NOVELTY - The apparatus has a light receiving module enclosure (10) comprising an internal cavity that includes a set of photovoltaic cells, and a breathable moisture barrier to allow air exchange between the cavity and ambient air outside the enclosure. A desiccant chamber includes a desiccant that is pneumatically coupled between the barrier and the cavity. The chamber is thermally decoupled from the enclosure such that temperature of the cavity lags temperature of the chamber. A heat collector is thermally coupled to the chamber.    USE - Concentrator-type photovoltaic (CPV) apparatus.    ADVANTAGE - The apparatus is designed such that reduction of thermal mass and maximization of surface area of the heat collector can insure that desiccant beads are made to chill faster than the air inside the modules, thus creating positive time delay to allow restoration of absorption capacity of the desiccant so as to dry the ambient air entering the apparatus when photovoltaic modules are made to chill down at sunset, and comprises a regenerative drying tube acting as a buffer to store water molecules and as a moisture pump, thus actively drying the air inside the modules by using combination of two functions of the heat collector and the drying tube in a cost-effective, reliable and autonomous manner without requiring field maintenance while utilizing heat generated from electronics to resolve control of condensation and condensation inside the modules. The modules can be equipped with a waterproof breather to prevent liquid water from leaking inside the modules and size or diameter of a breathable interface between the air inside the module enclosure and the ambient air is reduced, thus reducing ingress rate of moisture when the ambient air relative humidity is high, and hence maintaining dew point of the air inside the module enclosure below the temperature of the air inside the module enclosure for a greater duration of time during different temperature cycles experienced by the modules.    DETAILED DESCRIPTION - The heat collector is a parabolic or half-cylinder shaped metal reflector, and the breathable moisture barrier comprises an expanded PTFE membrane. An INDEPENDENT CLAIM is also included for a method for reducing moisture in a concentrator-type photovoltaic module.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of an experimental setup for evaluating performance of a regenerative desiccant drying tube that is pneumatically coupled to a photovoltaic module enclosure.    Light receiving module enclosure (10)    Drying tube heater (12)    Temperature sensors (13, 13A-13C)    Humidity sensors (14A, 14B)    Air flow sensor (15)