New online tool demystifies milk vat insulation

A simple online tool allowing dairy farmers to calculate how insulating their milk vat can help save on energy costs, has been launched by the Energy Efficiency and Conservation Authority (EECA).

The tool will also help farmers to understand how much faster their milk can be chilled in an insulated vat. This is important as new milk chilling regulations being phased in from August will require faster milk chilling.

EECA Project manager, Kirk Archibald, says around 80% of milk vats on New Zealand dairy farms are uninsulated, wasting up to $7 million of electricity and emitting around 4,000 tonnes of CO₂ more per year than they could be. This is equivalent to the energy consumption of around 3,000 households and the CO₂ emissions of 1800 cars.

“New Zealand dairy farms use around 180 gigawatt-hours of electricity per year to store milk at a safe temperature – that’s the same electricity use of about 25,000 households,” Mr Archibald says. “Insulating a milk vat protects it from heat gain, reducing the load on a farm’s refrigeration system and the amount of time needed to cool milk. Farmers can save up to 6% of their dairy shed energy consumption and around 40% of the energy used for refrigeration, and in summer months vat insulation can speed milk chilling by up to 20%.”

The new tool comes at an opportune time for dairy farmers with new regulations requiring milk to be chilled and to a lower temperature. Mr Archibald says the regulations will require around 30% more refrigeration capacity. While most farms will have this capacity spare, around 40% will have to make some changes to their refrigeration system to comply.

“Many farms will only need system tweaks or maintenance to meet the new regulations, but some will need to invest in refrigeration capacity or pre-chilling. For minimal cost, vat insulation can effectively increase refrigeration capacity by up to 20%. Our tool will help farmers determine how insulation can support compliance with the regulations without costly upgrades,” Mr Archibald says.

In New Zealand two companies manufacture and sell milk vat insulation wraps, Auckland based Tru-Test Ltd, and Dairycool Ltd in Canterbury. A milk vat wrap will cost farmers between $1,850 and $3,750, depending on vat size, so could be a cheaper way to increase refrigeration capacity than upgrading a farm’s refrigeration system.

“Insulation increases capacity while at the same time reducing energy use, over time paying for itself. Payback time depends on many factors, but most importantly whether installing insulation can avoid the need to upgrade systems. However, the payback on energy savings alone is generally between 3 - 7 years in Northland and 4 – 8 years for the rest of New Zealand, excluding Westland and Southland,” Mr Archibald says.

He says vat insulation also adds capacity to a farm’s refrigeration system without impacting peak demand, an important consideration on farms with power line capacity restraints.

Manawatu dairy farmers, Allison and Trevor Martyn, experienced the benefits of vat insulation on their Rongotea farm and became keen advocates. They were first-time farmers back in 1998, and during their first summers noticed their chiller unit cutting in and found their shed power bills excessive. When they wrapped their vat the benefits were immediate.

“I think we probably reduced our power bill by about a third,” Allison Martyn says. “We noticed once you get the milk down to temperature the wrap seems to keep it there and you hardly hear the chiller cutting in and out between milkings. For the cost of the wrap it’s been worth its weight in gold.”

She says another benefit of insulation is they no longer have trouble with the heat resistant bacteria thermodurics.

EECA’s new milk vat insulation tool is being showcased at a series of DairyNZ’s MilkSmart events being held around the country from the end of February 2016. Farmers can register to attend these events on the Dairy NZ website.

Dairy NZ website

The tool itself is available on the EECA BUSINESS website.

Milk vat insulation savings calculator - EECA BUSINESS website


Media enquiries:

Niels Reinsborg, Communications Advisor, EECA

Phone: 04 495 8254 or 027 487 7970