Why you need to monitor your energy use

Recording how much energy your equipment uses and when it uses it, helps you spot issues and take steps to improve energy efficiency, often at relatively low or no cost.

Back to: Energy efficient use of equipment on dairy farms

If you care for equipment that uses or consumes energy and keep it in optimum operating condition, it will reward you by running as efficiently as it can. While new equipment is very nice to have, it's also important to understand what you can do to improve efficiency of existing equipment, often with little effort and cost.

Many basic energy saving measures are fairly low tech and will pay for themselves fairly quickly. Regular maintenance and cleaning typically requires only time, care and attention.

Monitoring plays an important role as, without doing this on a regular basis, you may not realise the gradual reduction in equipment efficiency, and therefore may miss the opportunity to do something about it.

Monitoring individual items of equipment, either separately or together, may require access to specialist electrical equipment for reasons of accuracy or safety. However, installing simple kWh meters on your main equipment is low cost and you should get an electrician to do the install unless suitably qualified yourself, budget around £100 per meter. Occasionally, simple portable energy monitors including for plugin equipment can be used and will help to identify areas of importance.

Data from dairy farm energy surveys show the proportion of total energy used by process to be typically in the following proportions and you can use this to highlight areas of importance:

Milk cooling: 38%
Water heating: 30%
Vacuum pump: 20%
Washing: 6%
Lighting and other: 6%

How to spot potential problems

Once data is obtained it is usual to graph the results to show where and when changes in consumptions happen. These graphs, termed energy profiles, become the starting point for identifying problems and the benchmark by which you can see whether you have reduced demand or minimised time of operation and hence saved energy.

If you meter and record major energy uses separately, you can use the information to spot problems. You can see some examples in Table 1.

What you notice	What might be wrong
Refrigeration usage per litre of milk goes up a lot in summer.	You would expect some increase in consumption because outside temperatures are warmer however if the compressors are observed to be running longer by an hour or two, especially during the daytime hours, then it could be that the refrigeration condenser coil is not able to get rid of heat quickly enough. You should consider: · Cleaning the coils · Checking refrigerant levels · Shading the coils or moving them to a cooler location, such as a north facing aspect,if they are in direct sunlight · If fitted within a building, install a cowl to ensure that cooler air is drawn in from outside rather than recirculating hot air from within the building.
Water heater use moves incrementally day by day	Here you need to check that the time switch on the water heater is remaining synchronous with actual time, especially around daylight saving periods. Also check you are achieving the required water temperatures by the time you need to use the water. It’s also worth checking for build up of limescale around the elements as that will reduce their effectiveness
Overall consumption appears greater than industry averages	There can be many reasons for this for example: · Other consumptions being included · Faulty equipment · Older, less efficient equipment · Prolonged milking times

Table 1: How to use data to spot potential efficiency measures.

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Dairy