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Air Conditioner HFCs Are on the Way Out — The Kigali Amendment Explained

Air Conditioner HFCs Are on the Way Out — The Kigali Amendment Explained

by | Oct 12, 2022 | News

Kigali-friendly refrigerant
A storage facility at a farm in Rwanda using Kigali Amendment-friendly refrigerant technology. The international agreement phases out the greenhouse gas HFCs. Photo: Ministry of Environment — Rwanda, Flickr Creative Commons (CC BY-NC-ND 2.0).

TipSheet: Air Conditioner HFCs Are on the Way Out — The Kigali Amendment Explained

By Joseph A. Davis

The Senate’s Sept. 21 ratification (may require subscription) of the international climate treaty, the “Kigali Amendment,” means that refrigerants will be changing in air conditioners, refrigerators and cars.

The agreement amends the Montreal Protocol of 1987, which outlawed the cooling agent ​​chlorofluorocarbons, or CFCs, and other fluorinated compounds that destroy the stratospheric ozone layer.

It wasn’t until later that scientists realized that some of the gases used as substitutes for CFCs were potent greenhouse gases. The Kigali Amendment phases out the substitutes, typically the gases called hydrofluorocarbons, or HFCs, which are in very common use as refrigerants.

All this means that environmental journalists may soon be called on to explain what is happening with air conditioning. Some of us are breaking out in a cold sweat. TipSheet is here to help you get ready for the changes ahead.

Why it matters

Now that we’re living through drought, heat waves, record wildfires, epic rains and floods — not to mention the hurricanes — we probably don’t have to spell out why adding more greenhouse gases to the environment is of grave concern.

Climate heating is making life worse for many people in many parts of the world, and will continue to get worse.

HFCs are well over 1,000 times more powerful

in heat-trapping than carbon dioxide, the

greenhouse gas pollutant most often focused on.

Meanwhile, HFCs are well over 1,000 times more powerful in heat-trapping than carbon dioxide, the greenhouse gas pollutant most often focused on. Scientists estimate that if the Kigali Amendment were fully implemented, it would prevent 0.5 degrees Celsius worth of global heating.

But today, in many places, you can walk into an auto parts store and buy a can of R-134a, an HFC that works to recharge most car air conditioning systems. Eventually, you will need something else, but that widely distributed market for such refrigerants is a sign of how hard they may be to control. In fact, there is already an international black market in smuggled HFCs (some mislabeled and unlabeled).

The backstory

One reason why it was politically possible for the chronically deadlocked Senate to do something about HFCs is that it (and industry) has had more than a decade to get used to the idea.

Another reason is that the United States had already begun replacing them. At the end of 2020, Congress passed legislation mandating an HFC phaseout as part of the huge omnibus appropriation bill enacted before Biden officially took office.

The legislation’s HFC element was called the AIM Act, for American Innovation and Manufacturing, and it directs the U.S. Environmental Protection Agency to carry out a phasedown of the family of gases we call HFCs.

After the usual public rulemaking process, in October 2021, the EPA finalized its “HFC Allocation Rule.” The EPA rule would reduce HFCs by 85% over 15 years. You can find a lot more info on the EPA’s HFC phasedown here.

But as they say, history rhymes. So, HFCs were brought into use as a replacement for the ozone-destroying CFCs. And now that we have to phase HFCs out and replace most of their uses, it might be worth thinking through what we replace HFCs with.

Story ideas

Reporting resources

[Editor’s Note: Keep up with news on HFCs with EJToday’s headlines service.]

Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online’s TipSheet, Reporter’s Toolbox and Issue Backgrounder, and curates SEJ’s weekday news headlines service EJToday and @EJTodayNews. Davis also directs SEJ’s Freedom of Information Project and writes the WatchDog opinion column.

* From the weekly news magazine SEJournal Online, Vol. 7, No. 35. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.

This content was originally published here.

What a BTU Means to Your Air Conditioning System

What a BTU Means to Your Air Conditioning System

by | Sep 22, 2022 | News

healthy Home Humidity Levels

About Comfort

Comfort Air Conditioning + Heating is a premier high-end HVAC company serving Manhattan, Brooklyn and select parts of Long Island, including the East End. We specialize in everything from traditional to ductless air conditioning systems.

What a BTU Means to Your Air Conditioning System

When reviewing new air conditioning systems, you may run across the acronym ‘BTU’ when comparing different units. What is BTU, and how does it relate to air conditioning systems, furnaces, and heat pumps? Allow us to explain.

What is a BTU?

BTU is short for British Thermal Unit, a worldwide way to measure the heat needed to raise or lower one pound of water by one degree Fahrenheit.

BTUs and Your Air Conditioning System

Air conditioning systems need roughly 20 BTUs per square foot of living space. To determine the right amount of BTU for your home, multiply the square footage by 20. Let’s look at an example: If you have a 1400-square-foot house, you should be purchasing a unit that is roughly 28,000 BTU. Getting a system with too little or too many BTUs can lead to problems, so you must choose the right system for your home.

If you purchase a unit with too many BTUs, you will waste money and perhaps cause expensive damage. This is because your system will run for short, intense periods, shutting off, then run again. This rapid on and off cycle can lead to premature wear and uses energy inefficiently.

If you purchase a unit that doesn’t have enough BTUs, it may never shut off because it won’t be able to reach the desired temperature. This situation also wastes money and can potentially damage your system from excess wear and tear.

Choosing the Right System for Your Home

BTU is just one measurement used to determine the proper system for your home. Other considerations include tonnage, kilowatts, environment, and many other factors, large and small. To choose the appropriate system for your home, you should consult with a qualified HVAC contractor who can do a complete assessment of your cooling needs.

Living in a Home that Breathes

Living in a Home that Breathes

by | Sep 21, 2022 | News

My wife and I have been—dejectedly, half-heartedly—shopping for a house in Northern Virginia. I hardly have to explain why it’s not an encouraging endeavor. (If you’re not familiar, just input any locality in Fairfax County into Zillow and filter by “lowest price first.”)

Yet market travails aside, one of the most curious things I’ve noticed during open-house visits around here is that the windows in these expensive, very nice homes frequently do not work.

Sometimes they’re old and have never been replaced; sometimes they’ve been painted shut; some look fine but are so stiff they’ve likely not been opened for years; some are brand new but are so cheap that the plastic in the locking mechanisms warps under pressure so that the window cannot latch shut. Some don’t even have intact screens. (That can sometimes be explained by a realtor trick: Removing the screens lets in more light. In these cases, the screens are stowed in the garage or basement.)

But functional windows are one of the most obvious things to look for in a house, aren’t they? My late-summer plans depend on them: I can’t wait to take advantage of cool nights by getting a box fan running. (Our little condo has sliding windows that don’t accommodate a box fan, which I regret almost as much as the prohibition on barbecue grills.) How can it be that working windows aren’t a priority for affluent homeowners in Northern Virginia? I have to think it’s because they don’t use them: They just flick on the air conditioner instead.

If you’re looking to cool off while saving some energy by using a box fan, you might have to wade through some bad advice before getting a handle on its proper use; the practice is apparently outdated enough to have become foreign to many online. For example, as one site explains,

Box fans operate as any ordinary fan and are helpful for direct purposes, such as drying or cooling off individuals, rather than cooling an entire room.

Window fans operate in pairs, one blowing air in and the other blowing it out. The two fans work to remove the hot air and replace it with cool air.

If placed correctly, window fans can bring the temperature of a room down, while box fans only create a cooling effect.

True as far as it goes, but any experienced box fan user knows that you should open doors and windows to create a cross-breeze and ventilation in concert with the fan. Heck, buy two of them and place them in windows on opposite sides of the home, with one blowing in and one blowing out. Box fans are intended not just for a “cooling effect,” but for recirculating the air. Isn’t that obvious? Maybe not.

Beyond its energy efficiency, cooling a house with fans is, at least for me, the sort of “tactile” or “ritual” activity—like putting on a record, starting a wood fire, or setting an actual alarm clock—that is largely absent from life today. Doing it properly requires being attuned to the weather in a way you don’t need to be with A/C. Is it cool enough to open the windows? Is it too humid? Are the mosquitoes so bad that some fraction of them will get in through the screen? Considerations weighed, you throw the windows open, put the fan up, open doors and other windows to get airflow through the whole space—and you wait. Soon, the house comes to smell like the fresh air outside; the insects, which during cicada season you can probably hear over the fan motor, fill the house with their sounds. It’s almost like you’re out camping, except you’re still comfortably ensconced at home.

Because our reliance has shifted to other tools for cooling indoor spaces, current versions of the box fan aren’t manufactured to the robust standards that were common when fans were the best option. It’s easy to look at the flimsy white plastic model sold at Walmart during the summer ($16 when I last checked; maybe it’s $20 now) and wonder how anybody survived the heat before air conditioning. People embraced the easy relief offered by the new home-cooling system when it was introduced, and they gladly threw out, donated, or consigned to garage sales their old box fans, which had lost their primary use case. Many vintage models of the old fans are now rare, collectible, and very expensive as a result.

But as media theorist Marshall McLuhan understood, technological progress has complicated and mixed effects. Even as we gain new conveniences or abilities through new products, we often come to miss the old way. We get rid of yesterday’s tech when it becomes obsolete, but we want it back when it takes on that aura of antiqueness, becomes a historical curiosity, or even starts to convey intimations of forgotten wisdom. Consider things like surviving typewriters, cathode-ray tube televisions, and mechanical push mowers. Of course, nobody would have viewed these recently outdated things in such a rich way just as they were going out of fashion, and so there’s always something anachronistic about this way of assessing them. It might even represent its own kind of boutique consumerism. And it’s easy to romanticize a more difficult past from a comfortable present; innovation is good, and, given the option, most people outside small communities of enthusiasts would prefer not to return to these products over their successors.

But, sentimental projections aside, here’s how cooling the house worked in the heyday of electric fans. Growing up, my father had a General Electric all-metal, three-speed, electrically reversible box fan; it could change directions with the turn of a knob, and could turn a hallway in his childhood house into a wind tunnel. Today that GE fan would be worth over $200. My grandmother gave it away years ago when a nosy handyman working on her HVAC asked if he could have it. That’s more or less what everyone did with them.

But if you compare that fan to the current models, today’s fans look perfunctory, if not vestigial. The sharply angled steel blades of the classic model have become almost flat, thin plastic. These cheap blades produce less airflow, which can be generated by a much cheaper, lighter-weight motor, which in turn allows a thinner, flimsier frame. If you put my dad’s GE fan and the $16 Walmart fan side by side, the difference in size and heft would be astonishing.

Today’s box fans are a commercial afterthought, purchased as backups for a day when the air conditioning breaks down, or for use in old-fashioned college dorms that never got central air. Many sliding windows, like my own, can’t even physically accommodate a box fan, and the window fans they might be able to hold are similarly shrunken and lightweight compared to their predecessors.

What’s interesting in this is the way progress—and there’s no need to put it in scare quotes; air conditioning really does represent an important step forward—can end up disadvantaging the people most in need, putting them in a relatively worse position vis-a-vis everyone else. When widespread computer ownership and high-speed internet access make remote schooling feasible, it’s the people without reliable or recent computers, or without high-speed access, who suffer. When land use becomes oriented around the car, anyone who can’t afford a car is left stranded. And when the widespread adoption of air conditioning kills the profit in heavy, high-performance box fans, it’s the people stuck in buildings with broken or poorly-performing air conditioning systems who are forced to rely on the diminished fans that are still produced. Being at the mercy of a teacher in the classroom, or your own two feet, or the weather, has a natural leveling effect. By obviating these conditions for a few, technological progress can increase inequality for those who are stuck with them.

Now you’d be right to point out that poor families in the 1950s or 1960s weren’t sitting in the breeze of an electrically reversible top-of-the-line GE. More likely, they had a smaller fan, or a lesser name-brand, or a discount model from K-Mart or Sears. But even those units were designed with metal blades and heavy motors. They moved air in large volumes because they had to.

These days, I’m not opening my window and firing up my fan out of solidarity with those who don’t have better options. Some days this summer, I’ve practically gotten on my knees and thanked the Lord for air conditioning. But the vaguely counter-cultural allure of the good old-fashioned box fan calls out to me—as does the lower cooling bill, the freshly scented breeze, the pulsing late-summer trills of the insects, and seeing out the season by letting a little bit of the world in.

This content was originally published here.

What to do When Your AC Unit Freezes Up

What to do When Your AC Unit Freezes Up

by | Sep 20, 2022 | News

What to Do When Your AC Unit is Freezing Up

AC freezing up?

It can be surprising to see a chunk of ice sitting on your AC system in the heat of summer. But this is a fairly common occurrence. An air conditioning unit is a self-contained system comprising of several interconnected and interdependent parts. A glitch in any one of these parts can result in serious issues. And this is essentially the case with frozen ac coils.

So, how does this happen, and what can you do when your AC unit is freezing up?

How Does an Air Conditioning System Work?

Often, people assume that air conditioning works by injecting cool air into a building. But this isn’t entirely true. In actuality, an air conditioner works by removing warm air from inside a room and pumping it outside, similar to how a refrigerator works. The only difference is that a fridge cools a small, insulated space while an air conditioner has a much bigger job cooling indoor spaces.

Air conditioning systems come in a variety of shapes and sizes, but they all work on the same basic premise. They contain chemicals (refrigerants) that convert from gas to liquid and back again quickly. These chemicals are contained inside coils that travel through a closed loop system. There are three stations along the route that manipulate the state, pressure, and temperature of the refrigerant. These stations are the evaporator coil, compressor, and condenser.

Station 1: Heat is absorbed by the evaporator coil

Firstly, warm air from a room is drawn into the air conditioner and over the evaporator coil through a vent. The heat is absorbed into the refrigerant, thereby turning it from liquid to gas. A fan then blows the cold air into air ducts that distribute it throughout a room. At the same time, the refrigerant, now in a gaseous state, continues to travel along the loop system toward the second station – the condenser.

Station 2: Compressor raises the refrigerant temperature

The cooling fluid makes its way outside the house to the compressor, where it reaches as a low-pressure gas and exits as a high-pressure, hot gas before moving on to the condenser.

The compressor’s role, as the name implies, is to decrease the gas’ volume by squeezing it tightly between two solid objects, raising its gaseous temperature even more.

Station 3: Heat is transferred outside

The refrigerant is an extremely hot vapor when it reaches the condenser, where it is exposed to the cool outside air. If you’ve ever peeked into your AC unit, you’ll notice metal fins all around the housing. The purpose of these fins is to dissipate heat more quickly. As a result, the refrigerant is significantly cooler when it leaves the condenser. It has also changed its state from a gas to liquid because of the high pressure. The refrigerant, which has transformed back into a cool liquid, is now ready to return to station 1 and repeat the process.

What Causes an AC Unit to Freeze?

Air conditioners freeze when there’s a glitch that disrupts the functioning of the evaporator coil, causing the refrigerant to cool too much, fall below freezing, and ice over. For this reason, frozen ac coils definitely indicate a problem with your AC’s health.

It’s important to understand what may cause your AC unit to freeze, so you can diagnose and fix the underlying problem. There are two things that can lead to an AC freeze-up:

Blocked airflow

Air conditioners need a constant flow of air to prevent humidity from settling on the coils and freezing. Dirty or clogged air filters could disrupt airflow, causing your systems to freeze up. That’s why it’s important to change your system’s filters every one to three months.

Mechanical problems or refrigerant leaks

An air conditioner is a machine full of moving parts that can shut down or get stuck. Fans can stop moving, filters can become clogged, and leaks can happen. If any of these disruptions were to cause a drop in pressure, the refrigerant would then expand too much and become extremely cold. Same case if there was a leak that resulted in low refrigerant levels.

Steps to Take to Keep Your AC from Freezing

Seeing your air conditioner encased in ice can be an alarming sight. Fortunately, proper maintenance can prevent this from ever happening.

Have your unit serviced at least once every 12 months. Or even twice yearly, depending on how often you use it. Your air conditioner has a lot of moving parts that require regular maintenance if it’s to serve you efficiently throughout its years of service.

Regular servicing ensures your system is functioning at optimal capacity, providing for faster and more efficient cooling. It also reduces the burden on your AC as small problems can be identified and rectified early. Plus, scheduled checkups minimize the likelihood of unexpected repairs. For instance, a qualified HVAC technician is also trained to check for refrigerant leaks. Low levels of refrigerant are a surprisingly common culprit of frozen ac coils.

Aside from scheduled maintenance, there are some tasks you can perform as a homeowner that could extend the life of your air conditioning system. Something as simple as replacing your system air filter each month could save you thousands of dollars in repair costs and prevent your system from freezing up when you need it most.

What to Do if Your AC Freezes Up

If your AC unit is left frozen for too long, you may end up with a bigger problem on your hands. Often the issue can be solved with a little troubleshooting. If not, you’ll need to call up a certified HVAC technician to have a look.

Here’s how you can go about solving this issue.

Step 1: Thaw

First things first, turn the AC off and let the ice melt. Don’t operate the system again until it completely defrosts and dries. Make every effort not to use your ac unit when it’s frozen, as this could unduly strain the compressor.

Note: The compressor is the most expensive component of your AC. Excessive strain could damage this valuable component leading to a costly repair service call or replacement. On that note, don’t be tempted to break up the ice so it can thaw faster – you could damage multiple parts. Be patient and give your AC system time to thaw and dry.

In some cases, letting the system thaw and dry is all you need to do to get it running normally again. Restore power to your system and turn the blower on.

Step 2: Find the Cause and Fix It

There are several factors that could be causing your air conditioner to freeze up:

Check air filters and change them

Air filters ensure clean air circulation in your home. They need to be cleaned or changed periodically to sustain optimal functioning. During peak seasons, you should be cleaning your AC filter at least every two weeks and replacing them after every three months.

Check your thermostat & fan settings

If the set temperature is too low, your AC may be unable to adequately transfer heat from the inside to the outside. Similarly, low fan speed can excessively strain your unit, giving it a hard time maintaining the set temperature. The solution is to increase the fan speed on especially hot days to maintain the necessary airflow.

Cool summer nights can cause your AC to freeze as it’s designed to operate within a set of temperature thresholds. On nights colder than the optimum threshold, the refrigerant becomes too cold and freezes any moisture in the air before it can even properly circulate.

Bad compressor

Now, this is the worst-case scenario. A worn-out compressor can’t effectively compress the refrigerant, which in turn leads to frozen AC coils. Unfortunately, you cannot fix a bad compressor. Here’s where you contact your HVAC provider for emergency support

Some air conditioning problems are relatively simple to sort out on your own. However, the more complicated glitches warrant an inspection from a qualified HVAC professional.

Is propane a solution for more sustainable air conditioning?

Is propane a solution for more sustainable air conditioning?

by | Aug 31, 2022 | News

propaneCredit: Pixabay/CC0 Public Domain

Current severe heatwaves that will likely increase in severity and frequency in the future are driving a rise in the use of air conditioners, threatening the environment with their high energy consumption and refrigerants with high warming potential. A new study finds that switching to propane as a refrigerant could lessen the global temperature increase from space cooling.

We spend enormous amounts of energy on fighting off the heat in the summer, or throughout the whole year at lower latitudes—about one-tenth of the total worldwide electricity supply. If current temperature trends continue, the energy demands of space-coolers will more than triple by 2050. Apart from the rise in energy consumption, space-coolers also threaten the environment in different ways: by using halogenated refrigerants with high global warming potential.

Split-air conditioners (Split ACs) that use an indoor and an outdoor air unit connected by pipes are the most common appliances used for space-cooling. They mostly utilize HCFC-22 and HFC-410 as refrigerants, both of them characterized by a very high global warming potential score, up to 2,256—meaning that they trap up to 2,256 times more heat than carbon dioxide over 100 years. Urged by the Kigali Amendment to the Montreal Protocol, many manufacturers are looking for alternative refrigerants with lower global warming potential scores, such as HFC-32. However, with a global warming potential score of 771, HFC-32 still poses a significant climate hazard.

A study led by IIASA researcher Pallav Purohit in collaboration with researchers from the United Nations Environment Program and the University of Leeds, showed that by switching to propane, an alternative low (<1) global warming potential refrigerant for space cooling, we could avoid a 0.09°C increase in global temperature by the end of the century, thereby making a significant contribution towards keeping the global temperature rise below 1.5 °C.

In the study published in Proceedings of the National Academy of Sciences, researchers used the IIASA Greenhouse Gas—Air Pollution Interactions and Synergies (GAINS) model to compare the baseline halogenated refrigerant emission scenarios with scenarios of switching to HFC-32 or propane. While the switch to HFC-32 also lessened the global temperature increase (0.03°C by the end of the century), propane proved to be the superior solution in terms of sustainability.

“Propane exhibits significant environmental advantages through good energy performance and a global warming potential of less than 1. In split-ACs up to 7 kW, propane can be classified as a technically valid alternative to HFC-driven split-ACs,” says Purohit.

Energy-efficient split-ACs using propane are already available commercially in the Chinese and Indian markets. Despite performing similarly to split-ACs using HFC-32, and even better than the currently widespread appliances using HFC-410A and HCFC-22, some national regulations prohibit their use, primarily due to standards and codes restricting the use of refrigerants with higher flammability, hindering their wider adoption.

“To achieve the EU’s ambitious 2050 climate neutrality targets, early and aggressive action is needed. In the short term, converting new air-conditioning systems to more environmentally-friendly refrigerants can reduce their climate impact significantly, underlining the urgency of updating standards for policymakers,” concludes Purohit.

More information: Pallav Purohit et al, The key role of propane in a sustainable cooling sector, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2206131119

Journal information: Proceedings of the National Academy of Sciences 

Citation: Is propane a solution for more sustainable air conditioning? (2022, August 16) retrieved 16 August 2022 from https://techxplore.com/news/2022-08-propane-solution-sustainable-air-conditioning.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

This content was originally published here.

Who invented air conditioning, and why there’s more than meets the eye to his humble invention

Who invented air conditioning, and why there’s more than meets the eye to his humble invention

by | Aug 13, 2022 | News

With all the heating around us, god bless the man who invented the air conditioner, right? Air conditioning is surely a marvel of modern technology, so marvelous that it is considered the 10th greatest engineering achievement of the 20th century. But how does it work, and who invented it? Oh, and why is air conditioning a sort of mixed blessing?

Interestingly, the air conditioning (AC) wasn’t originally invented to cool down our homes, offices, and cars. Instead, the AC technology was actually developed to reduce humidity levels in printing plants so that the printed material would stay protected from moisture.

Later, scientists and engineers figured out various uses of the AC and today the technology not only helps us to stay chill on hot summer days but also plays an important role in the storage of goods, management of power plants, food preservation, medical treatment, and various other fields.

Who invented the AC?

American engineer Willis Haviland Carrier is the inventor of the first modern air conditioner (also AC). He built it in 1902 for Sackett-Wilhelms Lithographing & Publishing Company, a Brooklyn-based publisher.

The hot and humid environment inside the printing facility was causing the freshly produced paper to accumulate moisture. Due to the high moisture content, the paper brought for printing in the facility would shrink and lose its smoothness, and therefore ink could not be printed on it in the desired manner. 

Carrier solved this problem by developing a simple belt-driven system that pulled in the hot air from the room and passed the same through a fine spray of water (washing down dust particles). The treated air was further passed through coils with cold water, getting rid of the extra humidity while lowering the air’s temperature and finally, the dehumidified air was sent back into the room.

The printers loved this simple system. Not only did it solve their problem, but it also cooled the air down, making the printing room atmosphere more comfortable for the workers. On January 2, 1906, Wills H. Carrier received US Patent 808,897 for his air conditioner system named ‘Apparatus for Treating Air’. His system became the world’s first spray-type air conditioning equipment.

Later, Carrier founded the AC company which is now known as the Carrier Global Corporation, a home appliance manufacturer that currently sells its products in more than 150 countries. Interestingly, Carrier wasn’t the one who came up with the term “air conditioning”; it was Stuart W. Cramer, another American engineer who developed humidity regulating systems for textile manufacturing plants.

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It took some time for air conditioning to take off. The first practical room ACs were developed by inventors H.H. Schultz and J.Q. Sherman in 1931 and the first car AC was invented by Chrysler Motors in 1935. It took a few more decades for them to become popular.

How does an AC work?

An air conditioning system’s job is to pull in heat from your room and dump it outside your house. However, as simple as that may sound, there’s a clever bit of physics and engineering involved. So before you dive into the mechanical function of an air conditioner (AC), you must understand a few basic concepts of thermodynamics. 

Now that you have a fair idea of how heat transfer happens, let’s look at how the four major components of an AC work and provide you with the much-needed cooling on a hot summer day. 

The evaporator turns the liquid refrigerant (such as R-22 or R-410A) into a gaseous vapor by absorbing heat from your room and moving it to the refrigerant inside its coil. Due to heat absorption, the liquid refrigerant turns into a vapor that is then sent to the condenser. The evaporator’s temperature is always colder than your room in order to allow heat transfer to the evaporator coil. 

The condenser is located in an air conditioner’s outdoor unit (ODU). It has a network of metallic fins through which the condenser transfers heat from the vaporized refrigerant to the surrounding environment. Condensers are also known as heat exchangers because of their role in expelling heat out of the system. When the hot refrigerant vapor passes through a condenser, a drop in temperature forces it back into a liquid stage, ready to be fed back into the compressor. 

Expansion valve

Boiling occurs when a liquid gains heat and changes to the vapor state, whereas superheating happens when a vapor is heated above the boiling point of the liquid. Superheating is an essential part of the cooling process. It ensures that before leaving the evaporator and reaching the compressor, the liquid refrigerant of the air conditioner is completely vaporized. The vaporization of refrigerant is essential because the compressor can undergo severe damage if it comes in contact with liquid refrigerant. 

The thermal expansion valve between the evaporator and condenser controls the flow and amount of refrigerant that moves towards the evaporator and ensures a steady flow required to achieve superheating. 

The compressor is the heart of an air conditioning unit. The gaseous refrigerant is reduced in volume by compression and sent to the system in a liquid state. Next, the compressor receives a cooled-down refrigerant from the vaporizer and converts it into liquid form. Finally, it is ready to be fed to the vaporizer to continue the cooling cycle.

Applications of air-conditioning systems

From increasing our quality of life to keeping our surroundings comfortable even in extreme climatic regions and preserving food and medical supplies while they are transported from one corner of the world to the other, air conditioning has played a major role. Here are some other important applications of air conditioning systems:

Apart from these heavy applications, there are many more simple uses of AC units; for example, many animal farm owners use air-conditioning systems to keep their livestock comfortable during the summers so that the milk yield is not affected. So now you know air-conditioning is much more than just a means to feel relaxed, it helps factories function well and businesses grow fast. 

So is the AC a perfect invention?

Not everything is positive about ACs. In fact, they are highly responsible for increasing our carbon footprint and releasing harmful chemicals into our environment. Until recently, air conditioners used CFCs or chlorofluorocarbons as refrigerants (now, hydrofluorocarbon or HFC is used which is believed to be less dangerous to the environment). Upon release into the atmosphere, the CFCs damage the ozone layer, and form what is known as the ‘ozone hole.’ 

Since the beginning of CFCs production in the 1920s, the thickness of the ozone layer, on average, has reduced by three percent, and this has immensely contributed to the climate change threats that we are facing at present. Another big issue arising from widespread air conditioning use is the huge energy consumption. 

On average, a typical air conditioning unit consumes about 3000 to 5000 watts of electricity every hour, leading to increasing global electricity demand. Since most of the electric power in many countries still comes from burning fossil fuels, the increased demand is causing environmental pollution and more carbon emissions. 

Moreover, ACs can also lead to skin diseases and various health-related problems (such as arthritis, eye infection, respiratory ailments, etc.). A study was conducted on two groups, one working in air-conditioned cabins and the other in a naturally ventilated office, revealed that people who spent their working hours in the AC free office faced fewer health-related issues that the ones who worked in an AC equipped office

According to researcher William Fisk “A large body of research has found that occupants of offices with air conditioning tend to report more sick building syndrome (SBS) symptoms than occupants of naturally ventilated offices.”

The cost of the comfort that ACs provide is very high, and by cost, here you should not only consider your electricity bill but the environmental problems that are caused due to the use of ACs. In the times, when humanity is focused on creating more earth-friendly and sustainable solutions, we definitely need better cooling solutions, so the next time you see an air conditioner turned on, even when there’s no need, switch it off!   

This content was originally published here.

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