Green Heating

Energy from the Sun can be harnessed and used productively for domestic and industrial purposes. Two of the most common ways of ‘collecting’ the sun’s energy, are, using solar panels (which produce hot water) and photovoltaic cells (which produce electricity). Scientists are researching into ways of combining solar panels with photovoltaic cells in the same device in order to use the Sun’s energy even more efficiently. However, in this PRB you will concentrate on solar panels Energy reaching the Earth from the Sun can be transferred by solar panels to heat water moving around inside them. This solar energy is called infrared radiation. Radiation arriving at the outer surface is absorbed by the panel. The energy is used to heat water sealed in the solar panel unit. The energy from this water is transferred to the domestic hot water system via the heat exchanger. This hot water is used for houses, hospitals, offices or factories. The more of the Sun’s energy that can be transferred to the water, the better the solar panel is. We say it is more efficient. If we know how to make solar panels more efficient we can reduce the amount of energy which comes from burning fossil fuels. Coal, oil and natural gas are fossil fuels That we are so blindly using nowadays (on the next page there is a diagram of how a solar panel works)

Green Heating

The Solar Panel

Experiment 1:

•Does the color of a panel affect its efficiency?

•Darker colors are more effective.

Hypothesis

Aim

• Face solar panel towards sun and attach to voltmeter.

• Take reading after two minutes for solar panel when it has no color filter on it.

• Apply a color filter and take the reading after two minutes.

• Do the same for all the other colours you are testing.

Experiment 1: Method

• Solar panel• Volt meter • Coloured filters• Wires

Experiment 1: Equipment

Experiment 1: Results

Filter colour Voltage (V)

Red 1.56

Yellow 1.59

Light green 1.52

Dark green 1.48

Blue 1.54

Experiment 2AimWhether the shiny, dark or light surfaces absorb more heat.

HypothesisWe think that the darker the colour the more effective and absorbent the panel will.

Method

•Fill beaker with water•Cover beaker in aluminum-foil•Take temperature•Repeat for Black Paper and White Paper•Take measurement for uncovered beaker

Aluminum-Foil White Paper Black Paper Beaker 200ml Thermometer

Equipment

Results

Material Temperature (Celsius)

Black Paper 25®

Aluminium Foil 24®

White Paper 24®

Normally 23®

Experiment 3Aim: to see if infrared radiation is a form of electromagnetic radiation, like light, then surfaces which reflect light will reflect infrared radiation, and surfaces which absorb light will infrared radiation.Hypothesis: We think that the experiment will prove that infrared can heat when concentrated.Method: Put water in small beaker attached to solar boiler.Angle the solar boiler so that the focus of light is concentrated on the beaker at the end of the metal rod on the solar boiler.When water boils take pictures for evidence.As a backup experiment put a leaf in the concentrated ray of light and let it burn.Take a picture of that experiment for evidence.Equipment:Solar BoilerWaterCameraDry LeafResults:

Experiment 1 shows that Darker Colors are more efficient and effective.

Experiment 2 shows us that darker colors are more absorbent.

Report