A group of students submitted a report on a solar water heater to Sir Syed Saqib. The 3 sentence summary is: The report defined a solar water heater, described its key components like collectors and tanks, and explained its advantages in efficiency and ease of use compared to electric systems. Experiments were conducted to show how temperature in the water increases over time with sunlight and various methods were proposed to increase the efficiency, such as adding mirrors or insulation.

1. Solar Water Heater
Submitted to: Sir Syed Saqib

2. Submitted By:
• 2019-ME-152
• 2019-ME-157
• 2019-ME-163
• 2019-ME-162
• 2019-ME-171
• 2019-ME-175
• 2019-ME-178
• 2019-ME-182
• 2019-ME-186
• 2019-ME-189
• 2019-ME-191

3. What is Solar Water Heater
DEFINITION:
A solar water heater is a device
that captures sunlight to heat water.
CONSTRUCTION:
• Collector
• Tank(inlet, outlet)
• Stand
• Tubes
• Thermostat

4. ADVANTAGES
• Efficiency of solar thermal conversion is around 70% when
compared to electrical system.
• Solar water heaters play a vital role in domestic as well as industrial
sector due to its ease of operation and simple maintenance.
• The efficiency of a solar water heating system is based on the
performance of flat plate collector.
• These are characterized by its thermal performance and it largely
depends on the transmittance, absorption and conduction of solar
energy

5. Principle:
• The device has collectors
which absorb the radiations of sun and
converts it into heat
• Thermo-siphon is being relied upon to
exchange the heat in water tank

6. Diagram:

7. Working
• Through inlet cold water is provided in to the tank this
water runs into the solar collector tubes. The tubes
collect solar radiance heats up the water in them.
• This heated water in the tubes being less dense now
moves upward and is replaced by a high dense cold water
through convection currents, now the hot water at top is
extracted via outlet this phenomenon is know as
Thermosiphon.

8. Procedure:
• Make sure the tank is initially empty to avoid any error in the
original/experimental temperature readings.
• Set up Solar Water Heater assembly in direct sunlight
• Insert the thermostat, from the outlet, such that when the
tank is filled with water the indicator should be immersed in
the upper most layer of water. Enclose the outlet with the
help of the cork
• Open the inlet stopper and let Water flow into the tank from
the water source.

9. Procedure(Continued)
• Once the tank is filled, as indicated by the overflow, cut-off the water
supply and close the inlet
• Note the initial temperature reading on the thermostat.
• Now take the temperature readings after specific intervals say 5 minutes
• Note the time after which it reaches its steady state i.e. the time after
which the outlet temperature almost remains constant.
• Repeat the experiment by changing solar heater’s tilt angle and note the
difference between the times to reach steady state.

10. Table:
Time (mins) Temperature ( deg.
Celsius)
5 33
10 35
15 35.2
20 35.8
25 36.5
30 37.3
35 37.4

11. Graph:
33
35 35.2
35.8
36.5
37.3 37.4
32
33
34
35
36
37
38
39
0 5 10 15 20 25 30 35 40
Temp(deg.celcius)
Time(mins)
Temp vs time graph

12. Results:
• Temperature is increasing with the increase in time.
• Initially it is increasing in a straight line.
• After sometime, when temperature rises up from
reference temperature, it is increasing slowly and
becomes constant.
• Thus, time is an important factor in determining the
efficiency and working of solar water heater.

13. How To Increase Efficiency?
• There are different methods of increasing efficiency:
Decrease energy losses
Mirror Combinations
Add another covering between metal pipe and
Transparent covering
Use heat Absorptive Tanks
Increse the the insulation of tank and pipes

14. Mirror Combinations:
• Applying Mirrors at an angle cause more heating.
• Mirror increases solar addition to surface of heater is almost 2 times.

15. Mirror Combinations(Continued)
• But Angle of incidence is very important.
• If angle is more acute then there is less solar addition on surface
of heater .

16. Addition of Covering:
• Addition of covering will do a less heat loss from metal tubes to
the surrounding.
• Less heat loss will increase the efficiency.

17. Addition of Covering(Continued)
• Prevent blasting of outer surface (Due to overheating).

18. Use Absorptive Tanks:
• Cover your storage tank with Aluminum
foil to keep the inner temperature
constant for longer period of time.
• Use temperature sensors to see if the
internal temperature of tank is constant
or not.
• Use of space heating for getting a precise
temperature over longer period of time
using insulation.

19. Advantages and Disadvantages:
ADVANTAGES:
• Water heating bill savings
• Low maintenance
• Environmentally friendly
DISADVANTAGES:
• High upfront installation costs
• Dependent on climate
• Only heats water

20. Applications:
• Homes
• Community Centers
• Hospitals
• Nursing homes
• Hotels, Restaurants and Dairy plants
• Swimming Pools
• Canteens and Hostels
• Industry.

21. Thank You.