Basic concepts about cpv

1. CONCENTRATED
PV CELL
A.AJITH (B.E MECHANICAL)

2. WHAT IS CPV ?
Concentrator photovoltaics (CPV) is a photovoltaic
technology that generates electricity from sunlight. Contrary to
conventional photovoltaic systems, it uses lenses and curved
mirrors to focus sunlight onto small, but highly
efficient, multijunction (MJ) solarcells.
In addition, CPV systems often use solar trackers and
sometimes a cooling system to further increase their efficiency.

3. CONCENTRATION RATIO:
It could be defined as the ratio of collector aperture area and the
receiver area.
CR =
𝐴𝑟𝑒𝑎 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑜𝑟
𝐴𝑟𝑒𝑎 𝑜𝑓 𝑡ℎ𝑒 𝑟𝑒𝑐𝑒𝑖𝑣𝑒𝑟

4. OPPORTUNITIES:
• COST REDUCTION
• POSSIBILITY OF ENHANCING CELL EFFICIENCY
• EASE OF CELL MANUFACTURING

5. OPTICS FOR CONCENTRATOR PV:
• FLAT PLATE COLLECTOR WITH BOOSTER MIRRORS
• COMPOUND PARABOLIC CONCENTRATOR
• PARABOLOID REFLECTOR
• FRESNELS LENS COLLECTOR

6. FLAT PLATE COLLECTOR WITH BOOSTER MIRRORS:
• It is the simplest type of concentrating collector.
• It has a maximum concentration ratio less than 4.
• This type of concentrator not widely used.
• The efficiency of concentrator increase if the angle
of mirrors can be changed several times during the
Year.

7. COMPOUND PARABOLIC CONCENTRATOR:
• It is a non-focusing type concentrator.
• Concentration ratio is more than 10 suns.
• It does not require continuous tracking.

8. PARABOLOID REFLECTOR:
• It have high concentration ratio.
• The reflector is made by using a glass mirror
or an anodised A1 plate having high reflectivity.

9. FRESNEL LENS CONCENTRATOR:
• These lenses are light in weight as compared to
the conventional convex lenses.
• It is made up of polymer material.
Advantages:
• Large aperture area and short focal
Length.
• It can be cut into various shapes.
• It have high concentration ratio.

10. COOLING METHODS:
• To operate solar cells at high concentration levels one has to use to proper
cooling techniques.
Passive Cooling:
• Here, the cell is placed on a cladded cermaic substrate with
high thermal conductivity. The ceramic also provides electrical isolation.
• Concentration ratio less than 10 suns.
Active Cooling:
• Typically, liquid metal is used as a cooling fluid, capable of
cooling from 1,700°C to 100°C.
• Concentration above 10 suns.
• It increases the cost & complexity of the system.

11. TYPES OF CPV:
• LOW CONCENTRATOR PV
• MEDIUM CONCENTRATOR PV
• HIGH CONCENTRATOR PV

12. LOW CONCENTRATOR PV;
• It have a concentration upto2-100
• For economic reasons, conventional or
modified silicon solar cells are typically used.
• No tracking necessary.
• No cooling required.

13. MEDIUM CONCENTRATOR PV:
• It have a concentration upto 10-100.
• Single axis tracking sufficient.
• Passive cooling sufficient.
• Material : Silicon, CdTe, etc.

14. Single axis tracking:
• Single axis trackers spin on one axis, from east in the morning to west in the afternoon, to
track the sunlight.
• Homemade trackers have a single axis structure.
• Single axis tracking adds 25%-30% output power production over that of fixed solar
panels.
• These trackers are sturdier, simpler and therefore cheaper in production.

15. HIGH CONCENTRATOR PV:
• High concentration photovoltaics (HCPV) systems
employ concentrating optics consisting of dish
reflectors or fresnel lenses that concentrate sunlight to
intensities of 1,000 suns or more.
• Dual axis tracking required.
• Active cooling is required.

16. Dual axis tracker:
• The two-axis trackers combine the two motions (North to South and East to West)
in order to track sunlight in an optimal fashion.
• They adapt to the daily trajectory of the sun with
seasonal tilting.
• Dual axis tracking adds 35%-40% outputpower production over that of
fixed solar panels.

17. CPV STRENGTHS:
• High efficiencies under direct normal irradiance
• Low cost per watt of manufacturing capital.
• Low temperature coefficients.
• No cooling water required for passively cooled systems
• Additional use of waste heat possible for systems with active cooling possible.

18. CPV WEAKNESS:
• HCPV cannot utilize diffuse radiation. LCPV can only utilize a fraction of diffuse radiation.
• Power output of MJ solar cells is more sensitive to shifts in radiation spectra caused by
changing atmospheric conditions.
• Tracking with sufficient accuracy and reliability is required.
• May require frequent cleaning to mitigate soiling losses, depending on the site.
• Limited market – can only be used in regions with high DNI, cannot be easily installed
on rooftops

19. THANK YOU