Dilmieva E., Koledov V., Kamantsev A., Shavrov V., Mashirov A., Tereshina I., Nizhankovskii V. Mo.L-P37 - Direct measurements of the crucial characteristics of MCE refrigeration in high magnetic fields in a Gd sample. In: 20th International Conference on Magnetism, 5 - 10 July 2015, Barcelona (Spain) , Journal of Magnetism and Magnetic Materials Volume 400 , С. 1-384.
|
Текст
20th INTERNATIONAL CONFERENCE ON MAGNETISM-M-L-Mo.L-P37.pdf Загрузить (6kB) | Предварительный просмотр |
Аннотация
The coefficient of performance (COP) of cooling process is the relation of heat transferred from a cold body to a hot body of the refrigerator to the mechanical work spent for one thermodynamic cycle. For the purpose of experimental study of the process of magnetic cooling by Gd working body and direct estimation the COP the new technique was developed. It allows to determine at the same time the magnetocaloric effect (MCE) and the magnetization (M) of materials versus magnetic field (H) in quasiadiabatic mode. The full cycle of magnetic cooling was tested on Gd sample in the field of the Bitter magnet up to 12 T. The temperature growth is equal to deltaTon = 13,5 K at turning on magnetic field 12 T. The temperature drop is equal to deltaToff = -19 K at turning off the magnetic field. The resulting temperature change of the sample under cycle of magnetic field turning on/off is equal to deltaTtotal = - 5,5 K. DeltaTtotal is a consequence of the process of magnetic cooling. The in situmeasurement shows that M(H) dependence of the Gd sample during the process has hysteretic character. The calculation of integral of HdM on a closed loop allows one to determine the work of magnetic field during cooling cycle and to calculate the COP of magnetic cooling process. By calculating COP it is found that at initial sample temperature T0 = 298 K and the magnetic field change 12 T, COP = 15. By reducing the magnetic field to H = 2 T, COP increases COP = 92. The fundamental restrictions on COP are imposed by Carnot's theorem. COPCarnot (T0=298, H=2T)= 600, COPCarnot (T0=298, H=12T)= 60. The reasons for which the COP found by experimental estimation is significantly lower than COPCarnot are discussed.
| Тип объекта: | Доклад на конференции или семинаре (Постер) |
|---|---|
| Авторы на русском. ОБЯЗАТЕЛЬНО ДЛЯ АНГЛОЯЗЫЧНЫХ ПУБЛИКАЦИЙ!: | Е. Дильмиева, В. Коледов, В. Каманцев, В. Шавров, А. Маширов, И. Терешина, В. Нижанковский |
| Подразделения (можно выбрать несколько, удерживая Ctrl): | 192 лаб. магнитных явлений в микроэлектронике |
| URI: | http://cplire.ru:8080/id/eprint/2250 |
 |
Изменить объект |
