1、 Overall Overview of System Composition

The system consists of the following parts:

The function of the test chamber is to provide a testing environment with constant high and low temperature humidity, and alternating high and low temperature humidity; Including refrigeration system, heating system, humidification/dehumidification/water system, air duct system, control system, system safety protection device, etc;

2、 Main technical indicators of the test chamber

1. Studio size: 600 x 800 x 850mm (depth x width x height);

2. Dimensions: 1300 × 1400 × 1950mm (depth × width × height);

3. Temperature range: 0 ℃ to+150 ℃;

4. Temperature fluctuation: ≤± 0.5 ℃;

5. Temperature uniformity: ≤± 1 ℃;

6. Temperature deviation: ≤± 2 ℃;

7. Heating and cooling rate:

From+20 to ℃, about 20 minutes

From+20-100 ℃, approximately 40 minutes

8. Humidity range: 20% -98% R.H (AT+25 ℃ -+85 ℃)

9. Humidity error:+2/-3% R.H (above 75% R.H), ± 5% R.H (below 75% R.H)

10. Wind speed: 1.7-2.5m/s;

The above indicators were tested and measured under ambient temperature ≤ 25 ℃, normal pressure, no-load and no-load conditions, and within 1/6 space from the inner wall of the box;

11. Power: approximately 8.5Kw

12. Power supply: 380V ± 10% V; 50Hz;

Meet relevant standards and test methods:

GB/T2423.22-87Nb GJB1032-90 MIL-STD-2164/(E/C)

GB/T2423.4-93 GB/T2423.34-86 GJB150.9-86

Refrigeration system of test chamber:

1. Refrigeration principle:

The refrigeration section is the main part of the equipment that generates a cold source, providing the required cooling capacity for equipment cooling, low temperature, and constant temperature. Depending on the testing status of the equipment, the refrigeration system automatically starts to provide cooling capacity for the corresponding testing process, thereby achieving the goal of meeting the performance indicators of the equipment.

The design of refrigeration systems applies energy regulation technology, which is an effective way to ensure that the energy consumption and cooling capacity of the refrigeration system can be adjusted while the refrigeration unit is operating normally, reducing the operating costs and failure rates of the refrigeration system to a more economical state.

2. Refrigeration system components:

2.1 Compressor: The core of the refrigeration system is the compressor. In this solution, we use a French Taikang fully enclosed compressor to form a refrigeration system to ensure the cooling requirements of the studio. The refrigeration system consists of a high-pressure refrigeration cycle and a low-pressure refrigeration cycle, with the connecting container being an evaporator. The function of the evaporative condenser is to use the low-pressure cycle evaporator as the high-pressure cycle condenser.

2.2. Oil separator: Whether the compressor has sufficient refrigerant oil will directly affect its service life. If the refrigerant oil enters the system, especially in various heat exchangers, its performance will be greatly reduced. Therefore, the system needs to be equipped with an oil separator. Based on our company's previous experience and use of imported oil separators, we have equipped this equipment with a European and American "AiGao" ALCO oil separator.

2.3 Condensation evaporator: The world's advanced brazed plate heat exchanger produced by ALfaLaval or Swep in Sweden is used. This heat exchanger consists of several corrosion-resistant stainless steel sheets pressed into a herringbone ripple shape. Adjacent pairs of stainless steel sheets have opposite ripple directions, and the ripple back lines intersect with each other to form a large number of contact welding points. Due to the complex contact cross network channels, turbulent flow is formed on both sides of the fluid, which increases the heat transfer intensity. At the same time, the strong turbulent flow and smooth stainless steel surface make the inner surface of the brazed plate heat exchange channel less prone to scaling. The use of this heat exchanger overcomes the disadvantages of large size, poor heat transfer, and low efficiency of this component in previous domestic high and low temperature test chambers. At the same time, the system resistance is also reduced to the lowest level. Limitations.

2.4 Vibration reduction: Adopting compressor spring vibration reduction and overall secondary vibration reduction of the refrigeration system; The refrigeration system pipeline adopts the method of adding R and elbows to avoid copper pipe deformation caused by vibration and temperature changes, which may cause the refrigeration system pipeline to rupture.

2.5. Refrigeration evaporator: The evaporator is located in the air duct interlayer at one end of the test chamber, and is forcibly ventilated by a blower motor for rapid heat exchange.

2.6 Refrigeration auxiliary components: All other auxiliary components in the refrigeration system of this test chamber are imported components. Such as the Italian "Castel" solenoid valve, two-way manual valve, European and American "Aigo" ALCO oil separator, American "Spiran" SPORLAN expansion valve, dry filter, Danish "Danfoss" DANFOSS condensing pressure controller, etc.

2.7 Energy regulation measures: While ensuring the main technical indicators of the test chamber, it is essential to adjust the cooling capacity of the system according to different cooling rates and temperature ranges. Therefore, in addition to the corresponding energy regulation measures considered above, such as evaporation temperature regulation, energy regulation, and hot gas bypass energy regulation, we will ensure that the equipment energy consumption is reduced while meeting the main technical indicators.

2.8 Low temperature piping: High quality oxygen free copper pipes, nitrogen filled welding, and specialized piping processes are used for low-temperature piping. High quality oxygen free copper pipes are nitrogen filled and welded (traditional methods use ordinary copper pipes, direct welding methods can easily cause oxides to form on the inner wall of the copper pipes, causing blockages in the refrigeration system and preventing or slowing down the cooling of the test chamber). The process ensures welding quality.

2.9. Cooling method of refrigeration system: air cooling;

(The cooling method can be chosen by the user according to the situation. Air cooling requires high ambient temperature and loud noise. For specific installation requirements, please refer to Part 6 of this plan: Installation and Use Conditions.)

2.10. Refrigerant: R404a;

III Heating system:

Continuous PID regulation, using SSR solid-state relays as heating actuators, safe and reliable, with a separate over temperature protection system.

4 Humidification/dehumidification/water system:

4.1 Humidification method: stainless steel heating tube is used, with external humidification;

4.2 Dehumidification method: Freeze dehumidification;

4.2 Waterway system: The equipment water supply system adopts a built-in 20L stainless steel circulating water tank with low water consumption and stable circulation. The box is equipped with a drawer type water tank, and the circulating water tank level display device is used to observe the water level. It also has a water shortage indicator light accompanied by sound and light alarms to remind users to replenish equipment water in a timely manner. The separation of the humidification system pipeline from the power supply, controller, and circuit board can avoid the impact of pipeline leakage on the circuit and improve safety.

Five Air duct system:

To ensure a high uniformity index, the test chamber is equipped with an internal circulating air supply system; Inside the air duct interlayer at one end of the studio, there are devices such as heaters, refrigeration evaporators, and fan blades distributed; Use a fan to circulate the air inside the box. When the fan rotates at high speed, the air in the working chamber is sucked into the air duct from the lower part. After heating and cooling, it is blown out from the upper part of the air duct. The air that exchanges heat with the test sample in the working chamber is then sucked into the air duct and repeatedly circulated to meet the temperature setting requirements.

VI Control system:

Composition of control system:

6.1 Temperature measurement: Pt100 platinum resistor;

6.2 Humidity measurement: Pt100 platinum resistance dry wet bulb method;

6.3 Control device: Programmable temperature and humidity controller TEMI580. It can display set parameters, time, working status of heaters, humidifiers, etc., and also has automatic test operation and PID parameter self-tuning functions. The automatic operation function of the refrigeration machine can be achieved by simply setting the temperature. The control system uses an intelligent control software system, which has the ability to automatically combine the working conditions of subsystems such as refrigeration, heating, and humidification, thereby ensuring high-precision control over the entire temperature and humidity range and achieving the goal of energy conservation and consumption reduction. A complete detection device can automatically display detailed faults and alarms, such as the controller automatically displaying the fault status when an abnormality occurs in the test chamber.

6.5 Screen display: Set temperature and humidity; Actual measured temperature and humidity; Heating, humidification, time, temperature and humidity curves, and various alarm indicators.

6.6 Setting accuracy: Temperature: 0.1 ℃ Humidity: 0.1% R.H

6.7 Program capacity: 100 pieces, total number of program segments 1000, maximum single step time of program: 99 hours and 59 minutes; Programs can be looped and linked between programs;

6.8 Operation mode: Constant operation, program running;

6.9. Other major low-voltage electrical components use well-known brand products, such as Schneider AC contactors, thermal overload relays, OMRON small intermediate relays, Delixi circuit breakers, Taiwan Fanyi water level float switches, etc.

7 Safety protection device:

Studio overheating protection; Heater short circuit protection;

Humidifier short circuit protection; Fan overload protection;

Compressor overpressure protection; Compressor overload protection;

Water supply/shortage protection; Leakage protection;

Safe and reliable grounding device;