Radiational cooling film providing a variable wavelength and wavelength conversion device and system using the same

A wavelength conversion device providing a variable wavelength comprising:

• a radiational cooling film configured such that one surface of a base layer comprises a first region in which a heat barrier layer is formed and a second region in which the heat barrier layer is not formed, and a wavelength conversion layer comprises a pattern of a plurality of wavelength conversion sections, wherein the heat barrier layer reflects infrared band from sunlight;
• and
• a driving unit comprising two rollers configured to wind both ends of the radiational cooling film, a motor configured to apply rotational force to at least one of the two rollers, and a controller configured to control an RPM and a rotational direction of the motor,
• wherein the pattern of the plurality of wavelength conversion sections is repeatedly disposed in the wavelength conversion layer with a separating distance therebetween such that the first region has the same pattern of the plurality of wavelength conversion sections and the second region has the same pattern of the plurality of wavelength conversion sections.

A wavelength conversion system providing a variable wavelength comprising:

• a wavelength conversion device comprising a radiational cooling film configured such that one surface of a base layer comprises a first region in which a heat barrier layer is formed and a second region in which the heat barrier layer is not formed, and a wavelength conversion layer comprises a plurality of wavelength conversion sections separated from each other in each of the first region and the second region, and a driving unit comprising two rollers configured to wind both ends of the radiational cooling film, a motor configured to apply rotational force to at least one of the two rollers, and a controller configured to control an RPM and a rotational direction of the motor;
• a temperature sensor installed in a facility;
• and
• a management server configured to control the wavelength conversion device so that sunlight is radiated to one of the wavelength conversion sections of the first region if a value measured by the temperature sensor is greater than a threshold value;
• and
• a camera configured to photograph living bodies to be grown in the facility,
• wherein the management server comprises an analyzing module configured to determine a growth stage of the living bodies to be grown based on image data transmitted by the camera, and an indicating module configured to determine one of the first region and the second region based on the value measured by the temperature sensor and to control the wavelength conversion device so that sunlight is radiated to one of the wavelength conversion sections of the determined region to emit a necessary wavelength depending on the determined growth stage.