It seems that in spite of these two pieces of advice, and numerous studies that highlight efficiency degradation when equipment is not properly maintained, we continue to see elaborate custom cooling solutions when a simple "off the shelf" product will accomplish the same thing...and has a better chance of staying that way.
As an industry we bemoan the lack of qualified service technicians and then we turn around and send them to jobsites populated with unique, one of a kind, complicated HVAC solutions. What are we thinking?
I will admit that there are some cases that are so difficult to solve that something special is truly needed. Critical human medical care might apply. Some very high tech product production might apply. Production of pharmaceuticals might apply. But most server rooms and data centers no longer seem to apply. ASHRAE and the server manufacturers themselves have said that the old ways no longer apply. IT equipment can stand much higher temperatures and humidities than previously thought and much broader swings of those measures than ever before. So why design around complex custom equipment?
As a manufacturer we know, and can pretty accurately predict, how a standard piece of equipment will perform in any given situation. As soon as we are asked to "change it just a little"...which normally actually means throwing out the original design and starting over...then all bets are off. We can use the same standard of components that we would normally use with an expectation of similar performance but, in reality, we no longer know exactly what to expect.
And then there is the issue of compliance with the myriad of agency and code safety tests that all manufacturers must apply to their equipment. Standard equipment is designed, tested, and certified to meet those standards...custom equipment is designed to the standards but is probably not tested and certified to the standards.
And finally we have the issue of maintainability. Service technicians are trained to work on specific types of equipment. Many types of standard equipment require licensed technicians for service. Given the broad range of equipment types in the market today it would be extremely rare to find a service technician who could be proficient on all standard equipment....much less something he or she has never seen before.
The topic of "total cost of ownership" is starting to pop again in some publications. It is reassuring to see that some people are starting to go back to considering something beyond the initial capital expense...but operating expenses consist of more than just energy costs...remember the cost of maintaining the mechanical system in the long run so that the money spent up front for an efficient solution does not go out the window a couple of years down the road.