Chapter 8 LO5: Calculate The Amount Of Roof Space Required For A Domestic Flat Plate Solar Collector

Question 1

Describe 5 parameters that influence the area of solar collectors required for a solar thermal system.

Answer 1

1. Solar radiation Levels: Solar radiation values differ substantially at various locations on the Earths surface. A location near the equator has very high solar radiation values and thus would require a smaller sized solar collector area to meet a family’s needs. Conversely, for a location much further north (or south) such as the British Isles, for the same family, a larger area of solar collectors will be required due to the much lower solar radiation values.
2. Shading: One must not just consider the solar radiation values from online maps but also the unique location itself. If the proposed solar collector site has sunlight blocked at certain times of the day or year, by obstructions. Such as trees or buildings, then a larger solar collector area is clearly required.
3. Collector Type: The type of collector will offer different efficiencies. The flat plate collector can operate at 80% efficiency, while an evacuated tube can operate at 9% efficiency. As a result the evacuated tubes would require a smaller solar collector area for a family than the flat plate collectors.
4. Family size: It is logical that a larger family will require more hot water on a daily basis. Therefore, a larger family will require a larger solar collector area compared to a smaller family.

Lifestyle of users: The daily habits and lifestyle choices of people will also have an impact on the quantity of hot water used by a household. People who frequently, run, cycle, or play sports will require the use of showers and baths more frequently than households with family members that are physically inactive. A lifestyle choice such as being very active in sports will increase the area of solar collectors required to meet the needs of the family.

Question 2

If a project has a limited area available for solar collectors what type of solar collector should be used?

Answer 2

Evacuated tubes as they require less area

Question 3

Q3 + 4

Answer 3

EX 8.5