Chilled water buffer tank location in the system? 

Chilled water buffer tank location in the system? A chilled water buffer tank is usually added into the main chilled water circuit, but you’ve got some flexibility when it comes to where you install it; it all depends on how you’ve designed the hydraulic system and what you’re trying to get out of the tank. In many systems, the best spot for it is in the common return pipe, before the chiller. By doing it this way, warmer return water from the building can get dumped into the tank and then cycle through the chiller evaporator.

Putting the buffer tank on the return side of the system does a couple of useful things – it increases the overall volume of water in the system and makes for a more stable return-water temperature to the chiller. This in turn cuts down on the chiller compressor going on and off all the time, which gives better temperature control and helps protect the chiller when the building load is low.

But a buffer tank can also be installed in the chilled water flow pipe after the chiller, if that’s something you need to do. This might be used where keeping the flow temperature stable for some particularly sensitive equipment or process is super important. The downside is that the tank needs to be fully insulated and vapour-sealed, because it’s storing cold water all the time.

Our full range of chilled water buffer tanks / vessels (they are the same thing) are detailed here – Chilled water buffer vessels from Flexiheat UK

In the case of systems with primary and secondary pumps, you might want to put a four-port buffer tank between the chiller circuit and the distribution circuit. With this setup, the tank can not only provide a place for the chiller and system pumps to go at different flow rates, but it can also give you hydraulic separation.

When you’re choosing where to put the tank, you’ve got to make sure it’s getting good circulation and won’t get left high and dry when some control valves shut off. You should also be able to get in there for maintenance, draining, and the like.

Ultimately, where you decide to put it depends on the system designer, who will consider all the factors, including pump setup, minimum chiller water volume, flow rates, control strategy, and what the chiller manufacturer recommends.