The main working media in adsorption refrigerators are the adsorbent (carbon) and the coolant. In connection with this, it is necessary to know the physical characteristics of adsorbents to determine the operating parameters of such refrigerators. A method of determining the physical characteristics of adsorbents was presented in [1 ].An adsorbent is fully characterized by the following physical parameters: the true and apparent unit masses, porosity, the total volume of the pores [1]. These parameters must be known in order to correctly choose an adsorbent and to calculate the amount of adsorbent needed to absorb a given substance. Here, we propose a method of determining the apparent unit mass of an adsorbent.By the true unit mass d of an adsorbent, we mean the mass of a unit of volume of the dense (nonporous) material comprising the adsorbent. The value of d is determined pycnometrically. A pycnometer with a capacity of 25-100 ml is weighed on an analytical balance (m t is the mass of the pycnometer when it is empty). Then the pycnometer is filled to the mark with distilled water (it is preferable to use distilled water that has just cooled after being thoroughly boiled) and weighed (m 2 is the mass of the pycnometer with the water). The water is then poured out and the pycnometer is dried and again weighed: its mass should be equal to m 1.The adsorbent (1-5 g) is poured into the pycnometer and weighed (m 3 is the mass of the pycnometer with the adsorbent). The pycnometer is filled with water to roughly half its volume and the contents of the pycnometer are boiled for 1 h to remove air from the pores. The boiled water is allowed to cool, and then distilled water is poured in to a point slightly above the mark. The pycnometer is placed in a thermostat with a temperature of 20~ and kept there for 30--40 rain. Without removing the pycnometer from the thermostat, the water level is brought up to the mark and the weight is determined (m4).The volume v I of the weighed quantity of adsorbent is equal to the volume of the displaced water:where (m 2 -m 1) is the mass of the water in the pycnometer, g (kg); (m 4 -m 3) is the mass of the water in the pycnometer without the adsorbent, g (kg); p is the density of the water at the test temperature, ffcm 3 (k~m3).The true unit mass is calculated from the formula d = (m 3-ml)/V 1, where (m 3 -ml) is the mass of the adsorbent in the pycnometer.The apparent unit mass of the adsorbent ~ is the mass of a unit of volume of the porous material comprising the adsorbent.To determine 5, a weighed quantity of adsorbent having the mass m 5 is placed on a wire grid and lowered into melted paraffin. To remove excess paraffin from the outside surface, the grid is extracted from the paraffin and placed in a funnel for hot filtration. After the adsorbent and paraffin have cooled, they are placed in the pycnometer and the pycnometer is weighed (the mass m6). The remaining paraffin completely obstructs the pores of the adsorbent. It is assumed that the volume of the grains of the adsorbent rem...

621.575:661.183.2.The operation of adsorption-type gel refrigeration units makes use of the physical process of adsorption -the condensation of molecules of a vaporous coolant on the solid surface of an adsorbent. During cooling, the vapors of the coolant condense in the pores of the adsorbent. This process is reversible, and when heat energy is supplied, the coolant is desorbed from the surface of the adsorbent.Activated charcoal is used as the adsorbent in gel refrigeration units. Thus, study of the adsorption capacity of activated charcoal is important for improving the efficiency of such units.