This looks like a heat exchanger of a water-tube or bent tube boiler. Tube Boilers are "called" by what is inside the tubes.
Being that this is a large power-plant it could also be a Superheater, which raised the heat content of some of the steam exiting the main boiler.
It could also be an economizer which would warm the returning steam from the building before it entered the boiler. All depends on where it is positioned in the flow of water/steam and boiler flame/exhaust.
the big engine is being saved !! by the American Farm Heritage Museum at Greenville Illinois . Contact Andy Craig if you would like to help in our efforts . Craigexc1@sbcglobal.net
I can tell you the place is accelerating in decay. What was some what stable in 2014 is now quite risky. As of July 2015 I notice some clean up with bobcats to entrance to power building.
It a compressor that is part of the ammonia refrigeration system. It's driven by an open frame electric motor on the end (the thing Mr. Motts called an exciters).
The square holes in the flywheels are indeed for barring the engine which suggests that it has directly opposed cranks..i e...at 180 degrees apart. This gives smooth strokes when running but if the engine happens to stop on top and bottom centres it cannot re start and has to be manually turned slightly,perhaps no more than 10 or 15 degrees. In the picture marked 'Beast' can be seen the valve gear linkage bearing block close to the right of the flywheel rim. On the inside of this will be a stirrup which provides a leverage fulcrum for the barring levers to rest on. A good engine man could usually bring it to a halt without standing it 'on its ends' as they termed it. This beautiful engine should be preserved in a working museum instead of waiting for the inevitable wreaking crew to turn it into scrap. We've lost too many of them of late.
It is a common misconception that large steam engines and the rooms they occupy were unbelievably noisy places where ea plugs were needed. In truth, the big reciprocating engines were/are gentle giants as far as noise is concerned. I live close to the biggest running mill engine in the UK which during summer is run up five days a week for visitors to see. Other than the clack of pawls engaging lubricator ratchet wheels and the wheeze from a slight escape of steam through packing glands it is very quiet. The only indication of its power comes in the form of a slight tremour under your feet. Steam turbines are the noisy ones and you definately need earprotection near them.
When I was a wee sprout my Grandfather supervised a powerplant like this for Armour packing in st. Paul, MN., albeit on a much smaller scale.
His plant had turbine engines as opposed to piston operation, but was still powered by steam pressure. Being an old German immigrant (1908), you could serve dinner on the floor. The place was spotless. Once when I was there with my mom, one of the turbines was partially disasembled for maintenance. Even today (6 decades later) I still think that machine was on of the most facinating things I have ever seen.
Giant machines are always awesome! Thanks! A very famous and excellent book, The Jungle, by Upton Sinclair, 1906, is one I cannot recommend more. Sinclair worked in the meat packing plants in the Chicago Union Stockyards to collect information. He outlines the grueling working conditions and the actions of the robber barons like Armour. Find the unabridged version if possible. It's unforgettable.
Being that this is a large power-plant it could also be a Superheater, which raised the heat content of some of the steam exiting the main boiler.
It could also be an economizer which would warm the returning steam from the building before it entered the boiler. All depends on where it is positioned in the flow of water/steam and boiler flame/exhaust.