viernes, 30 de junio de 2017
martes, 27 de junio de 2017
lunes, 26 de junio de 2017
Important HVAC Regulations to Watch Out for in 2017
With the new administration in place, HVAC contractors across the
country are awaiting to see how it will influence their work. The
administration has repeatedly said that it intends to stop or withdraw
some of the legislation which was set in motion during the previous
mandate. And while it has made good on some of its promises — such as
pulling the so-called 'blacklisting rule' — its standing on other rules
currently remains unclear.
But even without the administration passing much new legislation concerning contractors, there are already a number of HVAC regulations that contractors need to keep in mind this year. Some have already went into effect while others will be rolling out soon. Below is a list of four regulations contractors should be aware of:
These revisions have extended the already applicable requirements for handling ODSs such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in air conditioning and refrigeration equipment to include substitutes such as hydrofluorocarbons (HFCs).
In terms of sales of such substances:
According to the new efficiency standards adopted by the Department of Energy (DOE), as of January 2018, the minimum efficiency of new rooftop air conditioners on low-rise buildings will need to increase by 10 percent in comparison to current standards. And as of 2023, that efficiency will need to increase up to 25-30 percent. New warm-air furnaces will also see a change in their efficiency standards, starting 2023.
The new regulations includes standards for seasonal energy efficiency ratio (SEER), heating seasonal performance factor (HSPF), and energy efficiency ratio (EER) of air conditioners and heat pumps. As with previous regulations, the DOE has retained the division of the country into three regions (North, South, and Southwest), with different standards applying to each region.
The DOE is yet to announce the test procedures which it will follow in establishing the efficiency of central air conditioners and heat pumps. It is expected that it will publish the final rule on these procedures by July 3, 2017.
Further provisions with delayed effective dates that employers need to comply with include:
But even without the administration passing much new legislation concerning contractors, there are already a number of HVAC regulations that contractors need to keep in mind this year. Some have already went into effect while others will be rolling out soon. Below is a list of four regulations contractors should be aware of:
1. SNAP Refrigerants Regulation
Last year the requirements for handling ozone-depleting substances (ODSs) in Section 608 of the Clean Air Act were revised. As of January 1, 2017, technicians, operators, and owners of refrigeration equipment have been asked to comply with new rules.These revisions have extended the already applicable requirements for handling ODSs such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in air conditioning and refrigeration equipment to include substitutes such as hydrofluorocarbons (HFCs).
In terms of sales of such substances:
- As of January 1, 2017, recovered ODSs and substitute refrigerants can only be resold to certified reclaimers of such substances
- As of January 1, 2018, recovered ODSs and substitutes can only be sold to certified technicians
- Pass a certification exam that will allow them to handle ODSs and substitute refrigerants
- Keep a copy of their certificate at their place of business at all times (as well as retain a copy up to 3 years after ceasing to operate as a technician)
- Keep precise records when disposing of appliances that contain between 5 and 50 pounds of refrigerant
- Evacuate ODSs and substitutes to new levels when opening or disposing of appliance with certified equipment
- 30 percent for industrial process refrigeration (IPR; over 500 pounds)
- 20 percent for commercial refrigeration equipment (50-500 pounds)
- 10percent for comfort cooling equipment (50 pounds or more)
2. Rooftop Units Regulation
Beginning 2018, HVAC manufacturers and other professionals who work with commercial air conditioners and heat pumps and commercial warm-air furnaces will need to comply with new efficiency requirements as well.According to the new efficiency standards adopted by the Department of Energy (DOE), as of January 2018, the minimum efficiency of new rooftop air conditioners on low-rise buildings will need to increase by 10 percent in comparison to current standards. And as of 2023, that efficiency will need to increase up to 25-30 percent. New warm-air furnaces will also see a change in their efficiency standards, starting 2023.
3. Residential Central Air Conditioners and Heat Pumps Regulation
On May 26, the DOE also provided notice of the adoption of the new energy conservation standards for residential central air conditioners and heat pumps. During the preceding months, the DOE received comments regarding the new standards but found that they did not provide a reasonable basis to withdraw the new standards.The new regulations includes standards for seasonal energy efficiency ratio (SEER), heating seasonal performance factor (HSPF), and energy efficiency ratio (EER) of air conditioners and heat pumps. As with previous regulations, the DOE has retained the division of the country into three regions (North, South, and Southwest), with different standards applying to each region.
The DOE is yet to announce the test procedures which it will follow in establishing the efficiency of central air conditioners and heat pumps. It is expected that it will publish the final rule on these procedures by July 3, 2017.
4. OSHA Walking-Working Surfaces and Fall Protection Standards
Тhe new OSHA fall protection standards are another piece of legislation that contractors must comply with as of January 17, 2017. The new standards are designed to allow for greater flexibility to employers in choosing a fall protection system. Employers can choose from a guardrail system, safety net system, personal fall arrest system, positioning system, travel restraint system, or ladder safety system.Further provisions with delayed effective dates that employers need to comply with include:
- Inspecting and certifying permanent anchorages for rope descent systems (November 20, 2017);
- Installing personal fall arrest or ladder safety systems on new fixed ladders over 24 feet and on replacement ladders/ladder sections, including fixed ladders on outdoor advertising structures (November 19, 2018);
- Ensuring existing fixed ladders over 24 feet, including those on outdoor advertising structures, are equipped with a cage, well, personal fall arrest system, or ladder safety system (November 19, 2018); and
- Replacing cages and wells (used as fall protection) with ladder safety or personal fall arrest systems on all fixed ladders over 24 feet (November 18, 2036).
sábado, 24 de junio de 2017
miércoles, 21 de junio de 2017
Should Ammonia Exit ASHRAE Standard 15?
Is it time to remove ammonia from ASHRAE Standard 15, “Safety Standard for Refrigeration Systems?”
Jeffrey M. Shapiro, president, International Code Consultants, says yes, although he cautions that the ammonia refrigeration industry must be prepared to continue its diligence in maintaining a standard that will ensure safe designs for ammonia refrigeration systems.
Shapiro, speaking at a recent meeting of the International Institute of Ammonia Refrigeration (IIAR), noted that with the ongoing phaseout of hydrochlorofluorocarbons (HCFCs) and phasedown of hydrofluorocarbons (HFCs) there is a focus on the approval of new refrigerants that fall under the ASHRAE classification of A2L — nontoxic but mildly flammable.
According to Shapiro, although there may be a temptation to simply treat A2L refrigerants as equivalent to ammonia with respect to flammability hazard, ammonia really is an entity unto itself. Like an A2L, it exhibits a low-flame velocity in flammability tests, but ammonia has the unique safety advantage of a strong and unmistakable odor that is typically present long before the onset of a flammability hazard. All of the current A2L refrigerants, on the other hand, are odorless.
“Do we really want to be putting an odorless, flammable gas in occupied spaces of commercial and residential structures?” asked Shapiro. “Is this a good idea? And, can we do it safely?”
Shapiro noted that these are the questions that need to be answered as a condition of A2L refrigerants entering mainstream usage in the U.S.
“To the credit of the A2L industry, they’re putting a lot of time and effort into safety research,” he said. “But, just like ammonia, standards for the design and installation of A2L systems must be crafted with due diligence.”
Shapiro said leak detection remains a concern with respect to deploying A2L refrigerants, unlike ammonia, with which there are many years of experience with leak detection. And while IIAR now provides detailed requirements on ammonia leak-detection systems in its standard, no such requirements are in place for A2L refrigerants.
Shapiro said a concern with ammonia remaining under ASHRAE 15 is that the parameters defining Group 2L refrigerants in ASHRAE could change at some point, perhaps forcing ammonia to be reclassified from Group B2L to Group B2.
“That would damage the ammonia refrigeration industry by increasing regulations with no justification other than an academic revision to the refrigerant classification scheme,” he said.
At the most recent ASHRAE Standard 15 committee meeting, Shapiro said the committee approved publishing an addendum for public comment that would remove ammonia from the standard. That’s the first of several steps that would have to take place, but the process could potentially lead to ammonia being taken out of ASHARE Standard 15 and put under ANSI/IIAR 2-2014, “American National Standard for Safe Design of Closed-Circuit Ammonia Refrigeration Systems.”
If that were ultimately to happen, Shapiro said, it would come with a great responsibility.
“If IIAR 2 is going to be the sole standard for ammonia safety without ASHRAE 15, we must continue to be diligent in managing that responsibility and in making sure our systems and the people who use them, and work on them are safe,” he said.
This would not be unfamiliar ground for IIAR, Shapiro noted. Since publishing its first ANSI standard in 1978, IIAR has been expanding its role as a standards development organization for ammonia refrigeration, and a mist of its model standards have been adopted by model codes. For example, the National Electrical Code (NEC) specifically references IIAR 2 for the electrical classification of areas with ammonia refrigeration systems. The International Fire Code (IFC) cites ASHRAE Standard 15 for refrigerants other than ammonia and IIAR 2 for ammonia, thus elevating IIAR 2 from its former subordinate role and placing the two standards on par.
“It’s a pretty big deal to get an NEC reference, and the IFC reference also represents a significant elevation in stature for IIAR 2,” Shapiro said.
The 2018 Uniform Mechanical Code (UMC) is actually going to go a step further. It, along with ASHRAE 15, will serve to regulate all refrigeration except for ammonia while, for ammonia, the 2018 UMC will defer entirely to IIAR 2.
“It’s very significant for a code to entirely defer to a reference standard,” Shapiro noted. “It achieves what I consider to be a major milestone for IIAR as an organization. Certainly, no other refrigeration-oriented standard has that stature.”
“Donald Trump talked a lot about regulatory reform on the campaign trail,” Randel said. “Now that he has taken office, I think it has proven to be a priority for his administration. His chief of staff has basically frozen any action on regulations until the new administration has a chance to get its legs under it, and that includes extending the effective date of any late-term Obama regulations that had been finalized but hadn’t gone into effect.”
Randel cited the U.S. Environmental Protection Agency’s (EPA’s) risk management program (RMP) final rule as an example of how the Trump administration may handle rules that affect the ammonia refrigeration industry. The administration extended the effective date of the RMP’s final rule until June 19 and has also proposed a rule that would further extend the effective date until February 2019. The additional time is designed to give new EPA policy officials an opportunity to fully examine the rule and potentially make changes.
President Trump also issued a “two-for-one” executive order that called for the removal of two existing regulations for every one new regulation. Although this would only apply to major rules with a potential annual impact of $100 million or more, it still sends a promising message to businesses, he said.
“It’s encouraging to hear the administration say it wants to reduce the regulatory burden on industry,” Randel said. “We think it’s a good general policy to perform a thorough review and remove any old, outdated, duplicative regulations before adding new ones.”
Randel stated he also is a fan of a Trump executive order that calls for the establishment of a regulatory reform task force at each agency. These groups would be tasked with identifying unnecessary and ineffective regulations and then doing what it can to get them off the books. The process also includes an accountability mechanism to measure the performance of government agencies relative to the executive order.
Randel added that interactions with regulatory agencies do not have to be divisive. For example, IIAR continues to work with the EPA on the agency’s national enforcement initiative (NEI).
“IIAR’s goal is to help the EPA better understand ammonia refrigeration facilities and IIAR standards, so the agency can do a better job of identifying where any true problems may exist in a facility,” he said. “This would also benefit operators of ammonia refrigeration facilities, who would be welcoming better-educated inspectors to their facilities and hopefully avoiding the misapplication of standards not appropriate for our industry.”
Randel concluded that the atmosphere for regulatory reform is very active right now, which presents an opportunity for HVACR contractors to participate in the process.
“The administration is actively seeking input and suggestions on regulations that are problematic, unnecessary, or duplicative and need to be reviewed,” he said. “So, if you have an idea of something that needs to be changed or recognize that something is not working, communicate that through your industry associations so they can amplify the message to the policy officials. I definitely encourage people to identify and communicate where they see ways to improve the regulatory system.”
Jeffrey M. Shapiro, president, International Code Consultants, says yes, although he cautions that the ammonia refrigeration industry must be prepared to continue its diligence in maintaining a standard that will ensure safe designs for ammonia refrigeration systems.
Shapiro, speaking at a recent meeting of the International Institute of Ammonia Refrigeration (IIAR), noted that with the ongoing phaseout of hydrochlorofluorocarbons (HCFCs) and phasedown of hydrofluorocarbons (HFCs) there is a focus on the approval of new refrigerants that fall under the ASHRAE classification of A2L — nontoxic but mildly flammable.
According to Shapiro, although there may be a temptation to simply treat A2L refrigerants as equivalent to ammonia with respect to flammability hazard, ammonia really is an entity unto itself. Like an A2L, it exhibits a low-flame velocity in flammability tests, but ammonia has the unique safety advantage of a strong and unmistakable odor that is typically present long before the onset of a flammability hazard. All of the current A2L refrigerants, on the other hand, are odorless.
“Do we really want to be putting an odorless, flammable gas in occupied spaces of commercial and residential structures?” asked Shapiro. “Is this a good idea? And, can we do it safely?”
Shapiro noted that these are the questions that need to be answered as a condition of A2L refrigerants entering mainstream usage in the U.S.
“To the credit of the A2L industry, they’re putting a lot of time and effort into safety research,” he said. “But, just like ammonia, standards for the design and installation of A2L systems must be crafted with due diligence.”
Shapiro said leak detection remains a concern with respect to deploying A2L refrigerants, unlike ammonia, with which there are many years of experience with leak detection. And while IIAR now provides detailed requirements on ammonia leak-detection systems in its standard, no such requirements are in place for A2L refrigerants.
Shapiro said a concern with ammonia remaining under ASHRAE 15 is that the parameters defining Group 2L refrigerants in ASHRAE could change at some point, perhaps forcing ammonia to be reclassified from Group B2L to Group B2.
“That would damage the ammonia refrigeration industry by increasing regulations with no justification other than an academic revision to the refrigerant classification scheme,” he said.
At the most recent ASHRAE Standard 15 committee meeting, Shapiro said the committee approved publishing an addendum for public comment that would remove ammonia from the standard. That’s the first of several steps that would have to take place, but the process could potentially lead to ammonia being taken out of ASHARE Standard 15 and put under ANSI/IIAR 2-2014, “American National Standard for Safe Design of Closed-Circuit Ammonia Refrigeration Systems.”
If that were ultimately to happen, Shapiro said, it would come with a great responsibility.
“If IIAR 2 is going to be the sole standard for ammonia safety without ASHRAE 15, we must continue to be diligent in managing that responsibility and in making sure our systems and the people who use them, and work on them are safe,” he said.
This would not be unfamiliar ground for IIAR, Shapiro noted. Since publishing its first ANSI standard in 1978, IIAR has been expanding its role as a standards development organization for ammonia refrigeration, and a mist of its model standards have been adopted by model codes. For example, the National Electrical Code (NEC) specifically references IIAR 2 for the electrical classification of areas with ammonia refrigeration systems. The International Fire Code (IFC) cites ASHRAE Standard 15 for refrigerants other than ammonia and IIAR 2 for ammonia, thus elevating IIAR 2 from its former subordinate role and placing the two standards on par.
“It’s a pretty big deal to get an NEC reference, and the IFC reference also represents a significant elevation in stature for IIAR 2,” Shapiro said.
The 2018 Uniform Mechanical Code (UMC) is actually going to go a step further. It, along with ASHRAE 15, will serve to regulate all refrigeration except for ammonia while, for ammonia, the 2018 UMC will defer entirely to IIAR 2.
“It’s very significant for a code to entirely defer to a reference standard,” Shapiro noted. “It achieves what I consider to be a major milestone for IIAR as an organization. Certainly, no other refrigeration-oriented standard has that stature.”
AN ENCOURAGING OUTLOOK FOR REGULATORY REFORM
Lowell Randel, vice president of government and legal affairs, Global Cold Chain Alliance, also spoke at the IIAR meeting. When it comes to regulatory reform, the direction of the Trump administration is encouraging for the ammonia refrigeration industry, he said.“Donald Trump talked a lot about regulatory reform on the campaign trail,” Randel said. “Now that he has taken office, I think it has proven to be a priority for his administration. His chief of staff has basically frozen any action on regulations until the new administration has a chance to get its legs under it, and that includes extending the effective date of any late-term Obama regulations that had been finalized but hadn’t gone into effect.”
Randel cited the U.S. Environmental Protection Agency’s (EPA’s) risk management program (RMP) final rule as an example of how the Trump administration may handle rules that affect the ammonia refrigeration industry. The administration extended the effective date of the RMP’s final rule until June 19 and has also proposed a rule that would further extend the effective date until February 2019. The additional time is designed to give new EPA policy officials an opportunity to fully examine the rule and potentially make changes.
President Trump also issued a “two-for-one” executive order that called for the removal of two existing regulations for every one new regulation. Although this would only apply to major rules with a potential annual impact of $100 million or more, it still sends a promising message to businesses, he said.
“It’s encouraging to hear the administration say it wants to reduce the regulatory burden on industry,” Randel said. “We think it’s a good general policy to perform a thorough review and remove any old, outdated, duplicative regulations before adding new ones.”
Randel stated he also is a fan of a Trump executive order that calls for the establishment of a regulatory reform task force at each agency. These groups would be tasked with identifying unnecessary and ineffective regulations and then doing what it can to get them off the books. The process also includes an accountability mechanism to measure the performance of government agencies relative to the executive order.
Randel added that interactions with regulatory agencies do not have to be divisive. For example, IIAR continues to work with the EPA on the agency’s national enforcement initiative (NEI).
“IIAR’s goal is to help the EPA better understand ammonia refrigeration facilities and IIAR standards, so the agency can do a better job of identifying where any true problems may exist in a facility,” he said. “This would also benefit operators of ammonia refrigeration facilities, who would be welcoming better-educated inspectors to their facilities and hopefully avoiding the misapplication of standards not appropriate for our industry.”
Randel concluded that the atmosphere for regulatory reform is very active right now, which presents an opportunity for HVACR contractors to participate in the process.
“The administration is actively seeking input and suggestions on regulations that are problematic, unnecessary, or duplicative and need to be reviewed,” he said. “So, if you have an idea of something that needs to be changed or recognize that something is not working, communicate that through your industry associations so they can amplify the message to the policy officials. I definitely encourage people to identify and communicate where they see ways to improve the regulatory system.”
Diagnosing a Faulty HVAC Compressor Valve
Diagnosing a faulty compressor valve is something HVAC technicians
have to deal with on a semi-regular basis, and while a bad valve is
often not the main reason a compressor fails, it is an integral part of
any condensing unit.
Members of The
NEWS’ trainer panel examined compressor valves and determined the best
methods for maintaining valves, diagnosing faulty ones, and implementing
proper troubleshooting techniques when they go bad.
NOTICING THE ISSUE
Joseph
Adeszko, program coordinator, HAC department, Moraine Valley Community
College, Palos Hills, Illinois, does not see bad compressor valves as
much as he used to, mainly because current technicians are doing a
better job of properly reading subcooling and superheat during service visits. Still, “technicians need to know the inner workings of a compressor to properly diagnose it,” he said.
Reciprocating compressors themselves have been around for decades.
“They
are reliable, dependable, and still looked at as the industry standard
by many people,” said Dennis Silvestri, lead instructor, MRS Educational
Training, New Haven, Connecticut. “Still available in the semi-hermetic
and fully welded hermetic designs, more reciprocating compressors fail
due to various electrical related issues than from compressor valve
problems. However, when you take a close look at reciprocating
compressor valve design, especially the ‘reed type,’ then we can see
what’s looked at as the ‘weak spot.’ The valves will wear, leak, and
even break. Floodback and slugging, even flooded starts can cause issues
with the valves.”
According
to Nicholas Griewahn, associate professor of HVACR, Northern Michigan
University, Marquette, Michigan, it is very important to be
knowledgeable about diagnosing any capacity loss in a compressor, mainly
for the sake of the customer.
“A
lot of time and money can be wasted on misdiagnosis, and it usually
ends with a lost customer,” said Griewahn. “Not only is it important to
be able to diagnose when capacity is lost due to damaged valves but also
what caused the damage. Valves that are leaking through due to
overheating call for very different diagnostic and corrective actions
than valves that are snapped off because of liquid slugging. I’m a big
believer that every compressor fails for a reason, and you should always
find the cause and correct it before or when you install a
replacement.”
Being
able to recognize the symptoms of a faulty valve are essential, and
Adeszko said problems can stem from a number of things.
“The
symptoms could be a loss of cooling or refrigeration,
higher-than-normal suction pressures with low discharge pressures, the
compressor being very quiet, or low amp draw,” he said.
Griewahn said he normally hears complaints of the system not maintaining the temperature setting during a mild load.
“In
refrigeration, the conditioned space will never make the control
setting, or the customer will notice the compressor running a lot more
than usual,” he said. “In air conditioning, the room temperature will
rarely, or never, make the thermostat setting. Really savvy customers
may notice an increase in their electric bills without a correlation
with the outdoor temperature. Valves that are damaged enough may cause
the compressor to overheat and overload, which leads to a no cooling
call.”
THE NECESSARY STEPS
Once a technician has recognized the issue, there are a few different steps needed to properly address it.
“An
in-depth procedure of checking the compressor valves requires the
compressor to have a suction service valve and the technician use their
low-side manifold pressure gauge,” said Silvestri. “With the compressor
off and the low-side pressure gauge installed onto the suction service
valve, front seat the suction service valve and turn on the compressor.
The low-side gauge should read at least a 20-inch vacuum within a minute
or so. If the gauge cannot read at least a 20-inch vacuum, then the
compressor’s suction valves are leaking, which means they are not fully
closing shut. The compressor’s discharge valves can also be checked to
see if they are leaking.”
Griewahn said it’s important to note that the first hint of trouble usually comes from the pressure readings.
“If
you’re familiar with estimating high- and low-side pressure, you’ll
notice the high-side pressure will be lower than normal and the low side
will be operating higher than normal,” he said. “Pressures being too
close together are the usual suspects for lost pumping capacity. I’ll
check superheat to confirm the metering device isn’t grossly overfeeding
and make sure there aren’t any hot gas valves bleeding through or
sticking open and rule them out. To confirm low pumping capacity, I
usually check for abnormal line temperatures, low compressor amp draw,
and an overheated compressor shell. Sometimes, depending on how badly
the valves or compressor are damaged, you’ll hear the valves bypass when
the compressor is turned off. If a whistling or ‘whooshing’ sound is
heard — not to be confused with the check valve seating in a scroll
compressor — when the compressor is turned off, it is likely that the
valves or other internal components are bypassing and faulty.”
Adeszko
added that there are no shortcuts to take when troubleshooting
compressor valves. “A good tech must gather the data necessary to
troubleshoot the system before analyzing the data to see what the issue
may be,” he said.
A FULL REPLACEMENT
While
the panel members agreed on most parts of the diagnostic process, they
had differing opinions on when exactly it is time to replace an entire condensing unit.
In
Adeszko’s opinion, if the compressor is more than five years old on a
residential condensing unit, it’s better to replace the condensing unit
completely. “This way the end user gets a new unit with a full five- to
10-year parts warranty,” he said. “The cost is not much more than a
compressor-only change out.”
When
faced with leaking or broken valves with the fully welded hermetic
compressor design, the discussion needs to revolve around replacing the
compressor or the entire condensing unit, said Silvestri.
“With
the semi-hermetic type, there is the option of replacing the
compressor’s complete valve plate(s),” he said. “This is not that
difficult of a compressor tear down, especially if the compressor has
both a suction service valve and a discharge service valve. This allows
for simple isolation of the compressor from the rest of the system. Many
factors need to be looked at when considering to replace/rebuild the
compressor or just replace the entire condensing unit, such as age of
the system, past problems, and how many refrigerant retrofits the system
has gone through.”
Griewahn recommends a full replacement of a condensing unit if it meets one or more of the following conditions:
- The cost of purchasing and installing a new condensing unit is the same or lower than a new compressor;
- The condensing unit is available sooner when the equipment is mission critical;
- There is substantial or unrepairable damage or corrosion on the old condenser or unit base; or
- There is a condensing unit replacement option that will substantially increase efficiency for the owner.
What’s Happening With R-134a?
Here are some alternatives to replace the venerable but high-GWP refrigerant
For many years, hydrofluorocarbon (HFC)-134a was the alternate refrigerant of choice to replace chlorofluorocarbon (CFC)-12 in many medium- and high-temperature stationary refrigeration, air conditioning, and automotive air conditioning applications. The pressure/temperature relationship and the latent heat values of R-134a are very similar to those of R-12. Also, R-134a is a very safe refrigerant with an ASHRAE safety classification of A1. This means it is not flammable and has very low toxicity levels. Because HFC-134a has no chlorine in its molecule, it has a zero ozone-depletion potential (ODP) and doesn’t deplete the stratospheric ozone layer.R-134a is not a refrigerant blend. It is considered a pure compound and has only one molecule. The R-134a molecule is ethane-based and consists of carbon (C), fluorine (F), and hydrogen (H).
EVAPORATOR TEMPERATURE APPLICATION
As a medium- and high-temperature refrigerant, R-134a is not usually used in low-temperature applications. R-134a loses some capacity when compared to R-12 in low-temperature applications. At lower temperatures, R-134a has a slightly lower pressure than R-12, and at higher temperatures, R-134a has a bit of a higher pressure when compared to R-12. Otherwise, both refrigerants’ pressure/temperature relationships closely compare.R-134a often operates with a very low pressure — if not a slight vacuum — in low-temperature applications. At about minus 15°F evaporating temperature, R-134a starts to fall into a vacuum. These lower pressures in lower temperature applications cause higher compression ratios, higher discharge temperatures, and low efficiencies — not to mention added stress on a system’s compressor.
LUBRICANT
R-134a refrigeration systems use synthetic polyolester (POE) lubricants while the automotive industry typically has used polyalkylene glycol (PAG) lubricants. Polarity differences between commonly used organic mineral oils and HFC refrigerants make R-134a insoluble, thus incompatible with mineral oils that were used in many refrigeration and air conditioning applications. R-134a was never intended to be a direct drop-in replacement for any refrigerant, and retrofit guidelines had to be followed when retrofitting a system to R-134a.GLOBAL WARMING LEGISLATION
R-134a has a global-warming potential (GWP) of 1,430. This means it traps 1,430 times as much heat per kilogram as carbon dioxide does over a 100-year period. Because R-134a has such a high GWP, the U.S. Environmental Protection Agency (EPA) listed R-134a as an “unacceptable” refrigerant for certain refrigeration and air conditioning applications under its Significant New Alternatives Policy (SNAP) program. These applications include:- New light-duty motor vehicle air conditioning, starting in 2021, with a few narrow use limit exceptions. The exceptions are for newly manufactured light-duty vehicles destined for use in countries that do not have infrastructures in place for servicing with other acceptable refrigerants. The narrow use limit will continue through model year 2025;
- Beginning in model year 2026, R-134a will be unacceptable for use in all newly manufactured light-duty vehicles;
- New vending machines as of Jan. 1, 2019;
- New stand-alone, medium-temperature units with a compressor capacity below 2,200 Btuh not containing a flooded evaporator as of Jan. 1, 2019; and
- New stand-alone, medium-temperature units with a compressor capacity equal to or greater than 2,200 Btuh and stand-alone medium-temperature units containing a flooded evaporator as of Jan. 1, 2020.
SOME R-134a REPLACEMENT OPTIONS
There are a number of candidates to replace R-134a in the applications for which it will be deemed unacceptable by the EPA.- HFO-1234yf — Hydrofluoroolefin (HFO)-1234yf is a low-GWP replacement for R-134a intended for use in mobile air conditioning systems in the automotive industry. It has an ODP of zero and a GWP of 4. HFO-1234yf’s GWP is more than 300 times less than that of R-134a. Many European and some U.S. car manufacturers are currently using HFO-1234yf for mobile air conditioning applications. HFO-1234yf has one of the lowest switching cost for automakers compared to other alternatives. It is classified as a low-toxicity but slightly flammable refrigerant by ASHRAE with an A2L safety classification. The continued development of standards and codes for safe use of mildly flammable A2L refrigerants is very important. HFO-1234yf is miscible in POE lubricants. The miscibility of HFOs with POE lubricants is comparable to that of R-134a. HFOs are not soluble in mineral oil or alkylbenzene lubricants.
- HFO-1234ze — HFO-1234ze can be used in vending machines, refrigerators, beverage dispensers, air dryers, and carbon dioxide cascade systems in commercial refrigeration. It has an ODP of zero and a GWP of 6. Other applications include both air- and water-cooled chillers in supermarkets and commercial buildings. HFO-1234ze offers excellent energy efficiency, is cost-effective, and can be used in existing equipment design with minimal changes. HFO-1234ze also offers advantages over R-32, which has a medium GWP, an A2 refrigerant safety rating, and high discharge temperatures. The miscibility of HFO-1234ze with POE lubricants is comparable to that of R-134a.
- HC-290 (Propane) — Hydrocarbon (HC)-290 has an A3 safety group classification, meaning it is highly flammable. Its molecule contains nothing but hydrogen and carbon. It has an ODP of zero and a GWP of 3. As long as the refrigerant charge doesn’t exceed 5.3 ounces (150 grams), it can be used in freezers, household refrigerators, combination refrigerators and freezers, room air conditioners, and vending machines. As with the A2L refrigerants, the continued development of standards and codes for safe use of flammable refrigerants is very important.
- HC-600a (Isobutane) — Like HC-290, HC-600a has an A3 (highly flammable) safety group classification. Its molecule contains hydrogen and carbon. It has an ODP of zero and a GWP of 3. As long as the refrigerant charge does not exceed 2 ounces (57 grams), it can be used in vending machines and retail food refrigeration (stand-alone commercial refrigerators and freezers). Again, the continued development of standards and codes for the safe use of HCs is very important.
- R-513A — R-513A is an HFO/HFC blend with an ODP of zero and a GWP of 63. R-513A has a close performance match to R-134a for new and retrofitted systems. It is the lowest GWP refrigerant in the A1 safety classification to replace R-134a in stationary systems.
- R-450A — R-450A is a near-azeotropic refrigerant blend containing an HFO refrigerant designed to replace R-134a in commercial and industrial refrigerators as well as air conditioning and chillers. It has a very low temperature glide and can be used in direct expansion or flooded evaporator systems. It is compatible with POE lubricants.
martes, 20 de junio de 2017
domingo, 18 de junio de 2017
Graphene oxide discovery helps boost rechargeable batteries
A
Kansas State University engineering team has discovered some of the
properties of graphene oxide could help improve sodium- and lithium-ion
flexible batteries.
The
researchers found that sodium storage capacity of paper electrodes
depends on the distance between the individual layers that can be tuned
by heating it in argon or ammonia gas. For example, reduced graphene
oxide sheets, or rGO, produced at high temperature have near zero sodium
capacity, while reduced graphene oxide sheets produced at 500 degrees C
have the maximum capacity.
Gurpreet Singh, assistant professor of mechanical and nuclear engineering, and Lamuel David, doctoral student in mechanical engineering, India, have published their findings in the Journal of Physical Chemistry in an article entitled 'Reduced graphene oxide paper electrode: Opposing effect of thermal annealing on Li and Na cyclability'.
Graphene oxide is an insulating and defective version of graphene that can be converted to a conductor or a semiconductor when it is heated. Singh and his team studied graphene oxide sheets as flexible paper electrodes for sodium- and lithium-ion batteries.
"The observation is important because graphite, which is a precursor for making graphene oxide, has negligible capacity for sodium and has long been ruled out as viable electrode for sodium-batteries," Singh said. "Graphite is the material of choice in current lithium-ion batteries because the interlayer spacing is just right for the smaller size lithium ions to diffuse in and out."
The researchers are the first to show that a flexible paper composed entirely of graphene oxide sheets can charge and discharge with sodium-ions for more than 1,000 cycles. Sodium perchlorate salt dissolved in ethylene carbonate served as the electrolyte in their cells.
"Most lithium electrode materials for sodium batteries cannot even last for more than a few tens of charge and discharge cycles because sodium is much larger than lithium and causes enormous volume changes and damage to the host material," explained Singh. "This design is unique because the distance between individual graphene layers is large enough to allow fast insertion and extraction of the sodium ions, thanks to the oxygen and hydrogen atoms that prevent sheets from restacking."
Singh and his team also studied the mechanical behavior of the electrodes made of reduced graphene oxide sheets. The researchers measured the strain required to tear apart the electrodes. Through videography, they showed the ability of the crumpled graphene oxide papers to sustain large strains before failing.
"Such measurements and study of failure mechanisms are important for designing long-life batteries because you want the electrode to be able to expand and contract repeatedly without fracture for thousands of cycles, especially for larger nonlithium metal-ion batteries," Singh said. "These days, almost every one is using crumpled graphene as either the conducting agent or elastic support or both."
Earlier this year, Singh and his team demonstrated large-scale synthesis of few-layer-thick sheets of molybdenum disulfide. They also showed the molybdenum disulfide/graphene composite paper has potential as a high-capacity electrode for sodium-ion battery. In that research, the scientists used graphene as an electron conductor for the molybdenum disulfide sheets and observed graphene to be largely inactive toward sodium.
Their latest research has shown that unlike sodium, the lithium capacity of rGO increases with increasing rGO synthesis temperature reaching maximum value for sample produced at 900 degrees C.
"It is only now we realize that sodium capacity of graphene, or rGO, is dependent on its processing temperature," Singh said. "The rGO specimens in our previous study were prepared at 900 degrees C."
The large abundance of sodium makes the element a potential candidate for replacing lithium-ion batteries.
By focusing on nanotechnology, Singh and his team have been able to explore and design materials that can store sodium-ions reversibly and without damage. They found their answer in graphene oxide, which can cycle sodium-ions for more than 1,000 cycles.
Singh and his team will continue exploring new nanomaterials and focus on materials that can be mass-produced in a cost-effective manner.
"We would like to perform fundamental studies to understand the origins of first cycle loss, voltage hysteresis, and capacity degradation that are common to metal-ion battery anodes prepared from 2-D layered crystals such as transition metal chalcogenides, graphene, etc.," Singh said.
Gurpreet Singh, assistant professor of mechanical and nuclear engineering, and Lamuel David, doctoral student in mechanical engineering, India, have published their findings in the Journal of Physical Chemistry in an article entitled 'Reduced graphene oxide paper electrode: Opposing effect of thermal annealing on Li and Na cyclability'.
Graphene oxide is an insulating and defective version of graphene that can be converted to a conductor or a semiconductor when it is heated. Singh and his team studied graphene oxide sheets as flexible paper electrodes for sodium- and lithium-ion batteries.
"The observation is important because graphite, which is a precursor for making graphene oxide, has negligible capacity for sodium and has long been ruled out as viable electrode for sodium-batteries," Singh said. "Graphite is the material of choice in current lithium-ion batteries because the interlayer spacing is just right for the smaller size lithium ions to diffuse in and out."
The researchers are the first to show that a flexible paper composed entirely of graphene oxide sheets can charge and discharge with sodium-ions for more than 1,000 cycles. Sodium perchlorate salt dissolved in ethylene carbonate served as the electrolyte in their cells.
"Most lithium electrode materials for sodium batteries cannot even last for more than a few tens of charge and discharge cycles because sodium is much larger than lithium and causes enormous volume changes and damage to the host material," explained Singh. "This design is unique because the distance between individual graphene layers is large enough to allow fast insertion and extraction of the sodium ions, thanks to the oxygen and hydrogen atoms that prevent sheets from restacking."
Singh and his team also studied the mechanical behavior of the electrodes made of reduced graphene oxide sheets. The researchers measured the strain required to tear apart the electrodes. Through videography, they showed the ability of the crumpled graphene oxide papers to sustain large strains before failing.
"Such measurements and study of failure mechanisms are important for designing long-life batteries because you want the electrode to be able to expand and contract repeatedly without fracture for thousands of cycles, especially for larger nonlithium metal-ion batteries," Singh said. "These days, almost every one is using crumpled graphene as either the conducting agent or elastic support or both."
Earlier this year, Singh and his team demonstrated large-scale synthesis of few-layer-thick sheets of molybdenum disulfide. They also showed the molybdenum disulfide/graphene composite paper has potential as a high-capacity electrode for sodium-ion battery. In that research, the scientists used graphene as an electron conductor for the molybdenum disulfide sheets and observed graphene to be largely inactive toward sodium.
Their latest research has shown that unlike sodium, the lithium capacity of rGO increases with increasing rGO synthesis temperature reaching maximum value for sample produced at 900 degrees C.
"It is only now we realize that sodium capacity of graphene, or rGO, is dependent on its processing temperature," Singh said. "The rGO specimens in our previous study were prepared at 900 degrees C."
The large abundance of sodium makes the element a potential candidate for replacing lithium-ion batteries.
By focusing on nanotechnology, Singh and his team have been able to explore and design materials that can store sodium-ions reversibly and without damage. They found their answer in graphene oxide, which can cycle sodium-ions for more than 1,000 cycles.
Singh and his team will continue exploring new nanomaterials and focus on materials that can be mass-produced in a cost-effective manner.
"We would like to perform fundamental studies to understand the origins of first cycle loss, voltage hysteresis, and capacity degradation that are common to metal-ion battery anodes prepared from 2-D layered crystals such as transition metal chalcogenides, graphene, etc.," Singh said.
The Green Transformation: HFC Phase Out Spurs Natural Refrigerant Growth
Refrigeration manufacturers said they would make production plans and
future product development decisions according to the expected
world-wide HFC refrigerant phase down put forth by the Kigali Amendment.
The amendment, last year’s Montreal Protocol add-on, will specify
phase-out deadlines for HFC’s, adding those refrigerants with high
global warming potential to the group of ozone depleting
hydrochlorofluorocarbons that are already being outlawed under the
international agreement.
Meanwhile, UN officials and manufacturers said they believed the amendment would encourage investment in clean, energy efficient technologies such as natural refrigerants and prompt countries with developing cold chains to skip traditionally used HFCs and HCFCs in favor of moving directly to low-global-warming replacements.
“This is about much more than the ozone layer and HFCs. It is a clear statement by all world leaders that the green transformation started in Paris is irreversible and unstoppable. It shows the best investments are those in clean, efficient technologies.” said UN Environment chief Erik Solheim.''
Mark Menzer, director of public affairs for manufacturer, Danfoss,
said the Kigali Amendment will allow both manufacturers and users of
equipment to make clear plans for what lies ahead. “Even though we
don’t have a full set of rules yet, we can look at the scheduled Kigali
time frame and pretty much figure out what refrigerants need to be
phased out when and plan accordingly.”
Lowell Randel, vice president, government affairs for the International Institute of Ammonia Refrigeration, said industry by and large has supported the Kigali agreement. He said that while some countries may have concerns about what the transition process will do to their economies, the agreement gives them additional time to meet the goals.
The Kigali Amendment establishes multiple legally binding schedules for
participating countries to cap and phase down the use of HFCs in favor
of alternatives which have lower global warming potential. The Kigali
Amendment will enter into force on Jan. 1, 2019, if it is ratified by at
least 20 parties to the Montreal Protocol or 90 days after ratification
by the 20th party, whichever is later.
“The developing countries have a much later freeze or cap followedby reductions,” said Lambert Kuijpers, who served as a senior expert to the United Nations Environment Program’s Technology and Economic Assessment Panel.
The phase-down for developed countries, including the United States and the European Union, starts in 2019, assuming the amendment has been ratified by then. Most developing countries, including China, several Asian and all South American and African countries will freeze at a certain level of HFC consumption in 2024 and begin reducing their use with a 10 percent reduction in 2029.
Other countries, including India, Iran, Iraq, Pakistan, Saudi Arabia and the Gulf Cooperation countries, will freeze their use in 2028 and make a 10 percent reduction in HFC consumption in 2032. More steps will follow.
The nearly 200 nations and parties to the Protocol, who met in Kigali, Rwanda, in October 2016 have been supportive of the action. In Europe, adoption is moving ahead, while in the U.S., political uncertainty may briefly stall action on the initiative, but is not expected to create too much of a delay.
In early February, the European Commission adopted a proposal for the EU
to ratify the Kigali amendment. “Not only will this landmark deal help
us meet our climate objectives, but also it will provide new
opportunities for European manufacturers of air conditioning and
refrigerants to access the global market, creating additional jobs and
attracting new investment,” said Miguel Arias Cañete, Commissioner for
Climate Action and Energy.
In the United States, uncertainty remains over how the Trump administration will respond and whether or not the U.S. will ratify the amendment.
IIAR’s Randel said industry groups have sent letters to the administration and to members of Congress, asking them to move forward with the agreement. “The fact that industry has generally been supportive of Kigali may mean that this is a fight the Trump administration doesn’t feel it needs to get into.”
Even if the U.S. were to fail to ratify the Kigali Amendment, Randel said he believes other countries will stay in. Randel said he believes that countries are planning to move forward with whatever their responsibilities would be under a ratified Kigali amendment. “When you look at European countries, most of them are where they need to be or getting close because of the EU policies. You have other countries that are not as far along as the EU but they will continue their efforts.” Kuijpers said the EU’s 2014 F-gas regulation targets a 79 percent reduction by the year 2030, from the baseline year 2015.
He added that the Kigali Amendment does not present a more stringent phase-down schedule than the schedule the EU has already embraced. “Under the Montreal Protocol, there are 194 countries in total, of which 40 countries are developed countries. In the developed countries, a large amount have already worked on how to deal with curbing HFC consumption,” Kuijpers said, adding that he believes it will be easy to have the 20 necessary parties ratify the Kigali Amendment. “People will ratify it because it will enable certain things to happen.”
Menzer said the goal is to keep countries from going from HCFCs to HFCs
and then to something else. “That is the path we went in this country.
We’re trying to get China and other developing countries to skip that
HFC step entirely and go [directly] to low-global-warming replacements.”
As one of the signatories to the Kigali amendment to the Montreal
Protocol, India has committed to cutting down HFC use, and Honeywell has
opened a new laboratory at the Honeywell India Technology Center in
Gurgaon, Haryana, India. The company said the new laboratory will
support local and regional partners in designing, incubating and testing
new refrigerants and help them transition to
low-global-warming-potential alternatives.
“Honeywell is committed to providing next-generation solutions that are available today as an option to support the Indian government on transitioning from HFCs to environmentally preferable materials,” said Julien Soulet, managing director for Honeywell Fluorine Products in Europe, Middle East, Africa and India. “With the launch of this laboratory at HITC, we look forward to working hand-in-hand with our Indian partners to design near drop-in refrigeration solutions that help them meet their environmental commitments.”
Kuijpers said that between 2017 and 2019, many parties are expected to ratify the Kigali Amendment.
“How to achieve the phase-down is something that has not been decided in all detail and that cannot logically not be expected at this moment,” he said, adding that he expects ammonia and carbon dioxide will help countries meet their HFC reduction goals.
Meanwhile, UN officials and manufacturers said they believed the amendment would encourage investment in clean, energy efficient technologies such as natural refrigerants and prompt countries with developing cold chains to skip traditionally used HFCs and HCFCs in favor of moving directly to low-global-warming replacements.
“This is about much more than the ozone layer and HFCs. It is a clear statement by all world leaders that the green transformation started in Paris is irreversible and unstoppable. It shows the best investments are those in clean, efficient technologies.” said UN Environment chief Erik Solheim.''
Lowell Randel, vice president, government affairs for the International Institute of Ammonia Refrigeration, said industry by and large has supported the Kigali agreement. He said that while some countries may have concerns about what the transition process will do to their economies, the agreement gives them additional time to meet the goals.
The Amendment contains several schedules: two schedules for two
groups of developed countries and two schedules for two groups of
developing countries.
“The developing countries have a much later freeze or cap followedby reductions,” said Lambert Kuijpers, who served as a senior expert to the United Nations Environment Program’s Technology and Economic Assessment Panel.
The phase-down for developed countries, including the United States and the European Union, starts in 2019, assuming the amendment has been ratified by then. Most developing countries, including China, several Asian and all South American and African countries will freeze at a certain level of HFC consumption in 2024 and begin reducing their use with a 10 percent reduction in 2029.
Other countries, including India, Iran, Iraq, Pakistan, Saudi Arabia and the Gulf Cooperation countries, will freeze their use in 2028 and make a 10 percent reduction in HFC consumption in 2032. More steps will follow.
The nearly 200 nations and parties to the Protocol, who met in Kigali, Rwanda, in October 2016 have been supportive of the action. In Europe, adoption is moving ahead, while in the U.S., political uncertainty may briefly stall action on the initiative, but is not expected to create too much of a delay.
In the United States, uncertainty remains over how the Trump administration will respond and whether or not the U.S. will ratify the amendment.
IIAR’s Randel said industry groups have sent letters to the administration and to members of Congress, asking them to move forward with the agreement. “The fact that industry has generally been supportive of Kigali may mean that this is a fight the Trump administration doesn’t feel it needs to get into.”
At a meeting in Las Vegas, Rajan Rajendran, vice president of
System Innovation Center and sustainability for Emerson, said that
although the United States’ participation in the Kigali Amendment is
uncertain with a Trump presidency, the path for Emerson and other global
manufacturers is clear.
“As a global company we have to be able to meet the needs of our
customers in Europe, Asia, Latin America and so on,” Rajendran said.
“And to the extent that all of them are going to sign on to the Kigali
amendment and start acting upon some of these phase-outs, we are going
to have to think about the products we offer to the rest of the world.
So even if we don’t necessarily go through some of [the Kigali
amendments] step downs in the United States, it is still happening
elsewhere.”
Even if the U.S. were to fail to ratify the Kigali Amendment, Randel said he believes other countries will stay in. Randel said he believes that countries are planning to move forward with whatever their responsibilities would be under a ratified Kigali amendment. “When you look at European countries, most of them are where they need to be or getting close because of the EU policies. You have other countries that are not as far along as the EU but they will continue their efforts.” Kuijpers said the EU’s 2014 F-gas regulation targets a 79 percent reduction by the year 2030, from the baseline year 2015.
He added that the Kigali Amendment does not present a more stringent phase-down schedule than the schedule the EU has already embraced. “Under the Montreal Protocol, there are 194 countries in total, of which 40 countries are developed countries. In the developed countries, a large amount have already worked on how to deal with curbing HFC consumption,” Kuijpers said, adding that he believes it will be easy to have the 20 necessary parties ratify the Kigali Amendment. “People will ratify it because it will enable certain things to happen.”
“Honeywell is committed to providing next-generation solutions that are available today as an option to support the Indian government on transitioning from HFCs to environmentally preferable materials,” said Julien Soulet, managing director for Honeywell Fluorine Products in Europe, Middle East, Africa and India. “With the launch of this laboratory at HITC, we look forward to working hand-in-hand with our Indian partners to design near drop-in refrigeration solutions that help them meet their environmental commitments.”
“How to achieve the phase-down is something that has not been decided in all detail and that cannot logically not be expected at this moment,” he said, adding that he expects ammonia and carbon dioxide will help countries meet their HFC reduction goals.
viernes, 16 de junio de 2017
martes, 13 de junio de 2017
domingo, 11 de junio de 2017
jueves, 8 de junio de 2017
martes, 6 de junio de 2017
lunes, 5 de junio de 2017
domingo, 4 de junio de 2017
sábado, 3 de junio de 2017
viernes, 2 de junio de 2017
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