A heat exchanger assembly, comprising: a frame for supporting the heat exchanger assembly on a support surface; first and second heat exchanger panels supported by the frame, the first and second heat exchanger panels being configured for exchanging heat with air pulled into the heat exchanger assembly, each of the first and second heat exchanger panels having an upper end and a lower end and including a tubing arrangement for circulating fluid therein, the first and second heat exchanger panels being disposed in a V-configuration such that a distance between the upper ends of the first and second heat exchanger panels is greater than a distance between the lower ends of the first and second heat exchanger panels; a fan for pulling air into an enclosed space of the heat exchanger assembly via at least one of the first and second heat exchanger panels, the fan being supported by the frame, the fan having a fan rotation axis extending generally vertically relative to the support surface; a plurality of lateral enclosing panels supported by the frame; and at least one middle enclosing panel supported by the frame, the at least one middle enclosing panel extending generally perpendicular to the lateral enclosing panels and defining therewith at least in part the enclosed space of the heat exchanger assembly, the at least one middle enclosing panel being disposed between the first and second heat exchanger panels, characterised in that the at least one middle enclosing panel has generally U-shaped lower end including: a first wall portion; and a second wall portion opposite the first wall portion, the lower ends of the first and second heat exchanger panels abutting the first and second wall portions respectively such that the first and second wall portions (134, 136) are deflected relative to one another by forces exerted thereon by the lower ends of the first and second heat exchanger panels causing a first seal to form between the first wall portion and the first heat exchanger panel and a second seal to form between the second wall portion and the second heat exchanger panel. a frame for supporting the heat exchanger assembly on a support surface; first and second heat exchanger panels supported by the frame, the first and second heat exchanger panels being configured for exchanging heat with air pulled into the heat exchanger assembly, each of the first and second heat exchanger panels having an upper end and a lower end and including a tubing arrangement for circulating fluid therein, the first and second heat exchanger panels being disposed in a V-configuration such that a distance between the upper ends of the first and second heat exchanger panels is greater than a distance between the lower ends of the first and second heat exchanger panels; a fan for pulling air into an enclosed space of the heat exchanger assembly via at least one of the first and second heat exchanger panels, the fan being supported by the frame, the fan having a fan rotation axis extending generally vertically relative to the support surface; a plurality of lateral enclosing panels supported by the frame; and at least one middle enclosing panel supported by the frame, the at least one middle enclosing panel extending generally perpendicular to the lateral enclosing panels and defining therewith at least in part the enclosed space of the heat exchanger assembly, the at least one middle enclosing panel being disposed between the first and second heat exchanger panels, characterised in that the at least one middle enclosing panel has generally U-shaped lower end including: a first wall portion; and a second wall portion opposite the first wall portion, the lower ends of the first and second heat exchanger panels abutting the first and second wall portions respectively such that the first and second wall portions (134, 136) are deflected relative to one another by forces exerted thereon by the lower ends of the first and second heat exchanger panels causing a first seal to form between the first wall portion and the first heat exchanger panel and a second seal to form between the second wall portion and the second heat exchanger panel. a first wall portion; and a second wall portion opposite the first wall portion, the lower ends of the first and second heat exchanger panels abutting the first and second wall portions respectively such that the first and second wall portions (134, 136) are deflected relative to one another by forces exerted thereon by the lower ends of the first and second heat exchanger panels causing a first seal to form between the first wall portion and the first heat exchanger panel and a second seal to form between the second wall portion and the second heat exchanger panel.