A Brief History

After the 17th century, as steam powered technology became more common, scientists needed a more precise method of measuring heat. Steam engines require careful calibration and calculation to make sure pressure limits stay within safe boundaries. As a result, British scientists began refining the metrics they used to measure heat energy. The exact origin of the British Thermal Unit (BTU), and who coined it, is unclear. However, engineering publications began referencing BTUs in the late 19th century. It became a standard thermal energy unit for the imperial measurement system. 

Meanwhile in 19th Century France, Nicolas Clement was formulating a unit of heat measurement that became known as the calorie. Calories are now the standard thermal energy unit for the metric measurement system.

What is A BTU?

A British Thermal Unit (BTU) is the amount of energy needed to raise the temperature of 1 pound of water at sea level by 1 degree Fahrenheit. Measuring heat is the same thing as measuring energy. For process cooling, BTUs are used to measure the amount of energy needed to remove heat.

Today, there are many different units used to measure heat for different applications. According to the US Department of Energy, 1 BTU is about equal to the amount of energy emitted by a single lit match. As an imperial unit of measurement, 1 BTU has equal metric system counterparts. 

• 1 BTU = 252 calories
• 1 BTU = 3.29 watts
• 1 BTU = 1055 joules

Many of us are familiar with using calories to measure units of food energy, watts and joules for measuring electrical energy, and BTUs and horsepower to measure mechanical energy. Let’s take a closer look at energy measurements for industrial coolers.

Measuring Energy for Process Cooling

When it comes to process cooling, industrial chillers take energy measurements one level further…”tons” of cooling. 

What are Tons of Cooling Power?

Why are chiller sizes listed according to tons? Well, the answer lies in the cooling practices of yesteryear. Before the age of electronic air conditioners, here in North America especially, blocks of ice were harvested from frozen lakes and rivers and used to cool homes during the summertime. 1 ton of cooling power was the amount of heat transfer needed to melt 1 ton of ice blocks in a 24 hour period. As cooling technology advanced, we began to shift from stored ice to mechanical chilling. In today’s measurements, 1 ton of cooling power = 12,000 btus per hour. Just like we still measure engines according to “horsepower”, the historical practice of using “tons of refrigeration” stuck around.

BTUs, Cooling Power, and North Slope Chillers

North Slope Chillers is proud to offer 3 levels of chill: Frost, Freeze, and Deep Freeze. These 3 classes of portable industrial chillers, offer an expansive range of cooling power from ¼ ton models all the way up to 10 ton models.

In addition, we are proud to provide the fastest customization process on the market. Our engineers can create tailor made chilling solutions that match your temperature requirements, energy needs, fluid choices and more. Contact us to find the right temperature control solution for your needs at (866) 826-2993 or [email protected]