R ate of heat transfer in polypropylene tubes in solar water heaters

A heat transfer rate was determined for polypropylene tubes in solar water heaters for the Reynolds number range 800–5600. Experiments were conducted in ambient temperatures of 34 to 37 8C. Data were correlated in the form of Nusselt 0.75 1 / 3 numbers as: Nu50.0015 Re Pr with correlation coefficient of 0.95. Such data can be used to predict heat transfer rates in a polypropylene solar heater in Tehran where the experiments were performed. An application of the results is shown in an example.  2003 Elsevier Ltd. All rights reserved.