Building Design Issues
Most buildings constructed before the latter part of the 1900's relied heavily on the sun for light and sometimes even for heat, while breezes or massive construction were used to temper the extremes of temperature during the day. These older buildings were seldom air-conditioned (except in the southern latitudes) and occupants were expected to grin and bear any discomforts. In fact, air-conditioning was originally justified on improvements in occupant productivity and product quality. And there are still many industrial environments (such as boiler rooms, foundries, and other process heating areas) where air-conditioning is simply out of the question because of its high capital and operating costs.
These older buildings were often originally heated with coal-fired hot water or steam systems using radiators under the windows. While the building walls were thick, they were relatively poor insulators, and much of the fresh air ventilation came from the failure of the windows and doors to properly seal shut! Most of these buildings have been renovated or torn down. The renovations included adding insulation to the exterior walls, replacing windows and doors with more efficient designs, and adding centralized heating, ventilating, and air-conditioning. However, they seldom are as energy efficient as a new, properly designed building. Therefore, the building design team will never again have a better opportunity to include cost effective energy efficiency concepts into a building as when it is being designed and constructed.
In addition, buildings designed today may outlast the economic availability of fuels that currently support them. Fortunately, the building HVAC system will need replacement before then as well. But, building energy system design should reflect a commitment to energy and water supply stewardship. These resources are not inexhaustible, and our consumption is conspicuous when compared to most other modern countries. The U.S. Department of Energy (DOE) recommends the use of geothermal heat pumps as one of the preferred technologies for space conditioning and water heating for this reason.
However, stewardship of building budgets is also a harsh reality. Some level of inefficiency is often quite cost effective. For example, small on-demand electric space heating for the morning building warm-up during cold weather can be much cheaper to build and operate than a centralized steam system, especially in southern climates where there are only a handful of days where morning temperatures would require electric heat operation. In addition, while gas heating may be cheaper to operate for water heating, venting combustion products can be costly in certain building designs. And, even though insulation reduces heating and cooling costs, each addition to the first levels of insulation suffers from the law of diminishing returns. So, economic stewardship is also a design professional's priority.
Never-the-less, the energy scares of 1973 and 1978 coupled with the fear of new power plant construction during the 1980's resulted in zeal for low-energy designs. In a sense, the pendulum swung from over-use of energy to under-use. Buildings were tightened up so much during this period that many indoor air quality problems emerged. The pendulum is swinging back towards a more balanced view.
Links to Related Topics
Building Construction Options
Indoor Air Quality
Energy Management Systems
Energy System Comparison
Solving Operational Problems
Power For Computers
Green Buildings (LEED)