Materials with a
low thermal emittance surface have been used for many years to create
reflective insulations that reduce the rate of heat flow across building
envelopes. Reflective insulation technology is now being combined with other
energy conserving technologies to optimize overall thermal performance. The
basis for the performance of reflective insulations and radiant barriers will
be discussed along with the combination of these materials with cellular
plastic or mineral fiber insulations to form hybrid insulation assemblies.
Calculations of thermal resistance for enclosed reflective air spaces and
current field data from Southeast Asia will be presented. These data show that
reductions in heat transfer across the building enclosure can be effectively
reduced by the use of enclosed reflective air spaces and attic radiant
barriers. Reflective technology increases the overall thermal resistance of the
building enclosure when used to insulate poured concrete structures.
This publication presents a technique of quantifying energy savings due to daylight. The technique is designated to be used in smart buildings or similar applications where daylight harvesting is welcomed. The technique is divided into three stages. In the first stage an optical sensor is evaluated for its P (power)-E (illumination) response characteristics. In the second stage the calibration of room properties is carried out. In the final stage photometric calculations are performed, and energy savings are calculated. The major advantage of the proposed approach is to determine energy savings during the design stage of a building, not after the building construction or retrofitting. The information obtained from the calculations is useful for investors, future tenants and environmentalists.