Suffering Contention?

If the number of conference and seminar invitations is any gauge of activity, there is an obvious, and intentional increasing interest in green building and energy efficiency sectors so what is the connection with contention?

Let’s be honest for a moment, if there is one area where the E&M or MEP engineers lack creativity it is engineering definitions. To the outside world engineers are often accused of speaking Klingon dialects, but between ourselves in many cases we still don’t have a simple word or phrase to convey complex engineering phenomena. Unlike the medical profession where they created an entire dictionary of new terms, engineers didn’t try very hard.

I coined the use of the word contention and pressed it into action for E&M engineering services to describe a very common engineering phenomena that is found in many facilities. And it is a lot easier to use than provide the entire word heavy description every time we need to explain it.

Here is a typical situation, imagine a large room with two (or more) air conditioning/heating/humidification devices installed, each fitted with its own automatic control system.  Now, imagine we operate the equipment, it is operated simultaneously and because each has an independently controlled, over time each starts to operate in a different control mode.

For example if one system senses rising room temperature it delivers more cooling, whilst another system senses dropping temperature and delivers more heating.  This double act wastes an enormous amount of energy as the systems figuratively “fight each other” simultaneously delivering either more heating or more cooling to the same space.  This also occurs when individually controlled humidifiers operating in the same space. one system senses dropping relative humidity and starts its humidification operation, whilst another unit sensing increasing humidity and its starts de-humidification cycle, both operating to cancel each other.

For the lack of a better phrase, engineers will often use a phrase like “the controls are fighting each other” hardly an elegant description I think you will agree.

This energy efficiency nightmare often occurs in datacenters, and other large areas such as hospitals and production areas with multiple systems in the same space.  It is common in datacenters and mission critical facilities that use packaged CRAC (Computer Room Air-Conditioning ) units since each has a complete inbuilt automatic control system, and during normal operations each attempts to “control” the space condition – that is contention, use it you might like it.

There are plenty of complex engineering situations that occur in the built environment arena that would benefit from improved terminology that would aid communications and replace a those drearly, wordy descriptions, perhaps we’ll leave those for another day.

John Herbert
Consultant
Kelcroft E&M Limited