太阳能热利用与技术考试题型.docVIP

Assignment for solar thermal conversion (No.1) This problem involves calculations on four surface: (1) vertical west-facing; (2) vertical north-facing; (3) vertical south –facing; and (4) horizontal. The results you will generate are common intermediate calculations in energy-conscious building design. (A vertical east-facing surface is omitted due to symmetry with the corresponding west-facing wall.) All calculations are to be performed for two dates: (1) 21 December; (2) 21 June; and for two times of day: (a) 10:00; and (b) 13:00 local clock time (not solar time and you need to convert from local clock time to solar time). The location is Kunming of China, latitude=25.01oN, longitude=102.7oE (A) Calculate the cosine of the incidence angle for each of the four surfaces, at two different times of day, for each of the two dates (altogether 16 calculations) (B) Calculate the sunrise/sunset hour (in solar time) on each of the four surfaces for each of the two dates. (C) Calculate the daily total extraterrestrial radiation (in MJ/m2) for each of the four surfaces, for each of two dates. (Be careful, in your calculations, to use the sunrise/sunset hour on the surfaces themselves, and be careful to use the correct unit of time and hour angle). Assignment for Solar Thermal Conversion (No.2) 1. The knowledge of the tilt and azimuth for a tracking solar collector is often essential in system design. For example, programming the microprocessor that controls the tracking requires an algorithm for the rate at which the collector must move for each minute of the day and each day of the year. Another example is tracking flat-plate photovoltaic systems. The collector tilt angle depends on time of day and day of year. This is important in the calculation of collectible energy since the collectible diffuse and ground-reflected radiation both depend on collector tilt angle. For the following tracking modes, derive expressions for both the collector tilt and the coll