Energy-saving interventions: a spectrum

WHEN thinkingĀ about possible energy-saving projects, you might ask yourself how radical you want them to be. There’s a spectrum from the relatively easy to the costly and disruptive. Readers may have their own views on this but I think the spectrum runs like this:

  1. Make sure control setpoints and timings are correct. This is generally the cheapest and least disruptive measure one can take;
  2. Enhance the control strategies. For example introduce floating setpoints on chilled water circuits, optimum start in place of fixed timers, or variable-speed control of motor-driven equipment;
  3. Implement loss-reducing modifications. Examples here include zone isolation valves in a compressed-air network or thermal insulation on hot pipework;
  4. Improve component efficiency. The classic case here is lighting technology (which may be cost-effective in its own right) but think also about things such as the introduction of higher-efficiency or better-sized motors (which may only be economical when replacement is necessary for other reasons);
  5. Improve process layouts and integration. Here I am thinking primarily about opportunities for waste heat recovery, but there are other special cases where part-processed materials may gain or lose moisture or heat while in transit between stages to the detriment of overall energy efficiency. And finally the nuclear option:
  6. Retire buildings or process plant in favour of more energy efficient replacements