Arsene Noume

Carmen Vasile

Amadou Coulibaly

1

Development of an efficient air-conditioning and heating

system based on Magneto-Caloric heat pump

New system architecture to fulfill the thermal comfort

and energy requirements of a FEV

Heating power: 5 kW

Cooling power: 3 kW

Temperature span:-7°C,+50°C

COP ≥ 3

2

Based on Magneto-Caloric Effect (MCE)

MCE: temperature changing of a magneto-caloric material

exposed to a changing magnetic field

Active Magnetic Regenerator (AMR)

3

Active Magnetic Regenerator cycle(AMR cycle)

(1)

Adiabatic magnetization

(2)

Isofield cooling

(Maximal magnetic field)

(3)

Adiabatic demagnetization

(4)

Isofield heating

(Minimal magnetic field)

4

Model of fluid flow and heat transfer in Minichannel

∇ ∙ 𝑢 = 0

𝜌𝑓 𝑢 ∙ ∇ 𝑢 = −∇𝑝+ 𝜇𝑓∇2𝑢

𝜌𝑓𝐶𝑝 ,𝑓 𝑢 ∙ ∇𝑇𝑓 = 𝑘𝑓∇2𝑇𝑓

𝑘𝑠∇2𝑇𝑠 + 𝑄0 = 0

ℎ =𝑞𝑤𝑎𝑙𝑙

𝑇𝑤𝑎𝑙𝑙 − 𝑇𝑓

Mass conservation equation

Momentum equation

Energy equation for fluid domain

Energy equation for solid domain

Equation for heat transfer coefficient

5

Physical model of AMR cycle

𝜌𝑓𝐶𝑝 ,𝑓 𝜕𝑇𝑓

𝜕𝑡+ 𝑢 ∙ ∇ 𝑇𝑓 = ∇ ∙ 𝑘𝑓∇𝑇𝑓 − 𝑄 𝑇𝑇

𝜌𝑠𝐶𝑝 ,𝑠𝜕𝑇𝑠𝜕𝑡

= ∇ ∙ 𝑘𝑠∇𝑇𝑠 + 𝑄 𝑀𝐴𝐺 + 𝑄 𝑇𝑇

𝑄 𝑀𝐶𝐸 = 𝜌𝑠𝐶𝑃,𝑠 𝜕𝑇𝑎𝑑𝜕𝐻

𝑑𝐻

𝑑𝑡+𝜕𝑇𝑎𝑑𝜕𝑇𝑠

𝑑𝑇𝑠𝑑𝑡

𝑄 𝑇𝑇 = ℎ𝛽 𝑇𝑠 − 𝑇𝑓 𝐼𝑛𝑡 :𝑓/𝑠

Energy equation for fluid

Energy equation for solid

Equation of MCE source term

Equation of heat transfer between

fluid and solid as source term

6

Interpolation of Cp and ∆Tad of Gadolinium

Variation of ∆Tad with temperature, for

0 ≤ µ0H ≤ 2 T

Variation of Cp with temperature, for

0 ≤ µ0H ≤ 2 T

0 0

0

, ,,

Gd Gd

MCE Gd Gd

Tad T H t dt Tad T H tQ Cp T H t

dt

7

x [mm]

Heat transfer coefficient

8000

10000

12000

14000

16000

18000

20000

0 0.005 0.01 0.015 0.02

Co

eff

cie

nt

d'é

chan

ge c

on

vect

if [

Wm

-2K

-1]

Longueur du canal [m]

h en fonction de la longuer de canal: comparaison des modèles numériques et des modèles empiriques

Comsol

Matlab

Shah et London

Churchill et Usagi

h [

W.m

-2K

-1]

8

Temperature field

solid

fluid

Hot end and cold end temperatures of the cycle

Contributions

A different and acurate approach to

calculate de QMCE

An accurate determination of heat transfer

coefficient

9

10

Implementation of QMCE

Requirement of high quantity of memory

Analyse the surface rugosity influence on the fluid flow and

heat transfer in microchannels.

Analyse the influence of the dimensions of the system (plate

thickness, channel height) on the heat transfer quantities.

THANKYOU!

11

12

0

50

100

150

200

250

300

350

0 200 400 600

Cp

[J/(

kg K

)]

T [K]

µ0H = 0 [T]

W-D-S (TD = 169 K)

Expérimental

W-D-S (TD = 220 K)

0

50

100

150

200

250

300

0 200 400 600

Cp

[J/(

kg K

)]

T [K]

μ0H = 1 [T]

W-D-S (TD = 169 K)

Experimental

W-D-S (TD = 220 K)