Commonly, ventilation systems treat the entire volume of the room. Therefore, they are referred to as “total volume systems.” These systems control the physical environmental factors that affect human comfort, such as air temperature, air velocity, and relative humidity. However, total volume systems consume a significant amount of energy. Besides, they lack the individual control that complies with the personal preference of each occupant. Displacement ventilation (DV) is a total-volume system that delivers the outdoor air into the room from an inlet located near the floor and extracting it using an outlet located near the ceiling. This system creates a vertical stratification due to the buoyancy forces generated by the heat sources in the room.

Personalized ventilation (PV) is a system that provides fresh air to the occupant’s breathing zone. It allows individual control over air velocity, direction, and possibly temperature too. It is recommended to improve both thermal comfort and indoor air quality. Researchers have investigated the performance of PV under various setups using human subjects, thermal manikins, or Computational Fluid Dynamics (CFD). Results indicate that PV always improves the indoor environment, in both heating and cooling seasons.

PV systems are typically connected to a duct that supplies fresh tempered air from the outdoor, which significantly increases the ductwork of a project. Furthermore, it restricts the arrangement of furniture in the room and affects its aesthetics. Therefore, a ductless personalized system was suggested. Ductless Personalized Ventilation (DPV) is a means of bringing cool fresh air from the lower level of the room and delivering it directly to the occupant’s face. It is used in combination with Displacement Ventilation (DV) due to the vertical stratification created by this ventilation system. This research aims to compare the performance of both ducted and ductless personalized ventilation systems.

The study consists of two parts: empirical measurements and computer simulations. Empirical measurements are taking place in the climate chamber of the Department of Building Physics, Bauhaus-University Weimar using various state-of-the-art technologies, such as a thermal manikin, tracer gas system, Negative Temperature Coefficient (NTC) thermistors, and hot wire anemometers. Computer simulations are used to investigate various design iterations that cannot be investigated using empirical measurements, such as changing the geometry of the climate chamber or studying different boundary conditions.

Funded by:

The German Academic Exchange Service (DAAD)

Project duration:

10/2015 - 09/2019

Contact partner:

Dr.-Ing. Hayder Alsaad, Assoc. AIA

Tel. +49 3643 584744