*California Energy Commission
PASSIVE SOLAR HANDBOOK
1.4 Optimal Use of Mass and Insulation
 |
 |
 |
 |
A heavy wall must have two qualities in order to dampen diurnal changes in the exterior environment relatively constant: heat capacity — the ability to store heat, and low heat conductivity — the ability to resist, or to insulate against heat flow.
If one intermittently exposes an adobe brick first to a blow torch and then to cold water (and if each exposure time is relatively short) the temperature of the brick never reaches either extreme, but oscillates somewhere in between. The heat capacity of the brick keeps its temperature from rising rapidly with the small heat addition,or dropping rapidly with the small heat extraction. The brick’s insulating quality prevents heat from entering or leaving very rapidly.
Adobe, however, does not happen to have the optimum combination of heat capacity and insulation. This problem can be resolved by the way the material is used which is as important as what material is used. The most effective way of maximizing the two qualities — eat capacity and insulation — in a building wall is to use two separate materials. Ideally,one would choose a material with little resistance to heat flow. By placing the insulating material next to the external environment, little heat is allowed into or out of the building and with the high heat capacity material next to the inside environment, what heat does enter or leave (primarily through windows and interior heat generation) cannot change the temperature of the heat capacity material rapidly.
Thus, little heat is let in or out, and the high capacity material slowly stores heat. The building’s thermal mass damps out temperature fluctuations.
Thus a more ideal wall than adobe alone would be one made of externally insulated adobe or externally insulated concrete. This concept of externally insulated, high mass construction is common to all of the passive concepts in this handbook except those using isolated heat storage arrangements such as the rock bed thermo-siphon system.
*Reprinted from the California Energy Commission “Passive Solar Handbook.”
Related Articles:
- Printable PDF version
- Alternative Energy -- Is It Stepping Over Dollars To Pick Up Dimes?
- "R" Fairy Tale -- The Myth of Insulation Values
- Passive Solar Handbook (Spanish Translation PDF)
- Monolithic Joins Energy Star Program
- Monolithic Dome R-value -- Effective 60!
- Renewable and Sustainable Energy
- Sprayed Polyurethane Foam Insulation
- Reaching for the E-Stars-- Dome Living Energy Savings
- Ceramic Coating-- Insulation or Reflective Surface?
- A Monolithic Dome's Two Batteries
Plug It In -- Energy Consumption, leaks and plugs
177
Dome Park Place - Italy, TX 76651
Tel (972)483-7423 - Fax (972)483-6662
| Press Room