How to Repurpose an Old Refrigerator into a Green Cooler

How to Repurpose an Old Refrigerator into a Green Cooler

Turning an old, inefficient refrigerator into an eco-friendly cooler is a great way to avoid wasting appliances and reduce your energy usage. With some simple modifications, you can convert a refrigerator into an insulated, electricity-free cooler that keeps food and drinks chilled without straining the power grid.

Reasons to Repurpose a Refrigerator into a Cooler

Here are some of the key benefits of repurposing an old refrigerator into an off-grid cooler:

  • Save energy: Refrigerators, especially older models, use a significant amount of electricity. By modifying one into a passive cooler, you eliminate its energy consumption.

  • Reduce waste: Old appliances often end up in landfills. Giving a refrigerator new life as a cooler keeps it out of the waste stream.

  • Lower costs: Passive coolers don’t require electricity or refrigerants, saving you money on utility and maintenance costs.

  • Customizable storage: You can modify the interior to create shelves, drawers, and storage baskets tailored to your cooling needs.

  • Eco-friendly alternative: Passive coolers don’t use refrigerants that can damage the ozone layer or contribute to climate change.

  • Preparedness: Having a non-electric passive cooler provides backup refrigeration in case of power outages.

How Refrigerator Coolers Work

Refrigerator coolers take advantage of the appliance’s pre-existing insulation and sealing to maintain chilled temperatures without power. Here are the key operating principles:

  • Insulation: The refrigerator’s interior insulation layer traps cold air inside, while preventing warmer outside air from entering. This reduces temperature exchanges between the interior and exterior.

  • Thermal mass: Items like chilled water bottles or ice packs placed inside the cooler absorb heat. This thermal mass helps regulate interior temperatures.

  • Convection: Cooler air sinks while warmer air rises, creating a natural convection loop that maintains a chilled lower section. Make sure warm air can escape through vents at the top.

  • Evaporative cooling: As water evaporates from water bottles or damp cloths, the evaporation process has a slight cooling effect. This can supplement the passive cooling system.

  • Shade: Keeping the cooler in the shade prevents solar heat gain from warming the interior. For best results, use the cooler indoors or in a shaded outdoor area.

Choosing an Old Refrigerator for Conversion

When selecting an old refrigerator for your passive cooling conversion, keep these guidelines in mind:

  • Condition: Pick a used refrigerator that is still in good working order, with an intact door seal and undamaged insulation. Units with cosmetic damage are fine.

  • Size: Choose a size based on your cooling needs. A larger unit holds more but requires more thermal mass. Under 10 cubic feet is best for casual use.

  • Efficiency: Older refrigerators with poor efficiency ratings are ideal candidates for conversion. New Energy Star models still have life left as refrigerators.

  • Style: Standard top-freezer and side-by-side models have large storage capacities. Compact dorm or apartment fridges work for smaller cooling needs.

  • Ask around: Check with family, friends, neighbors, community groups, and social networks for available used refrigerators before buying one.

Modifying the Refrigerator Into an Off-Grid Cooler

Converting an old refrigerator into a passive cooler requires some simple modifications. Here are the main steps:

Remove Refrigerant and Disconnect Components

  • Hire an HVAC technician to safely remove any remaining refrigerant. This prevents accidental releases of ozone-harming chemicals.

  • Disconnect the compressor, condenser coil, and related coolant system components.

  • Cut power to the refrigerator and disconnect the power cord.

  • Remove interior lights and digital temperature displays if possible.

Add Insulation

  • Glue rigid foam insulation panels to the inside of the refrigerator cabinet walls, doors, sides, and underside. This adds R-value.

  • Seal any gaps around the door, hinges, or base with spray foam insulation. Prevent air leaks.

  • Attach weatherstripping around the door opening and lid (for chest freezers). Help the door seal tightly.

Create Ventilation

  • Drill vent holes at the top of the cabinet walls or lid. This allows warm air to escape.

  • Install a duct or PVC pipe to function as a chimney vent at the very top.

  • Add mesh screens or perforated panels over vents to prevent insect entry.

Modify Interior Storage

  • Remove any sliding glass shelves. Replace with sturdy wooden shelves secured with brackets.

  • Add extra wire shelves or remove shelves to fit large items.

  • Install drawer slides or build pull-out wood storage boxes for the lower compartment. Utilize all interior space.

  • Attach hooks to hang storage baskets from shelves and walls. Use for organizational flexibility.

Make Exterior Improvements

  • Seal and waterproof the refrigerator cabinet with paint or sealant. Prevent moisture damage.

  • Attach handles or casters for portability. Locking casters allow the cooler to be rolled into place.

  • Optional: Build a vented wooden enclosure around the cooler to protect and disguise it.

Operating Your Passive Refrigerator Cooler

Once modified, using your DIY refrigerator cooler requires just a few simple steps:

Chill the Interior

  • Place several chilled water bottles or reusable ice packs inside the empty cooler overnight. This chills the interior.

  • For quick cooling, use frozen water bottles or ice packs. But limit these as they can freeze contents.

Load in Thermal Mass

  • Fill the cooler with chilled water bottles, taking up approximately 40-50% of the interior space.

  • Stagger the placement of bottles, avoiding clumping. Evenly distribute the thermal mass.

  • Include damp cloth bags or burlap sacks filled with sand. The evaporation provides a cooling effect.

Add Contents

  • Load in food and beverages that need to stay cool. Prioritize the bottom shelf and baskets.

  • Avoid packing the cooler more than 60-70% full. Airflow is needed for convection cooling.

  • Wrap or cover chilled contents with towels to maintain temperatures longer.

Use Strategically

  • Keep the cooler out of direct sunlight in an indoor room or shaded outdoor area.

  • Only open the door briefly when removing contents. Opening frequently reduces efficiency.

  • Replace melted ice packs or cycle in new chilled water bottles to maintain interior temperatures.

  • Use an instant-read thermometer to check cooler temperatures. Shoot for between 36-40° F.

Maintaining Your Passive Cooler

To keep your refrigerator cooler operating at peak efficiency, be sure to:

  • Check door seals annually and re-apply weatherstripping if worn or damaged.

  • Re-glue any insulation panels that become detached from the interior walls.

  • Monitor temperatures and adjust the thermal mass as needed to maintain cool temperatures.

  • Remove mold, mildew, or food waste that can compromise the sanitation of the cooler interior.

  • Clean the interior periodically with non-toxic cleaners like baking soda and vinegar solutions.

  • Drain any trapped water under cooling baskets through the floor drain (if present).

  • Keep the lid or door closed tightly to prevent cold air from escaping. Repair any damage.

With proper construction and regular maintenance, a converted refrigerator cooler can provide many years of chilled, off-grid food and beverage storage! Savor the savings in electricity and landfill waste.

Frequently Asked Questions

How cold can a passive refrigerator cooler get?

With adequate insulation and thermal mass, they can maintain interior temperatures of 36-42°F consistently. In hot climates or without sufficient chilling materials, temperatures may be closer to 45-55°F.

How long can a converted cooler keep food cold?

With a full thermal mass, food can stay properly chilled for 24-48 hours. Perishable food should not be kept much longer than 2 days. Supplement with fresh ice packs or chilled water as needed.

What are the best thermal mass options?

Water or ice packs have excellent thermal capacity. For alternatives, use damp sand bags, clay pots with water, chilled soil wrapped in burlap, or reuse safe plastic containers filled with salt water solutions.

Can I convert any kind of refrigerator into a cooler?

Upright, chest, and mini fridges can all be converted. Very small dorm refrigerators may not have enough insulation. Avoid refrigerators with extensive mechanical issues.

How much does a refrigerator conversion cost?

If you source a used refrigerator for free, the conversion costs less than $50 in most cases. Purchasing a unit and hiring for professional refrigerant removal will increase costs to $200-$300.