Temperatures in Hong Kong can get snug, to put it lightly. As a subtropical island city with warm summers and very mild winters, the concrete jungle is a heat and humidity trap of sorts, with the winding streets of Mongkok often measuring warmer temperatures than greener areas of the region. Even in winter, an ice cream cone melts rapidly, often half-liquefied within ten minutes- undoubtedly due to the efficient heat-retaining nature of humidity.
In Hong Kong, air conditioning can almost be taken as a commodity. Hotels and malls have air conditioning. Cha caan teng, or Hong Kong-style diners, traditionally all come equipped with air conditioning to provide customers refuge from the sweltering summer heat. On a consumer level, air conditioning units and dehumidifiers are massively popular, seen by homeowners as an essential.
The City Needs More
In a similar trend observed across major cities in the world, internet usage in Hong Kong spiked during and after the Covid-19 breakout, with a reported 20 to 30 per cent boost in usage as companies shifted operations online and employees worked from home. Many large industries in the city such as the financial sector and healthcare industry all require a healthy tech and data infrastructure.
The post-pandemic popularity of remote working and online services across multiple industries has led to a surge in data center demand, with the city now placing a confident third in a Cushman & Wakefield top 10 data center market report for the Asia-pacific region.
In many ways, a data center is an amalgamation of our progress through technology. The sheer scale of information and functions it can support is massive, and a facility often represents the single most expensive asset that a business will possess- both in terms of operational costs and as an investment.
The enormous amount of power needed to operate a facility produces a large amount of heat, and cooling measures are needed to ensure safety and efficiency. In a city where temperatures average out between 26 and 30 degrees celsius for most of the year, keeping data centers cool and dry is a more demanding undertaking than in other environments.
Full Of Hot Air
Data centers traditionally use air cooling measures as a means to counter system heat. Even with the evolution of technology over the years, the concept of air cooling has remained unchanged. Cold air is blown over hardware, dissipating hot with cold, before circulating the warmer air to a cooling unit and repeating the process. Air cooling systems in data centers either target rooms or racks, but the general idea remains the same.
Despite the simplicity and workability of air cooling, one massive drawback has been identified. Firstly; akin to how an air-conditioned room gets warmer with more people in it, cooling systems have to be able to cope with the increased and ever-growing server loads at facilities. The energy and infrastructural costs required for air cooling systems to keep up with increased loads is simply too much to be justified. Simply put; air cooling systems aren’t necessarily bad, they’re just not good enough anymore.
The Other One
This brings the alternative of liquid cooling. Water, and liquids in general, are much more efficient conductors of heat than air. Like air cooling, the basic approach for liquid cooling is straight-forward and simple. A coolant or liquid is sealed in a tank or container, and pipes carry the liquid across the physical components within a data center.
The coolant draws off heat produced and the closed-circuit of pipes circulates the warm liquid back into its original tank, before being cooled again. This method of cooling is more efficient, and allows a better coping of increased density within data centers.
Diving Into Innovation
A newer technology, however, has emerged as a possible frontrunner in this race to cool off. On a warm, sunny day, the best way to bring your body temperature down isn’t by enjoying a cold drink, or even staying in an air-conditioned room.
Diving into a pool brings our temperature down almost instantaneously, it’s refreshing and rejuvenating; studies have even shown that being submerged in water helps clear troubled or stressed-out minds.
Enter immersion cooling; to the industry-naive ear, the idea of submerging electronics in cooled liquids sounds like something straight out of a Ridley Scott film, but this cooling method is very real. Standard components are dipped into a cooled mineral oil- which are nonreactive and harmless to electronics. The oil absorbs heat, before cooling through evaporation.
Immersion cooling uses 99 per cent less electricity than air cooling and is noise-free, a welcome departure from the usual racket caused by air cooling systems.
Despite all the pros offered by liquid-related cooling systems, concerns have been raised, which have delayed widespread adoption by the industry.
Liquid cooling systems are prone to leakage and potential corrosion, both of which are imaginably disastrous in a data center. Immersion cooling systems require structural flexibility of facilities, and the initial training and electrical costs needed is enough to repel widespread industry usage.
Be Like Water
For a city like Hong Kong however, liquid cooling is an inevitable option that should be accepted as an industry standard. In a warm island city with massive space constraints, air cooling simply isn’t efficient in the long run, as the number and density of data centers increase. Only so many cooling towers can be built and rising energy costs are too much of a levy for many operators.
Both liquid cooling and immersion cooling should be taken up in the city, as the physical limitations of air cooling are reduced greatly and cooling efficiency is greatly increased. There will likely be a transitional period during this shift in systems, but for an ingenious city that has taken the approach of retrofitting old industrial buildings into data centers, the challenge is not a mighty but achievable one.