Academic literature on the topic 'HCFC-22 replacement'

Refrigerants used in air conditioning and refrigeration (AC&R) indusries have come full circle since the beginning of the industrialrevolution. With concern on issues relating to the environment such as the global warming and climate change issues, we should finda better alternative than to continue using these refrigerants that cause global warming and ozone depletion. AC&R industryplayers have blended in by introducing some new equipment and components that are specificallydesigned for hydrocarbon (HC) use. Mostnew refrigerators sold in Malaysia are already equipped with isobutane [a hydrocarbon designated as R-600a by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards]as refrigerants. Malaysia has ratifiedthe Montreal Protocol and targetted a 10% reduction in hydrochlorofluorocarbon(HCFC) consumption, beginning 2016 with the banning of 2.5 horsepower (hp) and below in air-conditioning (AC) equipment to be used. Instead,hydrofluorocarbon(HFC) R-410a was introduced as a replacement for HCFC- 22, whereas in other countries this HFC has been phased down. This article was initiated because of the difficultin findinga replacement for HCFC. Also, the possibilities of using HC as an alternative to replace HCFC insteadof using HFC as a transitional refrigerant in place of HCFC is reviewed in this article. The performance of HC is very similar to HCFC and flmmability issues could be easily overcome with the use of an effectivedesign. Their use could be facilitated with the adaptation of specific standards and properly enacted legislatio

This article discusses design and developments in the refrigeration and compressor fields to deal with Montreal Protocol’s announcement of expiration of R-22 as refrigerant. The Montreal Protocol dictates that by 2010 no new refrigerators or air conditioners will use R-22, a hydrochlorofluorocarbons (HCFC), as a refrigerant. The replacement, known as R-410A, is an HFC (hydrofluorocarbon) rather than an HCFC. Jim Crawford, director of regulatory affairs at The Trane Co., a heating and air conditioning company in Tyler, Texas, said that industry is adopting R-410A primarily in air conditioning. Companies like Trane have used the time allotted by the Montreal Protocol to design, test, and build R-410A equipment for 2010. Compressors have had to be optimized both for the refrigerant and the application. Since the heat characteristics are different between the two refrigerants, heat exchangers must be made larger or smaller. Many new air conditioners, like Trane’s XL16i, already use R-41OA, which contains no chlorine.

Electrical energy consumption in air conditioning systems reaches 60% to 70% of the total electric energy consumption in buildings. Therefore, saving electrical energy consumption in air conditioning systems would have a significant impact on the national electrical energy consumption. Currently, the air conditioning sectors were having a dilemma on finding the alternative substitutes for CFC and HCFC refrigerants which are proven to cause destruction of the ozone layer and contribute to the effects of global warming. This paper will discuss the problems faced by an Article 5 country similar to Indonesia in phasing-out HCFC especially in air conditioning and refrigeration sectors. This paper will also discuss the possibility to use hydrocarbon-based refrigerants, which have zero ozone depletion potential (ODP) and low global warming potential (GWP), in air conditioning sectors. Some results of field applications of this refrigerant will be reported, and in general it can be concluded that the air conditioning retrofitted with hydrocarbon refrigerant consumes 10%–20% less electrical energy. Mixture of R-290 and R-134a was also investigated. R-134a is used to reduce the flammability of R-290 and to make the saturation pressure close to R-22. The results show that at composition of 0.6 R-290/0.4 R-134a mole fractions, the mixture behave as an azeotrope refrigerant mixture and can be used for R-22 replacement. At this composition, lower flammability limit (LEL) is 3693%, which is higher than pure R-290. Hence, the refrigerant mixture can be classified as less flammable A2 class refrigerant. The performance test shows that the refrigerant mixture can be used as a drop-in refrigerant in the R-22 machine. The measurement of refrigeration capacity and compressor input work at the same chilled water temperature shows that the calculated COP of the refrigerant mixture is better than R-22's but lower than R-290's.

Since the 1987 Montreal Protocol, chlorinated refrigerants (CFCs and HCFCs) have been pointed out as responsible for the destruction of the ozone layer. The chemical industry has realized suitable replacement for CFC-12 and for HCFC-22 e.g. HFC-134a, HFC-404A, HFC-410A, HFC-507. This generation of refrigerants developed by the chemical industry can be characterized by the no ozone depleting potential and long atmospheric lifetime resulting in global warming potential. The contribution of the HFCs to the global warming brings up to discussion whether the HFCs should be considered as a transitional substance. Historically the use of natural and ecologically safe refrigerants was a strategy to eliminate environmental problems and avoid uncertainties with synthetic replacement fluids. Since ammonia is toxic, carbon dioxide provide high pressure, and the hydrocarbons are flammable, the general conclusion is often drawn that natural fluids gave safety problems. This paper will describe the possibilities of application as working fluids in low-temperature engineering refrigeration, heat pumping and organic Rankine cycles of the hydrofluoroolefins (HFOs) as third generation of synthetic working fluids.

HCFC-22 is the world�s most widely used refrigerant. It serves in both residential and commercial applications, from small window units to large water chillers, and everything in between. Its particular combination of efficiency, capacity and pressure has made it a popular choice for equipment designers. Nevertheless, it does have some ODP, so international law set forth in the Montreal Protocol and its Copenhagen and Vienna amendments have put HCFC-22 on a phase out schedule. In developed countries, production of HCFC-22 will end no later than the year 2030. Zeotropic blend HFC-407C has been established as a drop-in alternative for HCFC-22 in the industry due to their zero Ozone Depletion Potential (ODP) and similarities in thermodynamic properties and performance. However, when a system is charged with a zeotropic mixture, it raises concerns about temperature glide at two-phase state, differential oil solubility and internal composition shift. Not enough research has been done to cover all aspects of alternative refrigerants applications in the systems. This research intended to explore behavior of this alternative refrigerants compare to HCFC-22 and challenges facing the industry in design, operation service and maintenance of these equipments. The purpose of this research is to investigate behavior of R407C refrigerant in chiller systems. This includes performance and efficiency variations when it replaces R22 in an existing system as well as challenges involved maintaining the system charged with R407C. It is a common practice in the industry these days to evacuate and completely recharge when part of the new refrigerant blend was leaked from the system. This has proved to be extremely costly exercise with grave environmental ramifications. This research is intended to address challenges faced in the real world and practical terms. Theoretical and experimental approaches used as a methodology in this work. The system mathematically modeled to predict detailed system performance and effect of the leak at various conditions. To make this feasible and accurate enough, two separate approaches made, first system performance for pure R22 and R407C, and second system subjected to range of leak fractions. The earlier model was relatively straight forward when compared to the latter. Modeling a system charged with R407C ternary mixture and subjected to range of leaks posed enormous challenges. A sophisticated experimental test apparatus was also designed and built. Comprehensive and detailed tests at various conditions were conducted with special attention on instrumental accuracy and correct methodology. The first part has been successfully modeled and predicted all the factors and performance with excellent accuracy when compared to the test results. In these approaches pure refrigerants R22 and R407C were used and simulated the system behavior at range of conditions. However, the second part was the most challenging ever. Comprehensive leak process simulations produced trends of R32/R125/R134a composition change as function of rate of leak. Starting from this point, equations have been created to represent the composition change as function of percentage of the leak. The system thermodynamic cycle was also modeled to calculate capacity, power input and COP at the range of the conditions. Despite many affecting parameters and complexity of the model, the mathematical model successfully predicted the test outcome with a very reasonable accuracy, averaging around 3% with some times reaching to 5 to 6%. On the experimental stage the system charged with the new HFC-407C was deliberately subjected to refrigerant leak at various leak stages. The aim was to objectively determine to what extend the gas leak can be still acceptable without going through the expensive complete gas charge. The effect of leak was tested and verified at 10% steps, from 10% up to 50% mass fraction for the total charge. It has been observed that at the leaks beyond 30%, the adverse effect on the capacity becomes more significant, from 8 to about 15% decrease. While the power input decreased at slower pace, from 3% up to about 8% depending on the test conditions. This translated to COP decrease ranging from 4 to about 7%. This capacity loss and efficiency decrease are significant figures which suggests that the system, here chiller, can not be allowed to degrade the performance to that extend and still continue operating.

Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, 2006.
A thesis submitted for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2006. Typescript. Includes bibliographical references (p. 123-127).