Influence of installation of displacement ventilation diffusers above occupied zone on the vertical temperature gradient in simulated office rooms

¹ Halton Oy, Haltonintie 1-3, 47400, Kausala, Finland
² Aalto University, Department of mechanical engineering, Sähkömiehentie 4, 00076 Espoo, Finland
³ South-Eastern Finland University of Applied Sciences, Patteristonkatu 3 D, 50100, Mikkeli, Finland
⁴ College of Urban Construction, Nanjing Tech University, China

^* Corresponding author: panu.mustakallio@halton.com

Abstract

Displacement ventilation diffusers are typically installed to the occupied zone, which can limit the utilization of the displacement ventilation. This paper presents the full-scale test results of two simulated office rooms with installation of displacement diffusers near wall, above the occupied zone. Vertical temperature gradients are compared to full-scale tests with installation of displacement diffusers to the occupied zone. The full-scale test setup consisted of two displacement diffusers and ceiling exhaust in wellinsulated room with 20.7 m2 floor area and room heights of 5.1 m and 3.3 m. The internal heat loads simulated situations with 10 occupants (simulated with heated cylinders), fluorescent lighting units, solar load on window surface (heated foils in one wall) without/with direct solar load on floor (heated foil on floor). The installation of displacement ventilation diffusers above occupied zone influenced on the vertical temperature gradient above the occupied zone only slightly. It reduced the vertical temperature gradient in the occupied zone. This confirms the operation of the displacement ventilation with this installation. This can be advantageous due to the smaller temperature stratification in the occupied zone, still the ventilation efficiency can be slightly lower comparing to the typical installation of the displacement diffusers.