My experience with lithium-bromide machines is that it's very easy to simply run the little factory mounted vacuum pump more and more to deal with air inleakage, rather than fix the leaks. You can even install a LARGER vacuum pump, to maintain the vacuum. However, the internal corrosion rate just goes nuts, and the lifespan of the chiller plummets.
The estimated service life for absorption chillers based on ASHRAE 1995 is 23 years, however with proper maintenance and skilled operators this can be extended to 30+ years
You guys seem to be fortunate. The two 180TR steam fired Li-Br systems I ran, lasted for 6 years before going for a change of pressure parts and tubes. We used to have yearly cleaning schedule of filtering Li-Br and cleaning the entire circuit. We also had AMC with the manufacturer. The capacity before total revamping was around 120TR.
The life of an absorption depends on how well you maintain it.I have heard of machines working for 20 yrs working with no problems.I would recommend them for steady load conditions for eg in an industrial environment.Key to long life is proper maintenance of vacuum in the machine.If air leaks in, the corrosive LiBr wil eat it away in no time.
Both of our units were lithium bromide. The steam fired unit was 118 ton and I had no experience with it at all. The other units were direct fired units that could produce hot and chilled water in the summer, and hot in the winter. I had good luck with the direct fired ones, but I knew them and watched them closely. They were 8 years old when I retired. There was one incident of chrystalization during spring change over. One of the units went into excess purge (3 per day), and it did need to have the lithium bromide filtered.
I will say that if you don't have someone that is willing to learn the machines you will have trouble with them. Most vendors do have maintenance programs where they will perform periodic checks, start up, safety checks, and all required maintenance. But even with that you still need someone that knows the machines, or they will fail you.
I really think that the life expectancy depends a lot of things. Maintenance and operations training being the two biggest.
I work in an industry where chilled water systems are a support for the main product and are treated poorly. I have seen chillers crystallized frequently because operations cannot (or don't want to) follow a simple start up procedure. The main product equipment is significantly more complex than a chilled water system, but they just can't figure out how to run it.
I have also trained maintenance people how to operate the vacuum pumps and worked with their planners to put it on their schedules, only to show up on-site three months later and seeing the last purge date being when I trained them.
In the paper industry, with this type of care, I've seen an LiBr chiller last 10 years. I've also seen them at different mills last 25 years with a generator section rebuild.
If you have a lot of waste heat, they are great for chilled water at a cheaper energy rate. The maintenace rate for a chiller is expensive, but beats systems that have a number of smaller air cooled systems.
