Heat pump water heaters for dairy applications
This project, undertaken by HWHP Imports (NZ) Ltd was to design and build a prototype heat pump water heater to be used for sterilisation and washing water for dairy sheds.
This project builds on the previous development of a "Split Flow Technology" domestic heat pump water heater. For more details on Split Flow Technology, see this project description.
The system absorbs low grade energy from the milk vat and uses this to heat water while at the same time also improving the efficiency of the refrigeration system.
It is envisaged that it will be possible to build one "plug and play" unit that is suitable for any milk silo system within an average range.
A prototype model was built and installed into a dairy farm in Canterbury where three months of detailed monitoring was undertaken.
The testing highlighted some useful lessons, including:
- The time-of-day for milk collection made a big difference to a suitable system design (early morning collections required more rapid milk cooling)
- Training the system user was very important - in some cases the user manually refilled hot water cylinders out of convenience or habit.
Although the testing site was not ideal, it was estimated that energy savings of 52% could be made cost effectively.
As a result of the experiences gained in the project, four further products were introduced to the range to suit the large variation in farm installation types.
More details on the product developed can be seen at www.enersol.co.nz.