Author(s)

Liang Xia^1*, Tong Yang¹, Yue Chan², Llewellyn Tang¹, Yung-Tsang Chen³

¹Department of Architecture and Built Environment, University of Nottingham Ningbo China, Ningbo, China.
²School of Mathematical Sciences, University of Nottingham Ningbo China, Ningbo, China.
³Department of Civil Engineering, University of Nottingham Ningbo China, Ningbo, China.

Efficient Air Conditioning (A/C) system is the key to reducing energy consumption in building operation. In order to decrease the energy consumption in an A/C system, a method to calculate the optimal tube row number of a direct expansion (DX) cooling coil for minimizing the entropy generation in the DX cooling which functioned as evaporator in the A/C system was developed. The optimal tube row numbers were determined based on the entropy generation minimization (EGM) approach. Parametric studies were conducted to demonstrate the application of the analytical calculation method. Optimal tube row number for different air mass flow rates, inlet air temperatures and sensible cooling loads were investigated. It was found that the optimal tube row number of a DX cooling coil was in the range of 5 - 9 under normal operating conditions. The optimal tube row number was less when the mass flow rate and inlet air temperature were increased. The tube row number increased when the sensible cooling load was increased. The exergy loss when using a non-optimal and optimal tube row numbers was compared to show the advantage of using the optimal tube row number. The decrease of exery loss ranged from around 24% to 70%. Therefore the new analytical method developed in this paper offers a good practice guide for the design of DX cooling coils for energy conservation.

Optimal Tube Row Number, Entropy Generation Minimization, Direct Expansion (DX) Cooling Coil, Building Energy Efficiency

Xia, L. , Yang, T. , Chan, Y. , Tang, L. and Chen, Y. (2015) Optimisation of Direct Expansion (DX) Cooling Coils Aiming to Building Energy Efficiency. Journal of Building Construction and Planning Research, 3, 47-59. doi: 10.4236/jbcpr.2015.32006.