Sometimes trends come and go in cycles. Fashion is famous for being cyclical (think flared jeans and the grunge look). What you don’t typically see come back from the vintage pile is technology – that is, until recently. A new trend is re-emerging in air conditioning, bringing back a time-tested cooling method within an ever-growing tech industry. This cooling method is truly a marriage of fire and ice, using solar power and large vats of freezable water.
Ice has been used to help keep people cool for centuries. The Romans would bring ice and snow down from the Alps to chill the pools in bathhouses during the dog days of summer, giving citizens a chance to cool down and escape the oppressive heat. Flash forward to the 1930s and 1940s and ice was being used to cool movie theaters. Fans would be placed near giant blocks of ice and blow cool air into the theater’s seating area. The method was effective enough that the cool air became a bigger draw than the movies themselves, sometimes even taking top billing over the movie title.
Forty years later, ice was being used as a compliment to air conditioning in office and industrial buildings. Large cooling bins would be placed on the roof near the regular air conditioning units. During the night, when energy costs were at their cheapest, the water in the cooling bins would be frozen. During peak daytime hours, the cool air from the ice would be pulled into the building, allowing the compressor for the main AC unit to be turned off, reducing energy use during peak hours and saving money.
Now, the old technique of freezing water at night (thermal ice storage) has been combined with solar power. These two energy saving and environmentally friendly ways are coming together and keeping you cool when it’s so hot and sticky that you could cook eggs on the pavement outside.
Thermal ice storage’s role in cooling the building remains mostly unchanged. Frigid coolant is pumped into cooling coils that chill the hot air from inside the building, which is then pumped back into the building. The solar power comes into play during the refreezing process. Typically, the water is refrozen during non-peak hours when energy costs are the lowest, but, with solar power, peak hours become less relevant. Using solar power allows building owners to not only cut cooling costs, but also lessen their environmental impact by using a renewable power source like solar energy to freeze the ice.
Technology is something we normally think of as always pressing forward, always creating something new. But sometimes we need to look to the past to make a better future. By pairing the ever-evolving technology of solar energy with a decades old cooling solution of supplementing air conditioning with energy storage in ice form, we can work for a cleaner, cooler, and more energy efficient future.