In this collaborative webinar: https://www.youtube.com/watch?v=txqiwrbYGrs SAV Systems and SimScale will explain how to evaluate the airflow and temperature distribution in a classroom by running a convective heat transfer simulation within SimScale. More resources on HVAC and Ventilation from SimScale: What is CFD | Computational Fluid Dynamics?: https://bit.ly/3s8vOVu CFD Modeling, Analysis, and Online Simulation For Beginners: https://bit.ly/3eS5Fq1 HVAC Duct Design Software: Online CFD with SimScale: https://bit.ly/2NvhPd0 Optimize HVAC Designs: https://bit.ly/2ONixmE

1. CLASSROOM VENTILATION OPTIMIZATION
WITH SAV SYSTEMS
JON WILDE, JESUS VILAR and JONATHON HUNTER HILL

2. JON WILDE
VP Customer Success
15+ years of experience in CFD, application engineering
and team management.
Before joining SimScale, he worked with many other
CFD solutions and managed a team of technical support
engineers.

3. JESÚS
Application Engineer
Aerospace Engineer specialized in CFD with a
background in aerospace and automotive
aerodynamics.
First experience in industry with SimScale.
Post-sales role focused on support and customer
success.

4. JONATHON HUNTER HILL
Sector Manager for Education
Studies Mechanical Engineering and has worked at SAV
Systems since finishing his education.
Looks after the AirMaster Smart Ventilation Unit (SVU)
product range and the supply into UK schools, which
has recently opened up to mechanical ventilation
systems.

5. INTRODUCTION TO SAV SYSTEMS

6. INTRODUCTION TO SAV SYSTEMS
SAV SYSTEMS
● UK company of 20+ years who partner
with Danish technology experts to
bring their decades of knowledge to
the UK market
● ~£35m annual turnover
● 4,000+ projects supplied
● 90 employees

7. INTRODUCTION TO SAV SYSTEMS
SAV SYSTEMS
● Market leader in supply of Danfoss
Heat Interface Units to the UK
● EC Power Micro-CHP
● Kamstrup Energy Meters
● AirMaster MVHR / SVUs
● Heat Network Solutions
● FloCon Commissioning Modules

8. CLASSROOM VENTILATION

9. CLASSROOM VENTILATION
WHY IS IT IMPORTANT?
● Inadequate ventilation can lead to
uncomfortable build-ups of heat and
carbon dioxide from occupants and
equipment.
● Efficient ventilation produces good
indoor air quality, which in turn
improves concentration, alertness and
sense of wellbeing.
(Source: https://scarsdale10583.com/schools/6545-november-20-school-board-meeting-air-conditioning-is-out-for-now-safety-measure-for-greenacres-construction-are-in)

10. BB101 IN THE UK
Guidelines on ventilation, thermal comfort
and indoor air quality in schools
● Daily average CO2 levels < 1,000 ppm
● Winter: ΔT between room temp and
supply temp between 1.5 and 4°C
● Summer: ΔT not to exceed 1k for more
than 40 hours per year
● F7 filtration the minimum
recommended standard in schools
● 35 dB(A) maximum sound pressure for
standard classrooms
(Source: Building Bulletin 101. Guidelines on ventilation, thermal comfort and indoor air quality in schools)

11. BB101 IN THE UK

12. SAV Systems’ AirMasters aim to provide
consistently good indoor air quality over
the long term.
1. Heat Exchanger Design.
2. Good quality air filtration.
3. Effective noise control.
AIR MASTER WALL MOUNTED UNIT

13. ● Temperature in the room is controlled
by the extraction unit to ensure a
good thermal comfort.
● Thermal comfort is evaluated by
ASHRAE standards (PMV, PPD...)
taking into account the temperature
and velocity of the flow.
THERMAL COMFORT

14. ● Cold draughts can be an issue in
classrooms where the ventilation
system has not been designed to
modern standards.
● The greater the indoors-outdoors
temperature difference, the greater
the draught.
● Coanda effect enhances air mixing
and provides a better temperature
distribution.
DRAUGHTS AND COANDA EFFECT

15. CONVECTIVE HEAT TRANSFER
● Convective Heat Transfer (CHT) is
used when temperature changes in
the fluid lead to density variations
and movement of the fluid due to
gravity.
● This solver can be used for natural
convection but also for forced
convection, when air movement is
induced by external forces, such as
wind, pumps or fans.(Source: https://media.giphy.com/media/9PwWfo79Bnlpq08UnM/giphy.gif)

16. SETUP

17. CAD IMPORT
Upload your CAD model
or import it from other cloud
services into SimScale.
SIMULATION SETUP
All steps to define and run
a simulation are done
within SimScale.
DESIGN DECISION
Use the simulation insights
to make better and faster
design decisions.

18. OUR CASE: VENTILATION IN A CLASSROOM
Objectives
● Model mechanical ventilation and
heat sources.
● Detect ventilation patterns, hot
spots and draughts.
● Evaluate thermal comfort with
ASHRAE standards.
● Become familiar with Convective
Heat Transfer analysis in SimScale
and how the platform can help
designing ventilation systems.
(Source: http://blog.monodraught.com/top-3-benefits-of-installing-high-quality-school-ventilation)

19. CAD MODEL
A simplified classroom CAD model is
created with some interesting
elements for the simulation:
● MVHR unit
● Radiator
● People
Additional elements such us windows
and lights could be taken into account.

20. CAD Import
Closed inner region operation to extract
the internal fluid volume.
Analysis type (Convective Heat Transfer)
● Steady state.
● K-omega SST turbulence model.
● Incompressible flow.
Mesh Generation
Automatic + Refinement
● Radiator, inlet/outlet and inflation layer.
● 8.8 million cells.
GENERAL SETUP

21. BOUNDARY CONDITIONS
Extraction unit
● Fan curve outlet
● Atmospheric pressure inlet
Radiator
● Heat flux: 400 W/m2
People
● Heat flux: 70 W/m2

23. TEMPERATURE - VERTICAL SLICES
THERMAL COMFORT
● Temperature range from
290K to 300K (17o
C - 27o
C).
● Cooler regions near the walls,
the floor and the air stream.
● Warmer regions at the
radiator and above the
people.

24. PMV - VERTICAL SLICES
THERMAL COMFORT
● PMV range between -1 and 1.
● Ideal comfort range between
-0.5 and 0.5 (dark colors).
● Most of the room within the
desired range.
● The ventilation system
performs better closer to the
opposite wall.

25. TEMPERATURE - MID HEIGHT
THERMAL COMFORT
● Reference height for thermal
comfort with seating people
(ASHRAE).
● Uniform distribution all over
the room - around 22o
C.

26. PMV - MID HEIGHT
THERMAL COMFORT
● Confirmation of previous
results: Great thermal
comfort rate and distribution
along the room.

27. PMV - NON-COMFORTABLE RANGE
THERMAL COMFORT
● Isovolumes enclosing the
outbounding areas from the
desired PMV range.
● Uncomfortable areas near the
walls/ceiling/floor and above
people’s head.
● Hot spots identified in the
ceiling at both sides of the
extraction unit.
● No uncomfortable areas in a
mid height inside the room
affecting the students.

28. VELOCITY - VERTICAL SLICES
DRAUGHT
● Velocity slides to detect
possible draughts.
● Besides the air stream from
the extraction unit, low
velocities in the room.
● The air stream keeps attached
to the ceiling - Coanda effect.

29. TRACES
DRAUGHT
Two predominant flow patterns:
● MVHR unit - Cool air
attached to the ceiling
recirculating after hitting the
opposite wall. Efficient
ventilation!
● Radiator - Hot air from the
radiator raises attached to the
wall and mixes with the
surrounding air.
Air entering into the extraction
unit on the side.

30. SNEAK PEEK
Before you ask - PMV and PPD
should be available on SimScale
within days!

31. SUMMARY
EVERYBODY IS HAPPY!!
(Source: https://media.giphy.com/media/l0MYt5jPR6QX5pnqM/giphy.gif) (Source: https://media.giphy.com/media/Is1O1TWV0LEJi/giphy.gif)
(Source: https://media.giphy.com/media/hr5KMBloP8GYw/giphy.gif)

32. SUMMARY
● With SimScale, we are able to carry out a
complete HVAC CFD study.
● Different heat/cooling sources as
mechanical ventilation can be modeled.
● Helpful tool to optimize and improve
ventilation systems design.
● SAV Systems AirMasters performs as
expected - No undesired draughts,
uniform temperature distribution and
great thermal comfort.