Why resilient infrastructure underpins reliable cooling, heating, and wider societal wellbeing.

Last month we looked at goals one, two and three of the UN’s Sustainable Development Goals (SDGs). The next grouping of SDGs is “affordable and clean energy”; “clean water and sanitation”; and “industry, innovation and infrastructure.” These are goals seven, six and nine, respectively. So why group them in this order?

The link between refrigeration and energy is obvious. It is estimated that roughly one-sixth of the electricity generated in the world today is used in refrigeration systems of one type or another, ranging from the fridge in your house to the freezer that prepares your food for transport and delivery. In between these two are many links in the cold chain including big warehouses, trucks and shops, and, of course, don’t forget air-conditioners ranging from individual mini-split systems up to multi-megawatt chilled water cooling systems serving whole districts. Obviously, any improvement in the baseline efficiency of these systems means more generating capacity for other purposes.

The greatest shortfall in access to electricity is in sub-Saharan Africa—also the region that will see the largest increase in population over the next 30 years. It is vital that the infrastructure built to support that population does not copy the mistakes of the past. At a local level throughout the developed world exactly the same logic can be applied. Increased use of renewable energy has transformed the way our electricity is produced, distributed, sold and used. A refrigeration system that can adapt to that change can save lots of money for its owner, and in some cases can even earn money in the right circumstances with some minor changes to operating patterns.

Clean water and sanitation seems to have less to do with refrigeration but there are several touch points where the two worlds collide. In Scotland, where I live, it is easy to forget that fresh water is a scarce commodity because it routinely falls out of the sky. Only 3% of the world’s water is unsalted and more than half of that is locked into polar ice caps, glaciers and permafrost. Large refrigeration systems use freshwater in evaporative cooling systems because it is much more compact and more efficient than air-cooled condensing, especially in tropical climates (see goal seven, above). For coastal locations saltwater could be used instead of fresh, but brings several challenges to an evaporative cooling system including slight loss of thermal performance and corrosion of incompatible materials. The water may also be highly abrasive if it is not properly filtered and the level of salt in seawater (about 3.5% by weight) is not enough to ensure biocidal action against Legionellosis so some water treatment is still required. The merit of this approach however is that the freshwater is conserved for those who really need it.

There are technical challenges in adapting evaporative cooling systems to saltwater use, but they are not insurmountable.

The third goal in this set (industry, innovation and infrastructure) is all about building a sustainable and resilient world through the application of advanced technology to infrastructure. I have believed for a long time that the refrigeration world has been lagging behind in terms of innovation. Most of our creative effort over the last 30 years has gone towards addressing the twin bogeys of ozone depletion and global warming potentials. To incorporate a truly 21st century cold chain into the infrastructure required to serve an increasingly urban world population requires us to get our innovation mojo on fast. The demands of the heat pump market will be even bigger. As I have said before, it’s a great time to be a refrigeration engineer!

As easy as 7, 6, 9.