Heat exchangers are devices that efficiently transfer heat from once source to another. They also use reclaimed energy to heat or cool, thus saving money and resources that would have otherwise been lost. Heat exchangers are part of our everyday lives, but many people know very little about them. Let’s take a look at a few potentially unknown facts about heat exchangers, along with some heat exchanger world records.
Teaser: Consider that the most common and most efficient heat exchangers in the world are not manufactured, but are essential to our survival. We know these “perfect” heat exchangers as skin. In its simplest form, arteries carry warm blood to the skin’s surface where it is cooled off.
As veins carry the colder blood back to the interior of the body, it is warmed when it passes next to the warmer arteries and through the warm muscle tissue. The warmer blood enters the body’s “compressor,” the heart, and the process is repeated. The body regulates its temperature by constricting or dilating blood vessels to control the flow rate and pressure.
From a Mechanical or Manufacturing Perspective
- Heat exchangers are critical to the efficiency of large industries, but they are even more common in everyday life. In fact, the two most common heat exchangers are car radiators and refrigeration coils. In a car radiator, the heat source is the fluid used to cool the engine. The hot fluid leaves the engine and flows through the radiator which acts as the heat transfer medium. It is cooled by the air flowing through the radiator and is then recirculated back through the engine.
In refrigeration, the cooling fluid is compressed and pushed through coils along the back of the refrigerator. The ambient air cools the liquid before it is run through the refrigerator and ice box. Once inside the refrigerator and freezer, the fluid draws the heat out of the interior, cooling down the inside before it is returned to the compressor down the back side of the refrigeration unit.
- There are many different flow patterns in heat exchangers. The most common are the counterflow, parallel flow, and crossflow. The most efficient is the counterflow. It is also the most common type of liquid-liquid heat exchanger. In a counterflow exchanger, the hot liquid enters one side of the exchanger and the cool liquid enters the other. Because of the efficiency of the heat transfer, the surface area of the counterflow exchangers can be smaller than those accommodating other flow patterns.
- Heat exchangers are part of a multi-billion dollar industry, with sales nearing $15 billion each year. With increasing development of third world countries and the modernization of China and many areas of the former Soviet Union, the market is expected to face tremendous growth over the next five to ten years. The largest industrial users of heat exchangers include the chemical and petrochemical fields, pharmaceuticals, power generation, HVAC, and the food and beverage processing industry.
- The largest market for heat exchangers is Europe, which holds over 30 percent of the global market. Despite Europe’s stranglehold on the industry, the countries with the largest expansion of heat exchanger use are China, India, and Latin America. Of all the world’s nations, China is expected to produce the strongest growth in the heat exchanger market because of their expanding chemical, petrochemical, and oil and gas industries. Over the next decade, many African nations are also expected to join in the hunt for energy efficiency, and reduced heating and cooling costs.
- The multi-national megacorp Alfa Laval has the unique distinction of manufacturing the world’s smallest and largest plate and frame heat exchangers. On the small side, the heat exchangers are so compact that they can fit in the palm of your hand. Small heat exchangers like this are perfect for the food and beverage industry where space is almost always an issue.
On the large side, The Alfa Laval Packinox is the world’s largest plate heat exchanger. The Packinox stands 27 yards (81 feet) tall and weighs in at a whopping 450 tons. The Indian oil refinery that recently had one installed described it as “the weight of 83 Indian elephants.” Not to be outdone, the South Koreans have ordered $22 million worth of Packinox heat exchangers for one of their petrochemical plants. The installation is scheduled to take place in 2017.
- The most common form of heat exchanger design in large industry is the shell and tube. In this design, a shell is filled with tubes. The tubes have one fluid running through them, while the shell has another in it. Heat is transferred between the two fluids. When the tubes are not welded to the shell, the cleaning and maintenance of this type of design are among the easiest to perform. Because the heating and expansion of the tubes cause great amounts of thermal stress, it is imperative that the correct material for the tubes is chosen based on the fluid, temperature, and pressure to be used in the heat exchange process.
- The largest crude-oil stabilization plant in the world is Abqaiq in Saudi Arabia. The plant is so large that they process just under one million barrels of crude each and every day. Due to the high amount of severely fouling fluid, the tubes in their heat exchangers were fouled so frequently that they needed to be cleaned every four weeks. To improve efficiency, the standard reboilers were replaced with new self—cleaning heat exchangers. The results were so dramatic that they didn’t have to stop their processes to take care of fouling issues for six years.
- The largest set of geothermal heat pumps on the planet is located at Fort Polk, Louisiana. The project took more than 686 miles of heat exchanger piping. The pipes were used in conjunction with 8,000 borehole heat exchangers. The project required 27 drill rigs installing 100 borehole heat exchangers each day, at nearly 200 feet inside of the earth. The $19 million project will be paid off in less than 20 years by the energy cost savings alone.