Solar Air Heater Wizard:

Automating CFD

Geneviève Dutil & Yannick Sirois

ENGINEERING

SIMULATION

CFD FEA

LubiTM Collector (perforated glazing)

Existing wall

Metal backing (optional)

Spacing clips

LubiTM panels

Vertical

extruded bars

Goal:

Tool to simulate heat transfer in

wall before installation to predict

and optimize efficiency

Proposition:

Automated CFD analysis from

CAD to report through a GUI wizard

Previous Process

7

Design Building Measurements

Design of corrective methods

Building Delivery

New Process

8

Design Simulations Optimization

Building Delivery

Project Stages

• Simulation Strategy

• Simulation Model and Validation

• GUI Programming

• Optimization case

9

Simulation Strategy

• Use of simple geometry elements

• Porous semi-translucent modeled as

porous baffle

• No environmental modeling

• Trimmed cell mesh

10

Porous Baffle Calibration

• Detailed

simulation of a

section of the

perforated plate

11

Simulation & Validation

• Four fully instrumented solar collectors

12

CAD

13

Temperature and Flow Patterns

14

Mass Flow Rate & Pressure Drop

Across Porous Baffle

15

Simulation & Validation

• Simulation outlet temperatures and efficiency

significantly lower than the experimental values

• Environment plays an important role pre-heating

air before entering the collector

• Determination of a correction factor to the inlet

temperature influenced by:

– Mass flow rate

– Inlet temperature

– Solar radiation incident to the collector

background wall

16

GUI Programming

17

GUI Programming

18

GUI Programming

19

Optimization Case

20

Single outlet, left side

Junction between two

sections of different

length

Wider plenum

Side inlet

Optimization Case

21

Optimization Case

22

T_in Flow rate

Out

T out Δη

1) Original design

-15.6

°C

13543 CFM

3.4 °C 0 %

2) Outlet centered 6.0 °C. 10.3 %

3) 2+ Blocked top inlet 5.8 °C 9.4 %

4) 2+ Inlets left side 6.4 °C 11.6 %

5) 4 + blocked top inlets 6.3 °C 11.4 %

6) 2 centered outlets +

inlets on both sides

6.0 °C 10.4 %

7) 2 centered outlets +

no inlets

5.9 °C 9.9 %

8) 6 + blocked top inlets 5.9 °C 9.7 %

Optimization Case

23

Benefits of GUI

• Makes CFD accessible to non-expert

users

• Optimizes wall configuration before

building

• Helps in sales: show simulation results

to client 24

Thank you!

Questions?