Expanding a Plate Heat Exchanger
Morgan Byres | Apr 21, 2023
One great feature of plate and frame heat exchangers from CPE systems is that they are often expandable, allowing you to increase the number of plates, and in so doing increase its cooling capacity. Adding plates to a heat exchanger extends the amount of contact between the product and the cooling liquid, increasing total heat transfer. This can be helpful in a number of contexts, such as when your city water temperature changes, your use changes, or you require greater capacity. In this post you will learn how much you can expand your heat exchanger, how to calculate how many plates you need, and the directions to follow when expanding.
How much you can expand a plate heat exchanger depends on the frame. The plates must fit on the bars and leave enough room to properly assemble and tighten the bolts. Our order invoices include the maximum amount of plates per frame. It is possible to extend the bars, however this is costly and not usually recommended. If you overload your HX it becomes difficult to reassemble.
First, decide how much increase in performance do you desire? Let's work with a practical example. If you have a CPE60H-37D heat exchanger with 37 plates designed for 10 GPM of flow and you want to increase to 15 GPM, we are looking at a 50% increase. That means you need to add 50% more plates. (37 plates x 50% = 18.5 ) Plates are always added in pairs and since we can't add ½ a plate you can round down to 18 or up to 20 plates.
Expanding a heat exchanger is relatively easy, you simply add flow plates, but there are some rules to follow. Flow plates must be added in pairs: one left and one right plate. This maintains the honeycomb pattern (see figure to the right). It is also recommended that you add an equal amount of plates to each pass (the amount of passes your HX has will be written on the front of the unit). This maintains the original design and uniformity. For example, if you have a CPE60H with 37 plates and it has 3 passes, and you want to add 6 plates, you would add one L and one R to each pass. You cannot add an odd amount of plates to a pass, this would disrupt the honeycomb pattern. If you have a two stage heat exchanger, treat each section as its own unit.
Once you have added the plates and before you tighten the HX it is important to find your new A measure. Take your original A measure and divide it by the original amount of plates. Now multiply this number by the new total amount of plates. Keep this number somewhere safe, because you will need it every time you reassemble your heat exchanger.
For detailed instructions on how to disassemble or reassemble a plate heat exchanger please refer to our Heat Exchanger IOM.