2. Storage Wall (with and without vents)

3. Isolated Storage Wall (with vents and/or moving insulation) 4. Collection Wall (with storage floor, wall, or ceiling)

5. Collection Sun-Space (with storage floor, wall, or ceiling) 6. Combinations of 1 through 5

11.

Collection Roof (with storage floor, wall, or ceiling)

12. Combinations of 7 through 11

Remote Aperture:

13. Remote Collection with storage floor

14. Remote Collection with isolated storage (e.g., solar ponds) 15. Ground Preheat

MULTIZONE:

Single Story

Multi-Story

Community and Urban Projects

Space Cooling (Path C4)

Passive cooling involves the discharge of energy by selective coupling of the system to the cooler parts of the environment. If the environmental conditions are correct, this energy flow will occur by natural means. Possible environmental sinks for heat from the system are the sky, atmosphere, and ground.

In sky cooling, radiation from the system passes through the atmosphere and dissipates into outer space. Environmentally, it is the "purest" mode of cooling, since none of the energy discharged from the system appears in the local microclimate. Radiative sky cooling works well in environments with clear skies, and has the potential to cool the system below the ambient air temperature. The primary limit to this cooling mechanism is convective and radiative heat gain from the surrounding atmosphere.

Energy from the system can also be discharged directly to the atmosphere during those times when the ambient air conditions are favorable to such an exchange. Heat can be dissipated by raising the sensible heat energy of the surrounding air (e.g., night air cooling) or by raising its latent heat energy (e.g., evaporative cooling). In either case, the energy transfer can be greatly enhanced by increased air movement. The driving force for this movement can come from wind, fans, or special convective drive mechanisms. In dry environments, evaporative cooling has the potential, like radiative sky cooling, to reduce the system temperature below the ambient air temperature. Evaporative cooling has the disadvantage of expending water, a commodity which may be in short supply in the climates where evaporative cooling is most effective.

Because of the great thermal mass of the earth, ground temperatures during the summer will normally be several degrees below the average ambient air temperature. Unlike evaporative or radiative sky cooling, which require special climactic conditions such as dry air or clear skies, ground cooling can be used to displace a substantial fraction of the normal cooling load, even in humid, overcast