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Mod #41: Refrigerator Cooling Fan

Posted By Mark Corgan On July 18, 2008 @ 5:56 am In cooling, electrical | 37 Comments

When the temperature gets hot out, your RV refrigerator can struggle to keep it’s temperature cool enough to avoid food spoilage and to keep your beer at the perfect drinking chilliness. There are several factors that contribute to refrigerator efficiency, such as the sun beating down on the refrigerator side of your RV, or a dirty gas burner creating a poor heating flame. Even the levelness of your RV can cause inefficiency over time. One of the simplest and most effective mods that can be made is to improve the ventilation at the back of the refrigerator by using a fan to direct air up and out of the refrigerator vent column.

Mod Difficulty:

An RV refrigerator is not like a residential unit. It uses a heat absorption system rather than an electric compressor, condenser, and evaporator, as a residential refrigerator does. Heat absorption requires removing the heat from the absorption unit via chemicals and air circulation. This is accomplished by convection or draft. A narrow space behind the refrigerator allows cooler air to be drawn in to the space at the bottom of the unit. The air rises and passes over the heat absorption unit fins, and out of the vent on the roof above the unit.

Some refrigerator installations actually prevent this convection action to work. In a typical RV installation, a dead air space can exist directly above the refrigerator. This space can trap warm air and drastically reduce the draft effect. This reduction in draft is why you should do the refrigerator cooling fan mod. While not a cure all for a poor refrigerator installation, a fan can dramatically improve refrigerator cooling performance.

There are several fan types that can be used for this mod. It is recommended that you use one of the permanent-mount types as the battery-powered kind can require frequent replacement of the batteries, especially if you forget to turn the fan off when not using it. Some use computer fans that are 3 to 4″ in diameter. These require little power and move a surprising amount of air.

A thermostatically-controlled fan however, is the best way to install a refrigerator ventilation fan. These are permanently mounted and have a thermostat that provides power to the fan when the ambient air temperature reaches some set point. Different temperature set points are available with the most common switching at 80°F. A switch can also be wired in to the fan’s power supply so that you have control over when the fan is on.

There is some debate as to where the most effective place to install the vent fan. Camco, for example, has a solar powered fan and refrigerator roof vent combination. This puts the fan at the top of the vent stack, pulling air through the lower vent and up through the roof vent. Still others mount the fan at the bottom of the vent stack, right at the lower vent. This position pushes air up through the stack. Both have been found to work equally as well so the choice is your on which way to go. Either way, using a vent fan will ensure a cold beer on a hot day.

TipTry to park your RV where the refrigerator side of the RV will be in the shade as much as possible. This will help reduce temperatures inside the refrigerator vent column dramatically. If shade is unavailable and your refrigerator is on the curb side, use the awning to provide shade.

ModMyRV recommends these parts for this mod:
Valterra Products Universal Mount Fridge Vent Exhaust Fan
Valterra Products 3-Volt Fridgemate Inside Air Circulating Fan

General Reference
http://www.fridge-and-solar.net/fridge_vent.htm


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