The Minimum Air Volume Control Method of Mechanical Ventilation System in Caves

Abstract

The invention discloses a method for controlling the minimum air volume of a mechanical ventilation system in a cavern. The method comprises the following steps: (1) acquiring parameters; (2) calculating the pressure difference value delta P1 between the inner and outer sides of the cavern in an opening state; (3) calculating the flow coefficient c; (4) calculating the minimum air leakage rate Q1 of the cavern under the action of mechanical air supply, and then calculating the pressure difference value delta P2 between the inner and outer sides of the cavern at the moment; and (5) calculating the pressure value delta P3 provided by a mechanical air supply system, calculating the air supply volume Q2 required by the mechanical ventilation system through delta P3 and c, and determining the air exhaust volume Q3 required by the mechanical ventilation system according to the air volume balance, wherein the mechanical ventilation system is controlled by a pressure sensor in the cavern to control the system air supply and exhaust volume according to the air supply volume Q2 and the air exhaust volume Q3, and thus the pressure difference value between the inner and outer sides of the cavern is kept at delta P3. According to the method disclosed by the invention, the mechanical ventilation system is additionally arranged for the cavern. Through the control over the system air supply and exhaust volume as well as the static pressure in the cavern, a micro-positive pressure state of the cavern can be formed, high-humidity air in the atmosphere can be prevented from diffusing towards the cavern, and a stable humidity environment can be provided for cultural relics in the cavern during rain.

Description

technical field [0001] The invention belongs to the field of heating, ventilation and air conditioning, and in particular relates to a method for controlling the minimum air volume of a mechanical ventilation system. Background technique [0002] The weather in Dunhuang has changed in recent years, with short-term heavy rainfall. The heavy rainfall has had a great impact on the local extremely arid desert climate, and the relative humidity of the air has risen sharply in a short period of time. The highest relative humidity outside the cave is close to 100%, and the highest relative humidity inside the cave is 80%, reaching the deliquescence humidity of some crystalline salt in the floor of the murals of the Mogao Grottoes. The relative humidity stability in the cave was broken, which led to the migration of water and salt in the cave cliff, and accelerated the disease process of murals. At present, the main way to prevent atmospheric high-humidity air from penetrating int...

AI Technical Summary

Problems solved by technology

However, at present, there is no method in the HVAC industry to determine the air supply and exhaust volume of the mechanical ventilation system for the design purpose of water vapor penetration. The current research in the HVAC industry lacks the relationship between indoor static pressure and indoor and outdoor air exchange volume. There is also a lack of accurate research on the relationship between air supply volume and indoor static pressure. Therefore, determining the static pressure value in the cave required to prevent the infiltration of high-humidity air outside the cave, and determining the appropriate air supply and exhaust value are currently problems that need to be solved. key issues

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