Adaptive Roof Tiles May Be Key to Reducing Heating/Cooling Energy Consumption

According to market research estimates, the global roofing market can cross US$140 billion by 2033 from nearly US$82 billion in 2023. No construction work is complete without a roofing solution. It is equally essential to residential and commercial structures. The market has a dynamic nature since roofs require replacement at frequent intervals. Across North America, according to a market research estimate, 94% of roofing projects are roof replacements. 

Replacing old roofs is often about making them environmentally sustainable and energy efficient. Cool roofs, capable of reflecting solar radiation and reducing roof temperature, can save US$0.50 per square foot, as some studies show. 

Some estimates expect the global cool roofing market to grow at a CAGR of 5.7% through 2025. Reflective roofing materials, such as white membranes or coatings, can reduce roof surface temperature by as much as 50 degrees Fahrenheit. 

While cooling or heating properties have become a defining feature for roofing solutions, the interest in sustainability and energy savings shows that solutions must be efficient. 

We will start today's discussion with one such solution that has grabbed eyeballs across the roofing industry worldwide. 

Adaptive Roof Tiles: Sensitive to Outside Temperature; Helps Reduce Energy Consumption

Scientists at the University of California, Santa Barbara, have come up with academic research that details how roof tiles can cut heat and cooling costs. 

The purpose of the three researchers involved in this project, Charlie Xiao, Elliot Hawkes, and Bolin Lao, was to reduce the energy bill amounts of Americans and reduce the requirement of fossil fuels necessary to run in-home HVAC systems. 

These adaptive tiles come with a radiative switch to help toggle between heating and cooling states. It can switch between cooling and heating states within 3 degrees Celsius of the switch temperature. It can reduce cooling and heating needs by more than 2.5 times in comparison with static devices. 

The ‘switch,' or the passive thermoregulation device, is a 4-inch square. It serves as a movable surface that can change its thermal properties to respond to a range of temperatures.

According to researcher Charlie Xiao:

“It switches between a heating state and a cooling state, depending on the temperature of the tile.”

The researchers have devised the solution aiming for a temperature of 65 degrees Fahrenheit, which is around 18 degrees Celsius. 

But why is this solution received with so much anticipation by the roofing industry? Getting to the bottom of this question requires an understanding of the US building energy consumption scenario.

50% of the US Building Energy Consumption Goes Towards Heating and Cooling

The quantum of energy consumption that goes towards the heating and cooling of US buildings is enormous. According to the United States Energy Information Administration, the combined end-use energy consumption by the residential and commercial sectors accounted for around 29% of the total US end-use energy consumption in 2022. If one includes the electrical system energy losses, the residential and commercial sectors accounted for 38% of the total US energy consumption in 2022. 

With 50% of US building energy consumption going towards heating and cooling, the system needs to be energy efficient at any cost. Moreover, climate change and global warming will increase the need for cooling. Yet there will be areas where heating demand will also remain high and may even increase. 

Traditional cool roof systems, including reflective coatings, membranes, shingles, or tiles, work on the principles of cooling homes by reflecting sunlight. These solutions also release some of the trapped heat as thermal-infrared radiation. However, the problem with these solutions arises when cool-roof systems continue to radiate heat in the winter, driving up heating costs. In short, it lacks energy efficiency and cost-effectiveness. 

Taking into account all these aspects mentioned above, a solution that can switch between heating and cooling states in response to the outside temperature is no less than game-changing, more so because it runs without electricity. 

The solution is also deemed to play a defining role for the industry because it can address the requirements of heating and cooling in the same building on the same day. There are not many technologies available at present that can automatically switch between passive heating and cooling. The available solutions, however, are mostly inefficient for daily switching as they require a large temperature range to cycle states. 

The researchers also claim their design to be highly adaptable. It can achieve different temperature set points by altering the phase change material. For higher radiative cooling, enhanced heating performance, and superior durability, the adaptive tiles only need to alter their coating. 

Another feature that makes the solution lucrative is its simple design and low-cost production potential. 

While all these advantages and benefits wait to be leveraged by the industry and produced at a larger enterprise scale, multiple other building solutions are working towards reducing heating/cooling energy consumption. We will now look at some such solutions.

Smart-Roof Coating for All-Season Energy Savings

Scientists involved in a study led by Junqiao Wu, a faculty scientist in Berkeley Lab's Materials Sciences Division and a UC Berkeley professor of materials science and engineering, developed an all-season smart-roof coating to keep homes warm during the winter and cool during the summer. 

Like the earlier solution, this one also does not require natural gas or electricity. 

According to Junqiao Wu:

“(Our) all-season roof coating automatically switches from keeping you cool to warm, depending on outdoor air temperature. It is energy-free, emission-free air conditioning and heating, all in one device.”

To achieve their objective, the scientists developed a new material called a temperature-adaptive radiative coating or TARC. TARC automatically turns off the radiative cooling in the winter, ensuring there is no overcooling and energy waste. 

With TARC in place, scientists expect the average household in the United States will save up to 10% on electricity. The solution is capable of reflecting 75% of sunlight year-round. However, when the ambient temperature is above 25 degrees Celsius or 77 degrees Fahrenheit, its thermal emittance goes as high as around 90%. 

Junqiao Wu, expressing his excitement over what the solution could achieve, said:

“We originally thought the switch from warming to cooling wouldn't be so dramatic. Our simulations, outdoor experiments, and lab experiments proved otherwise – it's really exciting.” 

The researchers had plans to develop TARC prototypes suitable for applications at a larger scale. They were hopeful of TARC proving its worth as a thermally protective coating to prolong battery life in smartphones and laptops. Its other uses could include protecting satellites and cars from extremely high or low temperatures and making temperature-regulating fabric for tents, greenhouse coverings, hats, and jackets. 

Energy-efficient solutions for US buildings, especially with a focus on efficient roofing, are available at an enterprise level as well. We will see some such solutions in the next segments. 

1. Whitco Roofing, Inc.

Whitco positions itself as the largest commercial roofing contractor in Atlanta and one of the leading roofing contractors in North America. Whitco is one of only a few commercial roofing companies in North America that has Certified Green Roof Professionals as staff. It also offers solar roof panels that can efficiently supply more than 25 percent of a building's total energy. Its solutions also include Polyisocyanurate roof insulation. Applied correctly, this solution can significantly decrease heating and cooling costs across commercial and industrial use case scenarios. 

Founded in 2005, Whitco Roofing is a privately held company headquartered out of Atlanta, Georgia, United States. 

2. Grundfos

When it comes to a holistic approach to reducing heating or cooling energy consumption in buildings, Grundfos is the name that features at the top. Its solutions cater to both commercial buildings and domestic buildings. 

To make commercial heating energy efficient, Grundfos offers circulator pumps, mixing loops, distributed pumping solutions, booster sets, inline single-stage pumps, hydro boosters, and much more. For energy-efficient heating in domestic setups, Grundfos mostly depends on circulator pumps. 

In the financial year 2022, Grundfos registered a net turnover of DKK 33.3bn (2021: DKK 28.7bn). It witnessed a sales growth of 12.1% in local currencies versus the last financial year (2021). Return on sales in 2022 increased to 11.8% in 2022, compared to 11.4% in 2021.

3. Tesla Solar Roofs

The installation of Tesla solar roofs comes with the opportunity to power one's home with a fully integrated solar and energy storage system. It offers a 25-year warranty and 24/7 outage protection. The solar roof is complemented by Powerwall, a compact home battery for round-the-clock energy security. These batteries help store the energy produced by the solar roof to power the home anytime. 

Composition-wise, a solar roof comprises both glass solar tiles and steel roofing tiles. The glass solar tiles produce energy. The architectural-grade steel tiles are meant to impart longevity and corrosion resistance to the roof. 

According to numbers officially published by the company, the Tesla in-house team of energy professionals has installed close to 4 gigawatts of solar across nearly 480,000 roofs. Cumulatively, these roofs generate more than 25 TWhs of clean energy. 

The setup also includes Tesla Solar inverters to keep the system well-integrated, safe, reliable, and outage-rady. With the Tesla app, one can monitor energy production in real time. It is also possible to control the system from anywhere with instant alerts and remote access. 

In Q3 2023, Tesla registered a revenue of more than US$21.4 billion. Operating margin stood at 17.2%. 

Buildings and Energy Efficiency: The Road Ahead

Global warming and climate change is a civilizational concern. Governments, regulatory bodies, councils of nations, and enterprises are all keen to come up with solutions that help achieve efficient energy modules. Apart from specialized solutions, there are many ways one can tackle these concerns by making small, every day modifications in our building systems.

The United States Office of Energy Efficiency and Renewable Energy recommends many such solutions, such as adding insulation, using LED lighting, installing heat pumps, etc. 

People living in hot and humid climates can use dehumidifying heat pipes to reduce indoor humidity and improve comfort. Minimizing energy losses in ducts is another way to encourage energy efficiency. Insulating the ducts and air sealing them could be helpful. 

For efficient water heating systems in buildings, one can think of energy-efficient solutions like tankless coils, indirect water heaters, solar water heaters, etc. Introducing processes like drain-water heat recovery may also prove useful. 

There are many benefits to reducing heating/cooling energy consumption. It is not only about reducing the cost. It has greater community benefits. They help build community resilience and a system that is energy-wise and equitable. There are underserved communities in every region that need the help of cost-efficient technologies and infrastructure to get access to an uninterrupted energy supply. 

Energy-efficient systems also lead to less air pollution, benefiting the overall health of a community. The less burning of fossil fuel is also beneficial for our ecology, the plants and animals that surround us. 

Its benefit to the country's infrastructure economy is also significant. Efficient energy systems take the load off the grids. It helps minimize congestion and stress on power distribution at any given point in time. 

The benefits are so widespread and far-reaching in their impact that we need more solutions like adaptive roof tiles in the future. It is definitely an encouraging milestone in the journey towards efficiency and sustainability. 

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