How to ensure energy efficient water heating on dairy farms

Learn what options are available for keeping down the cost of water heating including insulation, using night rate electricity tariffs, heat recovery and the use of solar panels.

After milk cooling, water heating is usually the second largest consumer of electricity for a dairy farm - accounting for 25% to 35% of the total bill.  Most hot water is used for circulation cleaning of parlour milk lines with water temperatures up to 85°C.  Other hot water needs include tank washing (65^°C), calf feed milk (40°C) and general hand washing (40–50°C) and can account for between 10% and 30% of hot water requirements.

There are a number of simple and cost effective ways of keeping the cost of water heating down. When considering your own dairy farm strategy, it’s useful to prioritise and work through the various options in the following order:

1. Make sure pipes, tanks and lids are well insulated, and lids are well fitted.
2. If you have periods where electricity is cheaper (for example a two rate tariff where night time electricity is less than day rate or solar PV where electricity is at significantly less cost) ensure your timeswitches are correctly set to maximise consumption at these times and that there is enough water storage to enable all water to be heated in the lower rate period.
3. If you hot wash twice per day, consider reducing this to once per day where possible (ensuring that chemical costs are considered and bacterial growth rates are unaffected).
4. Consider installing a heat recovery unit to recover heat from your refrigeration system.
5. Consider solar water heating to reduce your water heating energy use.
6. Take a look at renewable boilers where you have a cheap source of renewable fuel and perhaps a secondary application where hot water is required.
7. Depending on location, regularly descale heater elements or consider water softeners.

The importance of insulation and how to optimise the use of cheap night rate electricity tariffs.

How heat recovery works, the different types of heat recovery units and key installation points to consider.

How to use solar heating panels to help heat water, including types of heat exchanger and key installation points to consider.