Heat transfer analysis and experimental verification of cast heat exchanger

Abstract

From the viewpoints of environmental conservation and energy efficiency, seawater-source heat pump system (SWHP) to provide district cooling and heating is applied in coastal areas. Based on the system, a heat transfer model was established for cast heat exchanger (CHE) adopted by SWHP systems. The CHE consists of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of SWHP system. An experimental study was carried out to test the validity of the model. A program was developed in VB language and the effects of inlet temperature, flow rate of the secondary refrigerant and length of CHE on the results were investigated. The results of the numerical simulation are in consistence with the experiments in both winter and summer conditions. As a result, application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.

Keywords

seawater-source heat pump / cast heat exchanger / mathematical model / experimental verification / numerical simulation

References

[1] SongY., YasunoriA.. Effects of utilizing seawater as a cooling source system in a commercial complex [J]. Energy and Buildings, 2006, 39: 1080-1087

[2] WuR.-h., ZhangC.-hu.. Energy-saving and environ-mental evaluation of surface-water source heat-pump system [J]. Journal of Harbin Institute of Technology, 2008, 40: 226-229

[3] ChenX., ZhangG.-q., PengJ.-guo.. The performance of an open-loop lake water heat pump system in south China [J]. Applied Thermal Engineering, 2006, 26: 2255-2261

[4] YangH., CuiP., FangZ.. Vertical-borehole ground-coupled heat pumps: A review of models and systems [J]. Applied Energy, 2009, 87: 16-27

[5] Värtan Ropsten—the largest seawater heat pump facility worldwide, with 6 Unitop® 50FY and 180MW total capacity [EB/OL]. [2008]. http://www.friotherm.com/downloads/vaertan_e008_uk.pdf.

[6] SatoruO.. A heat pump system with a latent heat storage utilizing seawater installed in an aquarium [J]. Energy and Buildings, 2005, 38: 121-128

[7] YuY.-s., MaZ.-l., LiX.-ting.. A new integrated system with cooling storage in soil and ground-coupled heat pump ground source heat pump description and preliminary results of the eco house system [J]. Applied Thermal Engineering, 2007, 28: 1450-1462

[8] LiZ., LinD., ShuH.. District cooling and heating with seawater as heat source and sink in Dalian, China [J]. Renewable Energy, 2007, 32: 2603-2616

[9] AITTOMÄKI A. Lakes as a heat source in cold climate [C]// Proceedings of 21st IIR International Congress of Refrigeration. Washington, 2003: 88–92.

[10] BüyükalacaO., EkinciF., YilmazT.. Experimental investigation of Seyhan River and dam lake as heat source-sink for a heat pump [J]. Energy, 2003, 28: 157-169

[11] TimP., JoyceW.. Lake-source cooling [J]. ASHRAE Journal, 2002, 44: 37-39

[12] KavanaughS., RaffertyK.Ground-source heat pump: Design of geothermal systems for commercial and institutional buildings [M], 1997AtlantaASHRAE Inc145-197

[13] ParsonsR.ASHRAE handbook-heating, ventilating, and air-conditioning systems and applications [M], 1987AtlantaASHRAE Inc249-288

[14] ParsonsR.ASHRAE handbook-systems [M], 1980AtlantaASHRAE Inc

[15] TaoW.-shuan.Numerical heat transfer [M], 20012nd EditionXi’anXi’an Jiaotong University Press1-47