ABSTRACT
This paper deals with the improvement of thermal performance of the heat recovery system in air-to-air unit by using a nanofluid of TiO particles and distilled water. The 2 experimental set-up equipped with 15 copper pipes of a 1000 mm length, 10.5 mm inner diameter, and 12 mm outer diameter was used. The evaporator section consists of 450 mm of heat pipes, the condenser section is 400 mm, and the adiabatic section is 150 mm. In experimental studies, 33% of the evaporator volumes of heat pipes were filled with working fluids. Experiments were carried out at temperatures between 25ºC and 90ºC by using five different cooling air-flows (40, 42, 45, 61, and 84 g/s), and two different heating powers (3 kW and 6 kW) for the evaporation section, to determine heat removed from the condensation section. Trials were performed for distilled water and nanofluid respectively, and the results were compared with each other. Results revealed that a 50% recovery in the thermal performance of the heat pipe heat recovery system was achieved in the design using TiO nanofluid as the working liquid, at a heating power of 3 kW, air 2 velocity of 2.03 m/s and air-flow of 84 g/s.
KEYWORDS
PAPER SUBMITTED: 2017-07-03
PAPER REVISED: 2017-11-29
PAPER ACCEPTED: 2017-12-04
PUBLISHED ONLINE: 2018-01-07
THERMAL SCIENCE YEAR
2019, VOLUME
23, ISSUE
Issue 3, PAGES [1755 - 1764]
- Noie-Baghban, S. H., and G. R. Majideian, Waste Heat Recovery Using Heat Pipe Heat Exchanger (Hphe) For Surgery Rooms in Hospitals. Applied Termal Engineering 20 (2000), pp.1271-1282.
- Faghri, A, Heat pipe science and technology, Global Digital Press, 1995
- Faghri, A, Heat Pipes: Review, Opportunities and Challenges. Frontiers in Heat Pipes 5 (2014) pp.1-48.
- Tosun, H., E. Söylemez, and M. Özşen. 2013. Isı Borulu Isı Geri Kazanım ve Nem Alma Ünitesi. 11. Ulusal Tesisat Mühendisliği Kongresi, 1 (2013), pp.373-391. (in Turkish)
- Zhu, Y., X. Cui, H. Han, and S. Sun., The study on the difference of the start-up and heat-transfer performance of the pulsating heat pipe with water−acetone mixtures. International Journal of Heat and Mass Transfer 77 (2014), pp. 834-842.
- Riffat, S. B., and G. Gan., Determination of effectiveness of heat-pipe heat recovery for naturally-ventilated buildings. Applied Thermal Engineering 18 (1998), pp. 121-130.
- Wang, X., T. Ma, Y. Zhu, H. Chen, and J. Zeng., Experimental investigation on startup and thermal performance of a high temperature special-shaped heat pipe coupling the flat plate heat pipe and cylindrical heat pipes. Experimental Thermal and Fluid Science 77 (2016), pp. 1-9.
- Zhu, Z., H. Fan, and C. Zhang. 2016. Experimental investigations on the effectiveness of micro heat pipe array heat exchanger for heat recovery for residential building. Applied Thermal Engineering 102 (2016), pp. 980-988.
- Sadeghinezhad, E. et al., Experimental investigation of the effect of graphene nanofluids on heat pipe thermal performance. Applied Thermal Engineering 100 (2016), pp.775-787.
- Noie, S. H., Investigation of thermal performance of an air-to-air thermosyphon heat exchanger using epsilon-NTU method. Applied Thermal Engineering 26: (2016), pp.559-567.
- Orr, B., B. Singh, L. Tan, and A. Akbarzadeh., Electricity generation from an exhaust heat recovery system utilising thermoelectric cells and heat pipes. Applied Thermal Engineering 73 (2014), pp. 588-597.
- Gedik, E., M. Yılmaz, and H. Kurt, Experimental investigation on the thermal performance of heat recovery system with gravity assisted heat pipe charged with R134a and R410A. Applied Thermal Engineering 99 (2016), pp. 334-342.
- ALARKO, Enerji Geri Kazanim Havalandirmasi. ALARKO Carrier Teknik Bülten 2013, 55.(in Turkish)
- Sözen, A. et al., A comparative investigation on the effect of fly-ash and alumina nanofluids on the thermal performance of two-phase closed thermo-syphon heat pipes. Applied Thermal Engineering 96 (2016), pp. 330-337.
- Zhang, J. et al., Experimental study on the heat recovery characteristics of a new-type flat micro-heat pipe array heat exchanger using nanofluid. Energy Conversion and Management 75 (2013), pp. 609-616.
- G. Huminic, A. Huminic, Heat transfer characteristics of a two-phase closed thermosyphons using nanofluids, Exp. Therm. Fluid Sci. 35 (2011), pp. 550-557.
- J.G. Coiller, J.R. Thome, Convective Boiling and Condensation, Clarendon Press, Oxford, U.K., 1996.
- S.H. Noie, S.Z. Heris, M. Kahani, S.M. Nowee, Heat transfer enhancement using Al2O3/water nanofluid in a two-phase closed thermosyphon, Int. J. Heat Fluid Flow 30 (2009), pp. 700-705.
