The National Academy of Engineering (NAE) ranks air conditioning and refrigeration number 10 in its list of the 20 greatest engineering achievements of the 20th century. The selection was based on the impact the technology had on the quality of life during the last century (

As NAE stated "Air conditioning and refrigeration changed life immensely in the 20th century. Dozens of engineering innovations made it possible to transport and store fresh foods and to adapt the environment to human needs. Once luxuries, air conditioning and refrigeration are now common necessities which greatly enhance our quality of life."

However, the futurist Issac Asimov once wrote, "No sensible decision can be made any longer without taking into account not only the world as it is but the world as it will be."

So what can we surmise by this exponential growth in the use of air conditioning? Will other regions of the world see similar growth? That growth will occur globally, and the typical client base for an engineering design will become increasingly international. However, the rate of that growth will depend on a number of variables as explained below.

The HVACR Market

With 38,000 CFC chillers yet to be replaced in the United States alone, there is a large market for new chillers, new technology, and new opportunities for the HVACR industry1.

In 2000, U.S. manufacturers shipped 7,731 non-CFC large chillers for use in the United States and abroad. The Air Conditioning and Refrigeration Institute (ARI) indicates that the new, non-CFC chillers will be 40% more efficient than the CFC units installed 20 years ago. With less energy consumption comes lower CO2 emissions from electrical generating plants.

ARI1 indicates that of the estimated 80,000 centrifugal CFC chillers that existed in the early 1990s, about 52% still relied on the ozone-depleting refrigerants at the start of 2002. The DOE predicts that with the replacement of old chillers by more energy- efficient units, there can be a reduction in energy consumption of 7 billion-kWh/year which will also result in a marked reduction in CO2 production. The U.S. EPA reports that the new, non-CFC chillers are typically one-third more efficient than the older CFC-based chillers and the ROI will be 25% to 35% due to energy savings.

Although shipments of unitary equipment peaked in 2000 followed by a slight decline in 2001 and early 2002, there now appears to be a trend of increased sales over the same period a year ago. For example, in July of 2002, shipments of unitary equipment and heat pumps were up 17% over the year before2. Since April of this year, there has been a consistent increase in shipments each month over the previous year.

What foresight can this information provide regarding the future of the HVACR industry? Trends indicate that the industry is responding to a robust market, that the market is significantly influenced by a concern for energy and the environment and that advancements in technology are responding to those concerns.

Influences on HVACR Applications

Buildings have a significant impact on our global resources. The DOE reports that in the United States, 34 quads of energy are consumed in the residential and commercial building sector each year. Refrigeration and cooling for comfort account for the largest portion of this (48%). Overall, buildings in the United States consume about 35% of the country's total energy consumption.

The Civil Infrastructure Systems Task Force of the U.S. National Science Foundation reported in 1993 that, "The solutions to infrastructure problems are probably 5% technical and 95% social, political, environmental, and economic."

A similar statement could also be made about the HVACR industry. Although as engineers we would like to think that ultimately the appropriate technology will be the final deciding factors in the systems we choose, we know from experience that this is not always true. Although technology is important, there are a multitude of variables that are not technical that affect the options we have for our design. The following is a description of some of these influences.


Few doubt that the energy we presently use is finite. The engineer who designs or operates equipment and systems has a commitment to minimize energy use for the long-term benefit of humanity as well as to save costs for the client. In the United States, the primary driver for energy conservation is not necessarily the finality of the source but the cost savings. Therefore, operating costs are a driver in the adoption of new technology.

Energy will definitely expand the role of the engineer in building design and operation. There will be an increasing need for engineering expertise in modeling building systems, including the building envelope, in the design of a building. In addition, the building operator will require a considerably higher level of technical knowledge as systems become more complex.

An entirely new area of expertise in building design and operation will also arise, as more buildings and systems incorporate on-site electrical power production capabilities. Photovoltaics (solar cells), fuel cells, microturbines, and other distributed generation technologies will all become part of the equipment that engineers will need to consider as they select equipment, design, and construct systems and eventually operate the building once it is occupied.

We can anticipate that energy will continue to play a dominant role in our designs, but we should not assume that we must sacrifice comfort for the sake of energy. Our challenge is to provide comfort while at the same time to conserve energy.


Perhaps more than energy, the environment has had even greater influence on HVACR technology than any other factor. First, ozone depletion became a global issue that is still being resolved. The phaseout of CFCs and other ozone-depleting chemicals continues to be debated even though the world community has agreed to a phaseout schedule. Developing countries are still permitted to produce CFCs and are doing so in record volume. Illegal imports of CFCs to developed countries is a continuing concern.

Likewise, local governments or groups of governments that attempt to ignore the Montreal Protocol cause major disruptions in the planned phaseout of refrigerants. For example, attempts to accelerate the phaseout of HCFCs would ultimately have had damaging effects on our environment, as less efficient equipment would have used more energy, thus increasing the production of CO2. Had this acceleration been adopted by certain nations, the effect would have been a global trade barrier influencing our entire industry, with negative benefit to society. For similar reasons, it is important that nations adopt similar standards that are technically sound and practical to implement.

Policies regarding climate change have also directly affected our industry. As we design and operate more energy-efficient equipment and systems, we use less energy - energy that, in many cases, comes from burning CO2-producing fossil fuels. Like artificial trade barriers, banning a replacement refrigerant such as HFC would have significant negative environmental effects.

When policies are made to protect our environment, the decisions must take into account more than the direct effect on a single environmental variable such as climate change. The decision must also recognize the impact on the indirect effects such as energy efficiency. Likewise, a decision based only on one variable such as ozone depletion could have a significant negative effect on climate change.

As stated by Clifford H. "Ted" Rees Jr., past president of ARI3, "Increased energy efficiency is one of the primary tools for reducing greenhouse gas emissions. When selecting a refrigerant, two significant impacts must be considered together in order to assess the true life-cycle climate performance: the direct effect of the refrigerant's global warming potential, and the indirect effect, represented by the carbon dioxide released in the generation of energy to operate equipment."

The energy consumed in 1998 by the residential and commercial sectors alone resulted in an estimated production of 523 million metric tons of carbon.

ASHRAE past president Jim Wolf noted in his presentations on climate change that if every centrifugal chiller had an efficacy of 0.48 kW/ton vs. 0.56, annual power plant emissions would be reduced by

  • Nearly 17 billion pounds of CO2;
  • Over 64 billion grams of SO2; and
  • Over 27 billion grams of NOx.

Which is equivalent to:

  • Removing over 2 million cars from the road; or
  • Planting nearly 500 million trees each year.

An interesting anomaly resulting from climate change is that some engineers are making an upward adjustment in design conditions that they use when selecting cooling equipment. Although this is only anecdotal information and does not indicate a trend, it does demonstrate that some feel it appropriate to make adjustments. Like energy, the environment continues to impact our industry. Fortunately, our industry has proven that it can respond in a timely way.

As the HVACR industry developed new, environmentally friendly products, the equipment that uses the new refrigerants proved to be more energy efficient. Each of us has an obligation to be prepared to adopt these new technologies in our design. We must also collectively support research that will help our industry meet new challenges in the future.

Human Factors

To reinforce the importance of designing for best value rather than lowest cost, we only need look at total building costs and why we dare not sacrifice environmental control in a building in hopes of saving money. For purposes of comparison only, annual energy costs for an office building in the United States may be approximately $2 to $4/sq-ft/yr. Maintenance and other building and operating costs are similar. The cost to rent or own the property might be approximately $10 to $40/sq-ft/yr. The total cost of personnel who occupy that building will range from $200 to $400/sq-ft/yr.

The point here is that, although the cost of energy can, and should, be minimized it should not be done at the expense of the productivity of the worker. Safety, health, comfort, and productivity are certainly influenced by the HVAC system that controls the environment. Air quality, noise, temperature, and humidity control and, in some cases radiant heat transfer are all controllable variables. As important as is good design, it is equally important that the system be operated to ensure a quality environment.

Beyond the immediate impact on the occupant, the level of control of the environment is also somewhat governed by occupant expectations. For example, in the United States, the occupants dress for indoor conditions that will be somewhat uniform regardless of exterior conditions because the buildings are maintained at a somewhat constant condition year-round. However, this level of precision in climate control may not be demanded by occupants in all countries, particularly with regards to air conditioning, thus clothing will vary accordingly.

As we better understand the impact of the environment on worker productivity, we may see an increased use of individual environmental control systems. Some systems may even provide individual acoustic control devices.

Political and societal influences

Whereas standards that are based on sound technical information and decisions are usually of benefit to a global society, those that have political overtones, particularly those that create a protectionism of local commerce, have a negative effect on both those outside as well as inside the country.

The dialogue between ISO, CEN, and other multinational standard-writing bodies is both commendable and productive. As engineers, we must continue to support the creation of standards based on a consensus of the industry and avoid undue political influence. The sharing of knowledge through conferences, scholarly publications, and cooperative activities of technical societies will all contribute to standards based on sound technical reasons rather than political ones.

There is a growing societal ethic for protecting our environment and extending the availability of our natural resources. "Green buildings" and sustainability are our obligation. The engineer, scientist, and technician can make a major contribution toward satisfying the goal to conserve energy and to minimize the impact of our industry on the environment.

We also have an obligation to ensure that our buildings are safe. In addition to the previously mentioned air quality, as best we can, we must protect the building occupants against injury caused by seismic activity as well as terrorists' actions.


Instant global communication has become commonplace. Already, engineers are regularly transmitting plans and specifications for new equipment and systems over the Internet. We can now be interactive in real time with engineers in multiple locations throughout the globe while we work simultaneously on the same drawing, set of plans, or documents.

Visual communication via a desktop computer allows us to converse face to face. What impact will this have on our industry? It will be significant and will be totally positive. We can now instantly share information regardless of our location. We can draw on the knowledge of individuals throughout the globe as we design and operate systems for the comfort and health of our building occupants.

In addition, the Internet gives us instant access to a vast array of current technology that was previously unavailable. For example, access to data is as easily accessible in Beirut as it is in Atlanta or Washington, DC. However, as engineers, we have an obligation to verify that the information provided on the Web is sound in principle and applicable to our particular need. It is imperative that we maintain a current knowledge of the "state of the art" of our profession so that we can make appropriate decisions in the use of information available to us in digital or printed format.

Looking Ahead

It is impossible to predict the impact of some of the technologies presently under development. For example, systems that do not rely on vapor compression - such as desiccant cooling or thermoacoustic and magnetic refrigeration and even older technologies like thermoelectric or vortex cooling - may all have significant effects on our designs in the future, particularly as there becomes an increased emphasis on personal climate control.

It may be easier to accurately predict the effect of improvements in more traditional technologies such as advances in the development of new refrigerants and in their use. We continue to benefit from improvements in the control of leakages as well as the need for less refrigerant volumes in our equipment. Both Europe and North America are experiencing growth in the use of natural refrigerants, particularly ammonia.

Whereas in the recent past we experienced significant changes in air-handling system designs ranging from VAV to displacement ventilation, innovations in computer-based control systems will likely have an even more dramatic effect on new designs. Many of the controls that once were part of a central EMS controller are now contained in individual pieces of equipment. Likewise, it is becoming more common for multiple buildings to be controlled from a central system with signals sent via the Internet.

As Ken Sinclair, in his article in Engineered Systems4 stated, "Buildings in the near future that do not have a Web presence will be viewed as fixer-uppers."

Regardless of the equipment or controls used, we will definitely see an increase in the integration of the environmental control systems and the building structure. An increasingly popular terminology in our industry is "the building as a system." The communication between the architectural profession and the engineering profession will increase with division of responsibility becoming more integrated.

I also anticipate that we will see a renewed emphasis on our knowledge of human factors. A wealth of information exists on how we respond to the thermal environment, yet humans may be the most complex part of the HVAC system. As we better understand the cause and effect of IAQ on occupants, the interaction with noise, light, air velocity, etc., the better will be our design for environmental control systems. I also anticipate that we will see an expanded use of radiant heating and cooling systems as we integrate the effect of radiation in our comfort control systems.

Specialty environments will also take on increased importance. Special needs in a variety of medical facilities, housing for the aging, manufacturing, and confinement housing for food animals will all present new challenges for our profession.

Preparing for the future

It is not unreasonable to predict that you may be part of a design team with engineers you have never met, working on a building you will never see, in a country where you have never been. Yet you will be in digital communication with your team throughout the day as you make engineering decisions. Instantaneous digital translators will permit the team to speak in their native language and then be translated into the language of the other team members. You will be selected to be part of this team because of some unique engineering skill that you have developed because you were proactive in learning new technologies.

So how will you develop that unique expertise that will cause you to be selected for this engineering team of the future? Conferences and professional meetings are two ways that we disseminate new technology. The Internet has provided us with even more ways to share knowledge.

Your value as an engineer is in what you know and your ability to apply that knowledge. As soon as your knowledge is less than state-of-the-art, your value to your client and employer declines. Therefore, it is imperative that you actively pursue new knowledge to remain competitive as well as meet the needs of your clients and employers. You can do this by designing your future just as you design building systems.

I predict that the future of our industry will be as dependent on lifelong learning as it is on the development of new technology. Virtual electronic classrooms are here today. Distance learning provides an opportunity for engineers from throughout the globe to share their knowledge regardless of their location, time differences, and political boundaries. Virtually everyone in our industry has some knowledge from which the rest of us could benefit.


The rate of change in our industry will be exponential. Some changes will be caused by improvements in technology, whereas others will be the result of influences outside our immediate control. As engineers, we have an obligation to be proactive in encouraging changes that are of benefit to the society that we serve. This, in turn, will have direct benefit to our industry and to each of us individually.

We are a "people-oriented" profession. Our designs have a direct impact on the people who occupy our buildings. We will continue to discover ways to ensure their comfort and health while reducing the impact on the environment and natural resources.

As the futurist Joel Barker stated, "Vision without action is merely a dream, and action without vision just passes the time, but vision with action can change the world." With our vision as engineers, we are changing the world to be a better place. ES

This article is based on a presentation given at the 2002 ASHRAE Annual Meeting and to various chapters of ASHRAE as part of its Distinguished Lecturer Program. For more information about ASHRAE, visit