This paper presents the design of a solar-biomass hybrid system for air-conditioning. Three possible overall system configurations were first considered, based on which the most suitable configuration considered for the design. The principles of component selection of a flat plate solar collector with storage, biomass gasifier with boiler, and a LiBr-H2O absorption system has been described, and the design criteria for the proposed system elaborated. The design was to satisfy a cooling load of 4.5 kW, and solar to auxiliary heat ratio of at least 0.7. Simulation at various solar collector size and storage tank volume for the weather conditions at Bangkok indicate the most suitable design and specifications for the size/capacity of the solar collector, storage tank, set point temperature of the absorption generator and biomass-gasifier boiler. (C) 2013 Elsevier B.V. All rights reserved.