Abstract: A method of conditioning a process stream of air in an air conditioning system wherein the process stream of air is dehumidified and cooled to provide a conditioned stream of air, the method comprising providing an adsorption wheel having a multiplicity of passages through which the process air can flow for adsorbing moisture therefrom, the wheel capable of adsorption of moisture from the process air and of regeneration on a continuous basis as the wheel rotates. The method further comprises passing a first portion and a second portion of the process air to be conditioned through the wheel to remove moisture therefrom, the first portion of the process air passing through the wheel after the regeneration to remove beat from the wheel prior to the second portion passing through the adsorption wheel; then introducing the first portion of the process air to a heat exchanger to remove heat from the first portion.