What is the unit of refrigeration? 

The unit of refrigeration is a measurement of heat removal used in the field of thermodynamics. It is most commonly used in the context of refrigerators and air conditioning systems. The unit of refrigeration is sometimes called a ton of refrigeration, especially in the United States. It is defined as the heat removal rate of one short ton of ice melting in a 24-hour period. The unit of refrigeration is a useful measure for comparing the cooling capacity of different refrigeration systems. 

What is one TR and How can we calculate it?

The definition of one ton of refrigeration (TR) is a unit of power used to describe the cooling capacity of a system. It is defined as the rate of heat transfer that results in the removal of one ton (2000 pounds or 907 kilograms) of water at 24 degrees Celsius (75 degrees Fahrenheit) in 24 hours.

One TR is equivalent to 12,000 British thermal units (BTUs), which are the units used to measure the heat content of water. One ton of refrigeration is also equivalent to 3.5 kilowatts (kW), which is the unit of power used to measure the rate of energy transfer.

The cooling capacity of a refrigeration system is usually measured in tons of refrigeration. But the power rating of the system, which is what determines the cost of operating the system, is usually given in kilowatts.

To calculate the cost of operating a refrigeration system, you need to know both the cooling capacity of the system in tons of refrigeration and the power rating of the system in kilowatts.

The formula for calculating the cost of running a refrigeration system is:

Cost = Cooling capacity (in tons) x Power rating (in kilowatts) x Hours of operation x Cost of electricity ($/kWh)

For example, let's say you have a refrigeration system with a cooling capacity of 1 ton and a power rating of 3.5 kilowatts. If you operate the system for 8 hours a day, the cost of running the system would be:

Cost = 1 ton x 3.5 kW x 8 hours x $0.15/kWh

That comes out to $4.20.