Solar power producing heat
4 marks · NormalA solar heating panel is covered with a glass sheet and insulated at the back.
State the function of the glass sheet.
What is the purpose of insulation at the back of the panel?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) — · must show glass allows sunlight/thermal radiation in, reduces heat loss by convection/infrared emission/traps heat
(b) — · must show insulation reduces heat loss at back, prevents energy transfer to surroundings, keeps more energy for heating water
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · States glass lets sunlight/thermal radiation in.
A1 (a) · 1 mark · States glass reduces heat loss (traps heat, or by convection/infrared).
M2 (b) · 1 mark · States insulation reduces heat loss at the back/bottom.
A2 (b) · 1 mark · Links this to more energy being available to heat water.
Worked solution
a) The glass sheet allows sunlight or thermal radiation to enter the panel and reduces heat loss by trapping heat (like a greenhouse), or by reducing loss through infrared emission and convection.
b) Insulation at the back reduces the amount of heat lost to the surroundings. This keeps more energy inside the panel to heat the water.