How to distinguish the quality of water curtain for greenhouse cooling equipment
Wet curtains are the most effective and energy-saving cooling method for multi-span greenhouses. What are the quality differences between water curtains?
1、 Introduction to Wet Curtain
Wet curtain, also known as water curtain, has a honeycomb structure and is produced by processing base paper. The production process of wet curtain is generally sizing, drying, pressing corrugated, shaping, gluing, curing, slicing, grinding, and deodorizing.
2、 Wet curtain model
In China, there are generally three types of wave heights: 5mm, 7mm, and 9mm, with a ripple of 60 ° × 30 ° staggered opposition, 45 ° × 45 ° staggered.
3、 Quality standard for wet curtain
1. The superior wet curtain is made of a new generation of polymer materials and spatial cross-linking technology, which has the advantages of high water absorption, high water resistance, mildew resistance, and long service life. Moreover, the evaporation ratio is larger than the surface, with a cooling efficiency of over 80%. It does not contain surfactants, naturally absorbs water, has a fast diffusion speed, and has a lasting effect. A drop of water can diffuse in 4-5 seconds. The international industry standard for natural water absorption is 60~70mm/5min or 200mm/1.5hour.
2. High quality wet curtains also do not contain chemicals such as phenol that can easily cause skin allergies. When installed and used, they are non-toxic and harmless to the human body. They are green, safe, energy-saving, environmentally friendly, and economical.
The cooling principle of fan and water curtain in summer aquaculture farms:
Wet curtain (water curtain) cooling mainly utilizes the physical principle that water absorbs heat from the air during the evaporation process of water, causing the air temperature to decrease. In practice, it is used in conjunction with a negative pressure fan. The wet curtain is installed on one end of the gable or side wall of a closed building, and the fan is installed on the other end of the gable or side wall. The cooling fan extracts indoor air, generating negative pressure to force outdoor air to flow through the porous wet curtain surface, converting a large amount of heat in the air and forcing the air entering the room to decrease by 4-10 ℃, and continuously introducing it into the room for heatstroke prevention and cooling.
Water evaporation and heat absorption are a common physical phenomenon in nature, and cooling with water curtains also applies this principle. The comprehensive application of wet curtain cooling systems and negative pressure fans utilizes the thermal principle of water evaporation and heat absorption to cool the air, fully demonstrating the three main elements of the principle of water evaporation and heat absorption:
1. Surface area in contact with water and air
2. Air circulation speed
3. The temperature of the water itself
And the heat absorption efficiency of water evaporation is directly proportional to the above factors:
Under the action of the water pump and gravity, water flows from top to bottom, forming a wrinkled water film with a total area equivalent to more than 100 times the outer surface area of the water curtain on the corrugated fiber surface of the wet curtain. Therefore, the contact area between the water film and air is very large.
2. Due to the “pressure difference” caused by the suction of negative pressure fans, outdoor air will quickly detour through the cooling water curtain and collide with the water film of the water curtain, facilitating the rapid absorption of heat in the air by a wide area of water film.
3. As the water temperature rises, evaporation intensifies, and as evaporation intensifies, the heat carried away by water increases. That is, the cooling effect becomes more obvious.
