Keith Shaughnessy designed a displacement ventilation system for Valeo Vision Systems to improve occupant comfort. Displacement ventilation introduces fresh air at floor level, allowing it to rise and remove heat and contaminants. Solidworks was used to model a study area and simulate airflow. CFD analysis showed air entering at 20°C and exiting at 28°C, demonstrating displacement ventilation. The PMV scale indicated occupants would be thermally satisfied. However, a more thorough CFD analysis of the entire production area is recommended.

1. The design of Displacement Ventilation
for Valeo Vision Systems
Student: Keith Shaughnessy Supervisors: Eddie Dunbar &
Gabriel Costello
B.Eng. (Honour) in Energy Engineering, GMIT School of Engineering
Dublin Road, Galway, Ireland
Introduction
Valeo Vision Systems is an electronics company in Tuam Co.
Galway. They are currently in the process of ramping up
production. In saying that a lot of heat gains are been produced
and causing occupants to become unsatisfied with the current
mode of ventilation. Displacement ventilation was the selected
mode of ventilation to counteract the problem. Displacement
ventilation works by introducing fresh air at floor level. It then
becomes heated and rises taking away any air contaminants and
leaving behind clean, fresh air for the occupants.
References
[1] http://ceae.colorado.edu/~brandem/aren3050/docs/ThermalComfort.pdf
[2] http://www.michiganair.com/newsletters/2011-1/section2.htm
Figure 1 : Mixing vs. Displacement Ventilation
Materials and Methods
•Researched design methods based on ASHRAE
findings.
•Pitot tube measurements were analyzed
•Developed a study area using Solid-works (figure 2)
•Assumed heat gains for
machines/humans/monitors/lights etc.
•Photo-shopped proposed design into the study area
(figure 3)
•Using the formula 𝑄 = 𝑚𝑐𝑝∆𝑇 an air flow rate was
determined
•Using the air flow rate the duct system was sized
•Diffuser selection software was used to determine best
size diffuser to use
Figure 2 : Study Area
Results
•Using CFD to model and simulate the design and flow
rates calculated from the pitot tube, the air enters at 20°C
and exits around 28°C (figure 4). There are two scales to
illustrate temperature and velocity, it clearly demonstrates
how displacement ventilation should work. Cool air enters
at low level supply and heats up and rises and exits through
high level extract.
•Using a Predicted Mean Vote Scale from ASHRAE, which
is a measure of an occupants comfort level. It is evident
that the occupants are thermally satisfied it. (figure 5)
Figure 4: ISO View of air flow
Conclusion
By doing the thermal comfort analysis in CFD the
simulations in figure 4 and 5 have showed the benefits of
implementing Displacement Ventilation and that it can
work in this type of environment and provide comfort for
the workers. Figure 6 is the PMV scale extracted from
ASHRAE and according to figure 5 the occupants are
predominantly neutral.
Recommendations
A more through analysis should be done on CFD, modelling the
entire production area and getting the correct heat gains from the
different machines etc.
Figure 4: PMV of Occupants
Figure 5: PMV of Occupants
Figure3: Study Area
3
2
1
0
-1
-2
-3
Figure 6: Predicted Mean Vote Scale