COOL BY DESIGN
OFF GRID COLD STORAGE
The pantry is an off-grid walk-in fridge designed to address the challenges of limited solar energy, seasonal variations, and the constraints of a high ground water table. This innovative cold storage system integrates efficient design, ecological principles, and practical functionality.
Structure and Design
At its core, the pantry utilises a repurposed 22-cubic-metre lorry freezer body, which forms the insulated base of a wooden-clad structure. Above this is an elevated, south-sloping roof that serves multiple purposes. It houses the refrigerant unit and ventilation system, optimises solar gain, and shields the pantry from direct sunlight. The roof also supports solar panels, which generate sufficient electricity to power the cooling unit during summer months.
Inside the main compartment, a smaller, double-insulated walk-in fridge room provides flexibility and efficiency. This inner room houses the cooling unit and can store items requiring permanent refrigeration. It is ideal for cold, dark, humid conditions, such as those needed for potatoes. When sealed off from the larger compartment, it operates with maximum efficiency. Additionally, it can be used as a freezer room, for frozen goods and mass ice storage as a battery.
Thermal Regulation
The pantry is designed to maintain low temperatures even when solar power is unavailable. A combination of passive and active cooling strategies ensures functionality:
Thermal Battery: A high-capacity thermal battery, consisting of water (chosen for its high specific heat capacity), provides thermal mass. The system stores up to 5,000 litres of water, supplemented by barrels as food and drink contents are consumed. Rainwater collected from the pantry roof supplies all water needs.
Passive Cooling: Automatic vents, strategically positioned on opposite sides, allow cross-ventilation by drawing in cold winter night air. The elevated, tilted roof leverages the Bernoulli effect, where wind passing over the structure creates a low-pressure zone, enhancing air circulation.
Insulated Vent Doors: Timer and automatic window openers regulate the vents, ensuring optimal airflow while reducing ripening gases and excess moisture.
Location and Integration
The pantry is conveniently situated near the house entrance for regular use and is surrounded by thoughtful design features to enhance functionality and minimise heat impact:
Southern Zones:
Social Seating Area: A shaded space features a “cool cone” that casts a broad shadow and creates a thermal draft. As the sun heats the wood shingles, hot air rises through the cone and escapes via a chimney cowl, producing a cooling breeze. This area offers a pleasant, ventilated retreat during hot summer days.
Solar Water Heater: Positioned vertically, the solar water heater maximises energy capture during autumn to spring while minimising overheating in summer. Beneath it, an outdoor washing and preparation area serves the site’s productive needs.
Eastern Zone:
A roofed area shaded by a kiwi vine provides a cool, inviting environment, ideal for educational activities and gatherings.
Sustainability and Efficiency
The pantry relies entirely on surplus solar energy from an off-grid electrical system. It is designed to Flow with the rhythms of nature using its well-insulated structure, thermal mass, and passive cooling methods to maintain low temperatures during power outages, which can last days or even weeks in winter.
By integrating ecological design principles and multifunctional features, the pantry demonstrates how thoughtful planning can create a sustainable and practical solution for off-grid cold storage while enhancing the surrounding environment.
Tiny Homes, Animal Structures, and Pantries
Building structures from scratch can be time-consuming, expensive, and often unnecessary. A viable alternative is using used van or lorry fridge box bodies, available on platforms like eBay. These are insulated, lightweight, and often easy to collect with a car and trailer. Constructed from high-quality materials, including aluminium, stainless steel, and composite foam, these fridge boxes make excellent building blocks.
For larger structures, multiple boxes can be bolted together or stacked. Fitting windows and doors is straightforward just use a drill and jigsaw, and it cuts through easily (preferably with extraction or a mask for safety). Cladding is simple and completely conceals the box, creating a seamless exterior.
For structural integrity, long stainless steel bolts can pass through a wooden frame, sandwiching the fridge wall in the middle. Pressure-treated wood, stainless hardware, and durable roofing ensure long-term reliability.
The insulation in these boxes provides a stable climate cool in summer and warm in winter making them ideal for pantries, animal shelters, or small living spaces. The floors are strong enough to support tiles if waterproofing or a more elegant finish is needed.
Consider the possibilities, embrace up-cycling, and make it happen.