The synergetic effect of an external magnetic field and the temperature gradient in the fluid constitutes a magnetocaloric pump. The miniature automatic energy transport device (AETD) is developed by using a temperature sensitive magnetic fluid as a coolant, in which the magnetic force resulting from the integrated effect of the external magnetic field and the fluid temperature variation drives the fluid in a loop. The flow and heat transport features of the AETD are experimentally examined in order to get insight into the mechanism and controlling approaches for such an automatic operation device. The micro-scale particle image velocimetry (mu PIV) technique is used to visualize the flow field of the magnetic fluid in the loop. Three types of AETD systems are established to study the effect of the loop structure and components on the AETD performance. By means of experimental data about the magnetic field, flow velocity and fluid temperature along the loop, the constitutive thermal, magnetic and fluid dynamic relationships of the AETD are discussed. (C) 2008 Elsevier Ltd. All rights reserved.