Milk Chilling Products
Milk cools to approximately 30-33°C as it passes through the milking system and should be cooled to below 18°C before entering the vat. To achieve these temperatures, a pre-cooler is an essential piece of equipment.
Benefits of removing heat via a pre-cooler include:
- It is more energy efficient and cost effective than using electricity via refrigeration to remove the heat.
- It speeds up the cooling process, meeting required standards and improving milk quality.
- It means that the size of the refrigeration unit required on the farm can be smaller, reducing capital cost.
- The outlet warm water can be directed to the hot water cylinders, thus reducing hot water heating energy and costs.
The most common type of cooler is the plate cooler. The plate cooler consists of thin stainless plates separated by rubber gaskets, which are held together by a frame. Milk and water flow through alternate channels, and as long as the water is colder than the milk, heat is extracted. The amount of milk that can be cooled in a given time is based on the total surface area between the milk and the water. The optimum temperature difference is 2°C between milk outlet temperature and water inlet temperature. The recommended ratio of water flow to milk flow is between 2 to 3:1.
Plate coolers need to be properly cleaned and maintained to provide efficient cooling and to prevent milk becoming contaminated.
In some areas the farm water supply may have higher temperatures - particularly in the summer – so other options may need to be considered, such as ice banks and chilled water storage.
To reduce refrigeration costs even further, consider insulating your milk vat.
Chilled milk standing in the vat will heat up according to the surroundings. The amount of heat gained will be dependent on ambient temperatures, sunshine hours and wind velocity. For this reason milk vats that are inside the shed are best. Outside milk vats are okay as long as they are sheltered from the prevailing wind and are mostly in the shade during the day. Either way, consider vat insulation as a way to reduce your long-term refrigeration operating costs.
Financial paybacks vary by farm size - see the case studies for examples.
To determine your farm's payback for a milk vat insulation wrap just complete the milk chilling section of our Dairy Efficiency Calculator.
Insulation Wrap products
DTS brand Polar Wrap™ PVC, perform extremely well in outdoor conditions and is made from super-tough, durable reinforced material that is also used for truck curtain sides and exterior petrol station canopies.
A more cost-effective option is the DTS Thermo Wrap™, which comes with an installation kit so you can fit it yourself.
Insulation wraps prices range from $1,400 to $3,000 depending on the size of the vat and quality of the wrap.
For more information about both of these products see www.dts.co.nz