.

1. SOLAR WATER HEATER
CAROLINE PACKARD

2. INTRO / BACKGROUND
• Solar water heaters serve as domestic hot water systems that are both
sustainable and cost-effective.
• SWHs use the greenhouse effect to trap solar radiation within the system
• The solar energy converts to thermal energy, heating up the water
• Cost and energy-efficient
• Can convert up to 70 percent of solar energy to heat energy
• Can reduce utility bills significantly

3. RECOGNITION OF PROBLEM / NEED
• Main benefit of utilizing a solar water heater involves reducing the use of
fossil fuels and unrenewable energy such as:
• Coal
• Natural gas
• Nuclear power
• Households use hot water more regularly than they realize:
• Showers, dishwashers, laundry, etc.
• Free solar energy is going to waste and harmful, unrenewable resources
continue to be used.

4. SPECIFIC GOALS
• Structural goal of capturing 500 Watts of solar radiation
• Can be calculated by MFR equation using change in temperature
• Significant increase of outlet temperature compared to inlet
• Constraints include lack of materials that would maximize the efficiency of
the system, ability to obtain those materials

5. LITERATURE REVIEW / THEORY
Two different types of “solar collector”
1. Flat plate collector: stationary; components
include black absorber plate, copper
risers/tubing, and the use of insulation
• Most similar to class/project version
2. Evacuated tube collector: heat pipe inside a
vacuum-sealed tube as insulation; utilizes liquid
to gas phase to transfer heat efficiently
Jamar,
A.,
et
al.
“A
Review
of
Water
Heating
System
for
Solar
Energy
Applications.”
International
Communications
in
Heat
and
Mass
Transfer,
vol.
76,
2016,
pp.
178–187.,
doi:10.1016/j.icheatmasstransfer.2016.05.028.

6. MATERIALS
• Plywood board (27’’x14.5’’)
• Cut two-by-fours to fit edge of plywood
(width1.5’’)
• Plexiglass covering (26’’x13.5’’)
• Black spray paint
• ¼’’ copper tubing (length 20 ft.)
• Insulation strips
• Hose to ¼’’ tubing adapter
• Simple flowmeter
• Hose adapter with faucets
• Thermometer / timer

7. TRIAL 1: Flow rate of 0.1 L/min
• Angled SWH perpendicular to the sun
• Adjusted flow until flowmeter read 0.1
• Measured inlet temperature (23 °C)
• Measured outlet temperature every minute for
minutes
TRIAL 2: Altered flow rate of 0.2 L/min
• Angled SWH perpendicular to the sun
• Adjusted flow until flowmeter read 0.2
• Measured inlet temperature (23.5 °C)
• Measured outlet temperature every minute for
15 minutes
TRIAL PROCEDURES

8. • Conditions:
• 72 °F outside
• Mostly sunny
• Small leak fixed with duct tape
• System was already in sunlight for
awhile, already hot inside
TRIAL PROCEDURES

9. RESULTS: FLOW RATE 0.1 L/MIN
Max outlet temp: 55 °C / 131 °F
Leveled off after 13 minutes

10. RESULTS: FLOW RATE 0.2 L/MIN
Max outlet temp: 33 °C / 91 °F
Leveled off after 4 minutes

11. CALCULATIONS
TRIAL 1 TRIAL 2

12. DISCUSSION / CONCLUSION
• The slower flow rate (0.1 L/min) led to a higher outlet temperature
• 131 °F compared to average hot shower temp 105 °F
• The slower flow rate (0.1 L/min) also produced more energy overall
• Produced 215.32 W of heat energy
• Did not reach goal of 500 Watts
• Could be improved by better insulation, lower flow rate, improved angle/conditions,
longer tubing, glass instead of plexiglass
• Conclusion: overall, the prototype system worked well
• Maximum temperature of 131 °F was very surprising

13. REFERENCES
• https://slate.com/technology/2011/02/solar-water-heaters-are-they-better-
than-solar-electric-panels.html
• Jamar, A., et al. “A Review of Water Heating System for Solar Energy
Applications.” International Communications in Heat and Mass Transfer, vol.
76, 2016, pp. 178–187., doi:10.1016/j.icheatmasstransfer.2016.05.028.

14. QUESTIONS?