Solar Photovoltaic-Thermal (PV/T) Technology and Development

Solar Photovoltaic-Thermal (PV/T) Technology and Development

Prof Dato’ Dr Mohd Yusof Hj Othman FASc

Puri PujanggaUniversiti Kebangsaan Malaysia (UKM)

National University of Malaysia

16 June 2014

7th Asian School on Renewable Energy

Associate Principle Research Fellow/Director, Institute of Islam Hadhari

Mohd Yusof Hj Othman 7th Asian School on Renewable Energy, Puri Pujangga UKM, Malaysia, 16th-20th June 2014

CONTENTS

• Introduction; Why PV/T?

• Current Research in PV/T Studies at SERI, UKM.1. Double-pass PV/T air heater with Fins

2. Double-pass PV/T air heater with CPC & Fins

3. PV/T air heater with V-groove collector

4. PV/T air heater with rectangular tunnel collector

5. PV/T air heater with honey comb collector

6. PV/T water heater collector

7. PV/T combi collector

8. Bifacial PV/T air heater

• Conclusion


INTRODUCTION

• Why PV/T?

– A combination of photovoltaic cell and solar thermal collector, hence maximizing space used.

– Generate both electricity and heat simultaneously.

– More efficient solar collector.

Solar water heater Solar air heater Solar electricity


Rational of PV/T

• PV technology is well established and accepted; high efficiency and high stability; widely used in isolated locations, stand alone, integrated, grid-connected.

• Solar thermal is also well established and accepted; high efficiency and high stability; widely used in hot water and hot air systems in domestic, space heating, industrial process heat, agriculture etc.


Comparisons: Thermal and PV

Solar Thermal

Harnessing solar energy for thermal applications –domestics, industries, hotels, hospitals, leisure, etc.

Use thermal energy for space heating, fluid and generate electricity.

Has been accepted worldwide as solar thermal power.

Photovoltaic

Convert solar energy to electricity.

Absorb 80% of incident solar radiation but convert only small portion to electricity.

Release excess heat during the operation.


Why PV/T?

• Increased PV module efficiency by decreasing temperature. About 0.4%-0.5% decrease in efficiency for every 1oC increase in

PV temperature.

Efficiency rate for generating electricity will increase by 10%-15%.

Cooling effect will ensure PV operate at rated electrical output and prevent damage by overheating.

• Replace the traditional heating fuel in the building. Can deliver additional 200%-300% more heat energy from

conventional PV system.


Why PV/T?

• Reducing the emission of greenhouse gases. Reduction in COx, NOx, & SOx because PV/T contributes to

displacing fossil fuel.

• Maximize usable roof space The installation produces more energy per unit surface area

compared to PV and Thermal systems installed separately.

• Replacing the roofing material with PV/T system reduces the payback period.

• PV/T systems has a total operating efficiency above 50%

• PV/T systems is proven to be feasible and cost effective

• Therefore, why not use PV/T collector that contributes both electricity and heat simultaneously?


Basic Idea of PV/T Efficiencies (?)

Area of Collector = Area of thermal

collector (At) + Area of PV panel (Apv)

Efficiency = ( thermal eff (t) + PV eff(pv))2

Thermal Efficiency = 60 %

Photovoltaic Efficiency = 10 %

Combined Photovoltaic Thermal

Efficiency = 35 %

Area of Collector = Area of thermal

collector (At) +Area of PV panel (Apv)

Efficiency = thermal eff (t) + PV eff

(pv)

Thermal Efficiency = 50 %

Photovoltaic Efficiency = 5 %

Combined Photovoltaic Thermal

Efficiency = 55 %

Air based PV/T system

Air Inlet

Blower

Auxiliary

Heater

PV/T

Collector

Drying

chamber/

space heating

On/off

Controller

Principle scheme

of air based

PV/T system:

PV/T module,

drying chamber,

blower, auxiliary

heater, controller


Liquid based PV/T system

Principle scheme of liquid based PV/T system:

PV/T module, storage and auxiliary heater


Schematic Diagrams of PV/T

Hybrid collector (Water & Air)


Research Study in Photovoltaic Thermal (PV/T) Collector at SERI, UKM


1. Double-pass PV/T air heater with Fins


The collector has three

essential components: a

glazing on the top, a plate

containing numerous PV

cells and a bottom plate.

The air enters through the

channel formed by the

glass cover and the PV

plate and then through the

lower channel. The fins on

the back of the PV panel

increase the heat transfer to

the air.

Fin

Glass cover

PV cell

Absorber plate

Air in

Air out

Insulator

Absorber

plate

Glass

coverPV cell

Fin


PV Cell

Absorber

Plate

Fins

SI/O

DATA ACQUISITION SYSTEM

Humidity sensor

Anemometer

Flowmeter

Air

heater

(2 kW)

Air

heater

(2 kW)

Blower

Speed

control

Blower

Gauge

screen air

mixer Flexible

hose

Air

straightener Glass

cover

Solar cells

Insulator

Data logger

I-VTermocouples

Pyranometer

Experimental set-up in laboratory

Experimental set-up to test PV/T collector


Performance of the double-pass PV/T collector

with fins

Variation of current (I) and power (P)

against voltage (V) at mass flow rate of

0.027 kg/s.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 5 10 15 20

V(Volt)

I(A

)

0

1

2

3

4

5

6

P(W

)

400 W/m^2

500 W/m^2

600 W/m^2

700 W/m^2

Efficiencies of the collector at solar

irradiance of 600 W/m2 and Tf1 = 35 oC




Basically, the design has similar

concept with the previous one,

except it has Compound Parabolic

Concentrators (CPC) attached to it.

Air enters through the upper

channel formed by the glass cover

and the PV cells, and is heated

directly by the sun. Next, it exits

through the lower channel formed

by the back plate and the PV cells.

The CPC concentrates solar

radiation onto the PV cells. The fins

on the back of the PV panel

increase the heat transfer to the air.

Fin

Glass coverSolar cell

Outlet air

Inlet air

Insulator

CPC

PV/T-CPC Collector under construction

CPC

Solar cells

Fins

PV/T-CPC Collector under construction


Performance of Finned Double-pass PV/T CPC collector

The electrical properties of the PV/T at 400 Wm-2 and mass flow rate at 0.069 kg/s

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 4 8 12 16 20

V (Volt )

I (A)

0

1

2

3

4

5

6

P (W)

Fins

CPC & f ins

3. PV/T air heater with CPC collector

0

10

20

30

40

50

60

70

80

90

100

0 0.05 0.1 0.15 0.2

mass flow rate (kg/s)

Effic

ien

cy (

%)

Thermal eff iciency

Electrical eff iciency

Combined eff iciency

The effect of mass flow

rate on efficiencies at

solar radiation of 600

Wm-2 of PV/T collector

with CPC and Fins

PV/T- CPC collector on the

roof top

Drying cabinet

PVT collector

DC fans

Drying of noodle using PV/T dryer




Based on the previous two

designs, the electrical

efficiency of the collector

reduced by nearly 50% since

the PV module is covered by

glass plate. Electrical energy is

considered as high quality

source of energy, and reducing

its value defeats the purpose of

having good quality of PV

module

PV cell

V-grooveInsulator



0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

0.00 5.00 10.00 15.00 20.00

V (Volt)

I (A

)

Tanpa

lengkuk-V

Dengan

lengkuk-V

The I-V curve at 0.006958 kg/s

0.00

5.00

10.00

15.00

20.00

25.00

0.00 5.00 10.00 15.00 20.00

V (Volt)

P (

W) Tanpa

lengkuk-V

Dengan

lengkuk-V

P-V at 0.006958 kg/s

Graf P lawan V pada 0.069581 kg/s



4. PV/T Air Heater with Rectangular Tunnels

INNOVATIVE SOLAR COLLECTOR

FOR THE PRODUCTION OF BOTH

HOT WATER AND ELECTRICITY

Cold Air In

Hot Air Out

Solar Panel

Insulator

4. Front View and Back View of Tunnels design

The structure and the PV/T

module used in this design

are similar with the design

in the previous collector,

except that the V-Groove is

replaced with rectangular

tunnel made of aluminum.

4 PV/T air heater with rectangular tunnel collector

4 PV/T air heater with rectangular tunnel collector

0.00

0.50

1.00

1.50

2.00

2.50

0.00 5.00 10.00 15.00 20.00

Voltan(V)/V

Aru

s(I

)/A

0.00

5.00

10.00

15.00

20.00

25.00

Po

wer(

P)/

W

Arus(I)/A

Power(P)/W

The I-V and P-V curves for the PV/T air heater with rectangular tunnel collector




Photovoltaic module

Aluminum sheet Heat Insulator

Honeycomb heat exchanger





6. PV/T Water Collector

Construction of flat box Al-alloy

absorber plate for hybrid PV/T water

heater system

• In this experiment, sensitivity study of the system has been performed and proved that by combining the systems, the installation area produce more electrical and thermal energy per unit surface area than one PV panel and one hot water system (thermal collector).


PV/T water heater collector


PV/T Water Collector

a) Direct Flow Design,

b) Serpentine Flow

Design,

c) Parallel-Serpentine

Flow Design,

d) Modified Serpentine-

parallel Flow Design,

e) Oscillatory Flow

Design,

f) Spiral Flow Design,

g) Web Flow Design,

NoCollector absorbers

design

1 Tunnel design 9.6 45.1 54.7

2 Spiral Flow Design 11.4 52.2 63.6

PVthermal PVT

Ambient temperature = 24 – 26 °C and Solar Radiation = 700 – 800 W/m2 (Typical clear day)

Efficiency of dual function solar collectors

Ambient temperature = 24 – 26 °C and Solar Radiation = 700 – 800 W/m2 (Typical clear day)

Efficiency of dual function solar collectors

NoCollector absorbers

design

1 He et al. [1], Taiwan R.O.C 9.87 40 49.87

2 Huang et al. [2], China 9.0 38 47

3 Chow et al. [3], Hong Kong 11.0 51 62

4 Ji et al. [4], China 10.15 45 55.15

5 Adnan Ibrahim et al[5] 11.4 52.2 63.6

PVthermal

PVT

Solar Panel

Cold Water In

Hot

Water

OutInsulator

6. PV/T water heater with spiral flow designed collector

DATA ACQUISITION SYSTEMThermal

Storage

Thermal Storage

Tank

Data Logger 24ch

Converter/

Inverter

Load

A

V

Anemometer

Pyranometer

Humidity sensor

Thermocouples

DC Current

transducer

DC Voltage

transducer

Flowmeter

Thermostat

I-V

Auxiliary

Heater

Grid

connected

Dual Function Solar

Collectors

http://images.google.com.my/imgres?imgurl=http://www.iusb.edu/~cted/summer/img/Computer.JPG&imgrefurl=http://www.iusb.edu/~cted/spring/computers.shtml&h=377&w=353&sz=20&hl=en&start=2&um=1&tbnid=JY0zA4972ttCLM:&tbnh=122&tbnw=114&prev=/images?q=computer+picture&um=1&hl=en&sa=N

http://images.google.com.my/imgres?imgurl=http://www.iusb.edu/~cted/summer/img/Computer.JPG&imgrefurl=http://www.iusb.edu/~cted/spring/computers.shtml&h=377&w=353&sz=20&hl=en&start=2&um=1&tbnid=JY0zA4972ttCLM:&tbnh=122&tbnw=114&prev=/images?q=computer+picture&um=1&hl=en&sa=N

NOVELTY :

INTEGRATED AS

ROOFING

MATERIAL

PV/T water heater for low

energy building at SERI,

UKM


INNOVATIVE SOLAR COLLECTOR FOR

THE PRODUCTION OF BOTH HOT

WATER AND ELECTRICITY

INNOVATIVE SOLAR COLLECTOR FOR THE PRODUCTION OF BOTH HOT WATER AND ELECTRICITY


7. PV/T combi (combination of liquid and air) collector

Glass

Air

Water

Insulator

PV Panel PV PanelAdhesive

7. PV/T Combi (combination of liquid & air) collector

Heat conductor

Sheet-and-tube PV/T-collectors.

(Zondag et al, 2003).

Channel PV/T-collectors.



7. PV/T Combi (combination of liquid & air)

Glass

Transparent

PV panelWaterWater

WaterAdhesive

Adsorber

Insulator

Free flow PV/T-collectors.


Two-absorber PV/T-collectors.


Transparent

PV Panel

Heat

absorber

Air

Air

Air

Water

Water

Water

Insulator

Insulator

Insulator

7. PV/T Combi: Mode air and water

Mode a

Mode b

Mode c

Alternative PV/T/dual design

modes, used to determine

the optimum arrangement of

the water and the air heat

exchangers.

(Tripanagnostopoulos, 2007)

Inlet air

Water

tube

Insulation

Transparent

PV cell

Outlet air

Absorber

plate

D1

D2

D3D4

Schematic Diagram of the PV/T collector

Mussalim & Othman (2013)

Schematic diagram the PV/T combi

Water out

Transparent PV cells

Outlet air

Inlet air

Water in

Collector plate

Water tube on top

Water tube on bottom

Double pass air

Insulation

The construction of the PV/T collector

Performance study of the PV/T collector





The concept of bifacial solar cell as

compared to monofacial solar cell.

• In this experiment, Bifacial PV module has been designed. The idea is to use both sides of the PV module to improve the electricity generation. The heat produce can be used for space heating or any other hot air applications.


Monofacial solar module Bifacial solar module

(front face)

Bifacial solar module

(back face)


Indoor testing facilities

(under construction)Outdoor testing facilities

(under construction)


Bifacial PV/T in

operation at

Madrid Airport



CONCLUSION


CONCLUSIONS

• We have presented 8 types of PV/T air & water heaters namely,







7. PV/T combi (combination of air and liquid) collector

8. Bifacial PV/T air heater.

• Each of the collector has it own specifications that may be fit in one of our applications.

• Hybrid photovoltaic collectors have great advantages: higher photovoltaic cell efficiency, higher total efficiency (both the thermal and the electrical combined), lower produced energy costs due to a better use of the energy conversion process

ACKNOWLEDGEMENT

We would like to record our appreciation to

UKM and the Government of Malaysia for

the financial support of this project (03-01-

02-SF0039; PRGS/1/11/TK/UKM/01/12;

FRGS/1/2011/TK/UKM/02/35; ETP-2013-

011)

THANK YOU TERIMA KASIH

WASSALAM

Tel: 03-89216988

Faks: 03-89216990

[email protected]