Solar Photovoltaic-Thermal (PV/t) parabolic trough

collector systemProject 1(BEB801)

Supervisor: Dr. Azharul Karim

MANAV R. SHAH2 JUNE 2016

Aim of the project

To make a hybrid system by integrating Solar PV cells on the absorber tube of the Solar thermal Parabolic Through collector system to increase the overall efficiency.

Objectives of project1

To integrate the cells on the absorber tube and design the layout to get maximum power by altering voltage and current.

Making the existing thermal system functional Try to convert maximum radiation into useful energy with

minimum thermal and electrical loss by altering the parameters. To obtain the value of efficiency of the thermal system

(theoretically)

Why PV/t integration?

Exposure to wider range of wavelengthsPV cell - 300nm to 1150nmsolar thermal collector- 200nm to 1000µm

Reduces the cell temperature --- improves PV performance Increases the life of PV cells by reducing thermal stress Exhibits higher yield per square meter in highly populated areas Reduces balance of system costs Lower production costs, life-cycle costs, needs less maintenance

Theoretical thermal calculations

Forced Convection: It occurs between water and the inner surface of the tube

Conduction: It occurs between the inner surface and outer surface of the metal

Radiation: It occurs from radiation from the sun to the outer surface of the pipe

Heat and mass transfer concepts on the system

Parameter Value Parameter Value

Flow rate 3LPM = 0.05kg/s Rayleigh number

3.28*

Effective surface area of the

absorber tube

0.184m2 Nusselt number 10.7

Surface area of the attached

solar cell

0.1135m2 Heat transfer coefficient

6.55W/m^2*K

Area of triangular inlet

and outlet

0.00117m2 Heat loss by forced

convection

66.3W

Bulk temperature

52.5 Heat loss by radiation

63.8W

Results from the theoretical calculations

Tin(0C) Heat flux from pyrometer(W/m2)

Flow rate (LPM) Flow rate (kg/sec)

Reynolds number

Tout (oC)

19.1 (minimum)

794.78 (minimum)

3.33 (minimum) 0.055 1407 23.19

19.5 (average) 800 (average) 3 (average) 0.05 1279.5 23.95

19.71 (maximum)

811.5 (maximum)

3 (maximum) 0.05 1279.5 24.25

Temperature difference

Percentage change (%)

Energy gained ( (kJ/s)

Available solar irradiance(kJ/s)

Thermal efficiency (theoretical) (%)

4.09 8.1 0.94 0.7486 79.6%

4.45   0.93 0.7536 81.03%

4.54 1.99 0.95 0.7644 82%

Results from the theoretical calculations

Recommendation

Attaching more RTDs at specific locations

PV integration

Why monocrystalline silicon?

After the cell is used for a longer time, temperature in the cell increases which leads to decrease in the cell efficiency by 0.34 %/ for monocrystalline silicon cells and 0.45%/ for polycrystalline.

  Option1 Option2 Option3Dimensions(mm*mm)

50*156 50*125 52*156

Quantity(pieces) 300 200 150Efficiency 18% 18% 19%Price US$300 US$400 AUD$367Pros and cons The quantity was

more than the required amount and it was the 300 pieces is the minimum quantity to be ordered.

The cost of cutting is very high. The supplier charged double the amount for precutting the cell to the required dimensions.

The efficiency was higher than others. The quantity was of desired amount. The supplier added auxiliary materials such as tabbing wires and busbars which otherwise have to be ordered separately.

Selection of cells based on received quotes

Size 52mm*156mm±0.5mmThickness 200mm±1mmFront Anisotropically texturized surface and dark silicon nitride

anti-reflection coatingBack Full-surface aluminium back-surface fieldEfficiency Eff (%) 18Power Ppm(W) 1.148Maximum Power current Ipm(A) 2.8Short circuit Current Isc(A) 2.8-2.9Maximum Power Voltage Vpm(V) 0.5Open Circuit Voltage Voc(V) 0.6Current Temperature Coefficient

α 0.04%/0C

Voltage Temperature Coefficient

β -0.32%/0C

Power Temperature Coefficient

γ -0.42%/0C

Cell specifications

Characteristics

High conversion efficiencies resulting in superior power output performance

Outstanding power output even in low light or high temperature conditions

Optimized design for ease of soldering and lamination Long-term stability, reliability and performance Low breakage rate

Orientation

Designing the layouts for the electrical system to obtain maximum output power

Layouts

Case1: Using 14 pieces of 52mm*156mm cells on 2 faces in series configuration

Case2: Using 14 pieces of 52mm*156mm cells on 2 faces in parallel configuration

Case3: Using 28 pieces of 25mm*156mm cells on 2 faces in series configuration

Case4: Using 28 pieces of 25mm*156mm cells on 2 faces in parallel configurations

Current status

Recommendation

Using the most efficient cell (for research purpose only)

Use the non-concentrating high efficiency cells recently developed by UNSW researchers

The triple-junction cell targets discrete bands of the incoming sunlight and are capable of converting 35% of the sunlight into electricity

Thank you for your time and patience