Development of switchless thin-plate type sorption compressor cell for 5 K sorption J-T refrigerator

Development of switchless thin-plate sorption compressor and miniaturized check valves for 5 K J- T cooler

“…The experimental apparatus of the sorption compressor consists of three parts as shown in figure 1; Sorption cells, pressure buffers and commercial check valves. Thin-plate type sorption compressor cells (cell #1 and cell #2) are fabricated according to the design in the previous work [6]. The cell #1 and the cell #2 are filled with activated charcoal (GAC1240W, Norit) of 22.8 g and 22.6 g, respectively.…”

“…A temperature gradient in the sorption cells can limit their capacity of adsorption and desorption rate [5]. Therefore, in the previous work of our research team, thin-plate sorption cells have been developed instead of cylindrical cells to minimize the temperature gradient of the activated charcoal in the cells [6]. The side length and the thickness of the thin-plate sorption cells are 100 mm and 4.6 mm, respectively.…”

Performance comparison of sorption compressors for methane using metal-organic frameworks and activated carbon as adsorbents

“…The volume changes of the adsorbent and adsorbed phase are small and their contribution to the internal energy can be neglected. Therefore, the changes in internal energy of the adsorbent and adsorbed phases can be calculated by, du sor = c v,sor (T, p)dT (8) du ads = x ads (T, p)c v,ads (T, p)dT (9) where c v,sor and c v,ads are the specific heat capacities at constant volume of the adsorbent and adsorbed phase, respectively. The mass of free gas is assumed to be constant in a small time step during the compression phase (A→B in Fig.…”

“…The dynamic analysis results indicate that heat transfer enhancement measures should be taken to improve the performance of sorption compressors, such as increasing the thermal conductivity of existing adsorbents by mixing with other materials with high thermal conductivity [46], developing new adsorbents with better overall properties (larger delivery amount, smaller specific heat capacity and higher thermal conductivity), optimizing the sorption cell structure (for instance, thin-plate type sorption cell [9]) among others.…”

“…However, due to the limited adsorption characteristics of these two adsorbents, research on sorption compressors had been stagnant for years. Presently, the physisorption compressors mainly use activated carbon as adsorbents [7], whereas helium-3 [8], helium-4 [9], hydrogen [10], neon [11], nitrogen [12], argon [13], oxygen [13], methane [14], krypton [15], xenon [16], ethylene [17], gas mixture of nitrogen and hydrocarbons [18] are used as working fluids. However, it is found that due to the low adsorption capacities of activated carbons at room temperature, they often need to be precooled below ambient temperature to obtain considerable adsorption capacities, which will increase the complexity of sorption compressors.…”