Design of Micro-environmental Humidity Measurement and Control System for Cultural Relics Display Case

The relative humidity is one of the most critical indexes for the preservation of cultural relics. To maintain the stability of the humidity in the microenvironment of cultural relics display cases, this paper designs and develops a humidity measurement and control system for the micro-environment of cultural relics display cases based on the principle of direct mixing of air and water for hot and cold exchange, combined with embedded system and automatic control technology. Focus on solving the compressor-evaporator type refrigeration problem of frost and large fluctuations in the humidity of the display case, and the system for the limit value and stability test. The test results show that when the environmental temperature of the cultural relics display case is
$25^{\mathrm{\circ}}\mathrm{C}\pm 2^{\mathrm{\circ}}\mathrm{C}$
, the system can control the humidity of the display case in the range of 30%~70%, and the fluctuation and accuracy of the regulation and control are less than
$\pm 1\%$
when working for a long time, which meets the technical requirements of Chinese cultural relics protection industry standard for humidity regulation device.