Typical building cooling requirements are a result of heat gains from office equipment, solar radiation, lighting. ventilation and the occupants. Energy use in buildings for these purposes, including heating, is a large contributor to global CO2 emissions. According to some scientists, global warming is now unavoidable and stabilization even at somewhat higher CO2 levels than the current 350 ppm will require a reduction in fossil fuel use by more than 60% worldwide. Atmospheric CO2 concentrations prior to the industrial revolution were closer to 280 ppm. DWSC offers a dramatic method for achieving a portion of these reductions.
Secondly, the substitution of naturally chilled water for manufactured refrigerants offers a safe alternative to the use of the ozone depleting chlorofluorcarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Global warming and ozone depletion may be the two most important current societal issues that our industry can positively influence. DWSC can contribute a part of the solution to these challenging problems. Further positive DWSC impacts are the elimination of the need for cooling towers and the decreased use of chemically treated colling water. Eliminating cooling tower use can reduce fresh water consumption, noise and blowdown water discharge.
The development of DWSC technology has been criticized by energy conservationists for diluting interest in energy conservation programs. In a worst case scenario, funding could be diverted from energy conservation efforts. According to Amory Levins, a prominent energy analyst, providing abundant and relatively inexpensive DWSC would do nothing to reduce energy consumption for lighting and office equipment.
As is true with any endeavor, there is no free lunch and there is no such thing as a completely renewable resource. The Issue then becomes what level of change can be tolerated. In some DWSC systems, there would be quantities of water withdrawal that would exceed the natural renewability of the resource. Increases in average air temperatures may impact the available cold water resource by depressing the average depth of the thermocline. Natural phenomena, such as wind induced internal wave action, can have a dramatic effect on the position of the thermocline. It will be important to know the limitations of any DWSC system. If sufficient localized proliferation of DWSC occurs, regulatory action may be necessary to protect the resource from degradation.