Refrigeration
Since early air compressor
designs in the mid 1800s, air compressor technology has progressed
substantially. Today, they are used to propel a range of
different technologies, such as air tools, earth drills, refrigerators,
and air conditioners. Although the last two technologies listed
are often taken for granted, their associated operating costs are
greater than many people realize.
According to the U.S. Department
of Energy (USDOE), air conditioning and refrigeration consumes over 27%
of all electricity in U.S. households. Furthermore, nearly
6% of our gasoline is used to power car air conditioning, and in
southern states such as California, Arizona, Texas and Florida, it may
account for up to 35% of automobile fuel costs.
In the average air conditioned
U.S. home, air conditioners use more than 2,000 kilowatt-hours of
electricity per year. In order to produce the electricity needed to air
condition the average U.S. home, the average power emits roughly 3,500
pounds of carbon dioxide and 31 pounds of sulfur dioxide per year.
These high costs associated with
cooling technologies largely stems from the energy needed to propel
compressors, which are present in most air conditioning and
refrigeration devices. However, engineers in the industry are working
towards signficiantly reducing these costs with innovative air
compression technologies.
The most energy-efficient air
conditioners on the market today consume 30-50% less energy than models
manufactured in the mid 1970s. In addition to energy
efficiency, recent air compressor innovations involve noise reduction,
new maintenance techniques and self-regulating intelligent
systems. When innovators develop technologies such as these, they
may be eligible for federal and state Research and Development tax
credits.
The R&D Tax Credit
Enacted
in 1981, the Federal Research and Development (R&D) Tax Credit
allows a credit of up to 13 percent of eligible spending for new and
improved products and processes. Qualified research must meet the
following four criteria:
New or improved products, processes, or
software
Technological in nature
Elimination of uncertainty
Process of experimentation
Eligible costs include employee
wages, cost of supplies, cost of testing, contract research
expenses, and costs associated with developing a patent. On
December 18, 2015, President Obama signed the bill making the R&D
Tax Credit permanent. Beginning in 2016, the R&D credit can be used
to offset Alternative Minimum tax and startup businesses can utilize
the credit against payroll taxes.
Energy Efficiency
Energy
costs are a significant portion of any compressed air system's total
lifetime cost. In fact, the amount of energy required to run an
air compressor for just one year can exceed the compressor’s total
purchase price. In light of these high energy costs, upgrading to
a newer, more energy-efficient air conditioner may be well worth the
initial cost outlay. Even if an air conditioner is just 10 years
old, upgrading to a new energy-efficient air conditioner could save
anywhere from 20-40% of cooling costs.
Despite advancements in
energy-efficient technology surrounding air compressors, there is still
room to further reduce energy costs. An open innovation
competition, called the Boston Innovation Prize, was created by two
organizations in Boston in hopes of discovering a way of lessen energy
consumption in air-conditioning systems. It was set by the Barr
Foundation, a private foundation that aims to improve the quality of
life of people in the Boston area, and the Cambridge Energy Alliance,
an organization that aims to reduce the carbon footprint of Cambridge,
Massachusetts. The goal of the competition was “to radically improve
efficiencies in space cooling and dehumidification” and to “identify
breakthrough technologies and/or designs which will provide cooling and
dehumidification with dramatically higher energy efficiency than
current room or window air-conditioning units, while maintaining
affordability.”
One major innovation introduced
to the market is a lightweight turbo compressor, designed by Muller
Industries, a heating and cooling technology company based in Memphis,
Tennessee. Designed to be both efficient and compact, this
innovative technology features a revolving compression system that is
much faster than what is found in most conventional appliances. This is
acheived through an integral motor comprised of woven, high-strength
fibers. Essentially, Muller Industries’ engineers realigned the
stressing forces in the fibers to provide greater strength and deliver
higher compression, resulting in greater energy efficiency. Some
analysts describe this energy savings potential as tremendous.
Additionally, the compressor is signficantly quieter, which is another
hihgly desired characteristic in the compressor industry.
Reduced Noise
One of
the most heavily researched aspects of compression technology involves
noise reduction. Noise level is an important factor that Consumer
Reports considers when testing refrigerators for consumer
preference. As air compressors create a high pressure pumping
system, they produce a lot of noise. This noise is undesirable in
most settings and can even cause ear injuries to users.
Therefore, a huge challenge for innovators is diminishing the noise
output created by compressors. Some solutions include the use of
acoustics or sound barriers in order to muffle the noise. Other
solutions involve creative techniques to release exhaust noise and
reduce vibration-radiated noise that is generated from the compressor
gears and bearings.
Exhaust and intake noise is often
identified as the primary noise source in compressors. When
operating, a refrigerator compressor produces a pulsating noise,
primarily driven by internal suction and discharge processes. To
alleviate this exhaust noise, compressors often have a muffler that is
located inside the refrigerator. There are many challenges associated
with designing effective mufflers. For example, the muffler must be
very compact in size and have an extremely low pressure drop. It
also must be capable of lessening noise over a wide range of
frequencies. Furthermore, it is also essential that the muffler
has an infinite expected life; if the muffler breaks down before other
components in the compressor, the whole unit will be undesirable by the
user.
Preventive Maintenance
Like
all electro-mechanical equipment, compressed air systems require
periodic maintenance to operate at peak efficiency and minimize
downtime. Proper air-conditioning maintenance is necessary to
ensure that air-conditioning units are working properly around the
clock. An air-conditioning compressor has a motor which contains moving
pistons that compress the refrigerant gas. Like all mechanical systems,
those moving parts need to be lubricated and cooled.
Some compressors within air
conditioning units have high compressor switches that users can turn on
to help prevent the compressor from over-heating. This is especially
useful for those who live in areas with polarized weather
conditions. In the summer, the switch can be turned on and vice
versa during the winter. Other compressors may have this feature
built in so that it switches on and off automatically. Automatic
monitoring and controls is another focal point for innovation within
the industry. With the advent of the Internet of Things, this
type of automation is likely to become increasingly intelligent and
more prevalent in newer model units as well.
Internet of Things
Today,
intelligent air conditioners and refrigerators are perhaps the most
breakthrough innovations in the industry. Some units can be
controlled by the user with a cell phone or an iPad. Others can
even pick up signals based on the phone’s location and adjust
temperature patterns so that less energy is used when the user is away
from home and more energy is used as the user approaches the
unit.
There are a few companies mainly
responsible for designing these smart apps and controls. Quirky,
the online community of inventors has one listed on their
website. Sensibo the Tel Aviv, Israel-based intelligent cooling
company, has a smart scheduling app that makes sure the user’s bedroom
is pre-heated so he or she wakes up in a warm room. Tado, the
United Kingdom-based smart thermostat company, utilizes cell phone
location to cut heating costs.
One user of the Tado smart
control technology had this to say about the product: “Our electricity
bill has dropped dramatically since we use the smart AC as beta
testers. Now the air conditioner does not need to run all the
time. Even at night our preferred temperature is set
automatically.” Another user said this: “The smart AC control
works completely automatically. You can set and save different
profiles which combine a certain AC mode, fan, temperature, etc.
And it’s super nice that the apartment is pre-cooled when you get
home.” Besides the Internet of Things (IoT’s), there are other
intelligent designs that can help save on energy costs . One, for
example, involves compressors that are smart enough to adjust speeds
based on the amount of compression that is needed at any given time.
Variable Speed Driven Compressors
Variable-speed driven compressors adapt the speed of the compression
element to match the compressed air demand. This is made possible
by use of a smart processor that controls the compressor motor.
Sensors are used to tell the motor when to vary its speed. The
motor then responds by shutting down some of the screws or pistons
which drive compression, while allowing others to function
normally. When less screws/pistons/rotars/etc. are turning, less
energy is being consumed, similar to shutting down unneeded cylinders
in a gas or diesel motor to save on fuel. For some compressors, this
can mean capturing an energy savings of over 35%.
There are many different
challenges associated with designing variable-speed air compressors.
For example, some products require duel compressors. In this
case, the compressors must be synced so that they operate most
efficiently as a tandem unit. Other challenges involve designing
an optimal lubrication ratio or ensuring the correct oil return in a
cooling circuit as well as the sizing of the suction and discharge
points are all critical factors that must be considered when an
adjustable component is introduced to a single speed compressor
model.
Efficiency Standards Drive Innovation
Energy
efficiency standards in the industry are largely shaped by Federal
regulations. In response to the 1970’s energy crisis, lawmakers pushed
to reduce energy consumption across all U.S. sectors. This set the
stage for the Energy Department’s Appliance and Equipment Standards
Program, which established a single federal energy efficiency standard
for air conditioner manufacturers, rather than a patchwork of
state-by-state standards.
Since 1992, the Energy Department
has issued conservation standards for manufacturers of residential
central air-conditioners and heat pumps. The initial standard is
expected to net $29 billion in energy bill savings from 1993 to 2023.
Furthermore, the standard passed in 2006 is anticipated to result in
$70 billion in energy bill savings from 2006 to 2035 and will prevent
more than 369 million metric tons of carbon dioxide emissions,
equivalent to the annual greenhouse gas emissions of about 72 million
cars. Already the program has been responsible for driving huge
improvements in efficiency for new air-conditioning technology that has
helped consumers save both energy and money.
Supermarket Refrigeration
Supermarkets are some of the most energy-intensive commercial
buildings. This is largely due to the amount of energy that is
dedicated to maintain chilled and frozen food in both product display
cases and storage refrigerators throughout the store. Typical
supermarkets with approximately 3700-5600 square meters of sales area
consume over 2-3 million kWh annually for total store energy use.
Compressors and condensers account for 60-70% of this energy
consumption. In these supermarkets, multiple large compressors
operate side by side simultaneously often times 24 hours per day.
In order to reduce energy
consumption and advance energy-efficient supermarket technology, the
International Energy Agency (IEA) established IEA Annex 26 (Advanced
Supermarket Refrigeration/Heat Recovery Systems). Annex 26
focuses on demonstrating and documenting the energy saving and
environmental benefits of advanced systems design for food
refrigeration as well as space heating and cooling for supermarkets.
The goal of the program is to identify supermarket refrigeration and
HVAC technology options that reduce the total equivalent warming impact
(TEWI) of supermarkets and their potential impact on global 3 warming.
The Annex currently has five participating countries: Canada, Denmark,
Sweden, the United Kingdom, and the United States.
There are other government
regulations, such as the U.S. Environmental Protection Agency (EPA),
addressing supermarket refrigeration technologies as well.
Recently, the EPA announced a proposal to ban the use of R-404A, R-507,
and a number of other perceived high-GWP refrigerants from use in a
wide range of commercial refrigeration equipment installed in 2016 or
later. Rusilla Hufford, director of the Stratospheric Protection
Division in the EPA had this to say about the legislation, “The EPA
continues to seek comments on technical challenges, availability of
alternatives, need for changes to manufacturing processes, safety
upgrades, and its ability to meet proposed compliance dates.”
Conclusion
Air
compressor technology is constantly evolving to be more energy
efficient, quieter, less maintenance oriented and more
intelligent. When companies develop these technologies they are
often eligible for federal & state R&D tax credits.
