What are cooling medium and refrigerants? What is the difference between cooling medium and refrigerant?
The cooling medium is a substance that transfers the heat of the cooled system to the evaporating refrigerant in an indirectly cooled refrigeration device. Also known as secondary refrigerant. The commonly cooling medium is water, but it can only be used in conditions higher than 0°C. When it is required to be lower than 0°C, brine is generally used, such as sodium chloride or calcium chloride brine solution, or an aqueous solution of organic compounds such as ethylene glycol or glycerin. Anyda will talk about the difference between cooling meduim and refrigerant:
The cooling medium and the refrigerant are collectively referred to as the refrigerant, both of which belong to the medium that transmits the cooling capacity. The cooling medium is usually a liquid, and generally does not undergo a phase change during the heat transfer process. The refrigerant transfers the cold energy to the cooling medium through phase change refrigeration, and then transfers the cold energy of the cooling medium to the cold storage room under normal pressure through the pump to realize refrigeration. The main cooling medium substitutes are calcium chloride brine, sodium chloride brine, methanol, ethanol, ethylene glycol, propylene glycol, dichloromethane, etc.
Next, let's introduce the refrigerant. Refrigerants, are medium substances used in various heat engines to complete energy conversion. These substances typically increase power with reversible phase transitions such as gas-liquid phase transitions. Such as steam in a steam engine, refrigerant in a refrigerator, etc.
When a general steam engine is working, it releases the heat energy of the steam and converts it into mechanical energy to generate the motive force; while the refrigerant of the refrigerator is used to transfer the heat from the low temperature to the high temperature. The more common working media in traditional industry and life are partially halogenated hydrocarbons (especially chlorofluorocarbons), but they are gradually eliminated because they can cause holes in the ozone layer. Other widely used working media are ammonia, sulfur dioxide and non-halogenated hydrocarbons (such as methane).
