Analysis of magnetic refrigeration systems with staged regenerators based on an idealized magnetic material entropy model: I

Technical Report · Thu May 01 00:00:00 EDT 1986

OSTI ID:5628668

Overton, Jr, W C

We have performed a computer analysis of magnetic refrigerators consisting of a single magnetic-material (MM) stage (with T/sub c/ = 70.5 K and resembling GdNi), a hot heat exchanger for rejecting heat to an LN/sub 2/ sink, a cold heat exchanger for removing heat from a cold cryogenic load and an external regenerator having an integral number n of isolated stages with5 less than or equal to n less than or equal to 10. We use the abbreviation REGMR for such a system. An idealized entropy-versus-temperature model is used to represent the magnetic material. The single MM stage REGMR model proves capable of producing refrigeration from 77 K down to less than 30 K. We estimate two such REGMRs in tandem could produce refrigeration to less than 15 K, depending on the cryogenic load. The numerical analysis is based on strict conservation of energy and we neglect the small hydrodynamic losses of the /sup 4/He exchange-gas system and heat-transfer irreversibilities. Performance is evaluated in terms of the lowest temperature achievable, the number of cycles required to reach ''cyclic equilibrium'', the effect of regenerator stage mass and number of stages, and the effect of cryogenic loads. A systematic comparison of the REGMR cycle with other thermodynamic cycles shows the former is unique. The coefficient of performance is evaluated and the REGMR efficiency is determined by comparison with the ideal gas Carnot-cycle refrigerator. 17 refs.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5628668
• Report Number(s): LA-10676-MS; ON: DE86013638
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MAGNETIC REFRIGERATORS
COOLING SYSTEMS
EFFICIENCY
PERFORMANCE
R CODES
CARNOT CYCLE
COMPUTERIZED SIMULATION
CRYOGENICS
HEAT EXCHANGERS
HEAT TRANSFER
MATHEMATICAL MODELS
SYSTEMS ANALYSIS
COMPUTER CODES
ENERGY SYSTEMS
ENERGY TRANSFER
REFRIGERATORS
SIMULATION
THERMODYNAMIC CYCLES
420201* - Engineering- Cryogenic Equipment & Devices