Experimental investigation on the effect of thermophysical properties of a heat transfer fluid on pumping performance for a convective heat transfer system

Reza Abdu Rahman,Muhammad Nurtanto,Agri Suwandi

doi:10.18186/thermal.1025910

Abstract

limited study that specifically discusses the relation between thermophysical properties of a Heat Transfer Fluid (HTF) and pumping performance. This study aims to find the effect of the change in thermophysical properties of HTF on the pumping performance, particularly for the delivery rate, slip factor coefficient, and volumetric efficiency. In this study, five different HTFs are used to assess the effect of working temperature and pumping speed on the pumping performance. Delivery rate is evaluated by setting the pumping speed from 0 to 1300 RPM where the working fluid temperature is set at 40, 140, and 200 °C. It shows that the HTF with a lower viscosity has a better delivery rate. The slip coefficient for all working fluid is ranging between 0.11–0.31 at temperature 200 °C. It is found that a higher working temperature for the fluid increases the slip coefficient and delivery rate. The volumetric efficiency is directly affected by the slip ranging from 69 – 89% at 200 °C. The heat transfer rate ranges from 40 – 98 °C for all fluids, which is mainly affected by the volumetric efficiency of the pump and also pumping speed where a higher pumping speed decreases the heat transfer rate. It can be concluded that the change in thermophysical properties of the working fluid will change the pumping performance. Therefore, it is important to adjust the pumping operation according to the temperature and properties of the working fluid to achieve the highest heat transfer rate for a convective heat transfer system.

Highlights

The innovation and improvement in thermal engineering are intended to enhance the overall efficiency of the system
The relation between viscosity and delivery rate can be observed for HTF2, HTF3 and HTF4, where lower viscosity value leads to higher delivery rate
Delivery rate is directly related to the viscosity of the Heat Transfer Fluid (HTF)

Summary

Introduction

The innovation and improvement in thermal engineering are intended to enhance the overall efficiency of the system. A good example is an increase in the utilization of concentrated solar power (CSP) and thermal waste for food and crops drying across the globe [2,3]. These innovations are feasible to be carried out on a small scale, hoping that more renewable energy can be utilized and broader renewable energy distribution [4]. An indirect solar dryer uses Heat Transfer Fluid (HTF) to distribute the heat energy from the solar collector to the liquid-to-air heat exchanger [6]. Using HTF improves the dryer’s reliability, where thermal energy storage can be installed to extend the operation time at nighttime [7]. The method is proven more reliable since the drying process could be extended and increase production capacity [8]

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Conclusion