question: why do air conditioners need to pull air from the outside while fridges don’t, being that essentially what both do is bring the temperature of the air inside of a room?
comment: A fridge and AC work in the same way: they cool one side and heat another. They both move heat, but actually do not move any air. That is, air is never exchanged between the outside and inside spaces. A fridge cools its internal space and heats your home. If the radiator were not insulated from the inside of the fridge it would have a net zero effect. You could think of the fridge as having its own little "room" inside. ACs cool your home and heat the outside air. If you ran an AC inside it would cool on one side and heat on the other meaning the room never actually gets any cooler. By sticking a hose to the outside world (or having the radiator hang outside for a window unit) it can heat the outside air, meaning you have a cooling effect on the room. I work in an electronics store and you wouldn't believe the number of people who think you can have an AC run without hooking it up to the window in some way. Retail truly has ruined my faith in humanity.
passages: A common commercial refrigerator is the glass fronted beverage cooler. These type of appliances are typically designed for specific re-load conditions meaning that they generally have a larger cooling system. This ensures that they are able to cope with a large throughput of drinks and frequent door opening. As a result, it is common for these types of commercial refrigerators to have energy consumption of 4 kWh/day.
  
  Section::::Styles of refrigerators.
   Another variant, uses air, water, and a salt water solution. The intake of warm, moist air is passed through a sprayed solution of salt water. The spray lowers the humidity but does not significantly change the temperature. The less humid, warm air is then passed through an evaporative cooler, consisting of a spray of fresh water, which cools and re-humidifies the air. Humidity is removed from the cooled air with another spray of salt solution, providing the outlet of cool, dry air.
   BULLET::::- When a chiller is not (fully) used for cooling, it can be (at least partially) re-converted into heat pump.
   Refrigerators require an easy transfer between different zones of temperature and humidity. High-speed doors work in order to best ensure the most comprehensive maintenance of temperature in a refrigerator through the latest technologies available. The easy temperature transition from zone to zone is blocked by technologies designed for this sector. In this case is very important the flexibility and rapidity of high-speed doors.
  
  Chemical Factory:
   When the ambient air temperature drops to a set temperature, a modulating valve allows all or part of the chilled water to by-pass an existing chiller and run through the free cooling system, which uses less power and uses the lower ambient air temperature to cool the water in the system.
  
  This can be achieved by installing an air blast cooler with any existing chiller or on its own. During low ambient temperatures, an installation can by-pass an existing chiller giving energy savings of up to 75%, without compromising cooling requirements.
   Section::::Refrigerator mother theory.
   The cooling requirements vary over a wide range during the day and over the year due to ambient conditions, occupancy and use, lighting etc. 
  
  BULLET::::- In comfort cooling, there may also be the need for a stable and accurate temperature and humidity control in areas such as hospitals, IT & telecoms, process cooling. In applications such as schools, restaurants and office buildings, it is important that the cooling system is able to adapt to wide daily shifts in load.
   Ventilating or ventilation (the "V" in HVAC) is the process of exchanging or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air.
   Mechanical, or forced, ventilation is provided by an air handler (AHU) and used to control indoor air quality. Excess humidity, odors, and contaminants can often be controlled via dilution or replacement with outside air. However, in humid climates more energy is required to remove excess moisture from ventilation air.
   Many if not most uses of ACH are actually referring to results of a standard blower door test in which 50 pascals of pressure are applied (ACH), rather than the volume of air changed under normal conditions. The Passive House standard requires airtightness so that there will be less than 0.6 ACH with a pressure difference between inside and outside of 50 Pa.
  
  Section::::Effects of ACH due to forced ventilation in a dwelling.
   Within these refrigerators and freezers, vaccines are also compromised through improper use of the door gasket to feed cables from data loggers and thermometers, allowing excess warm air in, and cold air out of the refrigerator or freezer. Over time this causes the compressor to work harder and eventually leads to failure. This can be remedied by using probe access ports, found on most clinical refrigerators and freezer. These are easy to open up and drastically reduce air intake and loss from inside the units.
  
  Section::::Solar powered vaccine refrigerators.
   Commercial buildings, and sometimes residential, are often kept under slightly positive air pressure relative to the outdoors to reduce infiltration. Limiting infiltration helps with moisture management and humidity control.
   Condenser subcooling differs from "total subcooling" usually because after the condenser, throughout the piping, the refrigerant may naturally tend to cool even more, before it arrives to the expansion valve, but also because of "artificial subcooling". The total subcooling is the complete temperature drop the refrigerant undergoes from its actual condensing temperature, to the concrete temperature it has when reaching the expansion valve: this is the effective subcooling.
   Section::::Operating principles.:Free cooling.
   In heating, ventilation, and air conditioning (HVAC) in winter months, large commercial buildings interior spaces may need cooling, even while perimeter spaces may need heating. Free cooling is the production of chilled water without the use of a chiller, and can be used generally in the late fall, winter and early spring, in temperate zones. Free cooling is not entirely free since the chiller is still operational.
  
  Section::::Methods.
  
  Assuming that the system can utilize free cooling, there are three ways to use free cooling:
  
  Section::::Methods.:Strainer cycle.
   Refrigerators and freezers may be free-standing, or built into a kitchen.
  
  Three distinct classes of refrigerator are common:
   The subcooling principle behind all these applications is the fact that, in terms of heat transfer, all the subcooling is directly added to the cooling capacity of the refrigerant (as superheating would be directly deducted). As compressors that are subcooling work on this "easier conditions", higher pressure makes their refrigerant cycles more efficient, and the heat withdrawn by this means, "cheaper" than the one withdrawn by the main system, in terms of energy.
  
  Section::::Transcritical carbon dioxide systems.
   Section::::Commercial and domestic refrigerators.
   Demand controlled kitchen ventilation (DCKV) is a building controls approach of controlling the volume of kitchen exhaust and supply air in response to the actual cooking loads in a commercial kitchen. Traditional commercial kitchen ventilation systems operate at 100% fan speed independent of the volume of cooking activity and DCKV technology changes that to provide significant fan energy and conditioned air savings. By deploying smart sensing technology, both the exhaust and supply fans can be controlled to capitalize on the affinity laws for motor energy savings, reduce makeup air heating and cooling energy, increasing safety and reducing ambient kitchen noise levels.
   In the early years of the twentieth century, the vapor absorption cycle using water-ammonia systems was popular and widely used, but after the development of the vapor compression cycle it lost much of its importance because of its low coefficient of performance (about one fifth of that of the vapor compression cycle). Absorption refrigerators are a popular alternative to regular compressor refrigerators where electricity is unreliable, costly, or unavailable, where noise from the compressor is problematic, or where surplus heat is available (e.g., from turbine exhausts or industrial processes, or from solar plants).
   BULLET::::- Cross ventilation - The strategy of cross ventilation relies on wind to pass through the building for the purpose of cooling the occupants. Cross ventilation requires openings on two sides of the space, called the inlet and outlet. The sizing and placement of the ventilation inlets and outlets will determine the direction and velocity of cross ventilation through the building. Generally, an equal (or greater) area of outlet openings must also be provided to provide adequate cross ventilation.
   Direct cool
  
  Direct cool is one of the two major types of techniques used in domestic refrigerators, the other being the "frost-free" type. Direct-cool refrigerators produce the cooling effect by a natural convection process from cooled surfaces in the insulated compartment that is being cooled. Water vapor that contacts the cooled surface freezes. Therefore, unlike frost-free units, direct-cool units require manual defrosting of the interior. Direct cool is less expensive in production and in operation, as it consumes less energy.
   BULLET::::- Peltier refrigerators are powered by electricity, usually 12 volt DC, but mains-powered wine coolers are available. Peltier refrigerators are inexpensive but inefficient and become progressively more inefficient with increased cooling effect; much of this inefficiency may be related to the temperature differential across the short distance between the "hot" and "cold" sides of the Peltier cell. Peltier refrigerators generally use heat sinks and fans to lower this differential; the only noise produced comes from the fan. Reversing the polarity of the voltage applied to the Peltier cells results in a heating rather than cooling effect.
   Free cooling systems can have very high efficiencies, and are sometimes combined with seasonal thermal energy storage so that the cold of winter can be used for summer air conditioning. Common storage mediums are deep aquifers or a natural underground rock mass accessed via a cluster of small-diameter, heat-exchanger-equipped boreholes. Some systems with small storages are hybrids, using free cooling early in the cooling season, and later employing a heat pump to chill the circulation coming from the storage. The heat pump is added-in because the storage acts as a heat sink when the system is in cooling (as opposed to charging) mode, causing the temperature to gradually increase during the cooling season.
   Section::::Japan.
  
  VRF systems have been used in Japan since the 1980s. Currently, in Japan, VRFs are used in 50% of midsize office buildings (up to 70,000 ft or 6,500 m) and 33% of large commercial buildings (more than 70,000 ft or 6,500 m). Daikin, a Japanese brand, is the inventor of variable refrigerant volume systems (or VRV by Daikin air conditioning, other manufacturers remarked this as VRF).
  
  Section::::Home automation integration.
  