In less than a year, an important regulation will force a major industry change of which commercial equipment specifiers need to be aware. The U.S. Clean Air Act mandates that the United States stop producing and importing hydrochloroflurocarbon (HCFC) refrigerants, such as the popular R-22 and R-142b, for newly manufactured equipment by Jan. 1, 2010. (Between 2010 and 2020, R-22 and R-142b can be produced or imported for the exclusive purpose of servicing existing equipment.) The phaseout will help eliminate refrigerants that contain chlorine, a substance harmful to the environment. Additionally, most systems using newer, non-chlorine refrigerants are designed to be more energy-efficient.
The phaseout means that new equipment will be designed to work with refrigerants other than R-22. It addresses the reality that approximately one-third of the energy used by commercial buildings is used for heating and cooling. Therefore, it is important that building owners receive heating and cooling systems that are compliant and affordable to maintain.
Global warming is a significant driver of refrigerant choice. Global-warming potential (GWP) is a measure of global warming that considers only the direct effect refrigerant has as a greenhouse gas when it escapes into the atmosphere. However, GWP does not take energy efficiency into consideration.
Hydrofluorocarbons (HFCs), such as R-410A, are global-warming gases. However, because of their combination of high-efficiency performance in air-conditioning systems and low direct GWP value, they have been identified as a good long-term solution for residential and light-commercial air-conditioning by the majority of HVAC-equipment manufacturers.
The air-conditioning industry developed a measure called total equivalent warming impact (TEWI) as a way to assess the impact of various activities on global warming. TEWI is accepted within the HVAC industry as the best measure of global warming because it considers not only direct GWP, but the sizable indirect global warming that results from the carbon dioxide produced by fossil-fuel energy. This calculation includes the effects of system efficiency, electricity sources (coal, nuclear, hydroelectric, etc.), and refrigerants when they escape into the atmosphere. Actual TEWI varies according to leakage rate and the type of power used. The higher energy efficiency of some refrigerants can significantly reduce an indirect effect and offset a somewhat higher direct GWP. Current HFC refrigerants appear to be good options when comparing their total global-warming impacts with those of halogen-free refrigerants. TEWI highlights the importance of overall system efficiency over the life of a product.
Commercial and residential air-conditioning-system manufacturers are focused on developing optimized R-410A systems. The efficiency, performance, and cost advantages of this refrigerant outweigh the disadvantages associated with higher pressures and direct GWP. By selecting the right refrigerant and optimizing the energy efficiency of air-conditioning equipment, greenhouse-gas emissions can be minimized.
Combining legal issues related to the phaseout of HCFC refrigerants in newly manufactured equipment with the environmental benefits of moving toward more earth-friendly refrigerants, it is hoped, will make consultants' and specifiers' jobs a little easier. Not only will it be important to specify heating and cooling systems that use newer refrigerants from a legal point of view, there are many technological and economic benefits to the switch.
Of non-chlorine refrigerants, R-410A is more dense than R-22 and has approximately 50-percent higher pressure and 50-percent higher cooling capacity. System designers are taking advantage of these properties, resulting in increased efficiencies and lower costs. Because R-410A has a higher density, system designers can use smaller tubing. The increased cooling capacity offers better heat transfer in evaporators, which translates into more system capacity. This means designers can use less copper coil in heat exchangers for the same amount of cooling produced with an R-22 system. So, in addition to being more energy-efficient and cost-effective than other refrigerants, R-410A can yield increased performance in new system designs.
As 2010 gets closer, the cost of replacement R-22 refrigerant and/or service parts will increase — a simple case of supply and demand. Though it may be tempting from a short-term cost perspective to provide a building owner with a discounted R-22 system, thought should be given to long-term maintenance costs. Surveys of HVAC contractors already are reporting that the cost of R-22 refrigerant is increasing; this is corroborated by the chemical manufacturers who produce the refrigerant.
As previously mentioned, chemical manufacturers still can produce R-22 to service existing equipment until Jan. 1, 2020. As a result, system manufacturers will be able to use only preexisting supplies of R-22, including refrigerant recovered from existing equipment, for new systems. After that date, chemical manufacturers will no longer be allowed to produce R-22. The U.S. Environmental Protection Agency forecasts shortages of R-22 for the service of older systems after 2014.
For equipment specifiers, refrigerant choice has a long-term impact on one's reputation. It is vital to specify high-efficiency equipment that can be serviced easily for years to come.
For previous Engineering Green Buildings columns, visit www.hpac.com.
Director of commercial-air-conditioning marketing for the air-conditioning division of Emerson Climate Technologies Inc., Bart Powelson has 15 years of experience in the air-conditioning and refrigeration industry. An active participant in the U.S. Green Building Council, he has bachelor's of science and master's of business administration degrees in marketing from Purdue University.