Environmental Engineering Reference
In-Depth Information
Fig. 5.7 Sources of electricity in the United States (2005)
become less plentiful, the conversion of coal into liquid fuels will increase to
meet the increase in demand. In addition to these raw economic factors, the use
of government regulation and incentive programs are likely to have a significant
impact on the economics of daylighting.
Concern over greenhouse gas emissions is expected to continue to fuel
contempt over the burning of fossil fuels (for transportation as well as electri-
city). As a result, it is likely that we will see carbon dioxide emissions regulated
in a way that raises the cost of electricity generated by burning fossil fuels.
Taxation of greenhouse emissions combined with tax incentives for using
renewable resources, such as solar energy, will make it easier to justify the
investment in daylighting systems that offset energy usage in non-residential
buildings.
If we accept that the economic factors for incorporating renewable resources
will continue to improve, it raises the question of how the use of daylighting can
be increased in non-residential buildings. The most obvious method requires
constructing new buildings with daylighting incorporated into their architec-
ture. However, to achieve an impact on the electrical lighting load presented by
existing non-residential space, there must be some means by which daylighting
can be incorporated into those structures. This was the driving concept behind
the development of the HSL fiber-coupled daylighting system.
5.6 Development of the HSL System
The HSL system was conceived at the Oak Ridge National Laboratory
(ORNL) in the mid-1990s. This system was more than a daylighting system, it
was a hybrid system that included electric light. The concept of a fiber-coupled
