A factory attempting to reduce energy costs would turn down the heat in the winter. So why was the fuel bill actually higher? Mysteries of Science
Transcript
A company appointed an engineer to act as the energy czar managing a cluster of factories. The first order of business was to add humidity sensors, track everything by computer, and save energy by adjusting the temperature and humidity in the R&D building and the machine shop.
The idea was to turn down the heat in the winter by bringing up the humidity. The R&D department saw savings, though modest, using this concept. However the fuel bill for the machine shop was actually higher.
There was no off hour usage that could account for this. The machine shop boiler was simply running longer during the day. What was causing the energy bill in the machine to increase despite all attempts to lower it?
Here's the rest of the story.
A close look at temperature fluctuations during the day revealed a clue. The temperature was 3 or 4 degrees above the set point, but then it started dropping, and then climbed again.
This happened twice a day. What event corresponded to the temperature changes? It appeared that someone must have been adjusting the thermostat controller. But the controller was in a locked cover box?
The relative humidity always increased before the heat went up, but only the thermostat sensor showed the change, not the remote units. The computer would lower the heat if humidity went up, so humidity must be a clue not the cause.
How could high humidity fool the thermostat into "thinking" that it was getting colder? Evaporation cools air as water vapor absorbs energy. Someone in the R&D room was placing a damp rag over the thermostat box and the cooling effect made the boiler run longer.
