Every solar freezer eventually meets the same hour: the sun goes down and the cabinet still has to hold temperature. Most systems answer with a battery. The Direct Drive 5 answers with ice.
Sealed ice packs sit against the inner wall and are frozen during the day by the compressor, which is running directly from the array. At night the compressor stops and the packs release that stored cold back into the cabinet. No battery, no charge controller, no electronics ageing in a hot room - just a phase change doing the work a battery would otherwise do.
It is the simplest architecture in the range, and for a lot of sites it is also the one that survives longest, because there is almost nothing in it that can fail.
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The night is carried by ice, not by a battery bankA battery stores electricity and then converts it back through the compressor, losing part of it on the way in and out. Ice packs store the finished product - cold - and give it back with no conversion step at all. The 110 mm foam wall is what makes that practical. A thin cabinet leaks cold faster than any pack can release it; a 110 mm cabinet with a full set of frozen packs holds deep-freeze temperature through the night without the compressor running. The panel connects straight to the cabinet through the supplied DC cable. There is no controller to program and no battery to replace in year three. |
A day in the life of the cabinet
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Morning to afternoon Panel output drives the compressor directly, 18 to 50 V DC. Product is frozen and the ice packs are charged at the same time. |
This is the only window in which the system needs anything from outside. On a clear day the packs are fully frozen well before the light starts to drop. |
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Evening and night The compressor stops with the light. Frozen packs release stored cold into the cabinet interior. |
Deep-freeze temperature is maintained by the packs plus the 110 mm wall. Nothing electrical is running, so nothing can fail at two in the morning. |
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Rain, or a run of cloudy days Move the manual switch from SOLAR to AC and run from a generator or the mains through the adapter. |
The switch is physical and deliberate. That is the trade-off for having no automatic changeover electronics in the cabinet. |
The switch is manual - and that is the pointAutomatic changeover needs sensing, relays and a board. Those parts are also what fails first in humid, dusty or coastal conditions, and when they fail the cabinet stops entirely. On the Direct Drive 5 the changeover is a two-position switch marked SOLAR and AC. If the panel is producing, the switch stays on SOLAR. If a week of cloud is forecast, it moves to AC and the generator or mains carries the load through the supplied 100-240 V adapter. The consequence is honest: someone has to be on site to move it. For a farm, a fishing station or a shop with a permanent attendant, that is not a burden. For a site with nobody present, it is the wrong product - the Direct Drive 4 does that job automatically. |
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Specification - Direct Drive 5
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Parameter |
Value |
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Model |
Direct Drive 5 - solar freezer system |
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Solar panel |
Required - 18 to 50 V DC, connected directly |
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Battery |
Not required - zero battery system |
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Night storage |
Sealed ice packs charged by the compressor during daylight |
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Backup power |
Generator or mains, 100 - 240 V AC through the supplied adapter |
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Changeover |
Manual two-position switch, SOLAR / AC |
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Running schedule |
24 hour cooling - solar by day, ice storage by night |
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Insulation |
110 mm ultra-thick high-density foam |
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Supplied with |
DC cable, ice pack set, AC adapter |
Panel wattage is sized per site from sun hours and cabinet volume. Cabinet-only supply is available where the array already exists.
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Where a battery-free system winsIsland fishing stations. The catch lands in the afternoon and has to hold overnight. Salt air destroys electronics long before it destroys a foam wall, so a cabinet with no control board is the one still working in year five. Remote farms and grazing land. Milk, meat and produce held at the point of production, with no diesel to haul in and no battery to replace. Markets that close at sunset. Stock is frozen during trading hours and simply held cold until morning. Clinics and medical stores. Where a cold room is needed for medical stock and the site has staff present to move the switch when the weather turns. |
Four things to confirm before ordering1. Worst-month sun hours. The packs must be fully charged on an average day in the worst month, not on a good day in June. 2. How many hours the night actually lasts. A pack set is sized to hold until sunrise, not indefinitely. 3. Whether someone is on site daily. Manual switch means a person, and that person has to know when to move it. 4. Backup source. Generator or mains - the adapter is 100-240 V and ships with the unit, but the source has to exist. |
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110 mm foam wall, castors, external condenser fan and mechanical thermostat.
Inside the factory that builds this system
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Hangzhou Juka Solar Technology was founded in 2015 around one problem: putting solar energy, new energy and smart control to work inside a refrigeration circuit. The range has since grown from a single DC chest freezer to solar refrigerators, solar ice makers, mobile ice-cream carts, delivery tricycles and beverage retail carts - all of them exported, most of them to Belt and Road markets. The work does not stop at the container. Partners in Ghana, Gabon, Cameroon, Nigeria, Kazakhstan and India are supported in setting up their own local production for retail and delivery refrigeration, which is how a cold chain becomes permanent rather than a series of one-off shipments. For a solar system this matters more than for a mains-only freezer. Panel sizing, controller rating and battery capacity all depend on cabinet volume and site conditions, so the cabinet and the electronics are engineered together instead of being bought separately by the importer. |
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What is decided before the cabinet is built
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Wall thickness is a production parameter 65 mm or 110 mm foam is set on the foaming line, not assigned in a brochure. Insulation that is specified but not achieved is the usual reason a solar cabinet underperforms in its first hot season. |
One bill of materials Panel, controller, battery and cabinet are listed together, so the importer receives a system whose parts were sized against each other rather than sourced independently. |
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Voltage as an order option DC input, AC adapter voltage, plug type and control panel artwork are selected per market on the same platform - no separate tooling run for a different destination. |
Repeatable on the second container Foam thickness, fittings and controller model are held per customer, so a follow-up order matches the first one instead of drifting. |
Certification and test documentation
CE marking covers the electrical arrangement, and utility model patents cover the cabinet and the direct-drive control layout. Documents travel with the order so they can be presented at customs and to institutional or tender buyers.
CE - low voltage and EMC |
CE - supplementary schedule |
Utility model patent - cabinet structure |
On the floor
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Six control points behind every cabinet
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01 |
Foaming runs inside a constant 20-23 °C room, so the foam quality does not shift with the season. |
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02 |
Condenser and evaporator are nitrogen purged before any pipe joint is made, keeping the internal circuit clean. |
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03 |
Vacuum is pulled to below 20 Pa. A unit that does not reach spec is never charged with refrigerant. |
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04 |
Two leak tests per cabinet with an INFICON detector - one unpowered, one running. |
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05 |
A constant-temperature test room confirms refrigeration parameters under identical conditions all year. |
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06 |
Production and quality control are separate departments. Only cabinets signed off by a QC inspector are packed and warehoused. |
Machines on the line
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Equipment |
What it gives the buyer |
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Automatic laser cutting machine |
Consistent panel geometry, tight tolerances, clean edges |
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Punch press and bending machine |
Repeatable cabinet forming from unit to unit |
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Dual-gun high-pressure foaming machine |
Even density across the whole cabinet, no thin spots |
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CACL high-precision filling machine |
Precise refrigerant charge on every unit |
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INFICON high-sensitivity leak detector |
Finds leaks that ordinary detectors pass |
OEM, ODM and local assembly
Cabinet-only supply, private label, SKD and CKD shipments are all available, together with technical guidance for partners who would rather assemble locally than import finished units. Helping partners build their own refrigeration business is the part of the work that outlasts a single purchase order.
What can be changed on a standard order:
✓ Customer logo and cabinet colour
✓ Voltage options and plug type
✓ Packaging design
✓ Product configuration, baskets and fittings
✓ Panel, controller and battery included, or cabinet supplied on its own
Quote a solar freezer system for your site
Send the destination, the worst-month sun hours and the number of hours the cabinet must hold without sun. The pack count, panel wattage and cabinet volume follow from those three numbers, and the quotation lists cabinet, panel and ice packs separately so each line can be compared.
If the site has nobody on hand to move a switch, say so in the enquiry - the Direct Drive 4 does the same job with automatic changeover, at a higher cost.
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