Solar Panels and Payback time
Solar Panels
Solar panels absorb infrared radiation from the sun. The energy is transferred from the panel to the metal pipes in the panel and from there to the water in the pipes.
Usually, a pump is not needed to move the water through the system. A natural convection current occurs in the system which transfers the energy to the hot water tank.
When the sun is shining on a cold day, there is still infrared radiation from the sun. This means that the solar panels can still heat water when the outside temperature is below freezing on a sunny day.
Usually, a pump is not needed to move the water through the system. A natural convection current occurs in the system which transfers the energy to the hot water tank.
When the sun is shining on a cold day, there is still infrared radiation from the sun. This means that the solar panels can still heat water when the outside temperature is below freezing on a sunny day.
Payback Time
You can cut down your energy bills by reducing the amount of energy that you use. Some ways of doing this do not cosy anything. For example, you could turn down the thermostat on your central heating down by 1 Celsius degree or draw the curtains when it gets dark.
Other methods do cost money. To decide whether they are worth doing, you need to calculate how long it will take to recover the amount of money you spend. This is the payback time. The method with the shortest payback time is the most cost-effective.
Other methods do cost money. To decide whether they are worth doing, you need to calculate how long it will take to recover the amount of money you spend. This is the payback time. The method with the shortest payback time is the most cost-effective.
Worked Example
Jack currently has 50 mm insulation in his loft. It will cost him £250 to increase the thickness of the insulation to the recommended 270 mm. His heating bill would decrease by £100 per year.
What is the payback time for adding the extra insulation?
Payback time = _______Cost_______ = ______£250_______ = 2.5 years
Savings per year £100 per year
Jack currently has 50 mm insulation in his loft. It will cost him £250 to increase the thickness of the insulation to the recommended 270 mm. His heating bill would decrease by £100 per year.
What is the payback time for adding the extra insulation?
Payback time = _______Cost_______ = ______£250_______ = 2.5 years
Savings per year £100 per year
Learning Objective
Solar panels, Payback time, Cost-effective. |
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