The refrigeration system of the refrigeration dryer belongs to compression refrigeration, which is composed of four basic components such as a refrigeration compressor, a condenser, a heat exchanger, and an expansion valve. They are connected in turn by pipes to form a closed system. The refrigerant continuously circulates in the system, changes its state and exchanges heat with the compressed air and cooling medium. The refrigeration compressor reduces the low pressure (low temperature) in the heat exchanger. ) The refrigerant is sucked into the compressor cylinder, the refrigerant vapor is compressed, and the pressure and temperature increase at the same time; the high-pressure and high-temperature refrigerant vapor is compressed to the condenser, in the condenser, the refrigerant vapor with higher temperature is lower than the temperature The cooling water or air exchanges heat, the heat of the refrigerant is taken away by the water or air and condenses, and the refrigerant vapor becomes a liquid. This part of the liquid is then delivered to the expansion valve, throttling through the expansion valve into a low-temperature and low-pressure liquid and enters the heat exchanger; the low-temperature and low-pressure refrigerant in the heat exchanger absorbs the heat of the high-temperature and high-pressure compressed air, and the compressed air In the case of keeping the pressure constant, the temperature is forced to decrease, thereby generating a large amount of supersaturated water vapor. The refrigerant vapor in the heat exchanger is sucked away by the compressor, so that the refrigerant passes through the four processes of compression, condensation, throttling, and evaporation in the system, thus completing a cycle.
One: Why does the plate type refrigeration dryer save energy?
The stainless steel plate heat exchanger used in the plate refrigeration and dryer is made up of many metal plates and connected together. The plates are welded and sealed to form cold and hot fluid channels on both sides of the heat transfer plate, which pass through in the flow process. The plate wall exchanges heat. The two fluids are in a counter-current heat exchange situation in the flow channel, and the surface of the plate is made of various shapes such as corrugation and herringbone, which is beneficial to destroy the laminar flow film of the fluid, generate vortices at low speeds, and form strong turbulence intensification The heat transfer function greatly improves the heat exchange efficiency of the pre-cooling regenerator, reduces the temperature difference between the inlet and outlet, and makes the compressed air enter the evaporator at a lower temperature. Obviously, when the same pressure dew point is reached, it is better than using ordinary shells. The refrigeration and dryer of the tube heat exchanger requires lower cooling capacity, which means that it needs to consume lower refrigerant compressor power. If the shell and tube heat exchanger wants to achieve the same energy saving effect, it needs to increase the heat exchange area by 5 to 10 times, and the cost of the copper tube and the size of the equipment are unimaginable.
Two: Other advantages of stainless steel plate heat exchanger:
Compact structure
Use thin plates, high heat transfer coefficient, less liquid stagnation
Low fouling factor
High turbulence reduces the fouling coefficient
No pollution
The internal structure is stainless steel 316/304L, it is not easy to rust, and the gas will not be polluted
Light weight
Only equivalent to 20%~30% of shell-and-tube heat exchanger
Lower pressure drop
Less than 0.018MPa
3: Comparison of energy consumption between plate type refrigeration dryer and ordinary shell and tube type refrigeration dryer
Example: When a HX-200NF (23m3/min) refrigeration and dryer uses a traditional tube-fin heat exchanger, the refrigerant compressor power is 5HP, while the HX-200NPF using a plate heat exchanger requires the refrigerant compressor power There is only 4HP, so if the refrigeration dryer works 12 hours a day, the electricity cost is 1.0 yuan/kWh, then the electricity savings in one year are calculated as follows:
12×1HP×0.735kw×1.0 yuan/degree×365 days=3219.3 yuan/year
If you work 24 hours a day and use multiple machines at the same time, you will save more electricity!
Four: other types of energy saving
Generally speaking, the design of refrigeration and dryers is designed according to the extreme conditions of full load, but the air consumption of many users often fluctuates greatly. Sometimes the air consumption is small or the exhaust temperature of the air compressor is low. At this time, the phenomenon of "big horse-drawn trolley" appears, which is likely to cause "ice blockage" when the heat exchanger is severely frosted, and it may carry liquid into the compressor, dilute the compressor's lubricating oil, and make the compressor zero. The components cannot be lubricated normally, which greatly reduces the service life of the refrigerant compressor and virtually increases energy consumption.
In response to this phenomenon, our company introduced a dual-head modular cold dryer.
The whole machine adopts automatic and manual dual modes. Automatic mode: always start and stop switch. After pressing the main start switch, the 1# compressor runs, the temperature controller is powered, and operates within the range of 3~10°C according to the set temperature. When the evaporator outlet temperature (pressure dew point) is higher than 10°C, Automatically start 2# compressor, when the temperature is lower than 3℃, automatically shut down 2# compressor.
This mode is easy to operate, safe and reliable, and has a significant energy-saving effect on occasions with relatively large load changes. It is obviously superior to inverter refrigeration dryers and similar products in terms of cost performance and reliability.
