HVAC ENERGY CONSERVATION TIPS AND TECHNIQUES

Periodic international events remind us of the vital role of energy in the economic well-being of developed countries. The ability of common folk in the industrial nations to live more opulent lives than the kings and queens of yesteryear is directly related to the energy servant.


Transportation, communication, agriculture, housing, manufacturing, health care services, and the like are all facilitated by the readily available supplies of energy, both fuel and power.



At the same time, there are recognizable limits to available energy sources. Despite new discoveries, coal, oil, gas, and other fossil or organic fuels can be estimated in total volume, with less this year than there was last. 


There is a finite limit to the potential development of renewable energies, all derived from the sun, such as wood, wind, hydropower, etc. In terms of magnitude, nuclear power (the fusion concept, at that) is the only known energy source that offers hope of being able to industrialize the third world and to sustain a growing world population over centuries rather than decades. 


Yet the use of nuclear power is mired in political quicksand in the United States. The conclusion for the designer of HVAC systems, all of which by definition are energy-managing and energy-consuming, is that there is an international mandate as well as a moral and economic imperative to design systems which are modest in their use of energy. 


Although the United States lacks a well-defined national energy policy, local and regional energy codes give some direction to the HVAC systems designer. These codes encourage the construction of buildings which have lower inherent energy requirements, lighting systems which derive more illumination from fewer watts, and air-handling systems which move more air and water with less fan, pump, and compressor power. 


Most of these codes are based on the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 90.1.


In a time when much HVAC design involves the renovation and retrofit of older buildings and systems, there is good opportunity for substitution of components and system concepts which will provide similar or improved comfort by using less energy. Thus we suggest the five T’s of energy conservation in both new and retrofit construction:


1. Turn it off! There is no substitute for the off switch. Provide a mechanism to turn off energy-using systems when they are not needed.


2. Turn it down! If it has to run, design it to run at the lowest level which will still meet the duty. Try to provide modulating control for all energy consumers.


3. Tune it up! To operators: Keep things in good operating condition. To designers: Design for reliability and for maintainability.


4. Turn it around! For retrofit designers: If you find a system which consumes disproportionate amounts of energy, improve it.


5. Throw it away! If a system is an energy hog and does not lend itself to rehabilitation, be willing to take it out. The retrofit design market for the year 2000 on into the next decades is a major industry market.


One good thing about energy conservation is that it nearly always pays for itself. But sometimes a bit of teaching and long-term vision are needed to get the message to the person controlling the purse strings.


A word of caution. Energy conservation is important in HVAC design, but it is not the purpose or function of the HVAC system. HVAC systems are intended to provide comfort, or a controlled environment.


If we conserve energy to the point that we lose sight of the system’s function, then we have failed in our duty. There is no glory in owning a building that drives tenants away with its energy-conserving but uncomfortable HVAC systems. 


Nor is there gratitude to an energy manager in an electronics plant where the production yield drops for lack of proper air quality even though energy costs are low. ‘‘Waste not, want not’’ is the energy motto. ‘‘Use what you need, but need what you use’’ is a corollary.

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