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Evaporator for Indoor Cassette Unit
The evaporator in indoor cassette air conditioning units is a critical component of the refrigeration system, responsible for absorbing indoor heat to achieve cooling.
Structural Components:
Fins: Typically made of aluminum or copper, with a thickness of approximately 0.1 mm and spaced 1.5-2.5 mm apart. Aluminum fins offer rapid heat dissipation and lower cost; hydrophilic surface treatment facilitates swift condensate drainage. Copper fins provide superior heat transfer but carry higher costs. Some fins feature corrugated or windowed structures to induce air turbulence and enhance heat exchange efficiency.
Copper Tubes: Typically 7-9 mm in outer diameter, with fine internal grooves that induce refrigerant rotation during flow, enhancing heat exchange. Tubes are arranged either flat or in a V-shape, with the V-pattern increasing heat exchange area by approximately 20%. Both ends connect to manifold pipes, which consolidate refrigerant from multiple tubes into inlet and outlet ports.
Distributor: Installed at the manifold inlet, this tree-branch shaped component evenly distributes liquid refrigerant to each copper tube. It ensures consistent flow rates across all lines, preventing localized frost buildup that could impair cooling performance.
U-Bends: Used to connect adjacent copper tubes. The bend radius must be moderate—too small impedes refrigerant flow, while too large wastes space. These joints are prone to leaks and are critical maintenance points.
Working Principle: Low-temperature, low-pressure liquid refrigerant enters the evaporator. When warm indoor air is blown over the evaporator by the fan, the refrigerant absorbs heat from the air, evaporating from liquid to gas form. This process lowers the air temperature, achieving cooling. Simultaneously, moisture in the air condenses on the evaporator surface, providing dehumidification. The heat-absorbed gaseous refrigerant then flows through pipes into the compressor, initiating the next refrigeration cycle.
