Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Using electrovalves as a flow distribution system for an active magnetic regenerator
Submission Author:
Sergio Luiz Dutra , SC
Co-Authors:
Alan Nakashima, Gislaine Hoffmann, Jaime Lozano, Jader Riso Barbosa Jr., Sergio Luiz Dutra
Presenter: Sergio Luiz Dutra
doi://10.26678/ABCM.COBEM2017.COB17-1587
Abstract
State-of-the-art magnetic refrigerators for room-temperature applications employ magnetic and hydraulic circuits to perform the thermo-magnetic Brayton cycle on an active magnetic regenerator (AMR). The cooling capacity and temperature span developed by AMRs are largely dependent on the hydraulic circuit parameters such as, mass flow rate, blow time fraction and magnetic field-fluid flow synchronization. Moreover, the AMR efficiency is also impacted by the pumping and the control power consumption. Therefore, the selection of hydraulic components, i.e. pump and valves, plays a vital role in the overall system performance. Most of the AMR devices developed so far employ mechanical concepts in either the pump and the flow distribution system (valve control), which may be a face-to-face sealing (known as rotary valves) or cam-actuated valves. However, recent studies have shown that friction losses, unbalanced flow conditions and operational parameters constraints are major issues of such alternatives, which require further development. Electronic control of valves might be a suitable solution for such concerns. They might greatly increase flexibility of synchronization parameters and enable comprehensive optimization of flow and control related variables. In this sense, this paper aims to evaluate a electric solenoid valve design for AMRs applications. A set of four valves was installed in an AMR apparatus, and their control was synchronized with the magnetic profile by magnetic field measurements of a hall effect sensor. Thermodynamic performance was assessed in terms of COP for a wide range of hydraulic circuit parameters and comparison against literature results determined their suitability for the present apparatus. Furthermore, electronic control of blow time fraction enabled real-time correction of blow mass imbalances.
Keywords
magnetic refrigeration, active magnetic regenerator, electronic solenoid valves
