Figure 7.24 Heat pump water heaters and demand water heaters are two variations on conventional hot water systems.

Lecture 8Solar Thermal Configuration

E-101 - Energy and Sustainability Professor Lonnie Gamble

Sustainable Living Department Maharishi University of Management

This presentation was prepared on solar powered computers

The Big OnesDirect Solar

Solar Thermal hot water distillationcookingdryingcooling/refrigerationPassive Solar Buildings

Solar ElectricPV Solar Thermal Electric

Pub 1964

Solar Hot Water System Design

Figure 7.25 Typical hydronic flat-plate collector and system diagram for a solar water heater.

Freezing ClimatePump Power

Antifreeze and Heat Exchanger

Drainback

Two Tank vs One Tank Systems

Non-freezing climates

Figure 7.31 An integral-collector-storage system needs no pumps, controllers or sensors. Whenever someone turns on a hot-water tap, cold water pushes heated ICS water into the regular backup water heater.

Figure 7.26 An energy analysis of a flat-plate collector

Figure 7.28 Unglazed collectors in mild weather may be best for pools; single-glazing makes sense for domestic hot water (DHW); double-glazing is needed for space heating.

Figure 7.29 An evacuated-tube solar collector showing how heat pipes deliver heat to the header.

Evacuated Tube Collectors

Figure 7.30 Inserting tubes into the header of an evacuated tube collector.

Collector Efficiency

Mounting

Pricing

• Rule of Thumb– $125 - $175 per sq foot

Solar Hot WaterRules of Thumb

Load estimate: 20 gallons of hot water per person

Collector Sizing:1 sq foot of collector per gallon of hot water neededTypical collector sizes: 3x6, 4x8, 4x10, 4x12

Storage:1-2 gallons of storage for each sq foot of collector (1 in colder areas, 2 in warmer areas)Typical tank sizes: 50, 80, or 120 gallons

Cost: $125 – 175 per sq foot of collector, complete system installed

Abundance EcovillageSolar Hot Water

Space Heating

Fairfield Glass Solar

Home Built Solar Heating

Annual Cycle Systems

Wisconsin System

Concentrating collectors

• Imaging, tracking• Non-imaging

CSP - SEGS, Solar one

• http://www.youtube.com/watch?v=rO5rUqeCFY4

SEGS/LUZ

300 megawatts since 1980’s – Kramer Junction - 50 miles east of LA

Concentrating solar video

Power tower/wind

• http://www.youtube.com/watch?v=XCGVTYtJEFk&feature=related

Power Tower

• http://www.youtube.com/watch?v=XCGVTYtJEFk&feature=related

Solar Cooking

1882

French printing press

Solar Oven Cooking

Solar Water Purification:Distillation and Pastuerization

Solar Water Purification

The principle is amazingly simple. Untreated water like sea water or contaminated water is added to an upper channel in controlled amounts. From there it drips over wicks and a black coloured absorber fleece through the collector. A part evaporates from the energy of the sun and the steam condenses under the glass cover. The condensation runs into the condensation channel. The remaining untreated water is collected in front of it and diverted out of the side of the collector. Both the untreated water channel and the condensation channel have supply points on the sides. Since there are no moving parts the whole system requires almost no maintenance.

Solar Distillation

Salt Gradient Ponds

END

Table 7.7 Levelized costs for various types of water heaters

Other Solar Thermal Applications

Salt gradient ponds

Solar cooking

Non-freezing climates

Table 7.8 Solar Water Heating Spreadsheet for the Atlanta Example

Figure 7.27 Collector efficiency is specified by the “y-axis intercept” and “slope factor” with the x-axis assumed to use Tin rather than TP.

Figure 7.32 Computer simulation of a 40-gallon ICS serving a 40-gallon, 120oF, load taken at 8:00 am versus 8:00 pm

Figure 7.33 With the tank placed above the collector, thermosiphoning systems don’t need pumps or controls.

Figure 7.35 Drainback systems are freeze protected by having an open loop that allows the collectors to drain whenever the pump is turned off.

Figure 7.34 A closed-loop, antifreeze-protected solar water heater system.