Energy From the Sun

What Energy From the Sun covers

Energy From the Sun is examined in Unit AS 1, The Earth's Capacity to Support Human Activity, a written examination. It covers solar radiation, tracking and concentrating solar power, flat plate and evacuated tube collectors, sizing a domestic solar thermal system, photovoltaic cells and semiconductor wafers, types of photovoltaic module compared, planning regulations and solar incentives and passive solar design in new and existing buildings.

The 7 subtopics

Each one has its own page.

• Solar radiation, tracking and concentrating solar powerUK solar radiation and seasonal variation, direct and diffuse radiation, single and dual-axis trackers and a tracker calculation, and parabolic trough, dish and linear Fresnel concentrating solar power with thermal storage.Open →
• Flat plate and evacuated tube collectorsThe absorber, selective coating, glazing and insulation of a flat plate collector, antifreeze and pumped circuits, the differential controller, evacuated tubes and heat pipes, a comparison of the two, and thermosiphon heaters.Open →
• Sizing a domestic solar thermal systemHow solar radiation, shading, collector type, family size and lifestyle set collector area, worked hot water and area calculations, orientation and tilt, the cylinder, seasonal output, maintenance and the benefits to a household.Open →
• Photovoltaic cells and semiconductor wafersThe structure of a silicon cell, n-type and p-type silicon, the p-n junction, photon energy, contacts and anti-reflective coating, modules and inverters, the effect of light, temperature and shading, and standard test conditions.Open →
• Types of photovoltaic module comparedMonocrystalline, polycrystalline, thin-film and thick-film modules, how they are made, their efficiency ranking, cost and longevity, where each suits, and panel efficiency and output calculations.Open →
• Planning regulations and solar incentivesPermitted development and when planning permission is needed, listed buildings, solar farms, network operator notification, the Feed-in Tariff and its closure, the Smart Export Guarantee, the NI Renewables Obligation, VAT and payback.Open →
• Passive solar design in new and existing buildingsSouth-facing glazing and window placement, low-emissivity glass, thermal mass and insulation, roof overhangs, west-facing windows, room layout, sunspaces, and applying passive solar ideas to existing houses.Open →

What you need to know

Answer each one before you reveal it.

Take Energy From the Sun further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Flat plate collector vs Evacuated tube collector

  Flat plate collector: a glazed insulated box holding a dark absorber sheet with pipes bonded to it. Evacuated tube collector: rows of glass cylinders with a vacuum between double walls around an absorber.

• Monocrystalline cell vs Polycrystalline cell

  Monocrystalline cell: a silicon wafer sliced from one continuous crystal grown slowly from a melt. Polycrystalline cell: a silicon wafer cut from a cast block containing many small crystals.

• Single-axis tracker vs Dual-axis tracker

  Single-axis tracker: a mount that turns panels east to west only through the day. Dual-axis tracker: a mount that follows both the sun's compass direction and its height.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Roughly how much solar energy falls on each square metre of ground in the UK each year?

   Model answer

   A horizontal square metre in the UK receives roughly 900 to 1,200 kWh of solar energy a year. Southern England receives the most, and northern Scotland the least.

2. 2

   Calculate the average daily solar energy on a square metre at a UK site receiving 1,000 kWh/m² a year.

   Model answer

   The average is about 2.7 kWh per square metre per day. The working is 1,000 kWh ÷ 365 days = 2.74 kWh.

3. 3

   Why does the solar energy reaching the UK vary so much between summer and winter?

   Model answer

   The sun is higher in the summer sky, so its rays are more concentrated and pass through less atmosphere. Summer days are also much longer than winter days.

4. 4

   What is the difference between direct and diffuse solar radiation?

   Model answer

   Direct radiation travels in a straight beam from the sun. Diffuse radiation has been scattered by cloud and air and arrives from the whole sky, as much UK sunlight does.

5. 5

   Describe the two main approaches used in solar collectors.

   Model answer

   Solar thermal collectors absorb sunlight to heat a fluid, usually for hot water. Photovoltaic panels convert sunlight directly into electricity using semiconductor cells.

6. 6

   What is an automated solar tracking system?

   Model answer

   A solar tracker is a motorised mount that turns collectors to follow the sun across the sky. Light sensors or a programmed sun-position calculation control the motors.

What is inside Levo

Six ways to work the same material.

Energy From the Sun revision questions

What does Energy From the Sun cover in CCEA A-Level Environmental Technology?

7 subtopics: solar radiation, tracking and concentrating solar power, flat plate and evacuated tube collectors, sizing a domestic solar thermal system, photovoltaic cells and semiconductor wafers, types of photovoltaic module compared, planning regulations and solar incentives and passive solar design in new and existing buildings. Each one has its own page with questions and model answers.

How is Energy From the Sun organised?

By the CCEA 3930 specification, subtopic by subtopic, so it matches the order you are taught it in.