A fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.

A fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.

The integrated solar absorption heat pump system includes an absorption heat pump assembly (AHPA) having a generator, a condenser in fluid communication with the generator, an evaporator/absorber in fluid communication with the condenser and the generator, and a heat exchanger in communicating relation with the evaporator/absorber; a solar collector in fluid communication with the generator of the AHPA; a photovoltaic thermal collector in communicating relation with the evaporator/absorber of the AHPA; a plurality of pumps configured for pumping a fluid throughout the system to provide the desired heating or cooling; a power storage source, e.g., a solar battery, in communicating relation with the photovoltaic thermal collector; and a coil unit in communicating relation to the evaporator/absorber for receiving an air-stream. The absorption heat pump assembly can include an absorber and a solution heat exchanger.