From AI to cooling paint: Here's how buildings in Hong Kong are doing to save energy and protect the environment

High-rise buildings account for about 90% of electricity consumption in Hong Kong and developers and construction companies are looking for ways to address the environmental impact of this.

Deep in the heart of Exchange Square - a complex building located in the heart of Hong Kong - is a mysterious underground system. It is a series of pumps and pipes that use seawater directly from Victoria Harbor to cool the area's air conditioning system, which is topped by three office blocks and a shopping mall. It is also home to the city's financial market and several consulates.

About 64,000 cubic meters of seawater flows through this system every day, and that's enough to fill 26 Olympic-sized swimming pools. It operates in a noisy way, but is helping to transform one of the world's busiest cities to reduce a large amount of carbon emissions released into the environment.

Sea water cooling system at Exchange Square.

The system also uses up to 35% less energy than conventional air-cooled systems, resulting in significant cost savings for its owner Hongkong Land. For further information, almost half of the energy consumption in this central district is used to operate air conditioning systems.

'We pioneered the direct seawater cooling system in Hong Kong,' said Hongkong Land's technical director, Derek Chan. "This refrigeration system is automatically controlled, so you won't find any operators here."

Hongkong Land, a unit of the Jardine Matheson group, has been using seawater since 1963 to cool a 450,000-square-foot property near the harbour. The entire monitoring and management process is located on the top floor of the 52-storey Two Exchange Square building. Here, artificial intelligence, machine learning, Internet of Things (IoT) and technology-rich applications of the 21st century are all concentrated in a command center of 400 square meters.

All of this has resulted in 30% energy savings and 40% reduction in carbon emissions by the end of 2021 compared to 2008, when the first comprehensive energy audit was conducted.

Andy Yeung, director and head of technical services at Hongkong Land, said in an email interview: 'Working with existing buildings presents many challenges, but we are determined to overcome these. challenge this with new technologies and systems.'

Hong Kong panorama.

Hong Kong has more than 10,000 tall buildings, including more than 2,000 skyscrapers over 100 meters high. It's no surprise that these buildings are becoming a major source of the city's carbon emissions.

According to the 2021 policy speech of former Hong Kong Chief Executive Lam Trinh Nguyet Nga, buildings account for about 90% of Hong Kong's electricity consumption. She highlighted the importance of green buildings in reducing energy demand as part of the government's efforts to achieve net carbon emissions by 2050.

The government has set a target to reduce electricity consumption of commercial buildings by 30% to 40% and of residential buildings by 20% to 30% by 2050 compared to 2015 levels. halfway to those goals by 2035.

Electricity consumption by demand in Hong Kong in 2019

Electricity generation is also a major source of emissions in Hong Kong. It accounts for about 60% of all emissions in 2020, sending about 20.4 million tons of carbon dioxide into the atmosphere, according to the latest data released by the Environmental Protection Agency in June. Other major emission sources are the transport sector at 19.7% and waste management at 8.7%.

Another major commercial home developer in Hong Kong, Swire Properties, has launched the Green Performance Pledge. This is an initiative that covers the entire tenancy cycle, from installations to office operations to help improve 'carbon footprint' and increase energy efficiency.

Real estate consulting firm JLL installed a smart meter system in its office as part of the plan. This system helps to monitor energy usage in different areas. And JLL found that almost half of the electricity is consumed outside of office hours. So they eliminated unused equipment such as ice machines, resulting in a 9.3% reduction in energy use in working areas and cafes between October last year and June last year. now.

The real estate consulting firm is also working on increasing the average room temperature of server room air conditioners and will replace all existing lighting - more than 1,000 bulbs - with LEDs.

The Netherlands-based asset manager, APG Investments Asia, which currently leases offices from Swire Properties, has also participated in the Green Performance Pledge and has managed to reduce its carbon footprint by 10%. his new room every year. For example, the use of motion sensors turns off electrical devices and maximizes daylight usage throughout the office.

Swire Properties also developed a smart waste reduction program by installing smart scales under the trash cans to collect recycling data and dispose of waste in the office. At the same time, they use displays connected to the data system to publicize the waste reduction progress of the participating units.

The seven-month trial involving 15 teams from seven office towers managed by Swire Properties resulted in a 14% reduction in waste per employee. According to calculations, this program has saved 51,847kg of carbon dioxide emissions, equivalent to planting 1,250 trees.

A building with typical air conditioners in Hong Kong.

Engineering technology company Negawatt Utility has chosen to develop a centralized digital platform to manage the carbon footprint of buildings.

Arthur Lam, CEO of Negawatt said: 'With IoT and data analytics, we can understand how a building is performing and make recommendations on how to refine it, such as why buildings are sometimes too hot and too cold'.

The company partnered with Schroders Capital in 2019 to conduct a pilot project at Worfu, a community shopping mall in North Point. Since then, the project's launch has helped reduce energy use by about 200,000 kilowatt hours (kWh) - the equivalent of 14 tonnes of carbon emissions - through the optimization of chillers.

Air conditioning accounted for 28% of Hong Kong's electricity consumption in 2019, according to data from the Department of Electrical and Mechanical Services. Therefore, a group of PhD students and researchers from the City University of Hong Kong sought to reduce the use of air conditioners.

They founded the company I2Cool in June 2021 and launched their first product, iPaint, a cooling paint that can lower the surface temperature of buildings. This patented paint is inspired by the self-cooling skin of the Saharan silver ant. It reflects more than 95% of solar radiation and emits infrared heat.

Air conditioning accounted for 28% of Hong Kong's electricity consumption in 2019.

Martin Zhu, co-founder of I2Cool, said that when compared to conventional white paint, iPaint can produce an instant cooling effect of 4 to 7 degrees Celsius when painted on the roofs of buildings. Using one square meter iPaint can save 120 kWh of electricity and eliminate 70kg of carbon dioxide emissions annually, the equivalent of planting six trees, according to the company's website.

In addition, reducing carbon in buildings - emissions associated with materials and construction over the entire life cycle of a building - is also an important factor for decarbonizing the built environment.

So construction companies and contractors like Gammon Construction have been using materials with a lower carbon footprint. The company has more than 480 certified low-carbon concrete products, with carbon emissions about 15 to 30 percent lower than conventional concrete, according to chief executive Kevin O'Brien.

'The reason why concrete is such a challenge is because part of the formula is cement, and cement uses a lot of energy to produce, both to extract the raw material and then the energy needed for cement production,' O'Brien said.

According to London-based research organization Chatham House, concrete production accounts for about 8% of the world's carbon dioxide emissions.