Selecting the right coil for your system is a balance between the proper number of rows/fins, desired coil pressure and long term vs. short term savings. Here are some important factors to consider any time a coil is needed:
Rows/tubes cost more than fins. An 8 row coil can cost considerably more than a 6 row coil. To do so without affecting performance more fins can be added per inch. A typical 5/8″ OD tube has 6-10 coils per inch. By increasing that to 14 fins/inch you can reduce the number of rows needed.
Coil circuiting is an important factor in coil performance. Circuiting is about selecting the number of tubes that you need to feed, and how many passes the water makes through the coil. This will determine the tube fluid velocity by your gallons per minute (GPM). The higher the GPM the fewer passes needed.
Fins do most of the heat transfer. The majority of heat transfer within a coil, about 70%, is done through the fins with the tubes handling the remaining 30%. Because of this, it is important that the connection between the fins and coils provides maximum heat transfer contact in order to maintain high efficiency.
It’s important to consider maintenance cost factors. Coils need to have regular maintenance performed during their entire life cycle. When deciding what coils to invest in, it’s important to consider the cost of that maintenance along with product cost, size, and materials. Sometime a design or size that saves $500 in actual costs can increase required maintenance by $5,000 or more.
- Coils typically last for 15-20 years. With proper selection and regular maintenance, coils can perform at high-effiiciency for a long time. That’s why it’s important to think long-term when considering any coil purchase. If done properly they are a great investment.
At Campbell-Sevey, our team considers all these factors when making coil recommendations and works directly with you to make sure they will fit your performance needs. Contact us to learn the best options for your coil project.