Natural Refrigerants: Pathways For Decarbonising Kiwifruit Cool Storage

The New Zealand Kiwifruit Post-Harvest Industry (KPHI) relies heavily on industrial refrigeration to maintain fruit quality and support global export growth. However, a comprehensive industry survey revealed that around 95% of refrigeration systems continue to use high Global Warming Potential (GWP) synthetic refrigerants, representing a substantial emissions liability of over 176,000 tCO2e.

Recognising that no single organisation could economically justify the scale of research required to address this issue, competing post-harvest operators Trevelyan’s, Apata, and DMS (under the G4 Kiwi Supply banner), together with Seeker and Humes, met in 2024 with a shared vision. Their goal was to facilitate an industry-wide solution to identify practical, commercial pathways for decarbonising New Zealand's kiwifruit cool chain.

The project was funded through the Ministry for Primary Industries’ (MPI) Primary Sector Growth Fund (PSGF).



DETA was commissioned as technical consultants, focusing on refrigerant emissions through three specific actions: switching to natural refrigerants, substituting older refrigerants in existing systems, and securing systems against leaks.

Report 1: Switching To Natural Refrigerants

The first report completed a comprehensive technical review of natural refrigerant options available for new coolstore developments and full system replacements.

Key Findings From Report 1

• Commercially Viable Alternatives: Proven natural refrigerant options are now available across all major kiwifruit post-harvest cooling duties.

• Lower Lifetime Cooling Costs: Carbon dioxide (CO2) and ammonia-based systems significantly reduce refrigerant-related emissions while delivering competitive lifetime operating costs.

• Staged Transitions For Existing Sites: For operating facilities, a phased transition is the most practical path—converting to secondary glycol reticulation while retaining existing plant assets until end-of-life.

• New Build Standards: Natural refrigerant systems are expected to become standard for all new coolstore developments, with CO2 direct expansion (DX) and ammonia-glycol systems delivering the lowest levelised cost of cooling.

• Focus On Energy Efficiency: Operating energy expenses represent a massive proportion of total lifetime refrigeration costs, making system efficiency critical during option reviews.
  

Download Report 1: Natural Refrigerants Technical Research

Access the complete 33-page research paper to explore natural refrigerant pathways, levelised cost models, and practical decarbonisation roadmaps for New Zealand kiwifruit cool storage.

Report 2: Substituting Older Refrigerants In Existing Systems

As older high-GWP refrigerants are phased out, the kiwifruit industry faces the challenge of managing ageing refrigeration assets that still have significant useful operating life remaining.

This second report summarises the findings of 28 pilot projects exploring whether lower-GWP "drop-in" refrigerant solutions can provide a practical alternative to premature plant replacement. The project generated valuable insights into retrofit costs, system performance, refrigerant recovery management, and practicalities across various coolstore configurations.

The pilot projects recovered 6,723 kg of R404A refrigerant and reduced potential site emissions by approximately 17,500 tCO2e—equivalent to taking 3,500 to 4,000 passenger vehicles off the road for a year.

Key Findings From Report 2

• Immediate Emissions Reductions: Replacing high-GWP refrigerants (such as R404A with lower-GWP R449A) delivers substantial, immediate emissions savings.

• Refrigerant Recovery Support: Specialist recovery and destruction service providers (such as Cool-Safe, RefSpecs, and A-Gas) offer financial buy-back support that helps simplify and de-risk transition projects.

• Energy Performance Neutral: Testing across 14 systems confirmed that replacing R404A with R449A had no consistent negative impact on refrigeration system energy consumption.

• Expansion Valve Selection: Mechanical expansion valves (TXVs) remain cost-effective for simple, steady-state coolstores, while electronic expansion valves (EEVs) provide operational flexibility for variable pre-cooling duties.

• Transitional Strategy: Lower-GWP drop-in synthetic refrigerants contain HFOs and should be viewed as transitional solutions to extend asset life rather than permanent replacements for natural refrigerants.

Download Report 2: Drop-In Replacement Pilot Study

Access the full Workstream 2 report covering retrofit costs, mechanical vs electronic expansion valve economics, and performance data across 28 coolstore pilot projects.

Report 3: Securing Systems Against Leaks

The third and final research report focusing on refrigerant leak mitigation, minimisation technologies, and detection protocols is currently underway.

• Expected Release: November 2026



Watch The Programme Webinars

Gain deeper technical insights directly from the project team and industry partners.

Webinar 1: Natural Refrigerants & Drop-In Replacements

Watch the recorded industry presentation covering the research findings from Report 1 and Report 2.

Discuss Your Site’s Refrigeration Strategy