Advanced Distribution and Decentralized Supply : A Network Approach for Minimum Pressure Losses And Maximum Comfort

The paper presents a new concept for a lowpressure drop supply system suited for theventilation of office spaces. Lower pressurelosses for the air distribution allow a downsizingof the fans cutting down the investment costsfor the equipment and the energy consumptionduring operation. Great potential savings inhigh-valued energy (exergy) are possible inlarge buildings where this concept could reducepressure drops by a factor up to ten. This supplysystem consists of decentralized air handlingunits installed near the facade. They feed aninterlaced duct network that is integrated in thefloor construction. The air is supplied to theroom at very low momentum through openingsin the floor. Following the low exergy principlethe heat exchangers of the air-handling unitsstrictly operate at supply temperatures close tothe room temperature, and hence would allow avery efficient operation of a heat pump with ahigh coefficient of performance. The proposedduct network design eliminates the problemoften found in decentralized systems ofinsufficient air supply to the core of thebuilding. It provides a regular distribution of theair over the entire floor space even in large openplan offices and under non-homogeneouspressure conditions from the wind on the faqadeor from a locally demand-controlled exhaustsystem as described by (Baldini andLeibundgut, 2005). As a proof of concept asteady state analysis of the air distribution hasbeen performed for different networktopologies. The simulations showed that aneffective distribution of the air is possible evenfor non-homogeneous pressure boundaryconditions when the network's topology is closeto the one of a mesh. The distribution system ismost robust to changing boundary conditions ifthe topology of the network is such that thevelocities within the pipes are small enough tolead to nearly homogeneous static pressures.