Plate Heat Exchanger in a Chilled Water System
A plate heat exchanger in a chilled water system can reduce energy usage by using colder outside air to provide cold water to the system. These types of systems are usually used when a cold supply of water is required year round such as internal units within a building that do not have outside air directly.
Plate heat exchangers used in a chilled water system are heavily dependent on the cooling tower and condenser water flow. The cooling towers are typically ran to cool the water as much as possible before sending that water through one side of the plate heat exchanger.
Chilled water is pushed through the other side of the heat exchanger, allowing for heat transfer from the chilled water to the condenser water. This method of cooling is very cost effective since it doesn’t require mechanical cooling of a chiller.
A very important part of using a plate heat exchanger in a chilled water system is to ensure isolation of the chillers from the colder condenser water. Some chillers are not designed to have the colder water continually flowing through them for extended periods of time.
Issues that can happen transitioning from chiller to plate heat exchanger
The most challenging part of operating a chilled water system that has a heat exchanger is when the outside air temperatures are close to the point of needing a chiller or not. The overall load on the system is also a big consideration as well.
Transitional temperatures can cause issues with transferring the system from mechanical cooling to heat exchanger. Timing of isolation valves and set point changes is critical to keep the system from having issues.
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