One of the primary functions of heating and air conditioning is to transfer heat. Not all forms of heat transfer are created equal though. Heat exchangers are used in furnaces, boilers, water heaters, condensers, chillers, and other HVAC components that require fluid cooling or fluid heating. They’re just as important as the furnace or boiler, and in some cases, they’re even more critical.
What Is a Heat Exchanger?
A heat exchanger is a piece of equipment that transfers thermal energy from one medium to another by direct contact. A household heating and cooling system uses several exchangers to transfer heat into or out of water that flows through your furnace or air conditioner. The heat exchanger is the core component of the heating and cooling system, transferring energy between various media.
This transfer is done with a fluid, usually water, running through tubes within copper coils wrapped around an aluminum finned core. This causes the hot fluid to pass into the colder one that heats it in turn. The heat exchanger’s core looks like a honeycomb, but the actual design can vary depending on your needs. Boilers and water heaters use high-capacity loops with finned cores to distribute hot water through your home quickly. Condensers are often split into multiple loops, including oil coolers that remove excess heat from the condenser.
Why Are Heat Exchangers Central to Heating and Cooling?
Heat is energy, and like any other form of energy, it can’t be created or destroyed; it can only change forms. So, where does this heat come from? A lot of the time, it’s supplied by combustion engines that run on gas, fuel oil, or propane. Combustion engines are the heart of heating and cooling systems, but they only do so much. The rest of the work is left to air handlers that draw in room air, cool it down with evaporator coils, and then push it out again through your vents.
Heat rises, so this process is even more difficult if you live on a second story or higher floor. That’s where heat exchangers kick in to help your system keep up with the demand for air conditioning or heating. They deliver results without adding extra stress on the engine, saving you time and money on maintenance costs over the years.
How Does a Heat Exchanger Work?
To know how a heat exchanger works, you need to know the three forms of heat transfer: conduction, convection, and radiation. You’ve probably heard about conductive and convective heat transfer in your heating and cooling system before, but what do these terms mean?
Conduction transfers thermal energy when two objects touch one another directly. For example, conduction occurs as the heat transfers from the heating element to the pan when you’re cooking something on the stove.
Convection is a more efficient form of conductive heat transfer. It’s caused by fluid motion such as air or liquid particles colliding, creating thermal energy. When you cook food in the oven, the heating element heats the air, which in turn cooks your food.
Radiant heat transfer is both the most complicated and common form of heat transfer. Radiant energy passes through any object that absorbs it, such as Earth’s atmosphere or your ceiling at home, and transfers thermal energy without touching either surface. Radiant energy isn’t visible to the naked eye, which is why we call it “invisible energy.”
As you can see, all three forms of heat transfer are important to heating and cooling systems. Heat exchangers, therefore, are designed to efficiently switch heat from one medium to another as it’s transferred into the air you breathe.
The process works like this: A gas or propane-powered furnace heats exchanger coils wrapped around the aluminum finned core. Hot water flows into the heat exchanger coils, which draw in cold water through opposite tubes. The cold water is heated up and pushed out to your home’s radiators, baseboard, or floor heating system. The now-hot water travels back into the exchanger coils, where it’s cooled off through a combination of conduction, convection, and radiant heat transfer. This makes the hot water ready for another pass through the core.
Do Heat Exchangers Transfer Heat Only From Hot to Cold?
No, they also do the opposite. Heat exchangers can also take thermal energy from a cold source and turn it into a hot one. The same principle goes from hot to cold fluids moving through tubes, but the piping design differs.
At Xtreme Heating & Cooling LLC, we have a variety of heat exchangers to meet your needs. We have plenty of options for every application, from oil coolers that remove excess heat from the condenser to dual-flow systems that enable you to switch more easily between heating and cooling modes on demand. Our other services include indoor air quality testing, plumbing services, geothermal and radiant heat, and water heating solutions. Call Xtreme Heating & Cooling LLC in Omaha, NE, today to schedule a free estimate!