The locally made Sunfrost refrigerator, running on 12 volt DC electricity, is 600% more efficient than a conventional refrigerator. The three factors that make the Sunfrost more efficient than any other refrigerator are:

  1. The compressor's location
    • The compressor on the Sunfrost rest on the top of the unit, unlike traditional refrigerators which have the compressor located at the bottom of the unit. The advantage to this is that in a traditional refrigerator the compressor generates heat which rises and creates an electric blanket of air around the refrigerator. The Sunfrost has no such problem.
  2. Compressor design
    • The small, well designed compressor, lack of fan and low percentage run time all contribute to the Sunfrost's exceptionally quiet operation. The Sunfrost;s compressors design contributes to the refigerator's high efficiency by maintaining lower system cost (fewer working parts), Reliability (one moving part) and noise reduction (no fan.
  3. The high R-Value insulation
    • The Sunfrost is well insulated by a 3-inch thick layer of polyurethane, and the freezer walls are 6-inches thick thus keeping food protected from warm air.

In terms of energy, the Sunfrost uses 8 gallons of oil less than a conventional refrigerator of the same size each month. If we changed every refrigerator in the U.S. to a Sunfrost, we would save one billion gallons of oil every month - 40% of the output from the Alaska pipeline.[verification needed]


Sun Frost - The World by Kosuke Itakura[edit | edit source]

Introduction[edit | edit source]

The Campus Center for Appropriate Technology values a healthy planet and ways to better treat our planet ethically. CCAT promotes sustainable living practices, along with new and old technologies to implement the idea of "sustainable living."

The CCAT house uses the Sun Frost Refrigerator in is its own kitchen. If you would like to see the Sun Frost Refrigerator yourself, you can visit the CCAT house, located on the Cal Poly Humboldt Campus in Arcata, CA.

Feel free to check the CCAT homepage for visiting hours.

Some facts about Sun Frost Refrigerators....[edit | edit source]

Why you should be concerned about the refrigerator in your home....[edit | edit source]

Since the refrigerator is the largest consumer of electricity in an otherwise energy efficient home, you should find out if the refrigerator you are using in your home can be more energy efficient. The energy efficient Sun Frost refrigerator makes powering a home with low output energy sources like photovoltaics, both feasible and affordable to the modern home owner. In a typical home using utility power, energy consumption for refrigeration will typically be cut by a factor of six.

What makes it the the world's most efficient refrigerator....[edit | edit source]

  • The Sun Frost refrigerator uses a number of new design methods and energy saving techniques to achieve its low energy consumption. The unit is cooled by two highly efficient top mounted hermitically sealed compressors. The top mounted cooling system reduces energy consumption in several ways. The heat generated by the compressor and condenser (the black coils on the back of many refrigerators) does not re-enter into the refrigerator. If these components run cooler, the cooling system's efficiency is increased.
  • As the temperature of the evaporator (cooling coils) is decreased, the efficiency of the cooling system is lowered. In the typical refrigerator, the 38F refrigerator section is cooled by an evaporator which is usually below 0F. In the Sun Frost refrigerator, the separate refrigerator section is cooled by an evaporator which is above 32F, resulting in a considerable boost in the cooling system's efficiency.
  • There is no air circulation between the refrigerator and freezer sections, unlike conventional manual defrost and automatic defrost refrigerators. This innovative design reduces infiltration of warm kitchen air when the doors are open.
  • The walls of the refrigerator contain 2.5 to 4.5 inches of polyurethane foam, the best non-exotic insulation available on the market. Most conventional refrigerator insulation use thermal bridges- metal supports between the inner and outer walls. These bridges reduce the efficiency of insulation in the refrigerator.
  • Another energy-saving design featured in the Sun Frost is the fact that it does not have strip heaters on the doors' gasket area. In a conventional refrigerator, these heaters prevent condensation happening in the system under humid conditions and also increase the system's energy use. Sun Frost refrigerators use waste heat from the condenser instead of these electric heaters to prevent condensation.
  • The use of a passive evaporator (no fans) and a condenser with a large surface area also adds to the Sun Frost's energy efficiency. When a fan is circulating air over an evaporator, energy is needed to run the fan. It also takes energy to remove the heat created by the fan motor.

Higher humidity means better storage conditions....[edit | edit source]

  • Higher humidity keeps foods more fresh. The increased moisture inside the refrigerator allows prolonged storage of vegetables. High humidity also prevents freezer burn and wilting caused by water loss in food products. The minimal water loss in foods stored in a Sun Frost refrigerator leads to foods lasting two to three times longer than in conventional refrigerator systems.
  • In a conventional refrigerator, usually water, which is a part of stored foods, is transformed into ice onto the freezer's cooling coils. This results in the dehydration of fruits and vegetables, increase of frost build-up, and increasing energy consumption. In a typical refrigerator, high humidity is created by storing foods in airtight containers. This creates high humidity conditions, but cuts off the food's breathing (O2) supply. Without oxygen, plant cells rapidly breakdown resulting in decreased shelf life for the food.
  • The Sun Frost allows the consumer to store food in breathable containers, such as brown paper bags, resulting in double the shelf life for foods.

Runs off less electricity than conventional refrigerators....[edit | edit source]

  • The Sun Frost Refrigerator reduces refrigerator energy consumption by a factor of five. The Sun Frost RF16 12 volt DC model consumes 20 KWH per month, or an average of 53 amp hours a day. Conventional refrigerator systems typically consume about 110 KWH per month or 305 amp hour per day (sun frost pamphlet).


  • In order to create the 110 KWH needed to power this refrigerator on a solar power system, it would cost around $12,000 in hardware, batteries, and inverter. A Sun Frost system will reduce this cost by a factor of at least six because of its increased efficiency and the elimination of inverter losses (sun frost pamphlet).

Quiet -- no humming noise....[edit | edit source]


Sun Frost RF12 Refrigerator / Freezer
shown with 24" cabinet

Models RF19 and F19 use a quiet and efficient fan to help cool the condenser. On other models the compressors are cooled passively. The new more efficient techniques used in the Sun Frost include a much smaller compressor which results in less noise than a conventional refrigerator.

More reliable....[edit | edit source]

  • A minimal number of moving parts incorporated in the design of the Sun Frost cooling system makes the system less susceptible to breaking. Both the DC and AC compressors use highly reliable, hermetically sealed, brush-less motors.
  • The top-mounted cooling system runs at a lower temperature than conventional systems, resulting in prolonged duration and life of the system's lubricants. This also reduces mechanical strain on the compressor. The Sun Frost cooling system is designed to provide excellent refrigeration services for well over 15 years.

References[edit | edit source]

O&M[edit | edit source]

The operations and maintenance page may be found at CCAT sunfrost refrigerator/OM.

Sendog6913 17:30, 2 March 2008 (PST) Cal Poly Humboldt - CCAT

Discussion[View | Edit]

600%?? What is the energy consumption of a sunFrost and what is the energy consumption of a similar energy star model? Last I checked the SunFrost was less efficient than a Maytag MTB1856 on a per cubic foot basis.

Cookies help us deliver our services. By using our services, you agree to our use of cookies.