G2: Solar Thermal System Flashcards
Nuclear reactions emit energy in what form?
Electromagnetic radiation of varying wavelengths
What is direct solar radiation?
radiation striking the earths surface travels in a straight line from the sun
Is direct solar radiation easy to relfect?
Yes, via polished silver or aluminum surfaces
What is diffuse solar radiation?
The result of direct radiation striking gas, vapour / dust particles in the atmosphere
What is the declination angle
Earths tilt
What is the solar altitude?
measurement from the fixed surface to the center of the sun
What is the solar azimuth angle?
Measurement from the true north in a clockwise direction
What is the Solar Thermal System?
Any device or combination of components intended to convert solar radiation into useable heat
What are the 2 systems of the Solar Thermal System?
1) Passive
2) Active
What is the Passive System about?
Are solar thermal systems that collect and distribute heat w/o the use of fans or circulators
What is Thermosiphoning?
warm water in the collector - expands volume –> becomes less dense / is pushed upwards by gentle convection currents created by cooler water below.
In colder climates what must be done passive solar systems?
The collector / any parts of the system that might freeze must be drained.
If water temps are greater than 140F - 60C what is needed?
A thermostatic mixing valve.
What is an Active solar thermal system?
A system that uses a circulator to move a fluid through a solar collector
What are 2 main types of solar collectors used in domestic hot water / space heating?
1) Flat plate
2) Evacuated tube type
