Kegerator
Kegerator, a portmanteau of "keg" and "refrigerator", is a refrigerator that has been designed or altered to store and dispense kegs. The kegerator keeps the keg in a refrigerated environment and uses CO to pressurize and dispense beverages from the keg. This keeps the contents of the keg fresh and carbonated for an extended period of time, on average up to 60 days. Specifically designed kegerators are available for both commercial and residential use, however a common refrigerator can be reconfigured into a kegerator with a kegerator conversion kit. Not all standard refrigerators have enough room for a keg , so kegerators are designed in a manner that will allow one or more kegs to fit inside along with the dispense system. Kegerators are typically used to dispense draft beer, but are also gaining popularity for dispensing wine, cold brew coffee, and kombucha with certain modifications. Components. A crucial part of any draft beer system is the keg coupler, the part inside the kegerator that actually taps the keg. Different types of kegs require different keg couplers, so you need to consider what you plan on serving and purchase the coupler that is right for you. The D, S, U  and G couplers are secured to the keg by twisting them in place (like a screw). The A System coupler is often called a "German Slider" because, unlike the other couplers, it slides in place and can be secured at any angle. The M-coupler also slides onto the keg, but it taps different brands than the German Slider. Home brew couplers are different in that they have a separate component for the gas in and the liquid out. Economics. Kegerators are known to have cost benefits that make them a viable choice over the purchase of smaller cases, such  as the typical 6-pack or 12-pack. Generally speaking, kegerators save costs because of their connection with business theories on bulk sales, as well as their savings on packaging smaller cases of beer. Since a keg typically stores large amounts of cold beer, many kegerators have been known to save up to 60% on costs when compared to the same amount of volume in cans and bottles. Depending on the brand of beer, cost savings can be even greater. Therefore, more specialized craft beers can often provide significantly higher savings than common brands like Budweiser. Conversion kits. A kegerator  conversion kit allows you to convert an existing refrigerator into a beer-dispensing kegerator. This may be a more economical solution if you already have the refrigerator or you're able to find a cheap used refrigerator (at a yard sale, classifieds, etc). An important thing to consider is whether or not the refrigerator will be able to hold a keg. Many refrigerators have a step inside them that houses the compressor and takes up half the bottom of the fridge, meaning that there is not enough space above or in front of the step for the keg. Pre-configured  kegerators are designed with this in mind and install the compressor in a manner that allows plenty of room. Conversion kits are configured to either dispense through the door of the fridge or through the top into a draft beer tower. Door mount kits have a shank that goes through the door, with an attachment for the faucet on the outside and a hose nipple for the beer line on the inside. A draft beer tower would extend above the top of the fridge and already includes the faucet, shank and 5' beer line. Installation requires a few rudimentary tools , such as a socket wrench set, screwdriver and a drill with a hole saw bit to modify the refrigerator. The CO tank can be installed inside the fridge if there is enough room, or placed outside the fridge and secured into place. You can also convert a top opening chest freezer into a beer dispenser (sometimes called a keezer) with the use of a thermostat control unit. The advantage of a keezer is that you are assured it will get cold enough to dispense beer at the proper temperature range (32-38 degrees Fahrenheit) and it usually has more interior  floor space than a refrigerator, allowing it to store and dispense more kegs. The disadvantage is that it requires the thermostat to be overridden to ensure you don't freeze your kegs and you have to lift the heavy kegs up and over the freezer wall. You can accomplish this conversion with a tower kegerator conversion kit or build an extension on top of the freezer to mount the door and taps onto. Configurations. Kegerators are generally designed for use with beer kegs, but they are gaining popularity for dispensing other types of drinks, most notably wine, cold brewed coffee , kombucha, and soda. With home brew kegs, you can put whatever liquid you want inside the keg, pressurize it and dispense it with a kegerator. Different types of liquids require different alterations to the dispense system. Wine and cold brewed coffee use a CO/Nitrogen blend to pressurize the kegs. These types of drinks also require all stainless steel contact with the dispense system fittings because the higher acid content can corrode the chrome plated brass normally found in dispense systems. You may also need to change out the beer line for silicone wine line, which is less likely to  impart flavors. In many larger cities, coffee houses and wineries are offering their products in commercial kegs for use in a kegerator. If that is not available, you can always fill a home brew keg yourself. Pouring Guinness or other nitrogen beers from a kegerator requires a stout faucet, nitrogen regulator and a nitrogen tank. The stout faucet has a small restrictor disc inside the faucet head. Forcing the beer through the restrictor disc creates the rich and creamy head that nitro beers are known for. A nitrogen regulator or CO2/nitrogen adapter is required and should be set to  30 psi. Nitrogen tanks are filled with a 75% nitrogen and 25% blend referred to as mixed gas or beer gas.