Commercial refrigeration and air conditioning for Mackay, Airlie Beach, Bowen, and Moranbah. Cool rooms, freezer systems, beer & post mix, and emergency repairs. QBCC licensed.https://mackay-refrigeration.pages.dev/en_AUhttps://mackay-refrigeration.pages.dev/blog/infrared-camera-refrigerator/https://mackay-refrigeration.pages.dev/blog/infrared-camera-refrigerator/Thermal cameras make the invisible visible – watch the refrigeration cycle in action as infrared imaging shows exactly where heat moves inside and around your fridge.Sun, 01 Mar 2026 00:00:00 GMTIn our last post we walked through how the refrigeration cycle works – compression, condensation, expansion, evaporation, repeat. If you haven't read it, worth a look before this one. But reading about heat transfer and *seeing* it are two different things. That's where infrared imaging comes in. The video below puts a thermal camera on a domestic fridge and shows exactly where heat is moving, where it's being released, and what the cycle looks like in the real world. ## What Is an Infrared Camera? An infrared camera – also called a thermal imaging camera – is a non-contact device that detects infrared energy (heat) radiating from a surface and converts it into an electronic signal. That signal is processed into a thermal image on screen, with different temperatures displayed as different colours. Hotter surfaces appear in warmer tones (reds, oranges, whites) and cooler surfaces in cooler tones (blues, purples, black). Importantly, thermal cameras don't see through objects – they read surface temperatures. What they're exceptionally good at is making invisible heat patterns visible at a glance. ## What You're Seeing in the Video ### The Back of the Fridge Glows Hot The first thing that stands out in infrared is the condenser. On most domestic fridges, the condenser coils run across the back panel or underneath the unit – and in thermal imaging, they light up. This is exactly what should be happening. The condenser's job is to dump heat. The refrigerant arrives there as a hot, high-pressure gas after being compressed, and it releases that heat into the surrounding room air before condensing into a liquid. In infrared, you can see that heat radiating clearly from the coil area. This is also why your fridge needs ventilation space around it. If you box it in tight against a wall or into a cupboard without airflow, the condenser can't reject heat efficiently, the system has to work harder, and your energy bills go up. ### The Cabinet Stays Cool Inside and around the cabinet itself, the thermal image stays in the cool colour range. The insulation is doing its job – keeping the heat out and the cold in. What you're looking at is the evaporator doing its work on the inside: absorbing heat from the air in the cabinet, cooling it down, and sending the refrigerant back around the loop. ### Hot Spots Around Door Seals One thing infrared makes obvious is door seal performance. If a seal is worn, cracked, or not sitting flush, warm air leaks in around the edges. In a thermal image that shows up as a warmer band running along the door frame – a clear sign the cabinet is working harder than it needs to. This is one of the most common and easily fixed causes of a fridge running constantly or struggling to hold temperature. ## Why Thermal Imaging Is Useful for Refrigeration Diagnostics A thermal camera turns an invisible problem into an obvious one. For domestic fridges it's a handy diagnostic tool. For commercial refrigeration – cool rooms, display cabinets, blast chillers – it's genuinely valuable. Here's what a thermal inspection can reveal that a standard visual check can't: **Condenser issues** – dirty or blocked condenser coils can't reject heat properly. In infrared, you'll see uneven or restricted heat distribution across the coil surface, or a coil running hotter than it should because airflow around it is compromised. **Insulation failures** – in cool rooms and refrigerated cabinets, insulation panel joints that aren't properly sealed create heat bridges: warm spots visible in infrared where outside heat is leaking in. This drives up running costs and puts product temperature at risk. **Evaporator problems** – ice build-up on the evaporator (often caused by a faulty defrost system or a door seal issue letting in humid air) changes how the evaporator looks in thermal imaging and affects its ability to absorb heat from the cabinet. **Compressor heat** – a compressor running hotter than expected can indicate it's under stress, possibly from a refrigerant charge issue, a blocked filter drier, or a struggling expansion valve. **Door seal leaks** – immediately obvious in thermal imaging. Warm patches along door edges show exactly where the seal is failing. ## The Bigger Picture What the infrared camera makes viscerally clear is the point we made in the last post: a fridge isn't creating cold. It's moving heat. The cold side of the system is cold because the hot side is doing its job of rejecting heat to the outside. When you see the condenser glowing in the thermal image and the cabinet sitting cool, you're watching thermodynamics in action. Heat flows from hot to cold. The refrigeration cycle exploits that principle in reverse – using mechanical work to push heat from a cool space to a warmer one. It's the same principle whether you're looking at a domestic fridge in a kitchen or a 50-pallet cool room in a meatworks.https://mackay-refrigeration.pages.dev/blog/how-do-refrigerators-work/https://mackay-refrigeration.pages.dev/blog/how-do-refrigerators-work/Your fridge doesn't create cold – it moves heat. Here's a plain-English breakdown of how the refrigeration cycle actually works, and what to watch for when it doesn't.Mon, 02 Feb 2026 00:00:00 GMTIt's one of those things most people never think about until it stops working. The fridge hums away in the corner of your kitchen, keeping your food cold and your beer colder, and nobody gives it a second thought. But the refrigeration cycle is genuinely clever. Once you understand it, you'll never look at your fridge the same way again – and you'll have a much better idea of what's actually going wrong when something breaks down. ## What Is a Refrigerator? At its core, a refrigerator is a thermally insulated box combined with a heat pump. Its job isn't to "create cold" – that's a common misconception. What it actually does is move heat from inside the cabinet to the outside environment, making the inside cooler than the surrounding room. That distinction matters. Refrigeration is about heat transfer, not cold generation. Understanding that is the key to understanding how the whole system works. ## The Four Key Components Modern refrigerators – whether domestic or commercial – use a vapour-compression refrigeration cycle. There are four main mechanical components, plus the refrigerant that flows between them: - **Compressor** – the engine of the system. It compresses the refrigerant vapour, raising its pressure and temperature, and pushes it around the circuit. - **Condenser** – a set of coils (usually at the back or underneath the cabinet) where the hot, high-pressure refrigerant releases its heat to the surrounding air and condenses into a liquid. - **Expansion device** – a valve or metering device that creates a sudden pressure drop in the refrigerant, causing it to cool rapidly before it enters the evaporator. - **Evaporator** – coils located inside the refrigerator cabinet where the low-pressure refrigerant absorbs heat from the interior air and evaporates back into a vapour. The **refrigerant** itself is the working fluid that carries heat around the circuit. Modern fridges typically use HFC refrigerants like R-134a in domestic units, or R-404A and R-448A in commercial systems, though the industry is increasingly moving toward lower global warming potential (GWP) alternatives like R-290 (propane) and R-600a. ## The Refrigeration Cycle, Step by Step Here's how it all fits together: ### 1. Compression The cycle starts at the compressor. Refrigerant arrives as a low-pressure vapour and gets compressed, which raises both its pressure and its temperature significantly. At this point the refrigerant is a hot, high-pressure gas. ### 2. Condensation The hot gas is pushed into the condenser coils – typically located at the back or underneath the fridge. Here, the refrigerant releases the heat it's carrying into the surrounding room air (this is why the back of your fridge feels warm). As it loses heat, the refrigerant changes phase from a gas into a liquid. It's still at high pressure. ### 3. Expansion The high-pressure liquid refrigerant passes through an expansion device – either a capillary tube in simpler domestic units or a thermostatic expansion valve (TXV) in more sophisticated commercial systems. This causes a sudden, sharp drop in pressure. That pressure drop makes the refrigerant cool rapidly, preparing it for the next stage. ### 4. Evaporation The now cool, low-pressure refrigerant flows into the evaporator coils inside the fridge cabinet. Because the refrigerant is colder than the air inside the fridge, heat flows from the air into the refrigerant. The refrigerant absorbs that heat and evaporates back into a vapour. The air inside the cabinet loses heat in the process – which is what actually keeps your food cold. ### 5. Back to the Compressor The low-pressure vapour returns to the compressor, and the cycle begins again. The whole process runs continuously (or in controlled cycles managed by a thermostat) to maintain the target temperature inside the cabinet. ## Why Does This Matter for Commercial Systems? Domestic fridges are relatively simple. Commercial refrigeration systems – cool rooms, display cabinets, blast chillers, refrigerated transport – operate on the same fundamental principles but at much greater scale, with more complex controls, larger compressors, and more demanding performance requirements. In commercial settings, the efficiency of the refrigeration cycle has a direct impact on running costs. A poorly performing system – one with refrigerant leaks, dirty condenser coils, a failing compressor, or a faulty expansion valve – has to work harder to move the same amount of heat, which means higher power bills and more wear on components. Common warning signs that something's off with a commercial refrigeration system include: - Unit running constantly without reaching target temperature - Ice build-up on evaporator coils (can indicate airflow issues or a faulty defrost system) - Warm condenser coils (may indicate refrigerant loss or poor airflow around the condenser) - Unusual compressor noise - Higher-than-normal energy bills without a change in usage ## The Refrigerant Question One area of active change in the industry is refrigerant selection. Older refrigerants like R-22 have been phased out due to their ozone-depleting properties. Current HFC refrigerants are being progressively regulated because of their high global warming potential. In Australia, the use and handling of refrigerants is regulated under the *Ozone Protection and Synthetic Greenhouse Gas Management Act 1989*, and technicians must hold an appropriate ARCtick licence to legally handle refrigerants. If you're operating commercial refrigeration equipment, it's worth knowing what refrigerant your system uses and whether it's subject to any upcoming regulatory changes. ## When Something Goes Wrong The refrigeration cycle is a closed loop. When any part of it underperforms – whether that's a worn compressor, a blocked expansion valve, refrigerant loss through a leak, or a condenser that can't reject heat properly because it's caked in dust – the whole system suffers. Routine servicing keeps the cycle running efficiently: checking refrigerant charge, cleaning condenser coils, testing expansion devices, and verifying that the evaporator is moving air properly through the cabinet. If your commercial refrigeration system isn't holding temperature, running efficiently, or behaving the way it should, get in touch with the team at Mackay Refrigeration and Air Conditioning. We'll find the fault, fix it properly, and make sure it stays fixed.https://mackay-refrigeration.pages.dev/blog/father-refrigeration/https://mackay-refrigeration.pages.dev/blog/father-refrigeration/The Scotsman who invented mechanical refrigeration, chilled Australia's beer, and nearly shipped frozen meat to Queen Victoria – meet James Harrison, the unsung father of refrigeration.Thu, 01 Jan 2026 00:00:00 GMTIf you work in refrigeration or air conditioning, there's one name you should know better than most. James Harrison didn't just tinker with cold air – he figured out how to make ice commercially, chilled Australia's first beer, and very nearly pulled off one of the greatest logistical feats of the 19th century. He should be a household name. He isn't. Here's why that's a bit of a national disgrace. ## A Printer From Scotland With a Chemistry Background Harrison was born on 17 April 1816 in Bonhill, Dunbartonshire – a small town on the banks of the River Leven in Scotland. His father was a fisherman, but James had bigger ambitions. He studied at Anderson's University and the Glasgow Mechanics' Institution, with a focus on chemistry. He then trained as a printing apprentice in Glasgow and worked as a compositor in London before emigrating to Sydney in 1837 to set up a printing press for the English publishing company Tegg & Co. From Sydney, he moved to Melbourne in 1839 and picked up work with John Pascoe Fawkner as a compositor and later editor on the *Port Phillip Patriot*. When Fawkner acquired a new press, Harrison saw an opportunity. He offered Fawkner £30 for the old one and headed to Geelong. The first edition of the *Geelong Advertiser* appeared in November 1840. By 1842, Harrison owned it outright. ## The Accidental Discovery That Changed Everything It was while running the *Advertiser* that Harrison stumbled onto something that would shape modern life. Movable type needed regular cleaning with diethyl ether. Working at the press one day, Harrison noticed that as the ether evaporated off the metal type, it left the letters noticeably cold to the touch. The evaporation was pulling heat out of the metal. Most people would have filed that away as a curiosity. Harrison, with his chemistry background, started thinking about what it meant. What if you could control that process? What if you could use it to make cold – deliberately, consistently, at scale?  ## Building the World's First Practical Ice-Making Machine Harrison began experimenting, and in 1851 his first mechanical ice-making machine started operating on the banks of the Barwon River at Rocky Point in Geelong. This was the first time anyone had produced ice mechanically at a meaningful scale. By 1854, he had a commercial machine running. The system worked by using a compressor to force refrigerant gas through a condenser, where it cooled and liquefied. The liquid then circulated through refrigeration coils and vaporised again, drawing heat out of the surrounding environment. The machine used a 5-metre flywheel and could produce around 3,000 kilograms of ice per day. In December 1855, he was granted an Australian patent for his ether refrigeration system. He then travelled to London and secured British patents in 1856 and 1857, covering both the process and the apparatus. His timing was good. Importing ice from the United States and Norway was expensive and unreliable for a remote colony like Victoria. A locally-made alternative was immediately attractive. ## Beer First, Then Meat Also in 1856, Harrison was commissioned by a brewery to build a machine that could keep beer cold during fermentation and storage. He delivered. The brewing industry adopted refrigeration almost immediately, and meatpacking factories weren't far behind. Think about what that meant in practical terms. In a country as hot as Australia, the ability to reliably chill food and drink wasn't a luxury – it was a genuine shift in how people lived and ate. Refrigeration changed what could be sold, stored, shipped, and served. In 1873, Harrison demonstrated the staying power of his process at the Melbourne Exhibition. He showed that meat kept frozen for months remained perfectly edible, and walked away with a gold medal. ## The Voyage That Broke Him By 1873, a new challenge was being debated: could frozen Australian meat be shipped all the way to Britain? American unrefrigerated beef had a stranglehold on the British market. Australian producers needed a way in, and refrigeration looked like the answer. Harrison decided to be the man who proved it. He prepared the sailing ship *Norfolk* and loaded it with frozen beef for the voyage to the United Kingdom. It went badly wrong. His approach relied on a cold room system packed with ice rather than an onboard mechanical refrigeration unit. Partway through the voyage, the ice ran out faster than anticipated. Temperatures rose. The cargo spoiled and had to be discarded. Harrison arrived in Britain without his meat and without his money. The failure bankrupted him and, perhaps more damaging, shook public confidence in refrigerated meat for years. ## Someone Else Got There First Six years later, in 1879, a separate team succeeded where Harrison had failed. Using a purpose-built refrigerated chamber and a slightly different approach, they delivered frozen Australian meat to Britain. Queen Victoria sat down to a thawed plate of Australian lamb. Harrison's name wasn't part of the celebration. It's a rough footnote to an otherwise remarkable career. The man who developed the practical mechanical refrigeration process, built the machines that changed the brewing and meatpacking industries, and proved frozen meat was safe to eat – lost the race by one critical engineering decision on one ship. ## What Happened to Harrison He returned to journalism after the failed voyage, becoming editor of *The Age* in Melbourne. He went back to Geelong in 1892 and died at his Point Henry home on 3 September 1893, aged 77. His legacy lives on in a few quiet ways. The James Harrison Bridge spans the Barwon River in Geelong. A plaque at 100 Franklin Street, Melbourne marks the site of the Victorian Ice Works he founded in 1859. The Australian Institute of Refrigeration Air Conditioning and Heating's most distinguished award is the James Harrison Medal. And the James Harrison Museum committee has acquired land at Rocky Point – the site of his original machine – with plans to build a museum there. ## Why He Matters to the Industry Today Harrison's work sits at the foundation of everything the refrigeration and air conditioning industry is built on. The vapour-compression cycle he pioneered in the 1850s is still the basis of how modern refrigeration systems work. The principles haven't changed. The technology has just gotten smaller, smarter, and significantly more efficient. Every cool room, every chilled display cabinet, every split-system air conditioner running in homes and businesses across Australia traces a direct line back to a Scottish printer cleaning type with ether in a Geelong newspaper office. Not bad for a bloke who started out setting type for a London publisher. --- *James Harrison (17 April 1816 – 3 September 1893) is recognised as a pioneer of mechanical refrigeration and the founder of the Victorian Ice Works. The Australian Institute of Refrigeration Air Conditioning and Heating's James Harrison Medal honours his contribution to the industry.*