Is it a storage tank or a compression tank??

[mpeck1982]

In industry I always hear the terms compression and expansion tank.... Is there a difference? Are they the same thing? We have expansion and compression tanks all over our site. These tanks handle our CHW and HW loads for the site/buildings. HW temps are 180 and CHW temps are 42.... We use compressed air in the tanks to regulate CHW and HW pressure. Ive noticed some people say expansion tank for CHW and compression tank for HW..... Any input?

 

[chicopee]

These tanks have bladders or diaphragms filled with pressurized air to regulate pressure; there are expansion tanks.

 

[LittleInch]

They are basically the same thing in that they regulate pressure in your system. Because the hot water will normally expand from ambient then it will compress the air in the tank, where's as the chilled water will contract from ambient and hence the air will need to expand to maintain a pressure. One needs to start empty and fills and the other needs to start full and then empty.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[chicopee]

I think that the problem here is more about semantics. Unfortunately, I have never heard of the term compression tank spoken by anyone for the purpose listed in the OP.