Avançando Soluções HVAC com Materiais Eletrocalóricos

A Demanda Massiva de Energia dos Sistemas HVAC

Modern industrial society uses a lot of energy. One application we tend to underestimate when it comes to energy usage is cooling and heating. Representa mais da metade do consumo total de energia mundial, à frente da eletricidade (20%) e do transporte (30%).

Portanto, talvez até mais do que os veículos elétricos, eletrificar os sistemas HVAC (Aquecimento, Ventilação e Ar Condicionado) e torná-los mais eficientes é crucial para reduzir o consumo de energia e as emissões de carbono. Especialmente porque a demanda apenas por refrigeração deve triplicar até 2050 devido ao desenvolvimento econômico em países de clima quente com grandes populações, como, por exemplo, a Índia e a Indonésia.

Fonte: Daikin

Até agora, a tecnologia preferida para alcançar HVAC de alta eficiência tem sido bombas de calor que utilizam compressão para refrigeração.

Uma nova tecnologia está surgindo para desafiar o status quo, baseada em um princípio físico chamado “resfriamento eletrocalórico”.

Como Funcionam as Bombas de Calor

All heat pumps, from compression heat pumps to future electrocaloric heat pumps, function on a basic principle: moving heat instead of generating it.

This is a very different principle from fossil-fuel-based and other electric heating systems, in which either electricity or gas/coal/oil is consumed to produce heat.

A heat pump, instead, takes heat from one side of a wall and transfers it to the other side. In winter, it absorbs heat from the outside and sends it into the building. In summer, it reverses this process to cool down the building and works like air conditioning.

Moving heat is a lot more efficient than generating it. This allows a compression-based heat pump to generate 2-4W of heat/cold for every W of power consumed.

Fonte: RMI

The heat is moving in and out of the environment, with the 2 main options being using outside air or the surrounding soil through underground piping.

Heat pumps are most often used to heat and cool down buildings like offices, commercial spaces, and homes. However, it can also be used in an industrial setting, reusing energy sources from one industrial process into another, leading to massive energy savings here as well.

Fonte: Sintef

Bombas de Calor Eletrocalóricas para Ir Além da Compressão

Progresso na Tecnologia Eletrocalórica

Traditional heat pumps use the thermal effect of compression & decompression to move the heat from one point to another. This requires refrigerant agents like hydrofluorocarbons or ammonia which have either direct or indirect greenhouse effects on the climate.

The electrocaloric principle is different. An electrocaloric system heats when exposed to electric fields, as it causes atoms to align in a single direction, reducing entropy. The reverse happens, causing cooling when the electric fields stop.

Fonte: Fraunhofer IPM

Electrocaloric effects have been known since the 1960s, but back then, the strongest temperature difference that could be achieved was only 2.5°C.

Some progress was made in 2006 when a thin film of lead-titanium-oxygen-zirconium achieved 12°C of cooling capacity.

However, the recent breakthrough of almost 21°C temperature change, achieved by researchers of the Luxembourg Institute of Science and Technology in Belvaux, shows that the technology is becoming powerful enough for commercial applications.

Protótipo Eletrocalórico

The team used a polymer and lead-scandium-tantalum-oxygen (PST) multi-layer capacitors (MLC).

Fonte: UPCommons

The Luxembourg researchers have created a prototype that achieved maximum cooling when under 10V per micrometer of power, creating a maximum cooling of 4.2W.

Fonte: Techspot

This is a radical improvement from all previously developed methods, with temperature span and cooling power, respectively, 50 % and 15 times larger than the previous best electrocaloric devices.

This puts the prototype leagues ahead of all previously tested electrocaloric concepts.

Fonte: UPCommons

Fonte: UPCommons

The material was also tested for repeated heating and cooling cycles and has shown no sign of degradation.

Among the many advantages of electrocaloric systems is that the direct use of electricity makes EC coolers compact in volume and suitable for miniaturization. So, besides future heat pumps, it could also be used in small electronics and batteries.

It also has very high efficiency, potentially much higher than the compression heat pump system can hope to achieve.

Aprimoramento Futuro

The research published in the journal Science describes a prototype. Some further improvements are discussed as well.

For example, the current prototype uses dielectric fluid rather than water to prevent short circuits. However, this dielectric fluid has poor thermal properties compared to water.

So, developing waterproof multi-layer capacitors (MLC) could significantly improve the speed and cooling capacity of the system.

Increasing the number and density of MLCs could also result in more cooling potential.

Finally, thinner and flatter electrocaloric modules would help, and it is not clear if applying higher electric fields is possible and safe.

Empresas Avançadas de Bombas de Calor

There is currently no company commercializing electrocaloric heat pumps or cooling systems. It is still very much an academic and applied physics field.

However, it is likely that now that the technology is evolving at a level of efficiency, making commercialization viable, these research institutes will look to monetize their patents.

So, it could be interesting to look at the leaders in the heat pump industry who could benefit from licensing the IP for electrocaloric devices.

It is also likely that the creation of commercial-grade electrocaloric systems and their distribution to end users will be a very capital-intensive process, favoring the largest actors in the industry.

1. Carrier Global

Carrier is a leader in HVAC (commercial and residential), cold chain, and fire & security, with 58,000+ employees. While not selling only heat pumps, it is a product category that is the focus of the company and that it sees as the future of the industry.

It is mostly focused on the Americas, with HVAC making more than half of its sales.

Fonte: Carrier Global [securities_stock_price_tag symbol="CARR" exchange="NYSE"]

It has an installed base of 330,000+ commercial HVAC, 33 million residential HVAC, 1.8 million refrigeration equipment, and 90+ million fire and security systems.

The company is determined to drastically reduce its greenhouse gas (GHG) emissions by 2030.

Considering that a lot of these emissions come from ammonia coolants, the possibility of switching to an electrocaloric system in the future offers the industry a path forward where its only emissions are related to energy consumption and metal mining, which will be powered by renewables.

Fonte: Carrier Global

2. Daikin Industry

The Japanese company founded in 1924 can claim to be the world’s number 1 air conditioning company.

The company has been active in the heat pump space since 2006 and has established as early as 2008 a business alliance with Gree Electric Appliance, China’s top air-conditioning manufacturer.

It is mostly selling in the Americas, Europe, and East Asia, but has experienced explosive growth in markets like India as well, with a 23x increase in sales between 2009 and 2022.

Fonte: Daikin

One of Daikin’s competitive strengths is its R32 coolant, with a much lower effect on global warming than its competitors.

This means that the emergence of electrocaloric systems might be in the short-term a threat to the company’s competitive position.

Fonte: Daikin

But at the same time, it reflects the company’s preexisting focus on the environmental effect of cooling systems and innovation capacities (it invested $300M in a new R&D center in 2015) and would make it a good candidate for developing these systems at commercial scale.

A strong indication of Daikin’s dedication to eco-friendly innovation is the worldwide free access to basic patents for R32 since 2015 and free access in 2019 to all the group patents since 2011.

3. NIBE Group

Investors interested in the prospect of heat pumps and electrocaloric systems might want a company fully dedicated to the sector, without the distractions and risks associated with other technologies.

In this case, they might be interested in Nibe, a European manufacturer of heat pumps, as well as wood stoves (another carbon-neutral heat source).

The company is originally from Sweden and still conducts a large part of its sales in Nordic countries, as well as Europe. It had 21,333 employees in 2022.

Fonte: Nibe

The company’s heat pumps have avoided the emissions of 360,000 tons of CO2 in just one year.

As a more focused company, Nibe is as big as Daikin or Carrier when it comes to heat pumps alone.

With research about electrocaloric materials ahead in countries like Luxembourg and Germany, this could open the way for European companies like Nibe to establish privileged relations with researchers and be among the first to expand their offer beyond compression-based heat pumps.