T. Nuttall, L. Jim, J. Stevenson, C. Grimshaw, R. Lee, A. Saunders & H. Owens

PHY 346TATA Group Industrial Project: Unglazed Transpired Solar Collectors

Design Brief

How does surface microstructure affect the retention of the thermal boundary layer?

Wind

TSC

Building

Wall

Fan

PlenumSun

Hot Air

What is the effect on performance of a heat reflecting wall?

Development

Surface Structure

Stereolithographic Approach

Adhesion

Hydraulic Press

Rig Operation

Method

Efficiency:

Lamp Stability

0 50 100 150 2000

100

200

300

400

Time (minutes)

Irradiance (W/m^2)

Lamp Stability

0 50 100 150 2000

20

40

60

80

100

Time (minutes)

Lamp Temperature (◦C)

Effect of Mass

848 852 856 860 8640

20

40

60

80

100

Mass (g)

% Efficiency

Wind Effect on Thermocouple Measurements

0 20 40 60 80 100 12023.25

23.5

23.75

24

With FanWithout Fan

Time (s)

Temperature (◦C)

Tests and Results

Different Backing Material

0 50 100

Matte Black Tape Avg 863.0gAluminium Avg 863.0gControl 863.0gLinear (Control 863.0g)

% Efficiency

94.7 ± 2.3 %94.6 ± 2.3 %

95.1 ± 3.3 %

0 50 100

Glue ChannelsGlue Channels ControlblankCircles on HolesCircles on Holes ControlblankCircles OutCircles Out Control% Efficiency

Surface Structure with No Wind

92.3 ± 3.5 %94.3 ± 3.5 %90.4 ± 3.5 %93.8 ± 3.5 %92.1 ± 3.2 %91.4 ± 3.2 %

0 50 100

WavyWavy ControlblankCocktail SticksCocktail Sticks Control

% Efficiency

Surface Structure with No Wind

83.4 ± 2.5 %90.4 ± 2.5 %88.5 ± 2.5 %91.1 ± 2.5 %

0 50 100

Control Av-erageWavyCocktail SticksCircles on HolesCircles InCircles Out

% Efficiency

Surface Structure with Wind

46.1 ± 3.3 %52.5 ± 3.1 %52.5 ± 3.6 %50.2 ± 3.4 %44.5 ± 3.1 %50.3 ± 3.1 %

Conclusion

Reflective and absorbing wall covering – No significant difference

Surface Structure without wind – Opaque objects reduced efficiency

Surface Structure with wind – Improved performance for separated, curved structures

Improvements

Questions?