1. The choice of the number of evaporative air cooler equipment

The number of air conditioners required in a certain space is determined by the number of air conditioners permeated, which is a common design method for evaporative air conditioners. This approach is generally used in actual engineering designs.

(1) 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 / (indoor area S× the height of the air supply port and the exhaust port H);

(2) The general environment requires 25 to 30 times of ventilation times/hour;

(3) Public places with dense traffic require 30 to 40 times per hour of ventilation;

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

(5) The number of air changes in the humid southern region is appropriately increased, while the hotter and drier northern region can be appropriately reduced.

Specific calculation steps:

(1) Calculate the area of the site to be cooled in the project S, determine the largest height of the feed or exhaust air outlet H, and then calculate the volume V of the refrigeration space;

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

(3) The volume of the cooling space V× the number of air changes N, to obtain the total supply air volume required for the space L;

(4) The total air supply volume is divided by the actual air volume L1 of the selected single air conditioner, that is, the number of required air conditioners is obtained n.

Selection of evaporative air conditioner (calculation of number of units and number of air changes)

T------- the number of air conditioners V------- need to cool down the volume of the site

S------- the area of the site to be cooled h------- the height of the air supply outlet

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

V = S × h (air outlet height)

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

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

2. Post air supply

The above is the general design calculation method of comprehensive air supply, but in many cases, some commercial and industrial buildings have high temperatures in some areas, such as machine heating, processing heating, etc., in this case, the indoor temperature is higher than the outdoor temperature, and the evaporative air conditioner can cool the outdoor air and continuously deliver it indoors. For example, there is a factory workshop whose equipment generates a high amount of heat, with indoor temperatures of up to 45°C and outdoors of only 38°C. The evaporative air conditioner can cool the outdoor air from 38 °C to 30 °C and send it into the room, which is 15 °C lower than the original indoor 45 °C, which can significantly improve the working environment. In this case, we generally do not calculate the heat load, only need to design a set of post air supply system, the air outlet continues to send cold air to the post, and the hot air around the post is continuously dispersed. In addition, the post air supply system can also be used in some completely open spaces, and these places consider post cooling as a more appropriate choice.

Determination of the air supply 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 find the total air supply volume required, and then the number of air conditioners that should be selected can be calculated. The air volume of each air outlet is determined according to the actual situation, but in general, the air volume of the air outlet is controlled as much as possible between 3 and 6m/s (according to the heat generation and personnel density of the installation site).

3. Determination of exhaust air volume

The evaporative air conditioner is to achieve the purpose of refrigeration and cooling by continuously injecting fresh cold air into the room to replace the turbid air in the room, so the basic form of the cold air cooling system is "one in and one out", rather than closed. In general, the indoor positive pressure is used for natural exhaust, and mechanical exhaust can be used in a confined space. In order to achieve a good ventilation and cooling effect, the exhaust air volume of the cold air cooling system of the air conditioning mechanism should reach more than 80% of the total supply air volume, and the speed of natural exhaust 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 (generally municipal tap water) and ensure that the pressure of the water source ≥ 1.0kgf/cm2.

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

(3) In order to prevent the rise and cracking of the water supply pipeline in winter, the outdoor water supply pipe of the air conditioner shall be equipped with a thermal insulation and drainage valve (determined according to the local water supply and drainage design specifications), and the water storage in the water tank in the unit must be drained when the cold function of the air-conditioning mechanism is not used in winter.

(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 specified by the nameplate of the machine.

(5) Air switches should be installed on the main circuit to avoid faults caused by short circuits, overloads, etc.