Abstract: An apparatus and process for dehumidification of a gas stream are provided. The apparatus includes a single semi-permeable osmotic membrane, at least one gas stream compartment, and at least one osmotic fluid compartment. The membrane includes a plurality of hydrophobic surfaced pores, at least some of which hydrophobic surfaced pores are water vapor condensing pores. The water vapor condensing pores are sized such that the hydrophobic surfaces of those pores allow water vapor to enter those pores and repulse the water vapor within those pores away from the hydrophobic surfaces causing the water vapor to condense. The hydrophobic surfaced pores provide a liquid travel path across the thickness of the membrane. The membrane restricts transport of an osmotic fluid across the thickness of the membrane. A refrigeration system utilizing a dehumidification unit and a heat pump system utilizing a dehumidification unit are also disclosed.