1. Selection of the number of evaporative air coolers

    Reference for the number of air changes in various occasions

      The number of air changes is used as a parameter to determine the number of air conditioners required in a certain space. This is a common design method for evaporative air conditioners. Actual engineering design generally adopts this method.

①The definition of the number of air changes: the number of air changes N (times/hour) = the total air supply volume of the refrigeration space L/(the indoor area S × the height of the air outlet and the air outlet, whichever is greater, H);

②General environment requires air change frequency of 25-30 times/hour;

③Public places with intensive human flow require 30-40 air changes per hour;

④The production workshop with heating equipment requires more than 40-50 times/hour of air exchange;

⑤ The number of air changes should be appropriately increased in the humid southern regions, while the number of air changes can be appropriately reduced in the hot and dry northern regions.

Specific calculation steps:

① Calculate the area S of the site that needs to be cooled in the project, determine the greater H of the air supply or exhaust outlet, and then calculate the volume V of the refrigeration space;

②Determine the number of air changes N according to the actual situation;

③The volume of the refrigeration space V×the number of air exchanges N to obtain the total air supply volume L required for the space;

④ Divide the total air supply volume by the actual air volume L1 of the selected single air conditioner to get the number of air conditioners required n.

Selection of evaporative air conditioners (calculation of the number of units and the number of air changes)

T-------Number of air-conditioning units V-------Volume of site to be cooled

S-------The area of the site that needs to be cooled      h-------the height of the air outlet

N-------Number of air changes        Q-------Air volume of selected unit

V = S × h (the height of the air outlet)

1) The calculation formula of the number of units: T = (V×N)÷Q  

2) The calculation formula for the number of air changes: N= (Q × T) ÷ V

2. Post air supply

      The above is a general design calculation method for full air supply, but in many cases, some areas of commercial and industrial buildings have high temperatures, such as machine heating, processing heating, etc. In this case, the indoor temperature is higher than the outdoor temperature. High, evaporative air conditioners can cool outdoor air and continuously deliver it indoors. For example, in a factory workshop, its equipment generates high heat, the indoor temperature can reach 45°C, while the outdoor temperature is only 38°C. The evaporative air conditioner can cool outdoor air at 38°C to 30°C and send it indoors, which is 15°C lower than the original indoor 45°C, which obviously improves the working environment. In this case, we generally do not calculate the heat load. We only need to design a post air supply system. The air outlet continuously sends cold air to the post, and the hot air around the post is continuously dissipated. In addition, the post air supply system can also be used in some completely open spaces. These places consider post cooling to be a more appropriate choice.

       Determining the air volume of the post: According to the actual situation of the post, first determine the air volume of each post, and multiply the required air volume of each post by the number of posts to obtain the required total air volume. Calculate the number of air conditioners that should be selected. The air volume of each air outlet is determined according to the actual situation, but in general, the air volume of the air outlet should be controlled as far as possible between 3~6m/s (depending on the heat generation of the place where the equipment is installed and the density of people).

3. Determination of exhaust air volume

    The evaporative air conditioner achieves the purpose of cooling and cooling by continuously injecting fresh cold air into the room to replace the turbid air in the room. Therefore, the basic form of the air conditioner refrigeration system is "one in and one out" instead of closed. Under normal circumstances, the positive pressure in the room is used for natural exhaust, and mechanical exhaust can be used in confined spaces. In order to achieve good ventilation and cooling effect, the exhaust air volume of the air-conditioner refrigeration system should reach more than 80% of the total air supply volume, and the natural exhaust air speed should be controlled within 2m/s to ensure the good operation of the system.

4. Water supply and power supply

(1) Use a clean water source (usually municipal tap water can be used) and ensure that the pressure of the water source is ≥1.0kgf/cm2.

(2) A shut-off valve should be installed near the water inlet pipe (DN20) of the air conditioner, and a water pipe joint for cleaning should be reserved.

(3) In order to prevent the expansion and cracking of the water supply pipeline in winter, the outdoor water supply pipe of the air conditioner must be equipped with heat preservation and drain valve (determined according to the local water supply and drainage design code). Water storage.

(4) Ensure that the power supply voltage is stable between single-phase 220～240V and three-phase 380～400V, and the current reaches the rated current calibrated on the nameplate of the machine.

(5) An air switch should be installed on the main circuit to avoid malfunctions caused by short circuits and overloads.