Abstract: Based on the requirements on the pressures of various components of the system and the mutual relationships between the design and flow type parameters, the minimum height of the solution elevation tube heated in full length in a small scale solar pumpless LiBr absorption chiller is calculated theoretically. An example for the calculation is given. The results of calculation indicate that the immersed height of the elevation tube in the thin solution and the design height of the absorber constitute the main part of the elevation tube height, and attributes to about 50% and 25%, respectively of the total length. With bullet type conditions of flow in the elevation tube, the height of elevation tube can be decreased by about 20% than is used in conventional design.