1. PASSIVE SOLAR DESIGN
ALTERNATIVE ENEGRY SOURCES

2. Solar Design The Sun and Solar Radiation provide energy for…
Heating and cooling a building
Water heating
Daylighting
Electrical generation via Photovoltaic cells
We will focus on how we can use the sun to aid in the heating of water.

3. Solar Design
Here are a few reasons why solar hot water systems make good environmental sense:  
On-site energy generation: Reduce the need to extract and transport fossil fuels.
Increased boiler and water heater efficiency and life expectancy
Reduced greenhouse gas emissions:
A 50-collector solar hot water system can offset over 50 tons of CO2 per year, or 5,000 tons over the life of the system.
A 100-collector pool-heating system can offset over 80 tons of CO2 per year

4. Solar Design Passive solar design
Solar energy is collected, stored, and distributed without the use of mechanical equipment

5. Solar Design
Sun charts can be used to determine the best design for rook overhangs and other shading devices

6. Solar Design Direct Gain Systems
Collect heat through South-facing glass and store the heat in high-mass materials such as concrete floors or masonry walls.
During nighttime hours the high-mass material slowly release the heat gained during the day
Indirect gain Systems
Similar to direct gain systems except that the thermal mass is not in direct sunlight.
Heated during the day by room air temperature and reflected sunlight.
Less efficient then direct gain systems
Trombe Wall
Vents at top and bottom to allow thermocirculation

7. Solar Water Heater

8. Passive Solar Water Heating Systems
Passive solar water heaters rely on gravity and the tendency for water to naturally circulate as it is heated.
There are two basic types of passive systems:
Integral collector-storage passive systems
Thermosyphon systems

9. Passive Solar Water Heating Systems
Integral collector-storage passive systems
Consist of one or more storage tanks placed in an insulated box with a glazed side facing the sun.
These work best in areas where temperatures rarely fall below freezing.
They also work well in households with significant daytime and evening hot-water needs.
They do not work well in homes or buildings with predominantly morning draws because they lose most of the collected energy overnight.

10. Passive Solar Water Heating Systems
Thermosyphon systems
Rely on the natural convection of warm water rising to circulate water through the collectors and to the tank (located above the collector).
As water in the solar collector heats, it becomes lighter and rises naturally into the tank above. Meanwhile, the cooler water flows down the pipes to the bottom of the collector, enhancing the circulation.
Indirect thermosyphons (that use a glycol fluid in the collector loop) can be installed in freeze-prone climates if the piping in the unconditioned space is adequately protected.

11. Passive Solar Water Heating Systems
Backup Systems
Solar water heating systems almost always require a backup system for cloudy days and times of increased demand which a conventional water heater serves as.