Engineering :: Renewable Sources of Energy

@ : Home > Chemical Engineering > Renewable Sources of Energy

51.

Suppose that we have an ideal piece of glass with ? = 0. If ? = 0.09 where ? = transmissivity ? = reflectivity and ? = absorptivity

A.	? = 0.09	B.	? = 1
C.	? + ? = 1	D.	? + ? = 0

52.

Which of the following is usually not used as the heat exchange fluid in a flat-plate solar collector?

A.	Air	B.	Fuel oil
C.	Water	D.	Ethylene glycol and water

53.

What is the serious problem with using a thin plastic sheet as the glazing material in a flat-plate solar collector?

A.	It is structurally too weak	B.	It absorbs too much of the incoming radiation
C.	Opacity to long wavelength radiation is reduced	D.	It is too expensive for routine use in collectors

54.

The percent transmission of incoming solar radiation through the top cover plate of flat-plate collectors is typically

A.	99	B.	85
C.	95	D.	30

55.

The absorptivity of the black absorber plate coated with a common flat=black paint is typically

A.	80%	B.	94%
C.	99%	D.	85%

56.

The radiative heat loss between the top cover of flat-plate solar collector at a temperature of Tp(K) and ambient air at a temperature of Ta(K) is proportional to

A.	Tp4 + Ta4	B.	Tp - Ta
C.	Tp4 - Ta4	D.	Tp2 - Ta2

57.

Compare the heat loss between the absorber plate of flat-plate collector and the cover with that between the cover and the ambient air at steady state.

A.	The two heat losses are equal	B.	The heat loss between the absorber plate and the cover plate is greater
C.	The heat loss between the cover plate and the ambient air is greater	D.	Information available is insufficient to decide

58.

If the wind is blowing with a 10 kilometer per hour the dominant heat loss mechanism(s) between the top cover plate of flat-plate solar collector and the ambient air is / are

A.	convection	B.	radiation
C.	conduction	D.	convection and radiation

59.

The efficiency of a flat-plate solar collector using water as a heat-exchange fluid is largest at which of the following temperature for the absorber plate? Assume Ta = 25?C.

A.	40?C	B.	60?C
C.	80?C	D.	100?C

60.

When solar radiation strikes the boundary between the air and top of the cover plate the percent of the incident intensity reflected is

A.	0%	B.	4%
C.	8%	D.	20%