I just looked at a building my company owns in a warm humid climate. The building is 27 years old, uses water source heat pumps installed in the ceilings, that are fed from closed loops cooled by a rooftop cooling tower. The cooling tower is original, 27 years old. For a number of years (prior to my company buying it) it was not maintained much, but the past several years it has been getting more thoroughly cleaned and seems to be working better.
The building is about 100,000 sf, four stories. I am pretty sure the cooling tower is galvinized. It is getting chemical treatment. There is also a gas boiler in the basement that adds heat to the water loop a few months in winter, but not needed much.
When I talked to the current service provider, he said it was past its life expectency. However, he then said he could keep it going for another 20 years if needed.
It does not show a lot of corrosion that I could see, has a little hard water deposits on the fill material, but does not look too bad to my untrained eye.
What am I losing by keeping the old cooling tower? Will it really last another 20 years with pan coatings and good maintenance? What would I gain by replacing it with a new one?
I assume the gas boiler, also original, I should just keep running until it dies, since it is not needed much. In the mild climate, the heat pumps would probably work enough to keep the building usable even without it if I had to do an emergency replacement at some point.
Thanks for any advice.