Abstract: A method is provided of operating an adsorption refrigeration system. The system includes a primary adsorption pump which is arranged in communication with a primary chamber containing coolant, a secondary adsorption pump and a high fluid impedance conduit which places the secondary adsorption pump and primary chamber into communication. The method includes saturating the primary and secondary adsorption pumps with coolant while each pump is at its respective operational temperature. The pumps are then heated above their operational temperatures to desorb the coolant such that the coolant pressure in the primary chamber and the secondary adsorption pump substantially equalizes through the conduit while the primary chamber is cooled. The secondary adsorption pump is then cooled causing coolant gas to be adsorbed and, therefore, a reduction in temperature and pressure of the coolant in the primary chamber is effected.