Evaporator and refrigeration system comprising the same

A refrigeration system comprising:

• a compressor;
• a four-way valve defining first to fourth valve ports, the first valve port and the third valve port being connected to the compressor;
• a condenser defining an inlet connected to the second valve port;
• a throttle mechanism defining an inlet connected to an outlet of the condenser;
• an evaporator connected between the fourth valve port and an outlet of the throttle mechanism, the evaporator including:
• a first header defining one end at which a first refrigerant port is formed;
• a second header defining one end at which a second refrigerant port is formed;
• a plurality of heat-exchange tubes each of which is connected between the first and second headers to communicate the first and second headers;
• a plurality of fins respectively interposed between adjacent ones of the heat-exchange tubes;
• and
• a defrosting tube defining a first end and a second end, wherein the first end is connected to one of the first and second headers to communicate with an interior of the one header, a position at which the first end of the defrosting tube is connected to the one of the first and second headers is spaced apart from the one end of the one header by a predetermined distance, and the second end is connected with the fourth valve port of the four-way valve directly or via a valve;
• and
• a refrigerant switching unit connected to the evaporator, connected between the fourth valve port and the outlet of the throttle mechanism, allowing a refrigerant to enter into the first header from the four-way valve through the throttle mechanism and flow out of the second header to return to the four-way valve when the refrigeration system is in a “normal operation” mode, and allowing the refrigerant to enter into the one header from the four-way valve through the defrosting tube and flow out of the other of the first and second headers to return to the four-way valve through the throttle mechanism when the refrigeration system is in a “defrosting operation” mode.