A new set of guidelines for the New Zealand coldstore industry were unveiled last week by Building and Housing Minister Maurice Williamson in Wellington, New Zealand. The 67-page “Coldstore Engineering in New Zealand” document was released by the Institution of Professional Engineers New Zealand (IPENZ) Coldstore Working Party, a partnership of IPENZ Technical Interest Groups, design engineering companies, coldstore operators, and government regulators working in the field of coldstores in New Zealand. The group’s aim was to write design guidelines in the form of a practice note, with a scope wide enough to cover economics, insurance, structure, insulation, refrigeration, electrical, operations and maintenance of a coldstore.

Hydrocarbons use expected to grow

According to the document, “it is likely, if carbon trading or greenhouse taxes are applied, for the synthetic refrigerants (R134A and R404A) to become too expensive for larger direct systems and for them to be utilised together with secondary refrigerants to minimise system charges and likelihood of leaks”.

“With the development of newer equipment and the necessary associated skills, hydrocarbons and carbon dioxide will be used on small systems and anhydrous ammonia on larger systems”. However, “volume production of the newer types of equipment will be required before these systems become cost effective,” the document concludes.

IPENZ: widespread use of propane as a primary refrigerant likely

The document states that “secondary refrigeration fluids can allow more accurate temperature control, avoiding the complications of phase change with primary refrigerants”. “IPENZ expects the widespread use of propane as the primary refrigerant in secondary refrigeration systems to occur in the future. Secondary refrigerants are typically water with a freezing point depressant additive (for example, monoethylene glycol) but others such as boiling carbon dioxide are increasing in application”.

Recommended standards

IPENZ recommends that almost all refrigeration systems comply with standard AS/NZS 1677 Refrigerating systems (SNZ, 1998), as this is adequate for all except low temperature cascade systems. This is also recommended in the case of systems using R290, as “adherence ensures that in the event of a leak, explosive concentrations are unlikely to form, and if they do form are unable to ignite.”

R290 in addition requires “compliance with a wider range of statutory regulations, notably with the PECPR Regulations (DoL, 1999), the HSNOA, and the Electricity Regulations (MED, 1997). If a location holds more than 100 kg it will also be subject to the HSNO test certification requirements (ERMA, 2004)”.

About IPENZ

The Institution of Professional Engineers New Zealand (IPENZ) is the professional body which represents professional engineers from all disciplines in New Zealand.