Experimental results for a novel rotary active magnetic regenerator

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Experimental results for a recently developed prototype magnetic refrigeration device at The Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators of commercial grade gadolinium (Gd) was employed. With operating frequencies up to 10 Hz and volumetric flow rates up to 600 L/h, the prototype has shown high performance and the results are consistent with predictions from numerical modelling. Magnetocaloric properties of the Gd spheres were obtained experimentally and implemented in a one-dimensional numerical AMR model that includes also the parasitic losses from the prototype. The temperature span for a thermal load of 200 W as a function of frequency was measured and modelled. Moreover, the temperature span dependence on the cooling capacity as a function of cycle frequency was determined. It was found that thermal losses increase as the frequency increases. Therefore, a detailed study of these parasitic losses was carried out experimentally and numerically.

Section: Methodsmentioning

confidence: 99%

Experimental and numerical results of a high frequency rotating active magnetic refrigerator

Lozano

Engelbrecht

Nielsen

et al. 2014

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“…Thus mapping out the parameter space will allow better knowledge of the optimal operating parameters for a desired output. More detailed studies of parameter variations are given in Engelbrecht et al (2012) and Lozano et al (2012a and2012b). An important tool for the study of AMR devices is numerical modelling as discussed in Nielsen et al (2011).…”

Section: Discussionmentioning

confidence: 99%

Development and experimental results from a 1 kW prototype AMR

Bahl

Engelbrecht

Eriksen

et al. 2014

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A novel rotary magnetic refrigeration device has been designed and constructed following the concepts recently outlined in Bahl et al. (2011). The magnet and flow system design allow for almost continuous usage of both the magnetic field and the magnetocaloric material in 24 cassettes, each containing an active magnetic regenerator (AMR) bed. As outlined in Pryds et al. (2009) a small scale AMR test device has been used for materials choice and optimising operation, with each component being thoroughly characterised and tested before implementation. The prototype design facilitates easy exchange of the 24 cassettes, allowing the testing of different material amounts and compositions. Operating with 2.8 kg of commercial grade Gd spheres a maximum no-span cooling power of 1010 W and a maximum zero load temperature span of 25.4 K have been achieved. For the purpose of actual operation, simultaneous high span and high performance is required. At a heat load of 200 W a high temperature span of 18.9 K has been obtained, dropping to a span of 13.8 K at the higher heat load value of 400 W.

“…A review of these machines was presented by Yu et al (2010) and more recent advances can be found in publications from Tura and Rowe (2011), Engelbrecht et al (2012), Tušek et al (2013) and Jacobs et al (2012). Research is currently focusing on improving the performance of such devices in order to make them competitive with conventional vapour-compression chillers.…”

Section: Introductionmentioning

confidence: 99%

“…One notable exception is the work by Jacobs et al (2012), who reported a layered regenerator which delivered 2049 W of cooling power at zero span and a peak performance of 1704 W over a span of 11.1 K with a COP of 2.24. Another example can be found in recent work from Engelbrecht et al (2012), who built a prototype which worked with gadolinium and achieved 1010 W of cooling power at zero span and a maximum span of 25 K with no load. These recent 5 results indicate that the performance is continuously improving.…”

Section: Introductionmentioning

confidence: 99%

Sizing of a reversible magnetic heat pump for the automotive industry

Torregrosa-Jaime

Corberán

Vasile

et al. 2014

This paper focuses on the design of an innovative air-conditioning system, namely a magnetocaloric air-conditioner for an electric minibus. An integrated design of the complete system is necessary, as the hot and cold side of the regenerator will work under dynamic conditions which depend on the instantaneous thermal load in the cabin.In order to assist the design of the system, a dynamic model has been developed for the cabin, the hydraulic loops and heat exchangers, and the magnetocaloric unit. This paper presents (i) a description of the dynamic models, (ii) an analysis of the operating conditions of the magnetocaloric unit and (iii) a discussion on the design of the magnetocaloric air-conditioner. The results show that 2 the electric minibus requests 1.60 kW of cooling power over a span of 37 K in cooling mode, and 3.39 kW of heating power over a span of 40K.