TY - JOUR

T1 - NH2-MIL-125 as promising adsorbent for adsorptive cooling

T2 - Water adsorption dynamics

AU - Solovyeva, Marina V.

AU - Aristov, Yuri I.

AU - Gordeeva, Larisa G.

PY - 2017/4

Y1 - 2017/4

N2 - Adsorption heat transformation (AHT) has attracted an increasing research interest as energy saving and environmentally benign alternative to vapor compression systems. Novel adsorbent NH2-MIL-125 could be promising for AHT owing to its high water adsorption capacity and good hydrothermal stability, although its dynamic properties have not been tested yet. In this paper the results of dynamic study of water adsorption on loose grains of NH2-MIL-125 are presented. The adsorption dynamics is studied by a Large Temperature Jump method under typical operating conditions of isobaric stages of adsorptive cooling cycle. The effects of the adsorption/ desorption temperature, adsorbent grain size and number of the grain layers are explored. The water adsorption on the grains of 0.2–1.8 mm size are shown to occur under at “grain size insensitive” mode as the adsorption rate is determined by the ratio S/m of the heat transfer area to the adsorbent mass regardless the grain size. Indeed, the ad/desorpion rate and the Specific Cooling Power (SCP) are proportional to the (S/m)-ratio. Quite high SCP-values of 0.4–2.8 kW/kg can be obtained in adsorption chillers having a large (S/m)-ratio of 1.6–6.9 m2/kg, which is of high practical interest.

AB - Adsorption heat transformation (AHT) has attracted an increasing research interest as energy saving and environmentally benign alternative to vapor compression systems. Novel adsorbent NH2-MIL-125 could be promising for AHT owing to its high water adsorption capacity and good hydrothermal stability, although its dynamic properties have not been tested yet. In this paper the results of dynamic study of water adsorption on loose grains of NH2-MIL-125 are presented. The adsorption dynamics is studied by a Large Temperature Jump method under typical operating conditions of isobaric stages of adsorptive cooling cycle. The effects of the adsorption/ desorption temperature, adsorbent grain size and number of the grain layers are explored. The water adsorption on the grains of 0.2–1.8 mm size are shown to occur under at “grain size insensitive” mode as the adsorption rate is determined by the ratio S/m of the heat transfer area to the adsorbent mass regardless the grain size. Indeed, the ad/desorpion rate and the Specific Cooling Power (SCP) are proportional to the (S/m)-ratio. Quite high SCP-values of 0.4–2.8 kW/kg can be obtained in adsorption chillers having a large (S/m)-ratio of 1.6–6.9 m2/kg, which is of high practical interest.

KW - Adsorption

KW - Adsorptive cooling

KW - Kinetics

KW - NH-MIL-125

KW - Water vapor

KW - TRANSFORMATION

KW - STORAGE

KW - MIL-125

KW - ACTIVE SALT

KW - LOOSE GRAINS CONFIGURATION

KW - COMPOSITE

KW - CHILLERS

KW - METAL-ORGANIC FRAMEWORKS

KW - DRIVEN HEAT-PUMPS

KW - OPTIMIZATION

KW - NH2-MIL-125

UR - http://www.scopus.com/inward/record.url?scp=85011887486&partnerID=8YFLogxK

U2 - 10.1016/j.applthermaleng.2017.01.080

DO - 10.1016/j.applthermaleng.2017.01.080

M3 - Article

AN - SCOPUS:85011887486

VL - 116

SP - 541

EP - 548

JO - Applied Thermal Engineering

JF - Applied Thermal Engineering

SN - 1359-4311

ER -