Solar Energy Multiple Choice Questions on “Solar Water Heater”.
1. What is solar water heater?
a) Use solar energy to heat water
b) Use solar energy to generate current which is then used to heat water
c) Use water to generate heat
d) Use solar energy to generate steam
Answer: a
Clarification: Solar water heater is a system that converts sunlight into heat. This heat is then used to heat water. As the water gets heated, steam may be produced but the purpose of solar water is to heat water and not produce steam. It does not generate current.
2. Which of the following determines complexity and size of solar water heating system?
a) Food
b) Changes in ambient temperature
c) Chemicals
d) Solar radiation constant
Answer: b
Clarification: Changes in ambient temperature during day-night cycle is one of the factors that determines the complexity and size of solar water heating system. Food, chemicals and solar radiation constant does not influence the complexity and size of the system.
3. What is freeze protection in a solar water heating system?
a) Ensures that the system is frozen
b) Prevents the operation of drainback system
c) Prevents damage to system due to freezing of transfer fluid
d) Ensures that the transfer fluid is frozen
Answer: c
Clarification: Freeze protection in a solar water system prevents the system being damaged due to freezing of transfer fluid. It does not prevent the operation of drainback system.
4. What are drainback systems in solar water heating system?
a) The system that reverses the direction of flow of transfer fluid
b) The system that tracks the sun
c) The system that pumps excess transfer fluid
d) The system that drains the transfer fluid
Answer: d
Clarification: Drainback systems are systems that drain the transfer fluid particularly to ensure freeze protection. This prevents the freezing of transfer fluid and any unwanted damage to the system.
5. How does freeze-tolerance work?
a) By expansion of pipes carrying transfer fluid
b) By compression of pipes carrying transfer fluid
c) By increasing the temperature of pipes carrying transfer fluid
d) By increasing the pressure inside pipes carrying transfer fluid
Answer: a
Clarification: Freeze-tolerance works by expansion of pipes carrying the transfer fluid. The low pressure pipes are made of silicone rubber that expands on freezing.
6. Which of the following metals are used to make pipes of low cost solar water heating system?
a) Gold
b) Copper
c) Polymer
d) Silver
Answer: b
Clarification: Copper is used to make pipes of low cost solar water heating systems. Though silver and gold are good thermal conductors they are expensive. Polymer is not a metal.
7. Direct solar water heating systems ______
a) offer great overheating protection
b) are called pumped systems
c) offer no overheating protection
d) offer great freeze protection
Answer: c
Clarification: Direct solar water heating systems are also called compact systems. They offer little or no overheating protection unless they have a heat export pump.
8. How is the heat transferred from transfer fluid to potable water in indirect solar water heating systems?
a) By directly exposing the substance to sunlight
b) By using an electrical heater
c) By circulating potable water through the collector
d) By using heat exchanger