In this study, experimental trials were conducted on an innovative solar-driven, directly air-cooled, single effect, 4.5 kW-LiBr/H2O absorption chiller prototype. The aim was to air-condition a 40-m(2) room located in Madrid. The solar facility consisted of a vacuum flat-plate collector field, with a total aperture area of 42.2 m(2), a 25-kW external plate heat exchanger and a 1.5-m(3) storage tank. The paper reports the findings in detail, including solar cooling facility temperatures and thermal power, solar fraction, COP and SCOP values on a day when the outdoor dry bulb temperature ranged from 30 to 37.7 degrees C. The daily results for the entire trial are also given. No solution crystallization problems arose inside the prototype even when the generator feed temperature reached 109 degrees C. The lowest chilled water temperature attained was 14.3 degrees C, and the mean COPth and SCOP values were 0.53 and 0.06, respectively. This study forms part of a larger project whose aim is to use solar power as a source of heat in air-cooled absorption chillers in residential buildings. (C) 2011 Elsevier B.V. All rights reserved.