Energy Saving

Energy Saving and Energy Conservation

Energy saving can be as simple as turning off lights fans, pumps, heaters and air conditioning units when they are not actually needed. Motors consume power even when idling and if it is inconvenient to switch loads On and OFF manually then it is relatively inexpensive to fit timers or sensors to do this automatically.

Energy saving and Energy Conservation can however encompass much more than the simple principle of turning off loads when they are not actually needed. The first step in any serious energy saving endeavour is to start by measuring present energy consumption (Janitza) and the effects of any improvements that are made. Energy saving is not confined to electrical energy but can be extended to include measurement of water and gas consumption together with utilities such as compressed air and heat recovery systems.

In North America for many years there has been a tendency to use motors which are larger than actually needed for their dedicated tasks, so many motors are running at less than full load. This can lead to poor power factor, lower motor efficiency and higher power consumption. Similarly traditional mechanical gearboxes on amchinery and damper systems on fans consume power and create inefficiencies.

Replacing older inefficient motors with modern correctly sized high efficiency motors and using variable frequency drives (VFD’s) can create significant energy savings.

Many industrial companies rely on compressed air for many of their processes but it is very common to find that compressed air lines and fittings have multiple small leaks which are left unattended for many weeks or months. Compressors continue to run to maintain pressure often when production lines are idle and significant electrical energy is wasted which could be saved by regular maintenance to air lines and the devices connected to them.

Electrical utilities typically charge for peak demand usage based on the maximum usage on any 15 minute period in a month and this demand charge is then applied to the whole month. For many companies the peak demand 15 period occurs at the beginning of the working week because electric motors can take up to seven times their normal running current for a few seconds while starting. It is relatively simple to reduce the peak demand, if it occurs in this way, by staggering the start of large loads by more than 15 minutes apart.

Typical examples are large compressors, fans, pumps and air conditioning units.

Other options for limiting peak demand charges are to use sophisticated metering combined with relays (Emax) to switch off non-essential loads such as water heaters, office air conditioning, pumps, fans, kitchen equipment, etc. for short temporary periods as loads in the 15 minute period approach pre-determined peak levels.

Energy conservation methods have included use of reduced voltage particularly for lighting where a drop in voltage of a few percent is rarely noticeable to the human eye and reported savings have been significant. It is important to note that lowering voltage can cause increased problem to sensitive electronic equipment from the effects of voltage sags (White paper) and although Voltage sag correction equipment is available (AVC2) it is important to take all loads into consideration before starting an energy conservation program based on reduced voltage.

There have been many energy saving initiatives proposed but in every case the only way to measure the effectiveness of any of these is by measuring actual consumption and this need s some form of metering (Janitza) and which should include a system which can capture data from energy sources other than conventional electrical meters (ProData) and a software system which can bring data together into a common database (GridVis)