Rooftop DX Air-Conditioning Units For Paint Booth Air Temperature Regulation

Rooftop DX Air-Conditioning Units For Paint Booth Air Temperature Regulation

Rooftop air-cooled direct expansion air-conditioning unit is the compressor, evaporator, condenser, fan and other core components integrated into a whole device, installed directly on the roof, through the air-cooled way of heat dissipation, without the need for a separate cooling tower or room, with a compact structure, easy to install, space-saving and other characteristics. The principle of “direct expansion” means that the refrigerant evaporates and absorbs heat directly in the evaporator, and realizes cooling (or heating) and dehumidification of the indoor environment through air circulation.

Paint spraying room has very high requirements on the environment, and the rooftop air-cooled direct-expansion air-conditioning unit is mainly embodied in the following aspects:

Precise control of temperature and humidity

In the process of paint spraying, too high a temperature is easy to lead to the paint drying too quickly, cracks; too low a temperature may make the paint leveling, adhesion is not enough; improper humidity will lead to blisters, pinholes and other problems in the paint film. The set can stabilize the temperature at 15-30℃ (adjusted according to the type of paint) and control the relative humidity at 40%-60% through temperature control and dehumidifying function to guarantee the quality of spraying paint.

Provide clean airflow

The units are usually equipped with middle and lower efficiency filters (some of them can be upgraded to high efficiency), which can filter dust and particles in the air to avoid them from mixing with paint and adhering to the surface of workpieces, ensuring the paint film is smooth and even.

Maintaining positive pressure environment

Through the reasonable design of air supply volume, the paint spraying room maintains micro-positive pressure (generally 5-10Pa), preventing the infiltration of unfiltered air from outside, and at the same time, the paint mist and solvent vapor will be discharged in time with the exhaust system to reduce the hazards to the operators.

Design Considerations

Load Calculation

The volume of paint spraying room, heat dissipation of equipment (e.g. drying equipment), heat brought in by workpiece, heat dissipation of personnel, and the number of times of ventilation (usually 8-15 times/h) should be considered to make sure that the cooling/heating capacity of the unit matches.

Solvent evaporation in the spraying process will release latent heat, need to pay attention to the dehumidification capacity of the unit to avoid high humidity environment affecting the curing of paint film.

Anti-corrosion treatment

Paint mist and solvent vapors are corrosive, the unit's air supply and return ducts, fan impellers and other components need to be corrosion-resistant materials (e.g., galvanized steel, glass fiber reinforced plastic) or anticorrosive coating treatment, to prolong the life of the equipment.

Exhaust synergy

air supply volume needs to be greater than the exhaust volume (generally 10% -15%) to maintain positive pressure, the exhaust system should be set up paint mist filters (such as water curtains, activated carbon adsorption), to reduce the pollution of the environment, and at the same time to avoid the exhaust air is too large to lead to negative pressure indoors, destroying the stability of temperature and humidity.

Installation and Maintenance

Rooftop installation should consider load-bearing, windproof and rainproof, and the foundation of the equipment should be leveled to avoid vibration noise.

Regularly clean the filter, check the refrigerant pressure, clean the condenser (to prevent dust clogging affecting heat dissipation), to ensure efficient operation of the unit.

Applicable scenarios: small and medium-sized paint spray booths (e.g. auto parts, furniture, hardware spray painting), places where there are restrictions on installation space and no need for complex machine room design.