Sorption cooler

In this paper we consider SHP as a combination of a loop heat pipe (LHP) and ammonia/ (active carbon fiber -I- chemicals) solid sorption cooler. Such system extends the limits of two-phase thermal control and ensures successful mode of electronic components cooling even in very harsh environmental conditions (ambient temperature 40 °C, or more) and ensures a deep cooling of space sensors down to the triple point of the hydrogen. 

L.L.Vasiliev, A.A. Antukh, L.L. Vasiliev Jr. Electronic cooling system with a loop heat pipe and solid sorption cooler in Proceedings of the 11 th IHPC, Tokyo, September 12-16, 1999, Japan, Preprint Vol. 1, pp. 54-60. 

Fig. 8.40 (a) Schematic of 19K hydrogen sorption coolers as to be mounted on Planck Spacecraft, (b) Layout of a Planck sorption cry-ocooler with its key components. 

In an open sorption storage system air is transporting water vapor and heat in and out of the packed bed of solid adsorbents (see Figure 235) or a reactor where the air is in contact with a liquid desiccant. In desorption mode a hot air stream enters the packed bed or the reactor, desorbs the water from the adsorbent or the salt solution and exits the bed cooler and saturated. In adsorption mode the previously humidified, cool air enters the desorbed packed bed or the... 

The considered experimented set - up can be applied in two different ways. The first one is to use is as a semiconductor sensor cooler with low heat dissipation to cool the sensor down to the ambient temperature. It is interesting to be applied in cryogenic range of temperatures. The second option is related with the cooler for high energy dissipation devices (for example laser diode cooler). The first set of experiments was performed with sorption heat pipe and ammonia as a working fluid to demonstrate the basic possibility to decrease the temperature of the heat loaded wall to compare with the temperature of this wall in the phase of loop heat pipe cooling mode. 

Sorption heat pipe can be used as an efficient multi micro jet cooler of the laser diode with good thermal contact of the SPH porous wick and heat loaded wall, insensitive to some g acceleration and capable to dissipate high heat fluxes q > 200 W/cm for ammonia with low surface superheat. 

Water sorption experiments were done with a Cahn RG balance on the PrintPack EX429-325 films. Constant water pressure was maintained using an MKS 2 5 2A pressure controller. The water source was contained in a round bottom flask and was flashed across a valve into the balance assembly. A low flow rate of water was maintained so that the pressure control valve could operate. Pressure was measured with an MKS 510A readout. The sample was suspended in a water-jacketed chamber at 20°C which was 4-5 °C cooler than the ambient so that the higher water vapor density in the sample tube minimized convection. 

Bowman Jr, R.C., Ryba, E.L. and Freeman, B.D., Characterization of prototype sorption cryo coolers for periodic formation of liquid and solid hydrogen. Advances in Cryogenic Engineering, 1994, 39 p. 1499. 

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