Expendable Refrigeration System With The Refrigerant
This simple system, sometimes called chemical cooling or open cycle cooling is becoming more popular. It is used on trucks and other vehicles in the transport sector and storage of chilled or frozen products. In fact, disposable refrigeration system with the refrigerant is strongly isolated space. Can cool being surrounded by pipe carrying boiling point of liquid nitrogen. Another way to cool consists of spraying liquid nitrogen directly into space cooling. In any case, disposable refrigerant system, in which the system ignores the refrigerant after she was gone.
Fig. 3-16 illustrates the spray system. Liquid nitrogen (dark red)supplied from a cylinder inside the refrigerated space, kept under pressure (200 psi). Dark blue indicates low pressure liquid refrigerant.
Sealed cylinder insulation. However, the auto-safety relief valve will be opened as a security measure, if necessary. This will nitrogen vapor to escape the pressure must exceed the safety valve setting.
The heat surrounding the cylinder can cause pressure steam to rise above the automatic pressure relief settings. Cold pairs of the nitrogen is released by automatic pressure release valve. It comes in a refrigerated space or in the cooling pipes, depending on the system. Temperature sensor control unit and fluid control valve to control the flow of liquid nitrogen from the nozzles. They maintain the preset temperature inside the refrigerated space.
Liquid nitrogen (dark red) vaporizes (boils and turns into gas) at a temperature of 320T (-196C) at atmospheric pressure (Fig. 1-26). Such a system is ideal for delivery of frozen products in Temperatures could be as low as desiredusually around -20F (29CC).
Simple designs such as this requires little attention. Sometimes it may be necessary to replace or recharge nitrogen storage cylinder. Another advantage of this system is its ability to work without power. Safety devices in places, cooled by liquid nitrogen to shut off the flow of nitrogen when a man opens the door to space. Cm. Chapter 18.
Another form of consumable refrigerant cooling system of natural gas supplied in a liquid form in large tankers. Natural gas, liquid under pressure, will evaporate. Some gas will evaporate. This evaporative cooling supports the remaining natural gas in liquid form. Evaporated natural gas is ducted to the tanker engines. There he be burned to power on the storage tanker...