Determination of Optimum Rotational Speed of the Heat Wheel through Computational Fluid Dynamics Simulation

Heat wheel is a kind of regenerative heat exchanger mostly used in Heating, Ventilation and AirConditioning (HVAC) systems for two main goals; energy recovery from the waste heat and /ordehumidification of the air. Performance of the heat wheel utilized merely for energy recoveryhas been numerically investigated in this study. For the aim of determining the optimum rotationalspeed, three different angular velocities have been used under the transient conditions. Thefindings obtained from the analysis have been compared to a validated experimental study inliterature. Consequently, it has been observed that they are in good agreement each other.

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Zhang L., Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts (First Edition), Elsevier, USA, (2014).
Ge, T.S., Li, Y., Wang, R.Z., Dai, Y.J., “A review of the mathematical models for predicting rotary desiccant wheels”, Renewable & Sustainable Energy Reviews, 12(6) 1485-1528, (2008).
Lee, D., Kim, D., “Analytical modelling of desiccant wheel”, International Journal of Refrigeration, 42 97-111, (2014).
Solmuş, İ., Dees, R.A.S., Yamalı, C., Baker, D., “A two-energy equation model for dynamic heat and mass transfer in an adsorbent bed using silica gel/water pair”, International Journal of Heat and Mass Transfer, 55(19-20) 5275-88, (2012).
Simonson, C.J., Besant, R.W., “Energy wheel effectiveness: part i-development of dimensionless groups”, International Journal of Heat and Mass Transfer, 42(12) 2161-70, (1998).
Simonson, C.J., Besant, R.W., “Energy wheel effectiveness: part ii-correlations”, International Journal of Heat and Mass Transfer, 42(12) 2171-85, (1998).
Nobrega, C.E.L., Brum, N.C.L., “Modeling and simulation of heat and enthalpy recovery wheels”, Energy, 34(12) 2063-68, (2008).
Zhang, L.Z., Fu, H.X., Yang, Q.R., Xu, J.C., “Performance comparisons of honeycomb-type adsorbent beds (wheels) for air dehumidification with various desiccant wall materials”, Energy, 65 430-40, (2013).
Goldsworthy, M.J., White, S., “Design and performance of an internal heat exchange desiccant wheel”, International Journal of Refrigeration, 39 152-9, (2013).
Zhang, L.Z., Niu, J.L., “A numerical study of laminar forced convection in sinusoidal ducts with arc lower boundaries under uniform wall temperature”, Numerical Heat Transfer Part A: Applications, 40(1) 55-72, (2010).
Sphaier, L.A., Worek, W.M., “The effect of axial diffusion in desiccant and enthalpy wheels”, International Journal of Heat and Mass Transfer, 49(7-8) 1412-9, (2005).
Ruivo, C.R., Costa, J.J., Figueiredo, A.R., “Numerical study of the influence of the atmospheric pressure on the heat and mass transfer rates of desiccant wheels”, International Journal of Heat and Mass Transfer, 54(7-8) 1331-9, (2011).
Wu, Z., Melnik, R.V.N., Borup, F., “Model-based analysis and simulation of regenerative heat wheel”, Energy and Buildings, 38(5) 502-14, (2005).
Tu, R., Liu, X.H., Jiang, Y., “Performance comparison between enthalpy recovery wheels and dehumidification wheels”, International Journal of Refrigeration, 36(8) 2308-22, (2013).
Niu, J.L., Zhang, L.Z., “Effects of wall thickness on the heat and moisture transfers in desiccant wheels for air dehumidification and enthalpy recovery”, International Communications in Heat and Mass Transfer, 29(2) 255-68, (2002).
Enteria, N., Yoshino, H., Satake, A., Mochida, A., Takaki, R., Yoshie, R., Mitamura, T., Baba, S., “Experimental heat and mass transfer of the separated and coupled rotating desiccant wheel and heat wheel”, Experimental Thermal and Fluid Science, 34(5) 603-15, (2009).
Sparrow, E.M., Tong, J.C.K., Johnson, M.R., Martin, G.P., “Heat and mass transfer characteristics of a regenerative total energy wheel”, International Journal of Heat and Mass Transfer, 50(7-8) 1631-6, (2007).
Sheng, Y., Zhang, Y., Deng, N., Fang, L., Nie, J., Ma, L., “Experimental analysis on performance of high temperature heat pump and desiccant wheel system”, Energy and Buildings, 66 505-13, (2013).
Ruan, W., Qu, M., Horton, W.T., “Modeling analysis of an enthalpy recovery wheel with purge air”, International Journal of Heat and Mass Transfer, 55(17-18) 4665-72, (2012).
Zhang, L.Z., Niu, J.L., “Performance comparisons of desiccant wheels for air dehumidification and enthalpy recovery”, Applied Thermal Engineering, 22(12) 1347-67, (2002).
ANSYS Inc. Fluent Theory Guide, USA, (2013).
Yıldırım, Z.E., “A study on isoterm characteristics of adsorbent-adsorbate pairs used in adsorption heat pumps”, MSc. Thesis, İzmir Technology Institute, İzmir, (2011).
Çiftçi, E., “Isı tekerleği performansının hesaplamalı akışkanlar dinamiği ile belirlenmesi”, MSc. Thesis, Gazi University Graduate School of Natural and Applied Sciences, Ankara, (2013).