© Sonja Mettenleiter: Installation of the solar panels for the PCM freezer.
Following a month of technology testing, the Lari farmers will be using PCM cold storage (charged in a solar-powered freezer) and insulated boxes to move temperature sensitive horticulture produce to market. They will be able to test the performance against their traditional vehicle with Carrier TRU as part of the Try Before You Buy (TBYB) programme.
The TBYB is the second phase of the SPOKE community engagement programme developed by the Clean Cooling Network (CCN) and Africa Centre of Excellence for Sustainable Cooling and Cold-Chain (ACES). In Phase 1 during 2024, the ACTS SPOKE team had provided the support, mentoring and training to support the community leaders and the wider community to establish a grassroot, community cold-chain ecosystem. The support was guided by an in-depth needs assessment to evaluate present and future cooling requirements of the community that would inform a business case for investment in cold-chain. In Phase 2, through the Try Before You Buy concept, a package of basic cold-chain equipment (static and transport) has been installed for the coming harvest, during which the community can test out their business model in real conditions with ongoing support and mentoring during this period.
To date, 163 smallholders have already registered to join the cooperative and more are joining as they can see the tangible benefit. The farmers are already reaping the benefits of the cold-chain: on average they fetch over 50% better prices for their produce than previously.
As part of the TBYB programme, a 500L solar-powered phase change material (PCM) freezer was installed at the beginning of July, 2025. The PCM freezer system is run off three 535W solar panels (49.8V). The installation was completed without incident, with all components passing functionality and safety checks. Routine maintenance guidance includes weekly cleaning of solar panels and regular defrosting of the PCM freezer to maintain peak performance. User training emphasised practices such as minimising door openings and avoiding overloading the unit.
Month-long testing included evaluation of the PCM freezer’s ability to reach and maintain target sub-zero temperatures and night-time operation using battery storage as well as confirmation of the proper function of all system components. Wireless Bluetooth temperature and humidity sensors were installed to remotely monitor internal conditions.
Key Findings
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PCM Freezer Components: The core refrigeration components (compressor, thermostat) are functioning optimally.
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Power System: The battery and charge controller performed well; however, the initial inverter had defects which were rectified through replacement.
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Night-time Operation: The PCM freezer sometimes struggled to maintain low temperatures overnight during cloudy periods, highlighting a potential need for expanded battery capacity or hybrid power backup.
With the testing completed, the farmers will start to use and test the equipment for onward moving of their produce to market. The installation and commissioning of the solar PCM freezer at ACTS marks a significant step toward sustainable, decentralised cold-chain, helping to deploy non-diesel transport solutions. While initial testing revealed challenges under variable weather, system refinements have improved reliability. As the PCM freezer enters its next phase of performance trials, it holds promise for enhancing cold chain solutions across rural and peri-urban Kenya.