Principle, structure and operation method of ammonia machine cooling

The refrigeration process of ammonia machine is carried out in a closed cycle system consisting of ammonia compressor, cooler, regulating valve and evaporator. After the ammonia water enters the evaporator under reduced pressure through the regulating valve, it absorbs the heat of the cooled medium and evaporates, thus reducing the temperature of the medium and achieving the purpose of refrigeration. The evaporated ammonia is sucked back by the compressor, compressed and discharged into the cooler, so that the ammonia is cooled and condensed into ammonia liquid, and then evaporated in the evaporator through the regulating valve to achieve the purpose of repeated refrigeration.

A complete refrigeration system generally consists of compressor, condenser, ammonia storage, oil separator, throttle valve, ammonia liquid separator, evaporator, intercooler, emergency ammonia leakage device, oil collector, various valves, pressure gauges and high and low pressure pipelines. Among them, compressor, condenser, throttle valve and evaporator (cold storage exhaust pipe) are the four most basic components in the refrigeration system. They are connected in turn through pipes to form a closed system. Refrigerant ammonia circulates continuously in the system, changing its state and exchanging heat with the outside. Its working process is as follows: liquid ammonia absorbs the heat of the cooled object in the evaporator, then vaporizes into low-pressure and low-temperature ammonia, which is sucked by the compressor, compressed into high-pressure and high-temperature ammonia and then discharged into the condenser, where it is cooled by cooling water and condensed into high-pressure ammonia liquid, which is throttled into low-temperature and low-pressure ammonia liquid by the throttle valve, and then enters the evaporator for heat absorption and gasification. In this way, ammonia in the system completes a refrigeration cycle through four basic processes: evaporation, compression, condensation and throttling.

In the actual refrigeration system, to complete a refrigeration cycle, the refrigerant needs to pass through the above four components and many auxiliary devices. These devices are provided to improve the economy, reliability and safety of operation. Taking the refrigeration system of two-stage compressor as an example, to complete a refrigeration cycle, ammonia must pass through the low-stage ammonia compressor, the first-stage oil separator, the intercooler, the high-stage ammonia compressor, the second-stage oil separator, the condenser, the ammonia storage device, the throttle valve, the ammonia liquid separator, the regulating station and the evaporator, and then return to the low-stage ammonia compressor, thus completing a cycle. The actual refrigeration process is more complicated.

The principle of refrigeration is a process of energy conversion. That is, electric energy is converted into mechanical energy, and mechanical energy is converted into heat energy, and then cold and heat exchange is carried out through the action of ammonia to complete the refrigeration process.