Solar powered ice makers freeze water using energy from the sun, creating a cold chain where the grid is absent or unreliable. They address a real gap in global food systems. The FAO estimates that about 14% of food produced is lost between harvest and retail, and a 2022 UNEP and FAO report on food cold chains found that lack of refrigeration directly caused the loss of 12% of total food production in 2017. By turning sunlight into stored ice, these systems allow communities, fishers and remote clinics to preserve perishables without relying on diesel generators or an unstable electricity supply.
The technology is not a single device but a collection of approaches. Some systems use standard solar panels to power electric compressors, while others harness solar heat directly to drive a refrigeration cycle with no electricity at all. The choice depends on context: tonnage requirements, local climate, water availability, and whether the goal is preserving vaccines, cooling milk, or making ice for a fishing community.
How it works
There are three main routes to making ice with solar energy. Each has distinct advantages and limitations.
Route A: PV plus compressor
This is the most common commercial approach. Solar photovoltaic (PV) panels generate electricity that powers a vapour-compression refrigeration cycle, the same technology found in domestic freezers. The system can be configured in two ways:
- Battery-backed: Solar energy charges batteries, which then power an inverter and an AC compressor. This allows operation during cloud cover or at night.
- Solar direct drive (SDD): The panels connect directly to a DC compressor, in some designs through a frequency converter. These systems bypass external batteries by using ice as the storage medium. When the sun shines, the machine makes ice. When the sun sets, the melting ice provides cooling.
This “ice as battery” principle relies on the latent heat of fusion. Melting one kilogram of ice at 0 °C absorbs about 334 kJ, which by our calculation equates to roughly 93 Wh of cooling stored. This is why many off-grid systems make ice while the sun shines and use it for cooling later, instead of storing electricity in batteries that are expensive to replace.
Route B: Solar thermal absorption
These machines use no electricity. Instead, they rely on a heat-driven cycle. Energy Concepts’ ISAAC ice maker uses a parabolic-trough collector to boil ammonia out of a water solution during the day. At night, a thermosyphon cools the generator, allowing the ammonia to be reabsorbed into the water, and ice forms in the evaporator. Because there are no moving parts and no fuel or electricity inputs, these units are mechanically simple, but their output depends on sunshine.
Route C: Solar adsorption
Adsorption systems use a solid material, such as activated carbon, to hold a refrigerant such as methanol. Solar heat drives the refrigerant out of the solid bed during the day. At night, the carbon re-adsorbs the methanol, a process that produces cooling and ice. Like absorption, this is an intermittent day/night cycle.
The 4 °C water trick
A distinct approach developed in Wales by Sure Chill uses water’s physical properties to hold temperature without power. The device surrounds the cooling cabinet with water. When power is available, ice freezes above the compartment and the water cools. Because water is densest at 4 °C, it sinks to the bottom, keeping vaccines cold for “days or even weeks” without electricity, according to the Welsh Government.
Real-world examples
Fiji: Rabi Island ice plant
Commissioned in late 2021, this government ice plant replaced a diesel generator that used about 600 litres of fuel a month. According to a Victron Energy blog, the system uses a 25 kWp solar array of 75 × 330 W JA Solar panels and a bank of 48 Narada 600 Ah gel batteries. It produces up to 750 kg of ice a day, and the diesel generator is kept as a back-up.
Indonesia: Sulamu and Kawa projects
A GIZ-led project in Sulamu, running since 2022, produces up to 1.2 tonnes of block ice a day (120 × 10 kg blocks). The system uses R290 (propane) refrigerant, a brine heat-storage tank and a 24 kWh battery, with a 12 HP semi-hermetic compressor. Partners include UNDP, IPNLF and ILK Dresden. It was nominated for The smarter E AWARD 2025.
A similar unit in Kawa, West Seram, launched on 15 October 2024 and makes up to one tonne of ice a day. IPNLF describes it as entirely off-grid and using thermal energy storage instead of batteries, although the related Sulamu design also includes a battery (“mainly thermal storage” is fairer).
Kenya: SolCoolDry
Running from September 2018 to August 2024, the Fraunhofer ISE project installed systems at Muhuru Bay (Lake Victoria) and Mwazaro. The Muhuru Bay plant produces 700 kg of ice a day, enough for about 2,100 kg of fish. One site used inverters and batteries; the other was DC direct-coupled through a frequency converter, with no batteries. The Mwazaro plant has been run by the local Beach Management Unit since August 2022 and, according to Fraunhofer, still produces high-quality ice. Muhuru Bay was handed over to a social enterprise, WeTu, in August 2024.
Vaccines, milk and ice cream
Gavi’s cold chain equipment programme (CCEOP) has installed more than 66,000 fridges, around 60% of them solar powered, and Gavi estimates they avert about 7,000 tonnes of CO2 a year. These solar vaccine fridges are often solar direct drive units with “a back-up battery made of ice”. In New York, Unilever trialled solar-powered ice cream freezers in Central Park in 2014, each using under 0.5 kWh a day. In India, Promethean Power Systems had sold about 150 milk chillers by 2015. These are not purely solar: a phase-change thermal battery stores cooling as ice when grid power is available and chills milk when the power is off.
Wales: Sure Chill
Sure Chill’s vaccine coolers use the 4 °C water density trick. The company received $1.4 million from the Gates Foundation to develop a vaccine cooler, after an earlier $100,000 for a proof of concept. By 2017 its vaccine fridges were operating in more than 30 countries, and 200 units had been shipped to the Philippines for UNICEF after Typhoon Haiyan.
What the numbers say
PV plus compressor output
In Fiji, the 25 kWp system produces up to 750 kg of ice a day. By our estimate that is roughly 30 kg of ice per day per kWp, in a tropical location with a battery-backed system. It is not a universal rule: output per kWp depends on how much sun a site gets, reflected in its capacity factor. In Indonesia, the Sulamu system needs about 100 kWh per tonne of ice, which works out at approximately 10 kg of ice per kWh of electricity.
Solar thermal output
Absorption and adsorption systems typically produce single-digit kilograms of ice per square metre of collector per day, at a low coefficient of performance (COP) of about 0.1. Energy Concepts claims its 11 m² ISAAC unit makes six 10 kg blocks (60 kg) a day, or about 5 kg per m², although 5 kg × 11 m² is 55 kg, so the company’s own figures do not quite match. A 2011 Cairo prototype using activated carbon and methanol produced between 1.38 kg and 3.25 kg of ice per m² a day, at a COP of 0.07–0.11. A larger Shanghai Jiao Tong prototype, using a CaCl2/activated-carbon and ammonia pair, produced 50 kg of ice a day at a COP of 0.11 when tested under simulated solar radiation. This is why PV plus compressor systems dominate tonne-a-day plants.
Costs
The ISAAC absorption unit can be built for under $7,000 if made locally, according to the company. India’s Ecozen Ecofrost solar cold room cost about £15,000 in 2018. The Fiji plant’s cost is undisclosed, but it avoids about 600 litres of diesel a month. We found no credible published price for commercial solar ice block machines, including those advertised in Nigeria, so we do not quote one.
Limitations: an honest assessment
Solar ice is not a magic bullet, and running costs are not close to zero.
Water dependency: Ice plants need fresh water. IPNLF notes that its Solar Ice Maker requires access to fresh water to operate efficiently, which can be a limiting factor in dry coastal areas.
Battery costs: IPNLF says replacing expensive batteries is often one of the biggest costs of solar applications. This is why the Indonesian designs lean on thermal storage (brine or ice) rather than chemical batteries.
Intermittency: Solar thermal units are measured per sunny day. The Cairo prototype’s output varied more than twofold depending on radiation levels.
Human factor: Projects need local operators and training. The Indonesian project includes training in handling, finances and asset management. The Kenyan plants were handed over to a local Beach Management Unit and a social enterprise to run.
Camping reality: For consumers, “solar ice maker” usually means a portable compressor fridge-freezer (such as the EcoFlow GLACIER) running off a portable power station and folding panels. We found no dedicated mass-market solar thermal ice maker for households. EcoFlow says the GLACIER makes 18 ice cubes in about 12 minutes, but it accepts solar input only when its optional 298 Wh battery is fitted.
The UK angle
The clearest UK contribution to off-grid cooling is in medical cold chains. Sure Chill, based in Tywyn, Gwynedd, and founded by Ian Tansley, developed the 4 °C water-density cooler described above. Its current deployment figures are not published in our sources.
Frequently asked questions
How does a solar powered ice maker work?
Solar powered ice makers convert sunlight into cooling. Most commercial systems use PV panels to power a compressor, freezing water into ice blocks that store cold. Alternative thermal systems use solar heat to drive an ammonia or methanol cycle, producing ice without electricity.
How much ice can a solar ice machine make per day?
Output depends on system size and technology. A 25 kWp PV system in Fiji produces up to 750 kg of ice a day, and a GIZ-led plant in Indonesia up to 1.2 tonnes. Solar thermal units are much smaller: the maker of the ISAAC claims about 5 kg of ice per square metre of collector per sunny day.
Can you run an ice maker off-grid with solar panels when camping?
Yes, but not with a dedicated thermal ice maker. Campers typically use portable compressor fridge-freezers (such as the EcoFlow GLACIER) paired with a portable power station or plug-in battery and folding solar panels. The battery keeps the unit running when the sun is not shining.
Is there such a thing as a solar ice cream machine?
Not as a dedicated appliance. “Solar ice cream” in practice means ice cream freezers, carts or trailers powered by small solar arrays. Unilever trialled solar-powered freezers in New York in 2014, and small businesses in India, the Netherlands and Canada have run solar ice cream carts and trailers, some with battery or generator back-up.
Do solar ice makers need batteries?
Not necessarily. Solar direct drive systems bypass batteries by using ice as the storage medium. However, many commercial systems (such as the Fiji plant) still use batteries for cloudy periods and night-time operation. Some projects lean on thermal storage (brine or ice) to reduce battery replacement costs.
Why do solar ice makers matter for fishing communities and food loss?
Fishers around Lake Victoria and in Indonesia use solar ice to preserve catches. IPNLF says better-iced, higher-grade tuna can let fishers reach export markets and nearly triple their income. Globally, lack of refrigeration caused the loss of 12% of total food production in 2017, according to UNEP and FAO. Solar ice offers a decentralised cold chain that reduces reliance on diesel generators.