Refrigerators work by causing the refrigerant circulating inside them to change from a liquid into a gas. This process, called evaporation, cools the surrounding area and produces the desired effect. You can test this process for yourself by taking some alcohol and putting a drop or two on your skin.
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What is the formula of refrigerator?
For a refrigerator the coefficient of performance is COP = Qlow/(-W). Details of the calculation: (a) COP = Qlow/(-W). (-W) = Qlow/COP = 120/5 J = 24 J.
How do you calculate work done by a refrigerator?
What is refrigerator in thermodynamics?
A refrigerator is a device which is designed to remove heat from a space that is at lower temperature than its surroundings. The same device can be used to heat a volume that is at higher temperature than the surroundings. In this case the device is called a Heat Pump.
How a refrigerator works step by step?
To put it simply there are 3 steps by which a refrigerator or a fridge works: Cool refrigerant is passed around food items kept inside the fridge. Refrigerant absorbs heat from the food items. Refrigerant transfers the absorbed heat to the relatively cooler surroundings outside.
What is the basic principle of refrigeration?
The absorption of the amount of heat necessary for the change of state from a liquid to a vapor by evaporation, and the release of that amount of heat necessary for the change of state from a vapor back to the liquid by condensation are the main principles of the refrigeration process, or cycle.
How do you calculate refrigerator energy?
To summarise the above calculation, we have: Fridge Wattage x Hours Per Day = Watt-hours per day. Watt-hours / 1000 = kWh per day.
What is COP in refrigeration formula?
For a refrigerator the coefficient of performance is COP = Qlow/(-W). Details of the calculation: (a) COP = Qlow/(-W).
Is COP of refrigerator always greater than 1?
Generally, T1 and T2 difference is less than T2 so efficiency is always greater than 1. Hence the correct answer is option (A). Thus, we can say that the COP of the refrigerator and air-conditioner can be less than one or greater than one.
What is the formula of efficiency of refrigerator?
The coefficient of performance of the fridge is the refrigerating effect per cycle, Q1, divided by the net work done on the fridge per cycle, and, for a Carnot cycle it can be calculated from T1/(T2 − T1).
What energy runs a refrigerator?
Refrigerators use electricity, which is then turned into kinetic energy by fans. Refrigerators are machines that work on the principle of removing heat from a cooler environment and transferring it to a warmer environment.
What is the output energy of a fridge?
The average home refrigerator uses 350-780 watts. Refrigerator power usage depends on different factors, such as what kind of fridge you own, its size and age, the kitchen’s ambient temperature, the type of refrigerator, and where you place it.
What is entropy in refrigeration?
Entropy is the work performed during the phase change. It is the quickening and separation of the molecules as they adopt a gaseous form. The opposite is true for the condenser.
How is heat transferred in a refrigerator?
In the evaporator, heat transfers from the process recirculating fluid (higher temperature) into the refrigerant (lower temperature). The condenser transfers this heat from the refrigerant (higher temperature) to the cooling source (air or water) at a lower temperature.
Why refrigerator is a closed system?
Kitchen refrigerator: Closed system. No mass flow. Electricity is supplied to compressor motor and heat is lost to atmosphere.
Which law is used in refrigerator?
The second law of thermodynamics claims that it is impossible for heat to spontaneously flow from a cold body to a hot body, but it can move in that way if some form of work is done. This is how the refrigeration process works, and an example can be seen in Figure 1.
Which gas is used in refrigerator?
Modern refrigerators usually use a refrigerant called HFC-134a (1,1,1,2-Tetrafluoroethane), which does not deplete the ozone layer, unlike Freon. R-134a is becoming much rarer in Europe. Newer refrigerants are being used instead.
What are the 5 parts of refrigerator?
The main working parts of a refrigerator include a compressor, a condenser, an evaporator, an expansion valve, and a refrigerant.
What are the 3 types of refrigeration?
- Evaporative Cooling. Evaporative cooling units are also referred to as swamp coolers.
- Mechanical-Compression Refrigeration Systems. Mechanical compression is used in commercial and industrial refrigeration, as well as air conditioning.
- Absorption.
- Thermoelectric.
How does refrigerant get cold?
When the Freon gas is compressed, its pressure rises, making it very hot. Next, the hot Freon gas moves through a series of coils, which has the effect of lowering its heat and converting it to liquid. The Freon liquid then flows through an expansion valve, which causes it to cool down until it evaporates.
What is refrigeration temperature?
Use an appliance thermometer to be sure the temperature is consistently 40° F or below and the freezer temperature is 0° F or below. Refrigerate or freeze meat, poultry, eggs, seafood, and other perishables within 2 hours of cooking or purchasing. Refrigerate within 1 hour if the temperature outside is above 90° F.
How much current does a refrigerator draw?
Amperage for most household refrigerators, is anywhere from 3 to 5 if the voltage is 120. A 15 to 20 amp dedicated circuit is required because the in-rush amperage is much higher. The average amperage is lower because the compressor isn’t running all the time, this is often measured in kilowatt hours KWH.
How many watts is a fridge compressor?
Running wattage for most household refrigerators, is usually between 350 to 750 if the voltage is 120. However, the average wattage will usually only be between 100 to 300 watts, because the compressor only runs about 30% of the time.
How many watts does a fridge use per day?
Conventional refrigerators typically have a starting wattage of 800-1200 watt-hours/day, and a running wattage of around 150-watt hours/day. Refrigerators are reactive devices that require additional power to start because they contain an electric motor, but significantly fewer watts to run as they remain on.
What is the 1 ton of refrigeration?
It was originally defined as the rate of heat transfer that results in the freezing or melting of 1 short ton (2,000 lb; 907 kg) of pure ice at 0 °C (32 °F) in 24 hours.