A novel fouling measurement system: Part I. design evaluation and description

Abstract

The enhanced tube is being used more often in water-chiller condensers because of their superior performance in heat transfer. Both the predicted and real-world performance of these heat exchangers is affected by the fouling build-up on the heat transfer surfaces. Thus, accurate quantification of fouling thermal resistance is required to address the correlation between the fouling resistance of heat transfer tubes and operation conditions. A newly developed Fouling Measurement System (FMS) supports research on the relationships between fouling development and operation condition by measuring fouling thermal resistance on the heat transfer surface. Part I of this two-part series describes the design and evaluation of FMS. An uncertainty analysis of fouling thermal resistance was conducted to identify measurement component contributions to the uncertainty of final results and guide component selection. In Part II, FMS commissioning was performed, and a primary fouling test and analysis on cooling water quality were conducted. The FMS consists of three subsystems: heat pump subsystem, cooling/chilled water subsystem and control and data acquisition (DAQ) subsystem. The FMS has three heat pumps individually installed with a shell-and-tube condenser and separately equipped with a cooling/chilled water supply loop. In the cooling/chilled water subsystem, these three heat pumps share the same cooling water pool and chilled water pool, which ensures that the cooling/chilled water supplied to each heat pump is uniform. A cooling water tower was installed outside the Air Quality Lab in University of Illinois at Urbana-Champaign to cool down the cooling water of the FMS, and to evaporate water and keep the cooling water at the required range. In the control and DAQ subsystem, the control of water temperature, water quality, water velocity, and refrigerant saturation temperature are described.