Solar

Question 1

Explain how an automated tracking system can maximise energy output from solar devices. {3}

Answer 1

Daily variations of the position of the sun during day light hours (earth spinning on its own axis).

Annual variations in the position of the sun in the sky depending on the season (Earths elliptical orbit around the Sun).

Variations in positioning in the Northern and Southern hemisphere (Earths tilt on its own axis is 23.45 degrees and elliptical orbit).

Question 2

Outline two ways in which automated solar tracking can maximise the energy output from solar collectors. {2}

Answer 2

It can tilt and rotate on its own axis to achieve optimum tracking.

It can track the variations in the sun’s position during daylight hours (earth spinning on its axis).

Question 3

In the space below sketch a diagram of a typical flat plate thermal solar panel.

Answer 3

Inlet and outlet connections. {1}
Flow tubes. {1}
Absorber plate. {1}
Insulation. {1}

Question 4

State two advantages provided by an evacuated tube solar collector compared to a flat plate solar collector. {1}

Answer 4

Conduction losses

Convection losses.

Question 5

State three factors which should be considered when calculating the roof area required to install flat plate thermal solar panels. {3}

Answer 5

Solar radiation levels of site / roof.
Shading.
Proposed collector type and performance specifications

Question 6

Explain the main benefit to households of installing a flat plate solar collector. {1}

Answer 6

Economic reasons. Cost more important in the application than efficiency. {1}

Question 7

State three benefits to households of installing a flat plate collector.

Answer 7

Reducing environmental impact.
Financial benefit – reducing energy costs.
Improved energy security.

Question 8

Explain the purpose of the antireflective coating. {1}

Answer 8

Maximises the efficiency of the cell by reducing the reflection of light (photons) from the surface. {1}

Question 9

Explain the role of the metal contacts.

Answer 9

Allows for circuitry to facilitate the flow of electrons in the circuit from the p to the n layer of the cell. {1}

Question 10

Explain the purpose of the anti-reflection coating. {2}

Answer 10

Anti-reflection coating maximises the efficiency of the cell {1} by reducing the reflection of light (photons) from the surface {1}.

Question 11

Describe one advantage and one disadvantage of monocrystalline PV modules. {2}

Answer 11

+Most efficient type of PV module. {1}

-Cost – Expensive manufacturing techniques required to ensure efficiency. {1}

Question 12

Name three other material types of PV modules. {3}

Answer 12

Polycrystalline.
Thick-film
Thin-film

Question 13

Name and briefly describe any two financial incentives that are available to homeowners considering the installation of solar panels. {4}

Answer 13

Green deal {1}
Financial assistance towards cost of installing solar panels {1}.

Feed-in-Tariff for Solar PV {1}
Where homeowners are paid for the amount of
electricity they generate and feed back into the grid {1}.

Question 14

Explain briefly any two passive solar design techniques that can be applied to new and existing buildings. {4}

Answer 14

High levels of thermal insulation {1}; Will reduce the heat loss of the building {1}

Provide eaves overhangs {1}; To reduce summer heat gain through windows {1}.

Question 15

Name three types of concentrating Solar Power (CSP) systems; {3}

Answer 15

Parabolic troughs.
Fresnel Reflectors.
Solar Dishes.

Question 16

Explain how Concentrating Solar Power (CSP) systems may be used in power plants. {2}

Answer 16

CSP plants produce electricity by converting the suns energy into steam using mirrors. {1} The steam is then sent through a generator to produce electricity. {1}