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Is HVAC just about blowing good air after bad?

  • 12 min read
Written by Branko Miletic

According to the Australia government’s Department of Climate Change, Energy, the Environment and Water: ‘Heating ventilation and air conditioning (HVAC) systems account for up to 50 percent of a commercial building’s energy use and dominate peak electricity demand. Capital and maintenance costs for these systems also comprise a high portion of overall building costs.’

‘Improving HVAC efficiency can therefore have a big impact on your bottom line by reducing energy use, maintenance costs and peak demand charges. It also brings reputational benefits through higher energy efficiency ratings, such as the National Australian Built Environment Ratings System (NABERS).’

Upgrading to a more efficient HVAC system can deliver significant energy savings over its 20–25-year lifespan. Due to technological advances, there are many more efficient options available.

So where is the wastage?

According to the NSW government, the structure of buildings influence energy consumption of HVAC equipment and components. The thermal performance of a building’s facade, air leakage and internal electrical loads within a building will affect the operation and performance of HVAC systems.

Energy wastage can be built into the design and construction phase of buildings. Minor alterations during operation, made to provide a quick fix for compliance or equipment problems, can accumulate to contribute to energy waste. This wastage is often masked by the HVAC system itself, which continues to provide adequate comfort to occupants, but at a higher energy cost.

But HVAC is also big business.

According to The Brainy Insights, the US $19.68 billion 2022 heat exchangers market will reach US $32.65 billion by 2030, with the Asia Pacific region expected to have 9.37 percent of the heat exchangers market.

But it’s not just about energy efficiency or market share. It’s also about being smart, and of course, sustainable.

The rise of smart power

“Smart homes are not science fiction; instead, thanks to rapid advancements in industry 4.0 technologies, smart homes are now a reality today. All the functions that can be controlled – such as blinds, lighting, heating, air-conditioning or door communication – are designed to make life simpler and smarter, while also gives homeowners the power to reduce their carbon footprint,” Dr Thorsten Müller, Head of Global Product Group Building and Home Automation Solutions at automation company ABB.

“Smart home technologies have advanced exponentially in the past few years. Apart, they each offer value to homeowners. Together, they connect home from the entrance, throughout the house and garage, making life more comfortable, safer, smarter, and more sustainable,” he says.

Furthermore, notes Dr Müller, “Adapting our buildings following the Covid pandemic is an invaluable opportunity to reimagine the relationship between buildings and the health of their occupants.”

Effects of the pandemic

“Covid-19 has changed beyond recognition the ways in which people work, live and connect with each other. In the space of just two years, homeworking has become the ‘new normal’ for many, blurring the boundaries between workspace and the home environment, and replacing or supplementing face-to-face interaction with virtual technologies and remote working,” says Dr Müller.

“Digital technologies, such as artificial intelligence (AI), the Internet of Things (IoT) and data analytics, will play a leading role in delivering strategic business plans and the workplaces of the future.”

“As we emerge from the shadow of Covid-19 we have a huge opportunity – using a popular slogan – to ‘build back better’. By reimagining the relationship between buildings and the health of their occupants, harnessing the power of digital, automation and electrification technology, we can create safer, more sustainable low carbon living spaces for future generations,” he says.

Becoming a fanatic

According to Amber Mostert from Big Ass Fans, it’s all about the fans this summer, both for sustainability reasons and of course, the cost of electricity.

“A Haiku ceiling fan stand out from generic brands thanks to its iconic design, unmatched efficiency, and unrivalled functionality. Its permanent magnet motor allows for whisper-quiet, energy efficient airflow, while its seven speed settings allow the fan the ability to mimic a gentle breeze,” says Mostert.

“Haiku includes built-in smart technology designed to adapt to the user’s every need at the push of a button. This smart technology includes motion and temperature sensing,” she says.

“Haiku’s motion sensors detect when you enter or leave a room, turning the fan on or off automatically. While Haiku’s temperature sensing monitors a rooms temperature, automatically adjusting Haiku’s speed when conditions change. Open a window at night and your Haiku ceiling fan will automatically reduce the fan’s speed as the temperature drops.”

Mostert also notes that their Haiku fans can move larger amounts of air than typical ceiling fans. “A 1.5m Haiku ceiling fan at max speed of 200RPM can have an airflow max output of 7,673cfm. Typical ceiling fan cfm is 4,000,” notes Mostert.

“Haiku ceiling fans can be used all year round, moving cold stagnant air created from air conditioning and create a gentle breeze in summer. Due to its ability to run at such a low-speed setting, Haiku Caramel is also able to move air in winter without creating a draft and instead helps mix air created from heaters around in a room. “

“Even running all year round,” she says, the Haiku Caramel ceiling fan “only costs $0.065 to run per day compared to Air conditioning costs on average of $0.82.”

When CO2 is good for you

According to Sandra Skelly, General Manager of Comfort Heat, we need to also be looking at the air being sucked in and not pushed out.

By using the company’s Intaflo Heat Pump technology, the heat pump draws in air where the heat is absorbed by refrigerant. This is then compressed, and the generated heat is put back into water which is circulated through the heating system.

The Refrigerant used is known as R32.

“The heat pumps are made to the specification for the systems Comfort Heat supply and design,” says Skelly.

“There is a good range of heat pumps in the series from 9KW, 12KW and 18KW single phase units to 24KW three phase units. All units can operate with a Coefficient of Performance (COP – a performance rating that tells us how effective a heat pump or air-con unit is) of 4.”

“Also, there is a range of buffer tanks and a domestic hot water tank which can be used with the full range of heat pumps.”

“The heat pumps are designed in size for residential installation with small monobloc design and quiet fans. They are ideal for installation with solar and have been used in off grid applications,” she says.

“They are not useful for small floor areas but for most residential homes with main living areas from 70 square metres the heat pumps can become an option.”

“For larger floor areas multiple heat pumps can be utilised,” she says.

Moreover, according to Rachael Rowbottom from Automatic Heating Global, heat pumps have many advantages when it comes to being used for HVAC applications.

“A heat pump is an electric-powered heating appliance that manipulates a confined refrigerant to extract thermal energy from the environment and produce heat,” says Rowbottom.

“Since it essentially only uses electricity to facilitate heat transfer between the environment and the circulating water, it can reach net efficiencies of up to 450% with respect to the electrical power input. This is much higher than typical boiler efficiencies which can reach around 95 percent.,” she says, adding that, “since it runs on electricity, it eliminates on-site carbon emissions.”

“There are several heat pump models available on the market, however, the most eco-friendly type is the CO2 heat pump,” she says.

“As the name suggests, the Revere CO2 heat pump uses supercritical carbon dioxide as the refrigerant, operating under a trans-critical cycle. This means that carbon dioxide is compressed beyond its critical pressure, allowing a much higher heat rejection through sensible cooling, and increasing the overall heat pump efficiency,” says Rowbottom.

“Also, carbon dioxide is known to have the lowest global warming and ozone depletion potential among all common refrigerants today. With a 1.0 GWP and zero ODP, CO2 heat pumps are undoubtedly the best option for sustainable and carbon-neutral buildings.”

This technology is suitable also for multi-residential developments, like the one Automatic Heating Global worked in Hawthorn in Victoria.

With no gas connection to the building, 10 Lilydale Grove required a fossil fuel free and energy efficient hot water solution for the reliable supply of domestic hot water to the entire development. The original design was based on instantaneous direct electric 3-phase DHW units with one unit servicing each apartment. At 20 amps each, these units would require 1820 amps of power.

Automatic Heating was tasked to design a more efficient carbon neutral system and as such, to satisfy the space requirements for the rooftop installation, the company designed, engineered, and built the hot water package on prefabricated skid frames. The skids comprised 2x Revere 26kW CO2 heat pumps and 2 x 2000L storage tanks.

The result was a CO2 Heat Pump system of 30 amps that produced 70°C hot water to service some 91 apartments.

Solar precooling of residential buildings so hot right now

In a recent media story, a team of Australian researchers say they have developed a way to use rooftop solar PV to run air conditioners to pre-cool residential buildings.

Known as “solar pre-cooling”, this new technology offers benefits such as mitigating low minimum demand in electricity networks, flattening the grid’s net demand profile, and reducing electricity bills, the researchers say.

The researchers also claim they have identified several factors that could help to reduce energy costs, including reducing peak power and shifting AC demand to off-peak hours with the use of cheap electricity prices.

These factors include the reduction of mechanical cooling requirements by using night ventilation, and higher efficiency of air-conditioning units as they operate in lower ambient temperatures.

The researchers were quoted as saying pre-cooling can be more beneficial if the surplus PV generation during the day is used to pre-cool the building instead of importing electricity from the grid, mainly because the feed-in tariff (FIT) paid for rooftop PV generation is lower than current retail electricity prices.

Using tried and tested air-conditioning systems with a smart twist

Fujitsu’s General Lifestyle wall mounted reverse cycle air conditioner range features the Japanese company’s proprietary anywAiR technology, which comes with ducted controller and Wi-Fi control that is operated through the anywAiR app.

This, the company says, allows users to control their air conditioner from wherever they are, either inside or outside the home, using a smartphone, tablet, or voice command when available. The smart technology can be used for new systems as well as older units as the technology is compatible with air conditioning systems up to 10 years old if it operates with a wireless remote control and infrared technology.

But it’s not just about the high tech. Chemicals still play an important role in HVAC efficiency, and as we well know, some of the gases from HVAC include carbon dioxide and methane, both of which play havoc with our environment.

In addition to making air conditioners more efficient, there’s also a pressing need to replace the hydrofluorocarbon (HFC) refrigerants that most air conditioners still use. In fact, HFCs are 1,000–3,000 times more potent than CO2 as a greenhouse gas that slowly leak into the atmosphere and escape when air conditioners are decommissioned.

This is one reason why Fujitsu General says that it is focused on lowering its global warming potential by developing more advanced refrigerant chemicals.

So, while refrigerants play a vital role in how an air conditioner works, with the most common being the R410A refrigerant, Fujitsu General’s air conditioners under 9kW come with R32 refrigerant, which is claimed operates with a 67 percent lower ‘global warming potential factor’ whilst still maintaining peak unit performance.

The 100 percent renewable grid coming to a home near you

According to Renew Economy, there have been simulations of a 100 percent renewable electricity grid for Australia, including some ground-breaking studies from Beyond Zero Emissions, the University of New South Wales and the ANU.

The results of this modelling could have important impact in how and where we use our HVAC systems.

This is just as well as according to the International Energy Agency, there are around 1.6 billion heating, ventilation, and air HVAC units globally.

By 2030 – a mere 7 years from now – it is estimated that this number will grow to nearly 5.6 million.

As noted by Emily Underwood writing in Scientific American, there HVAC companies are now in a dilemma as to whether they should focus their efforts on finding the climate-friendliest refrigerant, or on reducing their product’s electricity use?

For example, an air conditioner using a standard HFC refrigerant would have to use 6.4 times less electricity than the baseline unit. In contrast, a unit that uses a refrigerant with zero potential to contribute to global warming would need to be only four times as efficient.

Whichever path is chosen by the world’s HVAC makers, it is a given fact that new air conditioners alone won’t be sufficient to stave off the ravages of climate change —other measures, such as building with better insulation materials than glass and concrete, are also needed and doubly fast.

However, if history is any indication, as Underwood writes, “the fastest route to transforming how we stay cool will be a combination of innovation, competition, and regulation. And speed is essential, as the stakes of the global cooling race are not just comfort, but survival.”

In other words, global HVAC makers have an open path and a clear goal in front of them – now it’s just a matter of reaching it.