Experimental Investigation of the Air Exchange Effectiveness of Push-Pull Ventilation Devices

Energies

Constanze Bongs¹  Sven Auerswald¹  Hans-Martin Henning¹  Thibault Pflug¹  Carina Hörberg¹  Jens Pfafferott² 

[1] Fraunhofer Institute for Solar Energy Systems ISE, 79110 Freiburg, Germany;Offenburg University of Applied Sciences, Faculty of Mechanical and Process Engineering, Institute of Energy Systems Technology (INES), 77652 Offenburg, Germany;

关键词: decentralised ventilation;    ventilation effectiveness;    air exchange efficiency;    push-pull;   

DOI  :  10.3390/en13215817

来源: DOAJ

【 摘 要 】

The increasing installation numbers of ventilation units in residential buildings are driven by legal objectives to improve their energy efficiency. The dimensioning of a ventilation system for nearly zero energy buildings is usually based on the air flow rate desired by the clients or requested by technical regulations. However, this does not necessarily lead to a system actually able to renew the air volume of the living space effectively. In recent years decentralised systems with an alternating operation mode and fairly good energy efficiencies entered the market and following question was raised: “Does this operation mode allow an efficient air renewal?” This question can be answered experimentally by performing a tracer gas analysis. In the presented study, a total of 15 preliminary tests are carried out in a climatic chamber representing a single room equipped with two push-pull devices. The tests include summer, winter and isothermal supply air conditions since this parameter variation is missing till now for push-pull devices. Further investigations are dedicated to the effect of thermal convection due to human heat dissipation on the room air flow. In dependence on these boundary conditions, the determined air exchange efficiency varies, lagging behind the expected range 0.5 < ε^a< 1 in almost all cases, indicating insufficient air exchange including short-circuiting. Local air exchange values suggest inhomogeneous air renewal depending on the distance to the indoor apertures as well as the temperature gradients between in- and outdoor. The tested measurement set-up is applicable for field measurements.

【 授权许可】

Unknown