100 engineering ideas that have changed the world

In this series of articles, we will have a look at some of the greatest engineering ideas that have had an effect on our everyday lives. The list of 100 engineering ideas was compiled by The Institution of Engineering and Technology (IET). Our attorneys look at the IP milestones in the history of each of the inventions on the list and whether any IP protection was sought or obtained.

Air conditioning 

Air conditioning is not a new phenomenon. Yet many of our day to day activities either could not occur or would be extremely uncomfortable without it – imagine train or aircraft journeys without air conditioning! Temperatures in offices during the summer without air conditioning could be unbearable and even computers would overheat without air conditioning systems providing rooms with a constant supply of cooling air.

Air conditioning has been an idea in the minds of engineers since the time of the pharaohs. The early Egyptians would hang reeds, which would be kept damp with trickling water, in their windows. Air passing the damp reeds would evaporate the water cooling the air temperature, and thus the room, whilst adding humidity to dry desert air. Ancient Romans pumped water from their aqueducts through pipes in the walls of their homes to try and keep cool, whilst Chinese inventors used rotary fans to move air through rooms and spray from water fountains to reduce the temperature of the air.

The Medieval era did not see much improvement in the area of air conditioning. It seems that the main ideas used to try to keep rooms cool was to have large windows to let in a breeze but to make sure that sunlight could not directly enter that window to heat the air in the room.

In fact, until around the 18th century, most efforts to control the temperature of air in a room remained using water and air movement. In 1758, Benjamin Franklin and Cambridge University Professor John Hadley discovered that the temperature of an object could be reduced below the freezing point of water by the evaporation of highly volatile liquids such as alcohol and ether. And in 1820, Michael Faraday found that when compressed and liquefied Ammonia evaporated, it cooled the air. Neither of these innovations was protected by IP rights and both were available to be built on by other inventors.

The first step towards air conditioning occurred towards the end of the 1840s in America. Dr Gorrie believed that high temperatures caused illness and wanted to cool hospital rooms to increase patient comfort. As a result, Dr Gorrie invented what is regarded to be the first mechanised artificial room cooling. A patent, US 008,080, was granted to Dr Gorrie on 6th May 1851 for his Ice Maker which was a compressor powered by movement from an animal, air, water, or steam.

However, Dr Gorrie was unable to benefit from this patent because he was unable to acquire financial backing for his invention. He also had the small issue of political pressure from the ice industry in the North. Clearly, such an invention would threaten the ice industry because why would anyone import ice from far away when it could be made closer to or at home?

The invention of the modern air conditioner, although it was not known by the term “air conditioner” at the time, is attributed to Willis Carrier. His patent application, US 808,897, was granted on 2nd January 1906. The invention came about due to Carrier being tasked with providing a solution to preventing paper from wrinkling in humid summers with a view to improving printing quality. It was already known to heat objects with steam by sending air over hot coils. However, Carrier altered the process by filling the coils with cool water to produce cool air. Essentially, Carrier had invented a modern version of the Egyptian water reed system, except it no longer relied on a naturally occurring breeze. Instead, the air could be moved by a fan powered by electricity.

Shortly after, Stewart Cramer was confronted with a problem of how to add moisture to the air in a textile mill. His solution was to combine moisture with a ventilation system. The resultant invention, A Humidifying and Air-Conditioning Apparatus, had a patent application granted, US 852, 833, on the 7th May 1907. It was, in fact, Cramer who coined the phrase “air conditioning” after his invention combined the control of the humidity and temperature of air. This was achieved by spraying a heated liquid into the air to increase humidity or a cooled liquid into the air to reduce humidity. The apparatus comprised a series of separator plates which the air was forced around in a tortuous fashion. Therefore, liquid would be collected on the plates due to inertial forces as it was drawn along the path through the plates. 

Carrier further applied his invention to other applications for air conditioning technologies, including industrial manufacturing facilities and indoor theatres. It has been suggested that Carrier’s technology being installed in the Rivoli Theater in Times Square, New York City, in 1925, may have led to the rise of the summer movie blockbuster. Before this, the inside of a movie theatre would have been too hot during the summer for people to sit and watch films and so instead, would normally have been closed in the summer months.

Carrier further developed his air conditioning systems and in February 1914 was issued a patent, US 1,085,971, for a Method of Humidifying Air and Controlling the Humidity and Temperature Thereof. By 1922, his system had been refined and the size of the entire unit reduced. This ‘centrifugal chiller’ was the first practical method of air conditioning for large spaces and used a centrifugal compressor similar to the centrifugal turning blades of a water pump instead of a piston driven reciprocal compressor. This ‘centrifugal chiller’ also replaced the previously toxic and flammable refrigerants so that a safer air conditioning unit could be used in homes.

Since then, inventors have been working to improve the modern air conditioning system. This includes inventors like David Crosthwait, who has 39 US patents granted to him for inventions related to heating and ventilation. In more recent times, the focus has been on producing more efficient systems, as evidenced by US patent no. 8,744,632, for an energy efficient air conditioning unit, and in improving air conditioning systems used in the transport industry.

For more information speak to Jack Rogan.

3D printing

3D printing (also known as additive manufacturing – depositing material under computer control) has revolutionised how certain products are made. It is seen by many as an important disruptive technology, enabling the flexible design and production of complex parts, on-demand and with less waste. 

The technology gained attention in the early 1980s, and one of the first notable patent applications for this technology was filed in 1984 by Charles Hull, which related to a process called stereolithography involving directing a beam of ultraviolet radiation into liquid photopolymer, causing it to solidify into plastic, the trace of the beam creating successive layers of an object. Its potential was seen by many and the 1990s saw further innovation. In 1994, Scott Crump of StrataSys Inc. filed a patent application for a fused depositing modelling (FDM) process which is the process that most will be familiar with – extruding heated thermoplastic through a print head nozzle to build up layers. The late 1990s also saw interest in 3D bioprinting, particularly the fabrication of biological matter, with the potential to replicate functioning tissue and organs. 

By the end of the 1990s, the annual number of worldwide patent filings was modest, but maintaining growth. That figure started increasing rapidly after the year 2000, perhaps triggered by the availability of lower-cost printers. To date, according to one dataset, well over 30,000 patent applications had been published worldwide that involved some involvement with 3D printing. 

Recent filings relate to areas such as the use of sustainable materials, medical uses, and even printing food and buildings!

For more information speak to Rob Sayer.

Artificial hip system 

A story of collaboration and innovation: The earliest recorded attempts at hip replacement were carried out in 1891 using ivory to replace the femoral head, the ball of the ball and socket joint of the hip. Development continued very slowly because of the difficulty in finding suitable materials to replace the acetabulum, the socket of the joint. John Charnley, MD, at his clinic in Manchester, England, aggressively pursued the idea of a “low friction hip” in which the ball was replaced with a stainless steel stem and ball and the socket with a Teflon cup secured with acrylic cement. Importantly, the size of the ball was reduced in an effort to reduce wear. The Teflon, although low friction, proved to be too soft and so a denser material was sought. As a result of a lucky, but confused, encounter with a plastic salesman, Charnley came across polyethylene. By 1961, hip replacements using the Charnley hip, a combination of a stainless steel stem and dense polyethylene socket were performed regularly.

Robin Ling, MD, of Exeter, England working with engineer Clive Lee, built on Charnley’s work and studied the use of collarless tapered stems secured by bone cement. He patented his system in 1975, GB1409054B. Aware of the phenomenon of “creep” in bone cement, Ling went on to produce a collarless, polished, tapered stem with the capability to subside in the cement. The stem performed like a wedge moving and tightening at the stem-cement border. It was patented by Ling and Mikhail, EP 0530323B, which related to a Co-Cr version of the hip with a specified surface roughness. The patent was opposed by three companies but survived. 

For more information speak to Julie Mays.


Automotive inventions have come a long way from the Benz Patent Motor Car in 1886 and Nicolas-Joseph Cugnot’s 1768 self-propelled land based mechanical vehicle. The advances in technology over the last century have been significant; from Mary Anderson’s 1903 patent application for windscreen wipers, to fully electric vehicles with solar paintwork and the race to patent self-driving vehicle technology.

A recent study by the European Patent Office (carried out with the European Council for Automotive R&D – EUCAR) showed that in the last 10 years 18,000 patent applications were filed at the EPO for self-driving vehicle related inventions. From 2011 to 2017 patent applications filed at the EPO relating to self-driving vehicles increased by 330%, in comparison to a 16% increase in the same period across all technologies1.

Interestingly, the top four companies who filed these applications are not traditional automotive companies but ICT related companies. This shows how the automotive industry is evolving. A transport revolution is anticipated, with large scale production of self-driving vehicles expected to take off in the next few years.

Of course it is not only patent applications which have provided IP protection for the automotive industry. Registered Designs are widely used to protect the visible aesthetics of vehicles including parts and interiors. More recently there has been a rise in filings for Graphical User Interfaces (GUIs) intended for in-vehicle systems. In a rapidly evolving industry, the relatively low cost and quick registration ensures Registered Designs remain an attractive option to those wishing to protect their IP.

For more information speak to Emma Bridgland.

Solar energy

Solar power is often thought of as a relatively new technology. However, it all started in 1839 when Alexandre Becquerel discovered the photovoltaic effect which explains how electricity can be generated from sunlight. Despite the interest that followed, it took until the 1950s for what many consider to be the first practical solar cell to be developed by Bell Labs in the USA and for which a patent application was filed. It only offered 6% efficiency (the percentage of light that is converted to electricity), but it did provide usable power for several hours on a sunny day.

More recent innovation has been driven by the global impetus to reduce dependence on fossil fuels whilst catering for increasing demands on energy. Hoffman Electronics Corporation filed patent applications for photovoltaic cells achieving up to 14% efficiency, and such cells became an important power source for spacecraft and satellites. Materials innovation then became a big driver in pushing efficiency increasingly higher.

Figures reveal that nearly 15,000 patent applications were filed worldwide in 2017 for renewable energy, a 43% increase from the previous year. Of this, more than half were for solar power. A correlation is seen between a drop in the cost of solar cells and the number of patent filings. Patents are seen as an important driver in solar energy, acting as an incentive for research in this area and the sharing of innovation through standards bodies. Some patent offices, including the UKIPO, offer fast track “green channel” processing for applications relating to renewables. With solar energy expected to supply half of the world’s energy in the next 25 years, this trend is likely to continue.

For more information speak to Rob Sayer.


The field of microscopy has undergone enormous change in the last few years, thanks to the Nobel Prize winning development of a class of techniques collectively known as ‘super resolution microscopy’. 

In the past, the resolution it was possible to achieve with a light microscope was limited by diffraction to around 250 nanometres. However, with super-resolution microscopy it is now possible to achieve resolutions more than an order of magnitude greater, down to around 20 nanometres or less. This has been particularly important in the field of biology, where many of the structures and processes in which scientists are interested occur over spatial scales significantly smaller than the diffraction limit. For their contributions to the development of the field, Eric Betzig, Stefan Hell, and W.E. Moerner were awarded the 2014 Nobel Prize in Chemistry.

Broadly speaking, super resolution microscopy achieves this much higher resolution by circumventing the diffraction limit. A typical super resolution image is in fact a reconstruction composed of the localisations of many different molecules, determined from many images in which different molecules are emitting light. This allows each molecule to be localised with much higher precision than would have been possible were all of the molecules imaged at the same time, with their diffraction patterns overlapping. 

In a classic story of failure coming before great invention, the path to the Nobel Prize was not straightforward for Eric Betzig in particular. Along the way he quit science and had started working for his father’s engineering firm, before coming up with up with the concept which would go on to become Photo-activated Localisation Microscopy (PALM) – one of the first, and now main, super-resolution techniques – and building the first prototype of the microscope in the living room of a fellow scientist and friend. 

Although a patent for a super-resolution microscope was first granted in the 1980s to a Russian scientist, Victor Okhonin (SU1374922), it was only later experimental demonstrations by Betzig, Moerner and Hell et al. which led to these techniques becoming widely available.

For more information speak to Emma Lonnen.


“I want to say one word to you. Just one word. Are you listening? … Plastics. There’s a great future in plastics.” – Mr McGuire, The Graduate, 1967. 

The writers of The Graduate, seeking something utterly dull with which to bore the young Dustin Hoffmann, could think of nothing worse than plastics. After all, at that time many of the polymers which still surround us today (PVC, PTFE, Nylon, polythene, polystyrene …) had long since been invented and had passed into humdrum, everyday use. Nevertheless, 50 years later, Mr McGuire’s words have proven to be remarkably prescient; developments in polymer technology have had a major impact in very diverse fields. 

One of these many fields is aviation, in which aircraft increasingly make use of strong, lightweight composites, in particular carbon fibre composites, as reflected in the roughly 850 international patent applications in the name of Airbus or Boeing containing “composite” in the title or abstract of the patent application. An analysis of these filings reveals a sharp increase in the number of these patent filings in the early 2000s followed by a tailing off after about 2008, suggesting a move from research towards commercialisation of these composites or, perhaps more likely, an increasing reliance by these manufacturers on third party companies specialising in the development of new composites.  

Another is photolithography, which is used to make circuitry. According to Moore’s Law, the number of transistors on an integrated circuit doubles every two years, and the invention of chemically amplified photoresists helped the computer industry keep pace with this law during the 80s.

While composites and photoresists have already had a major impact on their respective industries, new applications of polymers are being explored in many other fields such as conducting polymers which offer the prospect of printed electronic devices, biocompatible polymers for implants or scaffolds for tissue growth and 3D printed products. Sound patent protection will almost certainly be an essential component of a successful commercialisation for any company operating in these fields.

Plastics. There’s a great future in plastics.

For more information speak to Anwar Gilani.

1 Yann Ménière, Ilja Rudyk, Lucas Tsitsilonis, “Patents and self-driving vehicles”, The inventions behind automated driving, November 2018, European Patent Office in co-operation with eucar, 2018, http://documents.epo.org/projects/babylon/eponet.nsf/0/65910DF6D3F02057C125833C004DB1E6/$File/self_driving_vehicles_study_en.pdf