Operating 500 hours a year at 90F (the peak of the allowable range) is unlikely to impact longevity. 100F is outside of the allowable range. Your opinion is contradicted by what IBM, Intel, Dell, Sun, and numerous datacenter owners along with the design professionals at ASHRAE have developed over the course of several years of research and many (mostly dull) hours of debate.
There are special cases, tape machines are glaring examples, but operating a datacenter at 80-90F does not have any correlation beyond old wive's tails with increased equipment failure. Indeed, such a 10F difference in actual component temperature (which is what matters) can occur merely between different manufacturer's case layout or the use of meshed back security rack.
I blame that bastard Carnot personally for this... They could get additional work out of that hot water, but it gets prohibitively expensive the lower your delta T between hot and cold gets. I was all stoked about finding some sort of stirling heat engine to run off some datacenter waste heat, until I worked the numbers and found the annual average maximum therorectical efficiency was under 15%.
Already happening in a way. Check out EDS's Wynyard facility. They didn't eliminate the chillers entirely last I looked, but in that climate they could have if they trusted the outdoor conditions and local code officials (open cooling towers are subject to abrupt shutdown if there is a Legionella scare anywhere near by in Europe).
Although the lure of unutilized MW is a bigger pull. It's always nice to site a datacenter where the local utility overbuilt and isn't going to ream you when you ask for a MW or twenty.
? 100% of the electrical power delivered to the computer is dissipated as heat. It's the law. It will be far less than the nameplate power (that electrical uses), and perhaps 80% of what is delivered to the building (after transformer, UPS, and PDUs), but it all ends up as heat (unless you're splitting hairs about the acoustical energy emissions and velocity pressure in the exhaust, which is small and quickly converted to heat).
The 81F water can be produced directly from open cooling towers (direct evaporation) whenever the wetbulb is lower than 76F (4 degree approach plus a 1F on your flat plate that isolates the datacenter loop from the open tower loop).
You designed an efficient datacenter, but you're five years behind cutting edge (not actually a bad thing for most critical environment clients). The next wave of datacenters will have PUEs of 1.2 or less and redefine the space from a noisy but cool space to hang out to a hot machine room with industrial heat exhaust design.
I actually just finished a chiller less 8MW schematic design and analysis for a bid. It was my second this month (the first was a cake walk - an extreme Twb of 67F, the second was west coast light conditions).
PS: Secondary pumps? Seriously? Unless you have to boost up to 25 psi to feed a Cray or some other HPC I thought everyone who cared had moved onto variable primary-only pumping. (Sorry, feeling a bit snarky after hitting a 40 hour week on Weds...)
Perhaps it would be better to engineer the hardware to run warm-hot. Having to chill the water down to outside ambient temp (no compressors needed) would save a lot of energy and cost.
YES! This is exactly the approach being used currently in the most efficient (short of insane, no-cooling in a tent one-offs) datacenters today. Design the system to provide adequate space control at the typical outside ambient. Direct water cooling isn't even required, it can be done with large coils and evaporation cooling towers to take advantage of the wetbulb depression. As for energy savings, well on a typical 15 MW datacenter you can save about 6 MW for 8000 hours a year... That adds up fast.
Personally, I find it prudent to not smoke, listen to my doctor, and not test the conclusion that licking a frozen flag pole is a bad idea. Accepting that any conclusion could be false - a fundamental aspect of the scientific method - is radically different than asserting that any that you don't like could be false and can therefore be ignored.
What? Every case of causation I've ever heard of also showed correlation. Correlation does not PROVE causation, but it is a big flashing sign with a buxom topless girl waving pom poms jumping around it pointing in the right direction.
Note that at this point, the link between smoking and lung cancer still doesn't have a definitively proven causation.
What I see is the scientific establishment diligently working to identify flaws in the existing theory of climate change and freely publishing any flaws found. The FACT is that the scientific community is vigorously collecting data to challenge and correct where necessary climate change theory, and has been for over two decades now. Note this is the same scientific community that has endorsed the current climate change theories and it's predictions - which include pretty fat error bars you know.
I understand that to be science and is why I respect the consensus of National Academies of Science (or equivalent bodies) across the first world in this matter (and not Mr Gore or Exxon or the headline of the week).