HVACR News February-March 2023

Photo by Andrew Bott

Usage of HVAC&R press fittings continues to grow as contractors see benefits over brazing

Although plumbing contractors have enjoyed the benefits of press‑to connect fittings since the 1990s, it wasn’t until 2015 that RLS (Rapid Locking System) introduced the first press fittings designed to withstand the high pressures of HVAC and refrigeration systems.

Not surprisingly, many HVAC&R contractors were reluctant to try the new fittings in their early days. But today, after more than 8 years and 15 million fittings installed, RLS press fittings are now in widespread use around the world. Their tremendous growth is due to number of important factors …

FASTER, EASIER, SAFER INSTALLATION

RLS press fittings make reliable copper tube connections in just 10 seconds, saving significant time and labor costs compared to manually brazing joints. Eliminating the use of an open flame also increases safety, and means contractors no longer need to haul heavy tanks and other brazing equipment to and from the jobsite, no longer need to nitrogen purge, no longer need to purchase and stock brazing materials, and no longer need to organize hot work permits.

PROVEN TO BE RELIABLE AND REPEATABLE

RLS fittings were specifically designed and engineered for the high pressures of HVAC&R, and are UL listed for pressures up to 700psi. Because the battery powered press tool does the work, RLS connections are consistent and repeatable – and only require minimal training – compared to the potential for leaks due to inconsistent manual brazing. And with an 8 year track record of success, contractors can feel confident that RLS joints will be leak free.

UNIQUE TECHNOLOGY, WITH 360° METAL-TOMETAL CONNECTIONS

Unlike the hexagonal press systems used in plumbing, the patented RLS press technology uses a double circular press – featuring two 360 degree metal to metal connections. Plus, the fittings start as soft copper and are work hardened during the press, creating a permanent bond to the tube. The circular press results in a permanent mechanical joint every time, with no potential leak paths.

A WIDE RANGE OF TOOL AND JAW OPTIONS

With RLS compatible jaws now manufactured by a range of companies, RLS fittings can be pressed with most 19kN, 24kN and 32kN press tools on the market – from popular brands like RIDGID, Milwaukee, Klauke, Rothenberger, Viega, Dewalt and others. That means contractors who already own a press tool only need to purchase the jaws (only in the sizes they use) to enjoy the time saving benefits of RLS fittings.

A COMPLETE PRODUCT LINE

RLS offers fitting sizes from 1/4" to 1 3/8" and a full range of products, including couplings, long radius 90 degree and 45 degree elbows, tees, reducers and much more. In addition, RLS supplies all the necessary tools and jaws, both individually and in convenient kits.

To learn more about RLS press fittings, visit rapidlockingsystem.com.au or contact Ian Robertson, Director of Sales for Australia and New Zealand, at irobertson@rapidlockingsystem.com

The most proven, most complete line of press fittings for HVAC/R.

• Over 15 million installed since 2015

• Range of products from 1/4" to 1-3/8"

• Jaws available for most press tools

RLS is the only brand of HVAC/R press fittings you’ll ever need. We offer the most complete product line – couplings, elbows, tees, reducers and more – plus RLS-compatible jaws are available for all major press tool brands.

Our products are also the most proven, with 8+ years of field use and more than 15 million fittings installed. You can rely on our patented double circular press, which results in two 360˚ metal-to-metal connections, creating a permanent mechanical joint every time, with no leak paths.

Trust the original HVAC/R press fittings for proven reliability, an unmatched track record and the most extensive product line, plus a wide range of other benefits:

• Connections in 10 seconds

• UL Listed to 700 psi

• 360˚ metal-to-metal joints

• No gas or brazing materials

• No flame, no fire hazards

• No nitrogen purging

• Works in tight spaces

• 15-year limited warranty

rapidlockingsystem.com.au

YOUR GAS IS AS GOOD AS MINE

Who would have thought that invisible and mostly odourless gases could cause such a stink?

A global debate around refrigerants has been raging for some time, and it is intensifying.

Australia is now five years into the official HFC phase down, a transition away from refrigerants that exacerbate global warming, towards more sustainable alternatives. Although there is often a gap between what the policy‑makers say and what happens at the “cold face”, you have probably noticed that some gases are now becoming less popular, especially refrigerants with a high global warming potential (GWP) such as R410A, R134a and R404A.

But while nearly everyone agrees that we must move away from the high GWP refrigerants, there is less agreement about which alternatives we should use.

It’s not as simple as choosing a gas with low GWP. Other properties need to be considered, from flammability to toxicity, from working pressure to temperature glide. You might reduce the impact of leaked refrigerant by choosing a low GWP option, but what if it comes at the cost of a less efficient system?

And because this is an area of rapid development, our knowledge is constantly evolving.

Lately, there has been mainstream news coverage of FPAS (per and polyfluoroalkyl substances), which are created when some of the new‑generation refrigerants break down in the atmosphere. Dubbed “forever chemicals”, FPAS persist in the environment and eventually, can find their way into humans. The concern is that these may be linked to health issues.

As I write this column, there are proposals in Europe to restrict PFAS, which would see bans on some of the refrigerants that were expected to replace HFCs. So where do we go from here?

Many are advocating for greater use of so called “natural” refrigerants. These include CO2, propane, and one very traditional refrigerant that is now being utilised in new ways: ammonia. Given that this is our refrigerant and refrigerants special issue, we decided to investigate the latest innovations with good ol’ R717. The feature starts on page 19.

I also encourage you to check out the article on page 24 about refrigerant GWP. Amid the weird and wonderful range of refrigerants on the market, it’s a great guide to the basic properties of all gases.

In the past our industry has shown a great capacity to adapt, to think outside the box, and find new solutions. It’s time for us to do it again.

1 Hey presto, new from Testo!

Testo has launched a range of new measuring instruments into the Australian market.

Testo says smooth and energy efficient operation of air conditioning and ventilation systems can only be ensured by regular measurements of the relevant parameters.

“With the new compact measuring instruments testo 417, testo 416 and testo 425, flow and volume flow measurement in ventilation ducts, at air inlets and outlets and when adjusting balanced residential ventilation is child’s play,” the firm says.

Testo notes that we spend almost 90 per cent of our time indoors every day. Indoor air quality and comfort are therefore essential for minimising health risks and ensuring performance in the workplace.

“Thanks to the new compact measuring instruments testo 535, testo 545 and testo 625, CO 2, illuminance, temperature and humidity are controlled quickly, easily and precisely, ensuring a healthy indoor climate that promotes performance,” says the firm.

“The new HVAC measuring instruments deliver precise results wherever you need them – fast, flexible, user friendly and connected to smartphones and tablets,” Testo says. “Whether installing and maintaining air conditioning and ventilation systems, servicing heating systems, ensuring indoor air quality and comfort, measuring pressure in industrial applications … the world market leader in measurement technology has the right measuring instrument for every relevant parameter.”

Go to testo.com.au ■

2 Dwyer’s bright idea

Dwyer Instruments has released a new carbon dioxide and temperature transmitter, the Series CDT S.

According to Dwyer, the transmitters accurately monitor the CO 2 concentration and temperature in indoor environments.

Built upon Dwyer’s standard carbon dioxide transmitter, the  S option has a front facing LED that illuminates when the CO 2 level exceeds 1,100ppm.

Designed for schools and classrooms, the transmitters offer multiple sensing capabilities, simple installation with backplate electrical terminations, and a reduction in the number of installed devices by using integral temperature sensing. Go to www.dwyer inst.com.au ■

3 s-Mext comes next

Mitsubishi Electric Australia has launched a new cooling system for IT environments, s MEXT.

The split cooling package consists of the s MEXT high precision air conditioner indoor unit connected to a Mr Slim R32 inverter outdoor unit.

“The product is monumental for data centres around the country, where 40 per cent of total electricity usage comes from air conditioning,” says Mitsubishi Electric.

“Aside from its energy efficiency focus, the new s MEXT air conditioning has been designed with data centres front of mind, and is equipped to precisely control temperature and relative humidity.”

According to Mitsubishi Electric, the small size design means it can easily integrate into small IT rooms, small data centres, or distribution rooms.

Mitsubishi Electric Australia National Product Manager Atesh Mani says the new product is an important innovation for data centres around the country.

“We’re really excited to launch the latest product in the Mitsubishi Electric IT cooling family,” he says. “The s MEXT has really been manufactured to provide IT environments with powerful cooling solutions while providing businesses with a R32 refrigerant option.”

Mani says increased power densities in IT environments have led to growing temperatures (up to 23°C) of intake airflows directed to the IT equipment.

The s MEXT and Mr Slim cooling package was designed to manage return air temperatures up to 35°C, matching the requirements of the most critical data centres.

“We’re very aware that a significant portion of the electricity consumed by data centres is by air conditioning,” says Mani. “As such, it is really important that we are constantly innovating to meet the highest energy efficiency standards.”

S MEXT is available in over (top air supply) and under (bottom air supply) variants, for a wider range of applications.

Go to www.mitsubishielectric.com.au ■

4 Elitech launches in Oz

The Elitech brand is launching in Australia.

“Elitech Australia’s wide range of refrigerant leak detectors offers refrigeration technicians precision at the time of identifying gas leaks in air conditioning systems and coldrooms,” the company says.

“The ILD 200 is a handheld refrigerant leak detector with a 10 year long life infrared sensor in a low cost package that detects leaks of CFC, HFC, HCFC and HFO refrigerants. This is eight times longer than a thermal diode.

“The ILD 200 includes strong anti interference technology, which avoids false alarms from interfering gases. A large TFT colour screen provides an excellent visual display.

“It’s ready for use in 30 seconds, and has three selectable sensitivity levels and eight hours’ battery life in a single charge.” There are three models: ILD 100/200/300.

Elitech says that the ILD 200 and ILD 300 offer peak recording and automatic calibration, which helps pinpoint leak points quickly.

Go to www.elitechau.com ■

5

Daikin’s commercial refrigeration push

Daikin Australia has launched a strategic new refrigeration business unit following the introduction of a range of commercial refrigeration condensing units. The units are designed specifically for refrigeration applications to operate display cabinets and coolrooms for supermarkets, convenience stores, service stations, as well as food and beverage services.

“On a global level, Daikin has over 100 years of extensive experience in the commercial refrigeration market including unrivalled quality and innovation in refrigerants, controls and compressors,” says General Manager Applied and Solutions Guarav Malik, Affil.AIRAH.

“The new local refrigeration business unit allows Daikin Australia to capitalise on the company’s global expertise and provide a broader suite of integrated solutions, service and support to our commercial customers.”

The condensing units are manufactured by J&E Hall, a worldwide member of the Daikin Group. They are designed for small capacity refrigeration applications with a number of new features and functions. “The new compact condensing units offer efficient operation, improved reliability and longevity,” says Daikin. “Microchannel heat exchanger technology reduces refrigerant volume in the system in a more efficient way than traditional fin and tube heat exchangers, providing savings on installation costs. A new adjustable fan speed and pressure switch provides added flexibility to deliver optimal operation for the chosen refrigerant.”

According to Daikin, the units are extremely quiet and efficient during operation due to the acoustically lined casing and the option of low fan speeds, making them suitable for noise sensitive projects.

The range includes 27 medium temperature models ranging from 0.9–15.5kW capacity and 14 low temperature models ranging from 0.8–12.8kW capacity.

“Daikin is dedicated to strengthening its presence in the refrigeration segment by eventually providing solutions in all phases of the cold chain,” says the company. “Customers can expect to see the introduction of a wider line of refrigeration equipment for commercial and industrial use in the near future.”

Go to commercial.daikin.com.au ■

6 The TradeMutt drop

TradeMutt is a social impact workwear brand, by tradies for tradies.

The brand aims to make tradies and workers of all kinds look and feel great at work, and in doing so, reduce the rate of blue collar suicide in Australia.

“Our loud and vibrant shirts act as a catalyst to starting the conversation around mental health in men,” the company says. “It’s a topic that has been hard to approach in the past for blokes, mostly due to the attached stigmas and perceived weakness.”

The company regularly releases limited edition styles on a range of workwear clothes such as high viz vests, workshirts and the like.

The latest drop is a style dubbed “Wipeout”.

“At TradeMutt we have always been about making the invisible issue of mental health impossible to ignore with our colourful, conversation starting work and lifestyle wear,” the company says. “However, as the brand and in turn our community has grown, so has our responsibility to provide resources that help facilitate and nurture the conversations that we start.”

Go to trademutt.com/collections/wipeout ■

INVISIBLE LINKS

An innovative research project initiated by the City of Melbourne has found a simple way to reduce energy consumption in office buildings while also decreasing the transmission of COVID-19. Louise Belfield reports.

Researchers used a smoke-laser test to trace air movement and measure the effectiveness of the different retrofit solutions.

The City of Melbourne is facing a twofold challenge. The first is to achieve zero carbon emissions by 2040. The second is to help save small businesses by attracting up to 40,000 office workers back to the CBD following COVID 19 disruptions. At first glance, one seems incompatible with the other.

Data from the Property Council of Australia shows Melbourne’s CBD occupancy rate dropped from 49 per cent to 38 per cent in July 2022. This was far lower than in all other capital cities, with Perth being the top performer at 71 per cent.

Understandably, retailers in Melbourne’s CBD are desperate for more workers to return to offices to help boost trade. Melbourne Lord Mayor Sally Capp says unless the return to office rate improves, business owners are “running out of choices” with many “on their last legs, trying desperately to stay alive”. But how to convince workers that it’s safe to go back into the water?

A BREATH OF FRESH AIR

Enter the Building Retrofit for Efficiency, Air Quality, Thermal Comfort and Health (BREATH) project – a research pilot project initiated by the City of Melbourne in collaboration with Cbus Property, the University of Melbourne, A.G. Coombs engineering, SEED engineering, Aurecon, Cundall, and Westaflex Australia. Designed to bring workers back to the city while reducing carbon emissions, the project has been lauded as an outstanding success by all involved.

“BREATH is a world first collaboration between local government, industry and academics, and has given us the knowledge to predict the best type of retrofit to simultaneously reduce carbon footprint and infectious disease transmission,” says Jason Monty, Professor of Fluid Mechanics and Head of Mechanical Engineering at the University of Melbourne.

“Since the majority of city energy cost goes to ventilation of our buildings, the outcomes from BREATH will improve our ability to reach net zero carbon faster.”

That’s good news for Melbourne’s Deputy Lord Mayor Nicholas Reece. “Bringing people back to the [CBD] safely is a key priority for us,” he says.

“This industry leading research has identified simple but effective changes that can be implemented in office buildings to help workers feel safe, comfortable and protected … We encourage building owners, tenants and partners to take [these findings] on board, and to help us create more healthy and sustainable workspaces in the CBD.”

PROJECT OBJECTIVES

The primary aim of the BREATH project was to test different air conditioning and ventilation rapid retrofit options that could be used to reduce the risk of aerosolised viral spread, particularly within a post‑COVID return to offices context, while also considering the energy, cost and thermal comfort impacts of the proposed solutions.

“We worked closely with clients, industry and government during the pandemic to highlight the role that ventilation in buildings can play in mitigating the transmission of aerosol borne diseases,” says Andrew Nagarajah, Senior Engineer of Sustainability at building services and HVAC specialists A.G. Coombs.

“Our participation in the BREATH project is a natural extension of that. Post COVID it is essential that building owners, occupiers and HVAC designers and service providers have an enhanced understanding of air distribution in the built environment and how this can be better configured to significantly reduce aerosol spread of disease.”

The project involved a group of industry experts in a community of practice to review and test assumptions and to discuss outcomes. This included sustainable engineering firm Cundall, with its track record of building retrofits and creation of high performance buildings. Amin Azarmi, M.AIRAH, a Cundall associate, says the BREATH project aimed to establish data and evidence on how HVAC solutions could provide a healthier workplace in an energy efficient manner. Studies focused on improving the filtration of the air conditioning system, using installed equipment in an office space donated by Cbus specifically for the project.

“This office space enabled Melbourne University, Melbourne City Council and the HVAC industry experts to come together to develop and test energy efficient solutions and ensure proposed retrofits to effectively reduce the virus transmission,” Azarmi says.

The pilot test evaluated three different ventilation systems on the first floor of the vacant CBD building over three months. These were:

• Displacement ventilation air conditioning

• In ceiling HEPA air filters

• Natural airflow through open windows.  A.G. Coombs was responsible for the design, installation and commissioning of the displacement ventilation air conditioning. The other retrofit design, the in ceiling HEPA filtered air conditioning, was by Westaflex.

KEY TAKEAWAYS

When comparing each of the two retrofit solutions against the base-case scenario of openable windows operating in conjunction with the base-building’s conventional mixed-air overhead air conditioning system, Andrew Nagarajah, Senior Engineer of Sustainability at A.G. Coombs says:

1. In ceiling filtration was essentially the more cost effective, practical retrofit solution. With an installation cost of approximately $28/m2, it had comparable aerosol transmission reduction to the open window scenario (in the order of a 50 per cent reduction in modelled aerosol spread) while using 10–20 per cent less energy than the open window scenario.

2. The column based displacement ventilation solution, at an installation cost of approximately $170/m2, reduced aerosol spread by more than 80 per cent, while using 20–40 per cent less energy than the open‑window scenario. The superior results of this retrofit solution need to be weighed carefully against its higher installation costs, retrofit practicality, and increased engineering design considerations, when compared to the relatively simpler in ceiling filtration solution. ■

Photo by Andrew Bott

“Both retrofit solutions were compared against the baseline scenario of utilising openable windows in conjunction with the base building’s conventional mixed‑air overhead air conditioning system,”

A. G. Coombs’ Nagarajah

explains.

“Here, the openable windows were operated in accordance with ASHRAE recommendations as the ‘conventional’ solution (in the context of the project) to minimising aerosolised viral spread.”

PROJECT FINDINGS

Cundall’s Azarmi says all three options “demonstrated improvements for reducing airborne virus spread compared to business as usual”.

“The key finding was that it is possible to retrofit improvements to ventilation systems that will improve worker safety and indoor air quality while also ensuring energy efficiency,” he says. “The research also showed the assumption that opening windows would be a suitable solution counter intuitively increases energy consumption by between 10 and 20 per cent, as the HVAC system needs to address resulting thermal comfort issues.”

In summary, the project found:

• All three ventilation systems reduced the potential transmission of airborne viruses when compared to standard ceiling based air conditioning, improving safety for office workers

• Displacement ventilation air conditioning – which supplies air from floor level – was the most effective and energy efficient system tested, reducing COVID 19 transmission by 83 per cent, while also reducing energy consumption by 20 per cent

• Displacement ventilation is the most expensive to install, but there are no additional ongoing maintenance costs

• In ceiling air filters reduced virus transmission by 49 per cent but resulted in a minor increase in energy consumption

Opening windows reduced virus transmission by 53 per cent, but increased energy use by up to 20 per cent with seasonal temperature variations

• Opening windows is not available to all office buildings and is not always a viable solution due to Melbourne’s climate.

Nagarajah says the project successfully demonstrated that “rapid retrofit ventilation solutions can create healthier office environments by minimising the recirculation of air and thereby reducing the potential for airborne virus transmission, while simultaneously reducing HVAC energy consumption against conventional increased ventilation strategies”.

A critical part of the project was the peer review carried out by international engineering, management, design, planning, project management, consulting and advisory company Aurecon. Peter Mathieson, F.AIRAH, Aurecon Australasia’s Technical Director of the Built Environment, says that Aurecon gave feedback on the research project assumptions and trial set up including

PROJECT SNAPSHOT

A baseline vacant operation was used to determine the baseline power usage of the vacant space as well as the equivalent air change per hour (ACH) value of the space before retrofit modifications were made. The numerous days in the baseline conditions helped to determine a correlation between chiller power usage and average high temperature.

For all operations, 1,600W of heaters in buckets of water were distributed throughout the space (on chairs to simulate seated person height) to replicate the heat load modelled by A.G. Coombs with the displacement ventilation system (100W per person with 60W worth of laptop/monitor, set up for 10 people).

Specifically, the 1,600W of heat was generated through two 300W and five 200W aquarium heaters. These heaters were set to their maximum temperature, which they were not able to achieve with the volume of water they were submerged in. Hence, they were

constantly outputting their rated maximum wattage.

OPEN-WINDOW OPERATION

This examined the impact of opening windows while leaving the HVAC running in its standard operating mode (19–21 per cent outdoor air and the remainder recycled indoor air). Only every other window on the east facing wall was opened (resulting in eight 1.0m x 1.6m windows being opened), to both prevent cross flow and minimise the chance for incoming wind to affect the measurements. While it was possible to open windows in this building, operable windows are not available for all high rise offices.

IN-CEILING FILTERED OPERATION

The study used three fan driven HEPA filter equipped, locally made ceiling mounted units to filter the air. The in ceiling HEPA units are low power devices (measured at 60W), equivalent to the fan/filter power of portable HEPA filters but that allow

testing. Aurecon also reviewed the team’s approach onsite, and the final report.

“Understanding the science of ventilation effectiveness and how air delivery and exhaust works to improve indoor air quality and minimise occupant exposure to airborne contaminants is a foundation of mechanical engineering design of air conditioning and ventilation systems,” Mathieson says.

“Yet many [HVAC personnel] demonstrate only a passing understanding. So, research such as this in real built settings is important to affirm industry design guidance and knowledge. It is not surprising that the displacement air system provided better air quality outcomes as this is well established. Similarly, the fan filtration units that simply increased the clean air delivery rate to the test space is also a well established approach to achieve improved indoor air quality.

“Aurecon has a history of delivering specific design solutions to manage indoor air contaminant for a range of Australian and international clients, including both of these principles in the design solution. BREATH is therefore a great affirmation of this previous work.”

IMPROVING WORKING LIVES

Cundall’s Azarmi says post pandemic, tenants are looking for healthy spaces that reduce the opportunities for infection spread.

“They also want workplaces that increase collaboration between people and improve their social life in the office,” he says. “This makes managing how air moves between people and within spaces critical.

“At the same time, the property market is prioritising spaces that have lower energy consumption as part of the broader net zero shift and ESG [environmental, social and governance] appetite. This is why the impact

for BMS integration, making them an industrial solution to the problem of increasing the ACH.

DISPLACEMENT VENTILATION OPERATION

A.G. Coombs used nine columns to retrofit slightly less than half the space for displacement ventilation. The floor was divided with floor to ceiling construction plastic. After some testing it was determined that the air exiting the displacement column needed to be 20°C, which is 2°C higher than the standard mixing operating temperature of 18°C.

AIR CHANGEOVER MEASUREMENTS

Ideally, the first period of measurements (where the building is not isolated) consisted of approximately four days of experimentation with three readings per day. Some deviations from this had to be taken. In these ideal conditions, the readings are taken in

the nominal morning, midday, and close of business (understanding that these times are nominal and can shift depending on the day). During these readings the team was taking an ACH reading as well as temperature readings of the space.

The purpose of these three readings was to capture any changes in the space as the outside temperature changed. Because of the short duration of the experimental campaign, it was hoped to capture different weather conditions over the four days. The study therefore used meteorological measurements of temperature as the source of “true” outdoor conditions. However, the reality of the full scale tests and the problems associated with both supply chain constraints and HVAC shutdowns following fire alarms meant that only the open window and baseline measurements were taken sequentially over four days. The other conditions – displacement ventilation and in ceiling HEPA –were taken as the space was available/ possible. ■

It is possible to retrofit improvements to ventilation systems that will improve worker safety and indoor air quality while also ensuring energy efficiency

of ventilation strategies on NABERS [National Australian Built Environment Rating System] ratings was one of the outputs of the research, because NABERS is the standard most potential investors, tenants or asset purchasers look to in making decisions about commercial space.”

One of the important attributes of the BREATH project was the ability to visualise the air movement patterns in a space, says Aurecon’s Mathieson.

“The challenge with understanding that infection is airborne is that it cannot be seen and so is forgotten or ignored,” he says. “BREATH provided a visual appreciation of infection movement in a space and a comparison of the effectiveness of its removal, building on an important body of previous research work. This visualisation is a vehicle to improve our understanding of the science of successful space air delivery and exhaust systems. Funding of further research is an important opportunity for education of the HVAC industry,” he says.

Azarmi says the project provides the necessary evidence that base contractors, consultants and HVAC professionals can use to improve the quality and performance of air conditioning and ventilation in cost effective ways.

“By giving clear metrics on the relationship between equipment type, equipment configuration, energy requirements, indoor air quality and operational costs, technicians and consultants can present clients with stronger business cases for retrofits.”

Nagarajah says HVAC&R technicians, engineers, consultants and contractors should be willing to question directives for conventional indoor air quality improvement solutions – such as simply increasing outside air rates, improving filtration arrestance or retrofitting air disinfection devices.

“They should also feel confident to cite research such as the BREATH project to landlords and facility managers,” he says, “for their consideration of alternative air distribution solutions that could also reduce operational energy consumption.”.

RESOLVING REAL- LIFE ISSUES

Cundall partner and Australian Managing Director Garrit Schot says the results of this project demonstrate how integrated approaches hold enormous value in ensuring we achieve optimum air quality from both a thermal and a health perspective, while also delivering on energy efficiency.

“It shows how cross sector partnerships can advance practices,” he says.

Azarmi also highlights the spirit of the BREATH community of practice.

“The manner in which Melbourne University, Melbourne City Council and HVAC industry experts collaborated to share knowledge and experience has been inspiring,” he says. “Unlocking the most energy‑efficient retrofit methods for mechanical services upgrades to increase workplace indoor air quality and indoor air safety is contributing to high‑performance buildings.

“Using a smoke laser test to trace air movement and prove the effectiveness of the retrofit solutions was one of the fascinating testing methods. I am looking forward to seeing ongoing collaboration between the university and industry experts to resolve real‑life issues in the built environment.” ■

BREATH PROJECT KEY OUTCOMES

Opening windows, standard heating, ventilation and air conditioning operations

In ceiling air cleaner, HEPA filtration units

Approximately 53 per cent less infections Nil Costs $6/m2 per year

Approximately 49 per cent less infections

$28/m2 with maintenance costs of $1.5–3/m2 per year

Saves $4.21/m2 per year

10–20 per cent increase in energy use, loss of up to ½ NABERS star

2 per cent increase in energy use, no impact on NABERS

Displacement ventilation air conditioning

Approximately 83 per cent less infections

$170/m2 with no additional ongoing maintenance costs

Saves $10.67/m2 per year

10–20 per cent reduction in energy use, addition of up to ½ NABERS star * NABERS is a simple, reliable sustainability rating for the built environment, which measures buildings’ efficiency across energy, water, waste and the indoor environment. NABERS provides a rating from one (making a start) to six (market leading) stars.

Retrofitting displacement ventilation proved to be the most effective – and energy efficient – way of reducing the spread of aerosols.

PACIFIC ISLANDS

ISLAND TIME

With support from the Australian government, AREMA and UNEP have started a project to help Pacific Island countries improve their training capacity around good servicing practices for refrigeration and air conditioning (RAC) equipment.

As a key part of the Montreal Protocol’s HCFC phase out (which covers R22), 13 trainers from the Cook Islands, Fiji, Kiribati, Vanuatu, Tonga, Solomon Islands, Micronesia, Palau and Samoa attended Box Hill Institute in Melbourne’s east to learn how to improve training offered in their respective countries.

“As a result of high quality training, technicians are able to deliver better equipment longevity and customer comfort, energy savings and reduced greenhouse gas emissions,” says AREMA President Mark Padwick.

The trainees benefited from the deployment of training pods, including a split system air conditioner and a refrigeration display cabinet. The training also focused on safely working with flammable refrigerants, both R32 and hydrocarbons.

Supplied without cost by Daikin and Danfoss, the pods will be provided to Pacific Island countries for continuing training. ■

USA

IONS IN THE FIRE

Californian scientists are researching the process of ionocaloric cooling, which takes advantage of how energy or heat is stored or released when a material changes phase, e.g., from ice to water.

The scientists hope to harness the process to provide alternative methods of large‑scale heating and cooling.

The ionocaloric cycle causes a phase and temperature change through the flow of ions (electrically charged atoms or molecules) derived from a salt.

“The landscape of refrigerants is an unsolved problem: No one has successfully developed an alternative solution that makes stuff cold, works efficiently, is safe, and doesn’t hurt the environment,” says UC Berkeley PhD candidate Drew Lilley, who led the study. “We think the ionocaloric cycle has the potential to meet all those goals.

“There’s potential to have refrigerants that are not just GWP zero, but GWP negative. Using a material like ethylene carbonate could actually be carbon negative, because you produce it by using carbon dioxide as an input.”

A provisional patent for the ionocaloric refrigeration cycle has been granted. ■

MEXICO

CLOUDY WITH A CHANCE OF COOLING

Inventor Luke Iseman has raised AU$700,000 to launch a sunlight reflection company, Make Sunsets. From land owned by Iseman in Baja, Mexico, the plan is to undertake three balloon test launches, releasing sulphur dioxide to cool the atmosphere. This is a process sometimes referred to as geoengineering, and is said to mimic the action of volcanoes. Make Sunsets prefers the term “albedo enhancement”.

“We make reflective, high altitude, biodegradable clouds that cool the planet,” says the firm’s website. “Mimicking natural processes, our ‘shiny clouds’ are going to prevent catastrophic global warming.”

The 1991 eruption of Mount Pinatubo in the Philippines released thousands of tonnes of sulphur dioxide into the stratosphere, which temporarily lowered average global temperatures by about 0.56°C.

Climate scientists experienced with solar geoengineering say the Make Sunsets balloon launches will not generate productive research, and that the field should be governed by an international body. But Iseman remains undeterred.

“I’m doing this because it needs to be done,” he says. “And no one else is.” ■

BELGIUM

PFAS RESTRICTIONS PROPOSED

PFAS (perfluoroalkyls and polyfluoroalkyl) restrictions proposed by five European countries could include bans on some lower GWP HFC/HFO refrigerants.

Proposals from Denmark, Germany, the Netherlands, Norway and Sweden were submitted to the European Chemicals Agency (ECHA) in mid January.

Known to be highly persistent in the environment, PFASs can contaminate groundwater, surface water and soil, and cause serious health effects such as cancer and liver damage. In addition to its potentially harmful effects on humans, PFASs can also harm nature, with the precise effects varying greatly depending on the specific PFAS.

The five nations have been working together since 2019 to draft a proposal for a European PFAS ban. It comes after the five authorities found risks in the manufacture, placement on the market and use of PFASs that are not adequately controlled and must be addressed through the European REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations.

It is possible that some lower GWP HFC and HFO refrigerants could be included within the restriction. ■

Factors affecting thermal comfort

Human comfort depends on a range of factors including temperature, humidity, air movement, clothing, and the type of activity, as well as cultural factors and personal preferences. Thermal comfort is a subjective experience that varies from person to person and over time. Historically, air conditioning controls have targeted a set room air temperature (DBT) and sometimes relative humidity (RH) level. We now understand that many other factors affect human comfort and their control can be exploited to optimise comfort air conditioning at greater energy efficiency. The ASHRAE 55 thermal comfort standard provides a mechanism for analysing human thermal comfort. The factors that affect comfort include:

• Air temperature (DBT/WBT)

Humidity levels (per cent RH)

• Mean radiant temperature (MRT)

• Air velocity (Air V)

• Activity level (MET)

• Clothing (CLO)

Seasonal variation

• Geographic location

• Adaptation

• Workplace and local culture.

A CLO is a non SI unit of clothing insulation, defined as the thermal insulation necessary to keep a sitting person comfortable in a normally ventilated room at 21°C and 50 per cent relative humidity. The thermal resistance of one CLO is equal to 0.155m2.K/W. A typical combination of garments for 0.5CLO would be underpants, shirt with short sleeves, light trousers, light socks and shoes. See Table 1 for typical CLO factors.

SELECTING INDOOR DESIGN CONDITIONS FOR THERMAL COMFORT

Human comfort is a subjective concept which varies from person to person and changes over time. Internal conditions that are considered universally comfortable in a temperate climate do not need to be exactly replicated in a tropical climate. Clothing differences, cultural difference and outdoor air humidity levels all must be considered.

By varying indoor humidity, dew point and air speed, designers can create comfortable conditions that are more practical and relevant to a specific environment, application or culture.

This Skills Workshop looks at the different factors affecting thermal comfort, and how to design for them.

a “Thin” garments are summerweight, “thick” garments are winterweight.

b 1clo = 0.155 (m2.K/W) c Knee length

Table 1 – Typical CLO factors for typical garments

MET is the unit of metabolic rate of people. One MET is defined as 58.15W/m2, which is equal to the energy produced per unit surface area of a person seated at rest. The surface area of an average person is about 1.8m2. MET rates for typical people undertaking particular activities are provided in Section 8.

Comfort zones

Comfort zones, or envelopes of acceptable internal comfort conditions, have been developed for refrigerative air conditioning, evaporative air cooling and naturally ventilated or fan assisted ventilative cooling applications. The evaporative air cooling comfort zone differs from the refrigerative air conditioning comfort zone because of the different air velocities used and because of the differences in how indoor humidity is considered. An advanced understanding of human comfort presents opportunities to save energy while still keeping occupants comfortable. The standard convention of attempting to maintain a narrow temperature band can be an energy intensive practice. Instead, using ASHRAE Standard 55 as a guide, designers may find that a wider temperature band will provide adequate comfort, saving a significant amount of energy.

The ASHRAE developed comfort zones shown in Figure 1 indicate a wide humidity tolerance. The operative temperatures have been determined based on the following criteria:

Light, primarily sedentary activity

A metabolic rate ≤1.1MET

• 50 per cent relative humidity

• Mean air speed ≤0.15m/s.

Accommodating a range of CLO, MET and air speed within comfort zones can be achieved using the analytical methods contained in ASHRAE 55. Comfort is not the only performance criteria applied to systems, however, and indoor air quality, condensation risk and operating costs all need to be considered.

ASHRAE Standard 55 is strictly limited to thermal comfort considerations, so mould issues and health issues such as dry throat or eyes at low RH are not accommodated in the ASHRAE 55 thermal comfort recommendations. With adaptation, an even greater psychrometric

The Graphical Comfor t Zone Method has been removed from the ASHR AE 55 standard as a “Meth od for Determining Acceptable Thermal Environment in Occupied Spaces” The Graphical meth od has been replaced by some example graphic ps ychrometric char ts that have been developed using the Analytical Comfor t Zone Method and the Elevated Air Speed Comfor t Zone Method

The Analytical meth od and the Elevat ed Air Speed method are now the t wo ASHR AE 55 methods for determining acceptable thermal comfor t.

region may be accepted as comfortable, particularly if summer indoor air velocities are increased above winter velocities, see Figure 1.

Thermal comfort, air temperature and operative temperature

Temperature is usually the most important environmental factor affecting thermal comfort. If the temperature changes are small (e.g., <1°C) and occur slowly over the course of a day, they are unlikely to prompt dissatisfaction. Larger diurnal changes can be acceptable if they are within the control of the building occupant, i.e., they can move to a different area, change clothing levels, operate blinds or shade curtains, turn on a personal fan, or open windows (when air conditioning is off). Temperature changes over longer time periods (e.g., in a summer heat wave) can be acceptable if they occur sufficiently gradually to allow building occupants to adapt to the change. Seasonal temperature changes are reflected by changed clothing.

The air temperature inside an occupied space can be measured on a standard (mercury in glass) dry bulb thermometer. This measurement of air temperature is representative for internal rooms where room surfaces are close to air temperature. This condition is described in Equation 1:

Equation 1

enclosed in a hollow black sphere referred to as a globe thermometer in ISO 7726.

Psychrometric charts are the tool of choice for many air conditioning assessments. The psychrometric chart used in ASHRAE 55 for visualising indoor thermal comfort is different to the AIRAH psychrometric charts in that the scale along the bottom is in operative temperature not air temperature. Air temperature and radiant temperature are combined as operative temperature. Operative temperature is not the same as actual/measured space temperature as measured by a thermometer or temperature sensor. Operative temperature (top) is defined as the uniform temperature of an imaginary black enclosure in which an occupant would exchange the same amount of heat by radiation plus convection as in the actual non‑uniform environment. Operative temperature can be shown mathematically as:

top = hr tmr + hc ta

hr + hc

Equation 2

It is also acceptable to approximate this relationship for occupants engaged in near sedentary physical activity (with metabolic rates between 1.0MET and 1.3MET), not in direct sunlight, and not exposed to air velocities greater than 0.20m/s. top

Where:

ta = air temperature; and

tmr = mean radiant temperature.

However, if an air conditioned space is subjected to direct solar radiation through a window, or infrared radiation through a poorly insulated roof or ceiling, then a simple mercury in glass thermometer measurement would be misleading if the temperature measurement is used to assess indoor thermal comfort. Comfort assessment under these conditions must also consider the radiant temperature of the surrounding surfaces. This radiant temperature (tr) can be calculated from a measurement using a standard mercury in glass thermometer

Where:

Equation 3

top = operative temperature

hc = convective heat transfer coefficient hr = linear radiative heat transfer coefficient ta = air temperature (DBT)

tmr = mean radiant temperature (MRT)

Most people have experienced the difference between air temperature and operative temperature. Recall the perceived temperature on a hot summer day when there is no breeze under a metal roof (without insulation) of say a park shelter. Then compare that to the lower perceived temperature under the shade of a nearby large and leafy tree. The difference is largely due to the greater protection from radiant heat offered by the leafy tree. Typically, radiant temperature in a room becomes noticeable when a surface temperature of the space exceeds the air temperature by more than 4°C.

Thermal comfort and air movement

The cooling effect of moving air is well known, and operative temperature can be increased to take advantage of this cooling effect, associated with differences between air temperature and radiant temperature, see Figure 2. Comfort is a function of both temperature and air velocity, and humans can be comfortable over a range of conditions. By increasing the velocity or air movement, the air feels cooler even though the air temperature has not changed.

Note that “Operative temperature” is not the same as the space temperature measured by a thermometer or temperature sensor. Figure 1 – Extending comfort zones

The principal physical factors for thermal comfort described in ASHRAE Standard 55 for office type spaces are environmental factors: air temperature, radiant temperature, air speed, and humidity; and additional personal factors: metabolic rate and clothing insulation. Given that psychrometric charts are two dimensional, displaying temperature versus humidity, the other physical factors,

i.e., the radiant temperature (tr) and an assumed air speed factor (A) are accommodated by combining them with the air temperature (ta), as an operative temperature (top). The simplest form of this combination is described in ASHRAE 55 as:

• When the operative temperature drops to lower values, the dry heat exchange is increased and the evaporative heat loss is mainly respired vapour loss. The skin temperature and the temperature of superficial and deep tissues drop, resulting in a negative heat storage.

• When the operative temperature exceeds 29°C, the rate of evaporative heat loss is significantly increased in order to counterbalance the reduction of dry heat exchange to maintain the thermal equilibrium.

The body temperature tends to rise only when the body is entirely wet, and the evaporative heat loss is inadequate. There exists a positive rate of heat storage.

Body temperature above 43°C may cause death.

ET and SET are very similar for “normal conditions” in air conditioned buildings, typically around 22°C to 24°C when relative humidity is around 50 per cent. However, if operative temperature rises above approximately 30°C, the effect of relative humidity in SET is greater than in ET.

SET focuses on “skin wettedness” in the calculation of evaporative cooling from sweating and is a more suitable index to use than ET when assessing thermal comfort in humid environments.

Comfort variables and SET analysis

The ASHRAE 55 preferred way to determine how much dry bulb air temperature can be offset by elevating air speed is to enter the relevant DBT, MRT, RH, MET and CLO conditions for the occupants and the space, along with the proposed elevated air speed into computer software analysis tools such as the ASHRAE Thermal Comfort Tool or the CBE Berkeley Comfort Tool.

The values for air speed factor (A) range from 0.5 for air speed less than 0.2m/s to 0.7 for air speeds from 0.6–1.0m/s.

Assuming uniform velocity airflow, turbulent airflow with a gusting frequency of around 0.5Hertz can significantly increase the cooling effect of air movement at the same velocity. The effect of air movement on the comfort of a person can be determined by comparing standard effective temperatures (SET).

Thermal comfort and humidity

Human comfort depends on temperature, air movement and the ability of the body to warm or cool itself to maintain a required body temperature. High levels of humidity generally lead to a feeling of discomfort as the increased levels of moisture in the air impede the body’s ability to perspire and cool itself through evaporation (evaporative body heat exchange).

The high humidity levels in tropical climate areas must be considered.

Unlike sunlight and temperature, humidity is a factor that is much harder to design for in the built environment. Humidity cannot be controlled through shade as we do the sun or insulated against as we do for the heat and cold. Instead, ventilative cooling by ventilation and air movement, or comfort cooling by air conditioning becomes the essential design consideration for controlling humidity. Although it is harder to avoid humidity by building design, good cross ventilation or assisted air movement using ceiling or wall mounted fans can improve the comfort levels at higher levels of room humidity.

Relative humidity is most relevant to body heat exchange and thermal comfort at operative temperatures above 30°C, refer to Figure 3. This accounts for significant differences between effective temperature (ET) and standard effective temperature (SET) values, see “Effective temperature and standard effective temperature”

Figure 3 shows the following:

• At an operative temperature of about 25.5°C for light clothed person (and 31°C for an unclothed person), there is minimal body heat exchange when the metabolic rate is about 1MET.

Effective temperature and standard effective temperature

Effective temperature (ET) combines operative temperature and humidity into a single index. Two different environments with the same ET should have a similar comfort response even though temperature and humidity levels are different. For the analysis to be valid, air movement and velocity, skin wettedness and clothing moisture permeability must also be the same. Some modified commercial versions of ET have been developed to better model human response to humid tropical and arid environments. Standard effective temperature (SET) is the effective temperature (ET) under a set of standard conditions (clothing, skin wettedness and activity) intended to represent typical indoor applications or activities. SET is based on a laboratory study with a large number of subjects using empirical equations for skin temperature and skin wettedness. SET is calculated by determining a value that satisfies the two equations for those environmental conditions. Computer software to perform the calculations includes the ASHRAE Thermal Comfort Tool. In the SET model, clothing insulation is linked to metabolic rate and skin wettedness is linked to mean body temperature. The standard MET rate is taken as 1.1MET and linked to a clothing insulation of 0.6CLO. However, a SET value can be calculated for any combination of the six thermal comfort factors: air temperature (DBT/ WBT), humidity levels (per cent RH), mean radiant temperature (MRT), air velocity (Air V), activity level (MET) and clothing (CLO).

These comfort tools will compute a range of outputs including SET. The SET is the equivalent air temperature of an isothermal environment at 50 per cent RH in which a subject, wearing clothing standardised for the activity concerned, has the same heat stress (skin temperature) and thermoregulatory strain (skin wetness) as in the actual environment.

Input the comfort factor values, note the value of SET calculated and then reduce the air speed value. A new SET will be computed. The difference between the original SET and the latter SET is the dry bulb temperature offset achievable from the elevated air speed. The SET index is used for hot humid tropical climates because it is the only index included in the tool that takes account of skin wetness, an important factor in human body heat exchange in warm conditions.

Comfort variables and PMV analysis

Originally developed through field experimentation, the predicted mean vote (PMV) analysis refers to a thermal scale that runs from cold ( 3) to hot (+3). A mathematical model of the relationship between all environmental and physiological comfort factors (or variables) was derived and adopted into ISO 7730 and ASHRAE 55. The PMV equation for thermal comfort is a steady state empirical equation for calculating (predicting) the average vote of a large number of people on a seven point scale ( 3 to +3) of thermal comfort. It only applies to humans exposed for a long period to constant conditions at a constant metabolic rate. The equation uses the steady state heat balance of the human body and develops a link between the thermal comfort vote and the degree of stress or load on the body caused by any deviation from perfect balance. The greater the load, the more the comfort vote will deviate from zero. The partial derivative of the load function was estimated by exposing a number of people to enough different conditions sufficient to fit a curve. PMV is a widely used thermal comfort index and ISO 7730 uses limits on PMV as an explicit definition of the comfort zone.

From the PMV, the predicted percentage of dissatisfied people (PPD) can be determined. As PMV moves away from neutral (PMV = 0) in either direction, PPD increases, i.e., more people are dissatisfied. The maximum number of people that can be dissatisfied with their comfort conditions is 100 per cent and the minimum number is 5 per cent. A 20 per cent PPD figure (80 per cent satisfied) is generally considered acceptable. ■

Next month: Controls and HVAC

Figure 2 – Air speed required to offset increased air and radiant temperature

Figure 3 – Effect of operative temperature on human body heat exchange mechanisms

skills workshop is taken from DA09 – Air Conditioning Load

. Explore the full suite of DA manuals at

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FLUID THINKING

Ammonia is a naturally occurring compound found in the environment. A key element in the nitrogen cycle, it is essential for many biological processes and is therefore found in water, soil and the air. In fact, it is one of the most abundant gases on the planet. Made up of one nitrogen atom and three hydrogen atoms, ammonia is described by the chemical symbol NH3. In refrigeration parlance, it is also known as R717. According to the International Institute of Ammonia Refrigeration (IIAR), it was first used as a refrigerant in the 1850s in France before being used to produce ice in the USA the following decade.

By the early 1900s, ammonia refrigeration machines were widely in use for block ice, food processing and chemical production facilities. This led to ammonia becoming the backbone of the cold storage and food processing industries, with the first commercial production of synthetic ammonia occurring in 1913.

Over a century on, global production of ammonia topped 236 million tonnes in 2021.

“Presently, there are an estimated two billion metric tons of ammonia in the world (and) of this amount, approximately 5 per cent is man made,” says the IIAR.

Less than 2 per cent of the world’s ammonia is used for refrigeration. As well as the huge quantities of ammonia that are used in agriculture as fertiliser, it is also a building block in pharmaceutical products and in the manufacture of plastics, explosives, textiles, pesticides, dyes and other chemicals.

As one of only two fuels that combust without the formation of carbon dioxide (CO2), ammonia’s use as a fuel is also the subject of much research and development around the world, including here in Australia.

Renowned for its favourable thermodynamic properties, ammonia has been used as a refrigerant for more than 150 years. Despite this longevity, its adoption by the Australian refrigeration and air conditioning industry has remained largely in the sphere of industrial application. Sean McGowan reports on how that’s changing.

The ammonia refrigeration system in the Walmart-SCM Balzac distribution centre in Canada.

Source: Green Energy Futures on Flickr.

ZERO HERO

As far as refrigerants go, ammonia ticks many boxes. It is a substance with zero ODP (ozone depletion potential) and zero GWP (global warming potential) – giving it an advantage over HFC (hydrofluorocarbons) and the HFO (hydrofluoroolefin) refrigerants and blends used as we transition away from synthetic refrigerants.

Ammonia also possesses highly favourable thermodynamic and transport properties.

“Ammonia is the refrigerant of choice in almost all large scale industrial refrigeration and freezing applications,” says Stefan Jensen, F.AIRAH, Managing Director of Scantec Refrigeration Technologies. Its latent heat of vaporisation is several times that of other commonly used refrigerants including other natural refrigerants like CO2 and propane, with very

little required to perform the same amount of cooling. Despite these advantages, Jensen says a significant challenge for practitioners designing ammonia refrigerating plant lies in making ammonia the best it can be.

“Put differently, the challenge is to maximise the inherent advantages of ammonia refrigerant through the refrigeration system design,” he says.

Historically, liquid overfeed systems have been widely associated with the use of ammonia as a refrigerant since the concept was patented by the York Corporation in 1925. Almost a century on, it remains the most popular approach in large‑scale ammonia refrigerating plant.

In liquid overfeed ammonia refrigerating plant, the suction line network contains large amounts of liquefied ammonia. The operating principle of these systems is that the evaporator(s) is supplied

NH3 KNOWLEDGE

with significantly more liquefied refrigerant than is vaporised. The term “overfeed rate” refers to the ratio between the quantity of liquefied refrigerant supplied versus the generally smaller quantity vaporised on a mass basis.

But recently, evidence is emerging from practical installations that the presence of large amounts of liquefied ammonia in the suction line network of some types of large, expansive liquid overfeed refrigerating systems in fact jeopardises energy efficiency much more than previously thought.

“A common plant type comprises ceiling suspended evaporators (air coolers), refrigerant pipelines in the ceiling cavity and a plant room at ground floor level,” says Jensen. “In these types of plant, specific energy consumption differences of approximately 30 per cent have been recorded.”

This margin, he says, represents the difference between the presence of liquefied refrigerant in the suction line network versus a network conveying saturated vapour only.

Consequently, decades long ammonia refrigeration plant design practices are now being challenged. These include ammonia inventories, part load energy performance, overfeed rate control, plant oversizing and resilience, maintenance costs, technical life, the design of small and medium‑size plant, control and monitoring.

“Some deeply entrenched myths pertaining to the suitability or otherwise of ammonia refrigerant in certain applications are also being challenged,” says Jensen.

This has led to the application of ammonia in medium  and large scale air conditioning plant, supermarket systems, aquatic centres and small‑to‑medium foodservice facilities.

“A decade ago, these were almost exclusively serviced by air cooled HFC based refrigerating plant with electric defrost,” says Jensen. “Major refrigerated distribution centres that were serviced by R22 based liquid overfeed systems 15 years ago and consumed around 100kWh/m³ per year now routinely record specific energy consumption values that are around 10 times lower when serviced by centralised, low‑charge NH3 refrigerating plant.”

Andrew Pang, AM.AIRAH, Director of Andrew Pang and Associates, says that as well as keeping up to date with the latest advances in ammonia refrigeration technologies, professionals in the commercial and air conditioning sectors of our industry should consider brushing up on ammonia safety.

AIRAH offers a number of training courses specifically related to ammonia refrigeration.

Industrial Ammonia Plant Operations (3 days)

A popular and much sought after course both in Australia and New Zealand, this covers how various ammonia refrigeration plants work, their components and controls, maintenance, basic troubleshooting, legislative requirements, and ammonia safety. Suitable for ammonia plant operators, electricians, fitters, refrigeration mechanics and maintenance contractors, planners, supervisors and managers/engineers.

Ammonia Safety Awareness (half-day)

This course covers the understanding of ammonia properties, first aid requirements, ammonia safety equipment, basics of ammonia emergency site procedures, and preventative maintenance requirements for ammonia plants. Suitable for OH&S and emergency services personnel, mechanical services/air conditioning and commercial refrigeration professionals, refrigeration equipment manufacturers and suppliers, store personnel and anyone working in and around ammonia plants.

Ammonia Emergency Response (1 day)

This course provides participants with the skills to competently manage an onsite ammonia leak. It covers ammonia properties, first aid requirements, personal protection equipment, legislative framework including relevant safety standards and dangerous goods state codes, ammonia vapour and cloud dispersal, methods of control for vapour and liquid leaks, detailed ammonia emergency planning and preventative maintenance requirements. Suitable for ammonia plant operators and managers, refrigeration mechanics, and OH&S managers.

For more information and enrolment details, visit www.airah.org.au/education

This centralised dual-stage, low-charge ammonia plant in Melbourne – designed by Scantec –was a finalist in the Excellence in Refrigeration category at the AIRAH Awards 2021.

SAFETY NOTES

Although ammonia is highly toxic – reflected in its refrigerant classification B2L where “B” refers to toxicity and “2L” refers to its flammability class –well developed and highly mature safety standards for ammonia have been developed globally by organisations like the IIAR.

But unlike other class 2L (lower flammability) refrigerants, ammonia gives off a pungent odour that can be detected by humans at concentrations as low as 0.6 parts per million (ppm). A concentration around five hundred times higher than that is required to reach the IDLH (Immediately Dangerous to Life or Health) value of 300ppm.

“Ammonia is very often highlighted as a toxic and explosive substance,” says Andrew Pang AM.AIRAH, Director of Andrew Pang and Associates.

A consultant in the HVAC&R field for more than 20 years and a former RMIT University lecturer, Pang presents a number of refrigeration and air conditioning courses for AIRAH including the Ammonia Awareness and Emergency Response course.

“Ammonia is flammable, but it is not explosive. It burns with low energy and its flame propagation is low –7.2cm/s compared to 45cm/s for propane and 317cm/s for hydrogen. A very high temperature of 651˚C is also required to ignite ammonia, and 680mJ of ignition energy compared with 0.26mJ for propane and 0.02mJ for hydrogen.”

He says for ammonia to be flammable, its concentration needs to reach as high as 167,000ppm.

“This value being the lower flammability limit,” he says, “while the upper flammability limit is 340,000ppm. These values are well above detectable levels.”

ATTENTION TO DETAIL

An ammonia refrigeration plant differs from those designed for other refrigerants in almost every aspect, with these differences driven by two main factors: material compatibility and refrigerant toxicity.

Other factors to also be considered in the plant design are the demands of the ammonia plant user, the safety standards applicable both mechanically and electrically, the thermodynamic properties of ammonia, ammonia/oil miscibility, and ammonia surface tension.

“The ammonia plant is almost always more industrial in every respect than systems designed for other natural and synthetic working fluids,” says Jensen.

“This translates into a service life that is often two or more times longer than HFC, HFO or CO2 based systems. In the ammonia refrigeration industry, there is also a greater tendency towards repairs and overhauls as opposed to simple parts and plant replacement. This fits the modern sustainability agenda.”

Although the basic principles of ammonia refrigeration are similar to other refrigerants, there are some stark differences.

For instance, ammonia corrodes copper, zinc and their alloys very quickly. These metals are therefore not used in the piping and refrigeration components of ammonia refrigeration systems.

Ammonia can also absorb a small amount of water without the detrimental effect of ice formation at the orifice of the expansion valve, which can block refrigerant flow into the evaporator. Because of this, a desiccant drier is not installed in the liquid line of an ammonia system.

“Instead, an in line strainer is installed prior to the expansion valve,” Pang says.

Pang also notes that ammonia and the commonly used compressor lubricating oils are not miscible. Hence, an oil separator is installed after the compressor discharge to remove a very large percentage of the oil.

“Some oil will still get through the oil separator and into the rest of the system,” he says. “It usually ends up in the low side of the system with the oil at the bottom of the accumulator (liquid/vapour separator) as oil is denser than liquid ammonia.”

Oil should be periodically drained from the accumulator.

GOING LOW

Prior to the development of low charge DX systems, the evaporators used in ammonia refrigeration plant were usually of the flooded design type and either gravity fed or liquid overfeed.

Scantec Refrigeration Technologies has pioneered the use of low charge ammonia systems in Australia. This journey began when the individuals who later founded the company installed a DX NH3 system at Tingalpa in Brisbane in the early 1990s.

“Many lessons were learnt, some hard, but the plant remains operational today,” says Jensen.

The Tingalpa plant was followed by a central, dual‑stage DX NH3 system with screw compressors that has served a 10,000m2 distribution centre in Brisbane since 2003.

Both these ammonia refrigeration plants were fitted with evaporators manufactured from carbon steel and hot dipped galvanised after manufacture, while injection control was superheat based.

Another installation fitted with a low temperature evaporator manufactured from a less conductive material than carbon steel performed poorly – another hard lesson.

Following demands for a guaranteed maximum temperature differential across the evaporators between refrigerant and air, Scantec developed a centralised, low charge NH3 refrigerating plant design. Thirty of these now operate around Australia, as well as in China and Malaysia.

“One of these is a high rise with a refrigerated volume of approximately 125,000m³ and a specific energy consumption of 8.5kWh/m³ per year, beating the guaranteed value of 15kWh/m³ per year by a considerable margin,” Jensen says.

EXPANDED HORIZONS

Ammonia has become the go to working fluid for industrial refrigeration applications, and many believe it can and will penetrate other sectors that have previously been the domain of HFC and HFO blended refrigerants.

These include large scale air conditioning systems employing reticulated chilled water as a secondary refrigerant, and small to medium foodservice facilities with a refrigerated volume range of 5,000–30,000m³.

“There is no reason, with its refrigeration applications covered by mature and well developed technical and safety standards, why ammonia cannot be used as a primary refrigerant for water chilling and/or heating for air conditioning application in buildings,” says Pang.

Ammonia based packaged liquid chillers were shown to be successful in a retrofit of an existing air conditioning system servicing the administration building of the Logan City Council south of Brisbane. Similarly, ammonia based chillers have provided air conditioning to London Heathrow Airport’s Terminal 5 for many years, as well as at the Zürich Airport in Switzerland.

The Danish government has almost completed 20 medium to large scale heat pump installations using ammonia to serve district heating systems in local communities. Even the International Space Station (ISS) uses liquid ammonia through an external coolant loop in the station’s main shell to transport heat and keep equipment cool.

“In the US and Europe, ammonia and other natural refrigerants have been shown to be the best and most viable alternatives to meet the objectives of global agreements as well as more local regulations such as F Gas in Europe, and US EPA programs like SNAP and the AIM Act,” says IIAR International Director, Yesenia R Rector.

“Particularly in Europe, countries like Germany, Sweden, Norway, the Netherlands and Denmark are exploring ways to limit the use of PFAS (perfluoroalkyl and polyfluoroalkyl substances) chemicals, which will affect the use of HFOs and some HFCs as these degrade into harmful substances.”

For Australia to follow suit, Jensen believes investment in research and development needs to increase significantly, while training at all levels – from vocational to tertiary – must improve dramatically to advance the local skill set.

Despite this, there is evidence to suggest that Australian practitioners are leading the way in some ammonia refrigeration technologies.

“In miscellaneous narrow fields of application for ammonia refrigerant, it is fair to say that Australia has made world leading progress,” Jensen says. “But these advances have been made within the contracting fraternity more so than within academia – and it’s fair to say they have also been achieved completely without government facilitation of any kind.”

So far as the adoption of ammonia in air conditioning is concerned, Jensen says there is no doubt the local industry can do better.

“Ammonia has a very bright future in applications outside the industrial refrigeration sector, but the challenge for industrial refrigeration practitioners is to have the capacity to assist the progress of ammonia within these sectors using the expertise and experience earned within core refrigeration applications.”

Over to you, readers. ■

PROVEN CONCEPT

Among a number of centralised, low charge NH3 systems to be installed by Scantec, three stand out for the significant energy savings they have delivered.

Replacement of an existing R404A based, air cooled plant with a two stage NH3 DX system delivering a reduction in specific energy consumption (SEC) from 206kWh/m³ to 72kWh/m³ per year (refrigerated volume overall 5,250m³).

Replacement of a screw compressor based NH3 plant with gravity flood refrigerant feed with a dual stage DX NH3 plant with reciprocating compressors delivering a reduction in SEC from 106kWh/m³ to 45kWh/m³ per year (overall refrigerated volume 10,000m³)

A 248,000m³ new refrigerated distribution centre with blast freezing serviced by the largest NH3 DX system designed and constructed to date – the plant was commissioned in the middle of 2022 and featured in Ecolibrium, Summer 2021. ■

Ammonia was selected for the active thermal control system on the International Space Station because of its heat transfer properties and a low freezing point.

Source: NASA Johnson on Flickr.

WHAT’S IN A NUMBER?

In a follow up to the article in the October‑November issue on refrigerant names, Graeme Dewerson explains the significance of GWP.

WHAT IS GWP?

GWP refers to global warming potential and is a measurement of how much global warming a molecule will deliver if released into the atmosphere. It is particularly relevant to refrigerants, because many widely used synthetic refrigerants have high GWP values and are referred to as “super” greenhouse gases.

The most common greenhouse gas that humans emit is carbon dioxide (CO2), which is produced from the combustion of fossil fuels for power generation, space heating, cooking and from vehicle engines. It is by far the largest contributor to global warming CO2 and is therefore the focus of international efforts to combat climate change. Accordingly, it is used as the yardstick that all other global warming chemicals are measured against. It has a GWP of 1.

When you see a GWP value such as 3,922 for R404A, this means that 1kg of R404A causes the same global warming as 3,922kg of CO2 if released into the atmosphere. When a refrigeration technician walks out of a wholesaler with a 12kg cylinder of R404A, they are actually carrying the equivalent of over 47 tonnes of CO2!

HOW IS GWP CALCULATED?

GWP values are calculated by the Intergovernmental Panel on Climate Change (IPCC), a United Nations body that assesses the science related to climate change. The values reflect the amount of time a chemical resides in the atmosphere before it naturally breaks down (atmospheric residence), and the frequencies of electromagnetic radiation that it absorbs. Due to the complex nature of atmospheric chemistry and the long atmospheric residence of many chemicals, climate science continues to evolve –and so do the GWP values of refrigerants.

The IPCC produces comprehensive “Assessment Reports” based on the most up to date climatic science; the IPCC is currently working on its Sixth Assessment Report (AR6).

To make matters more complicated, the measurement of GWP can also be carried out over different time horizons. Commonly used time horizons include 20 years and 100 years, which have starkly different GWP values.

WHICH GWP VALUES SHOULD I USE?

1,397

3,922

631

When choosing GWP values, the logical course of action is to use values that are relevant to our industry and the regulation that drives it. Australia is a signatory to the Kigali Amendment to the Montreal Protocol, the international treaty that underpins our phase down of HFC refrigerants. The Montreal Protocol and Australian regulations use the 100 year GWP values from the IPCC Fourth Assessment Report (AR4). These are used to calculate import quotas for bulk refrigerant imports and are recognised throughout the industry as the official GWP values. It should be noted, however, that as climatic science evolves, the UN may migrate the Kigali Amendment to a more up to date Assessment Report. Equipment manufacturers should consider AR5 and AR6 GWP values within their strategic thinking.

1,387

605 466 148

5

GWP OF COMMON REFRIGERANTS

HFC refrigerants in common use

Refrigerant Safety class GWP (AR4 100-year)

1,430

HFO/HFC retrofit replacements with lower GWPs Refrigerant Safety class GWP (AR4 100-year) Replaces

A CHANGING LANDSCAPE

The transition towards more environmental refrigerants has seen the growth of lower GWP retrofit gases. These are designed to mimic the performance of commonly used HFC gases while maintaining an A1 safety class.

The use of natural refrigerants in new equipment is also a growing trend. Technology around their use is now mature.

HFO refrigerants have much lower GWP than HFCs due to a reduction in their stability, which results in significantly lower atmospheric residence times. HFO refrigerants and lower GWP HFO/HFC blends often have mild flammability and an A2L safety class.

Due to differences in performance, pressures and safety class, the “lower” and “very low” GWP alternatives tend to be used in new equipment and are not suitable for retrofit application.

Graeme Dewerson works with the Expert Group, consulting with business and government bodies on climate change policy, renewable energy and energy-efficiency projects.

1

NSW LICENCE UPDATE

RAC contractors and technicians in New South Wales have been scrambling to confirm whether they will need to apply for the new mechanical services licence, which goes live on March 1, 2023. More concerns arose after NSW Fair Trading sent an email to contractors indicating that the licence will be legally required by those “testing and commissioning mechanical heating, cooling or ventilation systems”.

In response, industry groups including AIRAH, RACCA and AMCA Australia have met with the NSW government to clarify the rules. They confirmed that people who already hold an air conditioning and refrigeration licence and are doing work within the scope of that licence, need not apply for a mechanical services licence.

“We have confirmed directly with NSW Fair Trading that if you hold an air conditioning and refrigeration licence, you can continue to do the work under that licence without needing a mechanical services licence,” says AIRAH CEO Tony Gleeson, M.AIRAH. “This includes testing and commissioning of air conditioning systems.”

The information on the NSW Fair Trading website has been updated to clarify the requirements for air conditioning and refrigeration licence holders. Go to www.fairtrading.nsw.gov.au ■

2 NEW MD AT TESTO

Testo has appointed Jason Mair as its new Managing Director. The company says it is looking forward to continued success and partnerships utilising his leadership and extensive experience.

Mair was formerly Head of Sales for SICK Pty Ltd, responsible for sales across Australia and New Zealand. Before that, he was responsible for the Product Management and Marketing teams, where he repositioned the Product and Market Management team from an operational to a strategic function.

Testo says Mair is a customer focused professional who excels in a team environment, removes barriers, empowers staff and builds meaningful relationships at all levels.

Mair describes himself as authentic, fun, hardworking, resilient and empathetic, and is also a Western Bulldogs supporter and club member of 31 years. He says his mission and vision for Testo is to create an environment where the business can exceed customers’ expectations. Go to www.testo.com.au ■

3 CHECK THE NOTICEBOARD!

There’s a new local resource site for the Southeast Queensland HVAC&R community: the HVACR Noticeboard. Founded by local mechanical engineer Wes Mergard, it has two purposes.

First, it provides a central online meeting place for Southeast Queensland to support and showcase the work of local HVAC&R industry leaders, in the forms of articles, posts, industry events, comprehensive resources and business/product listings.

“Similar to social media, you can share your advice, pose a burning industry question, upload a design or installation guide, announcement, product release or anything else the local HVAC&R industry can benefit from,” says Megard.

“Unlike social media, your content is local, curated by leaders in our industry, categorised, searchable and easy to find for years to come. We are about fostering alliances without the algorithms.”

The second purpose of HVACR Noticeboard is social impact, with 20 per cent of sales and 50 per cent of profits going directly to TIACS – a free and confidential counselling service for truckies, tradies, rural and blue collar workers and those that care about them Australia wide.

“HVACR Noticeboard is a ‘legend of TIACS partner’ in recognition of raising funding and awareness for TIACS,” says TIACS Head of Partnerships Jason Banks. ”We are stoked that each major supporter of this social enterprise sponsors a full 45 minute counselling session through TIACS – each year.”

Every major supporter will be recognised each year with a certificate of appreciation (see above) for the social impact they have made and supporting locals through this industry initiative. Go to www.hvacrnoticeboard.com.au ■

4 INSTALLATION RULES CHANGING IN SA

Installation rules for air conditioners functions are set to change in South Australia from July 1, 2023. From July 1, technicians must not install or connect certain air conditioners unless they comply with the demand response requirements in the Technical Regulator’s new guideline.

Air conditioners covered by these requirements include single phase, three‑phase and close control air conditioners with a cooling capacity of up to 19kW:

The requirements do not apply to evaporative or portable air conditioners, or air conditioners that plug into a mains socket/wall socket and don’t need to be installed via hard wiring.

“Installers will have a legal obligation to ensure that certain air conditioners comply with demand response requirements,” says SA’s Office of the Technical Regulator.

“It is critical to note that while these changes legally require certain air conditioners to have demand response capabilities, they do not require consumers to participate in demand response programs. Consumer participation in these programs is voluntary.”

The government has made available a suite of resources, and will hold in person and online information sessions in the lead‑up to the July 1 implementation date.

Go to bit.ly/3DS9tmM ■

5 A BURNING ISSUE

The NSW government has made important changes to its fire safety regime to address shortcomings of the system.

The Fire Safety Regulation 2022, published in December 2022, requires engineers to seek comment from the Fire Commissioner when developing performance solutions for Class 2–9 buildings, ensuring that the NSW fire authority is more engaged in the design phase for proposed building works.

New templates and procedures have been introduced to improve the accuracy and effectiveness of fire safety schedules. And building owners must ensure that fire safety measures are maintained in line with AS 1851–2012, or, where a performance solution has been used, with the performance solution. Also, the commissioning of fire safety systems will need to be performed by an “accredited fire safety professional”, who must ensure not only that systems have been installed as per the design, but that they are performing correctly.

The Fire Safety Regulation forms part of the response to a report produced in 2021 that provided recommendations on how to improve fire safety in new and existing buildings.

Go to www.fairtrading.nsw.gov.au ■

6 FUJITSU GOES OFF-GRID

Fujitsu General’s R32 Bulkhead Reverse Cycle Split Systems contributed to the aesthetic of a recent eco tourism project on a greenfield site in Inman Valley, South Australia.

Created by luxury accommodation business ESCA, the project involved two standalone resort style suites overlooking the Inman Valley to Encounter Bay and the Southern Ocean. The suites rely on their own energy infrastructure, including an off‑the grid system of solar panels and batteries. This required an air conditioning solution that met strict design and energy management criteria. It also had to successfully integrate with a Schneider automation system, which would trigger a welcome scene when guests checked in: opening blinds, setting mood lighting, and activating the air conditioner at a set temperature.

The Fujitsu units were, for the first time in Australia, successfully fitted with UTY TTRXZ1 thermostat converters that would allow the air conditioning system to integrate with each suite’s automated system. The converters connected to both the indoor unit bulkhead from one end and the Schneider supplied thermostat controller at the other end, allowing the units to be controlled via the Schneider thermostat controller and BMS.

Go to www.fujitsugeneral.com.au ■

7

BRONTE BRINGS IT HOME AGAIN

The Bronte series of wall mounted split system units from Mitsubishi Heavy Industries Air‑Conditioners Australia (MHIAA) has been awarded the 2023 ProductReview Award for the best rated split system. This is the third year in a row that the Bronte series has received the award, having similarly taken out the 2021 and 2022 award alongside the company’s Avanti unit.

The ProductReview awards are independent, based on a determining criteria alongside independent judging from the ProductReview Data and content team. Award nominees meet a range of criteria – including a minimum average consumer rating of 4.1 stars with 10 or more reviews – after which the ProductReview team performs qualitative analyses and metric comparisons to gauge a sentiment score and determine the winner for each category.

With a 4.7 star rating from 577 consumer reviews, the Bronte series is the highest rated overall split system from the ProductReview community. Go to www.mhiaa.com.au ■

8

RELIABLE NETWORK GROWS

Reliable Controls has added a new dealer to its network: South Pacific Air Conditioning (SPAC), based in Papua New Guinea.

According to Reliable Controls Regional Sales Manager Jason Duncan, Affil.AIRAH, SPAC passed all the qualification requirements to be approved as a Reliable Controls Authorised Dealer.

“We are very excited about this new partnership and are looking forward to working together with SPAC and the people of Papua New Guinea to deliver quality building automation products and solutions that assist with making buildings safe, healthy, and comfortable with the minimum possible impact to the environment,” says Duncan. Reliable Controls Corporation has been developing the Reliable Controls Authorised Dealer network since 1986. The group is

made up of locally owned independent controls contractors who sell, install, program, and service Reliable Controls products.

Authorised dealers must pass and maintain adherence to its stringent qualification guidelines. Reliable Controls says these guidelines ensure dealers are competent and deliver high standard projects and service.

Go to www.reliablecontrols.com ■

9 OZONE SAVIOURS

A new report has confirmed that the ozone layer is recovering – and the Australian Refrigeration Council (ARC) has hailed the role of Australia’s HVAC&R sector in making this happen.

The UN backed Scientific Assessment Panel to the Montreal Protocol on Ozone Depleting Substances delivered the news in its four‑yearly assessment report. It expects the ozone layer to recover to 1980 values (before the appearance of the ozone hole) by around 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the world.

ARC chief executive officer Glenn Evans says the recovery of the ozone layer is a credit to the global HVAC&R industry, and especially to Australia’s 125,000 licensed technicians and businesses.

“The Montreal Protocol came into force in 1989, and Australia has been in the forefront of applying it to the real world in refrigeration and air conditioning licensing,” he says.

“Our ARCtick licensing scheme operates under the Ozone Protection and Synthetic Greenhouse Gas Management Regulations 1995, and results such as the ozone layer recovery are the living proof of its value.

“Licensed technicians play a crucial role in protecting the environment from ozone depleting substances and synthetic greenhouse gases in refrigeration equipment.”

According to Evans, since its inception, the licensing scheme has delivered more than 25Mt CO2e of direct emissions savings. ■

Name: Craig Fiander

Occupation: Mech plumber/ A Grade electrician

What’s the best thing about working in HVAC&R? The variety of work and solving issues. How long have you worked in the industry? I’m now in my 37th year.

What is the biggest thing that has changed about the industry since you started working in it? Technology – mobile phones and computers.

If someone wanted to find you on a worksite, they should look for the person who is … Walking around with plans under his left arm.

Favourite tool: Milwaukee battery tools. Best on-the-job advice you ever received: Never stop learning.

What’s the happiest a client has been with your work? Letters to the company with thanks.

Dream car: SLR 5000.

Dream holiday: Did it in 2015 – travelled the entire Route 66 USA.

Favourite smoko snack: Caramel slice, but only a few times a year.

What did you listen to on the way to work today? 3AW.

Sporting hero: Peter Brock.

When I’m not working I’m … Riding my adventure bike or getting away in my 4X4.

Craig and his offsider, Ody.

SUPERFLY

A small city in northern Sweden is home to a flying school for aspiring electric plane pilots.

Just quietly (as silently as an electric engine, perhaps), Sweden has established itself as a sustainable powerhouse, with more than half of the country’s daily power needs supplied by renewable energy.

In the small northern regional centre of Skellefteå, the entire town is powered by renewables – a mix of hydro and wind power, mostly.

Indeed, Skellefteå wears its green credentials proudly, with more than US$100 billion invested in clean tech in the region.

Not only is it home to the 500,000m2 Northvolt battery factory, it also boasts the Green Flight Academy, the world’s first professional flight school to offer training on electric planes.

The school has three Pipistrel Veils Electro micro aircraft, the first electric plane to be approved for use in Europe. The 400kg two seater aircraft can be wheeled out by hand, and has been designed to be as aerodynamic as possible. Alas, its range is limited to only 45 minutes.

Skellefteå and surrounds are growing rapidly, but without the ground transport to link the region together. It’s thought commercial electrical transportation might provide part of the solution.

“You have to think in a different way, and manage your energy,” he explains. “The range is not the same. But when it comes to handling, it flies exactly the same as any other aeroplane.” ■

The school’s flight instructor Johan Norberg says the transition to electric flying is similar to that of moving from traditional petrol powered cars to electric vehicles.

VOTE FOR THE

1 A SOLUTION THAT REALLY STACKS UP

Chris spotted this beauty in Toowoomba, and couldn’t walk away without a quick photo. Graham says: While there may be a good reason to stack air conditioners to resolve space issues, I am sure this installation would not meet manufacturers’ requirements, and may therefore put warranty at risk!

2 SPACE INVADERS

“How’s this for pipe support?” says Craig, who found this at a site in Wollongong.

“Gotta give it nine out of 10 for ingenuity!”

Graham says: I was using some wire ties in the garden today; they are a great invention and have changed our world. But that doesn’t make them the solution for everything, and they are unlikely to last the requirements of the installation!

3 PUT DOWN THAT WEAPON

Another Craig, this time from Melbourne, was called out after hours when a customer tried defrosting an evap coil with an ice pick!

“Quick repair job and up and running,” says Craig. Graham says: Why do people continue to believe that brute force and ignorance are adequate for defrosting coils? So, who is responsible for the discharge of refrigerant to the atmosphere?

4 LET’S PARK THAT IDEA

“Customer was complaining of water in the garage of their newly built house,” says Neil from Toowoomba. “Rocked up and found this.”

Graham says: Apart from the obvious condensate drainage issues. it does appear that airflow over the “outdoor” coil would be severely restricted.

5 THE KEY TO GOOD FAULT‑FINDING

Daniel in WA replaced an old unit tripping the circuit breaker.

“Turns out the client was storing her spare house key inside the isolator,” he says.

Graham says: Well found, often tricky to pick something like this. I don’t suppose the culprit was an electrician, as I can’t imagine any old punter thinking of an isolator as a hiding place.

Additional comments and observations provided by Graham Boyle, L.AIRAH, portfolio manager, heavy automotive and refrigeration at South Metropolitan TAFE. Please note that the comments are provided on the basis of the photos only and should be read with this in mind – not all issues or solutions are apparent from a 2D image.

HAVE

YOU COME ACROSS SOMETHING SCARY, UGLY OR JUST PLAIN FUNNY?

If your entry is deemed the winner, a 700ml bottle of Jim Beam will be on its way to your door. Please include a postal address with your entry. Entrants must be 18 or over. Send your hi res (>500KB) photos to Editor, Mark Vender at mark.vender@airah.org.au

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