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SPF Unit

(Solar Powered Fridge)

SPFs are refrigerated shipping containers that operate reliably off-grid to provide rapidly deployable solutions for a wide-range of cold-storage applications.

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State-of-the-Art

Refrigeration Systems

SPFs employ a split refrigeration system using vapor compression cycles with an external condenser for heat rejection from the cold storage space to the ambient.

The refrigeration cycle condensing units utilize highly efficient, quiet compressors that are sized to run cyclically even on hottest summer days to maintain cold-space temperatures between user-specified limits.

Our units implement refrigerants that meet new and forthcoming standards on global warming potential. This will enable our customers to sustain operation as the refrigeration industry moves this transition period to the new family of refrigerants that provide lower effective carbon footprints.

To facilitate reliable off-grid, operation, we focus on solar panels that have high efficiency (above 20%) and utilize PV panel architectures that provide good low-light performance.

These panels are deployed in multiple panel strings on the roof and canopy off both sides of the refrigerated container to provide adequate solar power for the refrigeration and for recharging the batteries even on days with less than perfect solar insolation.

With manually adjustable angles for the canopied panels, our systems can be quickly adjusted between two or three settings to increase solar power production throughout the yearly cycle.

The SPF is designed such assembly can be completed before deployment. This enables short times within one day from arrival onsite to full system operation.

Units are shipped such that the solar panels are ready for rotation to preferred seasonable positions and up and running for electric power generation. The design also has a robust structure and deployed units in California have remained in operation through the Tropical Storm Hilary in late summer 2023.

The design of units are well suited for emergency management cold-storage needs where rapid deployment, off-grid operation, and structural robustness provide key elements for reliable operation.

A critical component of reliable off-grid operation are the power electronics that includes:

1 – The solar-charge controller that converts the high voltage of the PV panel strings to the appropriate battery voltage and

2 – The power inverter that converts the battery voltage to AC electrical power for supporting the large AC loads associated with the refrigeration system. The battery pack communicates with the solar charge controller to provide a reliable nominal 48 VDC power source that drives an AC inverter for powering the refrigeration loads.

The SPFs utilize all-in-one power electronics package from a leading supplier in the solar, off-grid power electronics space. The solar charge controller supports high voltage panel strings for reducing costs and provides reliable utilization of excess solar power when the batteries are fully charged. The power electronics package works well for freezer containers as large as 40 ft. Remote monitoring of the power electronics enables users to assess system performance remotely and rapidly.

We ensure that all of the major components are outfitted with appropriate controls to provide information remotely through a cellular modem to support.

Our partner Wattch.io provides computational cloud services to host the data for users and provides some basic remote controls. Key performance metrics such as battery state-of-charge, PV power output, and AC power draws are tracked and monitored remotely, to inform controls for the refrigeration loads and battery charging parameters. SPFs can be managed remotely in order to ensure reliable off-grid operation.

Other instrumentation including a cold-space gas sensor provides information for informing ventilation systems and monitoring food quality for applications involving the storage of fresh, local produce.

Through internal research and support from the USDA, Radiant is completing the role out of our unique model-predictive control software (patent pending) that will allow users to purchase a cloud-based computer control to ensure reliable off-grid operation of the unit even through periods of limited solar insolation over several days.

The cloud-based control software relies on the thermal energy models of the SPF units and dynamic weather forecasting to manipulate power loads to maintain adequate battery state-of-charge through forecasted weather events.

This software can be offered as a service for users to implement to combine remote monitoring with the model-predictive controls for off-grid reliability.

Effective unit design for

Rapid Deployment.

Get to know our solar-powered

Refrigerators/Freezers

Freezers & Refrigerators

Available as refrigerator or freezer

(20ft, 30ft and 40ft lengths).

SPF

low-temperature for freezer applications (down to -20 °C)

SPR

More moderate temperatures (above 0 °C) for refrigerator

Frequently Asked

Questions

Delivery typically takes between 6 to 8 weeks from the order date. This can vary depending on the specific requirements and location of the installation. Our team works diligently to ensure your solar-powered cold storage is up and running as swiftly as possible.

Absolutely, we offer comprehensive support after purchase. This includes remote monitoring of the unit, customer service assistance for any queries, and a dedicated team for maintenance and technical support to ensure your system operates efficiently.

Yes, we do offer financing options to make the acquisition of our solar-powered refrigeration systems more accessible. We understand that upfront costs can be challenging, so we provide various financing plans to suit your budget and cash flow.

Our systems are designed to be as maintenance-free as possible, but we do provide software updates when necessary to enhance functionality and performance. These updates are made available remotely, ensuring your system is always running on the latest technology without any inconvenience.