat Mass Transf. 36(9): 962–968CrossRefGoogle Scholar
  7. 7.
    Weiss W and Rommel M 2008 Process heat collectors. State of the art within Task 33/IV. IEA SHC-Rast 33 and solarPACES-Task IV: solar heat for industrial processes. Gleisdorf (Austria): International Energy Agency. AEE INTEC. pp 1–58Google Scholar
  8. 8.
    Kumar R, Adhikari R S, Garg H P and Kumar A 2001 Thermal performance of a solar pressure cooker based on evacuated tube solar collector. Appl. Therm. Eng. 21(16): 1699–1706CrossRefGoogle Scholar
  9. 9.
    Yao K, Li T, Tao H, Wei J and Feng K 2015 Performance evaluation of all-glass evacuated tube solar water heater with twist tape inserts using CFD. Energy Procedia 70: 332–339CrossRefGoogle Scholar
  10. 10.
    Juanico L 2008 A new design of roof-integrated water solar collector for domestic heating and cooling. Solar Energy 82(6): 481–492CrossRefGoogle Scholar
  11. 11.
    Huang K, Feng G and Zhang J 2014 Experimental and numerical study on phase change material floor in solar water heating system with a new design. Solar Energy 105: 126–138CrossRefGoogle Scholar
  12. 12.
    Joudi K A and Farhan A A 2014 Greenhouse heating by solar air heaters on the roof. Renew. Energy 72: 406–414CrossRefGoogle Scholar
  13. 13.
    Sarachitti R, Chotetanorm C, Lertsatitthanakorn C and Rungsiyopas M 2011 Thermal performance analysis and economic evaluation of roof-integrated solar concrete collector. Energy Build. 43(6): 1403–1408CrossRefGoogle Scholar
  14. 14.
    Lai C M, Hokoi S and Ho C J 2014 Thermal performance of an innovative curtain-wall-integrated solar heater. Energy Build. 77: 416–424CrossRefGoogle Scholar
  15. 15.
    Nahar N M 2003 Year-round performance and potential of a natural circulation type of solar water heater in India. Energy Build. 35(3): 239–247CrossRefGoogle Scholar
  16. 16.
    Krishnavel V, Karthick A and Murugavel K K 2014 Experimental analysis of concrete absorber solar water heating systems. Energy Build. 84: 501–505CrossRefGoogle Scholar
  17. 17.
    Sokolov M and Reshef M 1992 Performance simulation of solar collectors made of concrete with embedded conduit lattice. Solar Energy 48(6): 403–411CrossRefGoogle Scholar
  18. 18.
    Varghese J and Manjunath K 2017 parametric study of a concentrating integral storage solar water heater for domestic uses. Appl. Therm. Eng. 111: 734–744CrossRefGoogle Scholar
  19. 19.
    Zhang X, You S, Xu W, Wang M, He T and Zheng X 2014 Experimental investigation of the higher coefficient of thermal performance for water-in-glass evacuated tube solar water heaters in China. Energy Convers. Manag. 78: 386–392CrossRefGoogle Scholar
  20. 20.
    Hamed M, Fallah A and Brahim A B 2017 Numerical analysis of charging and discharging performance of an integrated collector storage solar water heater. Int. J. Hydrog. Energy 42(13): 8777–8789CrossRefGoogle Scholar
  21. 21.
    Khalifa, Abdul Jabbar N and Abdul Jabbar R 2010 Conventional versus storage domestic solar hot water systems: A comparative performance study. Energy Convers. Manag. 51(2): 265–270CrossRefGoogle Scholar
  22. 22.
    Khalifa and Abdul-Jabbar N 1999 Thermal performance of locally made flat plate solar collectors used as part of a domestic hot water system. Energy Convers. Manag. 40(17): 1825–1833CrossRefGoogle Scholar
  23. 23.
    Garg H P 1975 Year-round performance studies on a built-in storage type solar water heater at Jodhpur, India. Solar Energy 17(3): 167–172CrossRefGoogle Scholar
  24. 24.
    Mohsen M S and Akash B A 2002 On integrated solar water heating system. Int. Commun. Heat Mass Transf. 29(1): 135–140CrossRefGoogle Scholar
  25. 25.
    Ekici B B, Gulten A A and Aksoy U T 2012 A study on the optimum insulation thicknesses of various types of external walls with respect to different materials, fuels and climate zones in Turkey. Appl. Energy 92: 211–217CrossRefGoogle Scholar
  26. 26.
    Ozel M 2014 Effect of insulation location on dynamic heat-transfer characteristics of building external walls and optimization of insulation thickness. Energy Build. 72: 288–295CrossRefGoogle Scholar
  27. 27.
    Kayfeci M, Keçebaş A and Gedik E 2013 Determination of optimum insulation thickness of external walls with two different methods in cooling applications. Appl. Therm. Eng. 50(1): 217–224CrossRefGoogle Scholar
  28. 28.
    Prakash D 2015 Transient analysis and improvement of indoor thermal comfort for an air-conditioned room with thermal insulations. Ain Shams Eng. J. 6(3): 947–956CrossRefGoogle Scholar
  29. 29.
    Pasupathy A and Velraj R 2008 Effect of double layer phase change material in building roof for year-round thermal management. Energy Build. 40(3): 193–203CrossRefGoogle Scholar
  30. 30.
    Prakash D and Ravikumar P 2013 Transient analysis of heat transfer across the residential building roof with PCM and wood wool—A case study by numerical simulation approach. Arch. Civil Eng. 59(4): 483–497CrossRefGoogle Scholar
  31. 31.
    Tiwari G N 2005 Solar energy of fundamentals, design, modeling and applications. New Delhi: Handbook of Narosa Publishing HouseGoogle Scholar
  32. 32.
    Koffi, P M E, Andoh H Y, Gbaha P, Toure S and Ado G 2008 Theoretical and experimental study of solar water heater with internal exchanger using thermosiphon system. Energy Conver. Manag. 49(8): 2279–2290CrossRefGoogle Scholar
  33. 33.
    Karabay H, Arıcı M and Sandık M 2013 A numerical investigation of fluid flow and heat transfer inside a room for floor heating and wall heating systems. Energy Build. 67: 471–478CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  1. 1.School of Mechanical EngineeringSASTRA Deemed UniversityThanjavurIndia

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