Hot Water Boiler: In the design of air conditioning system, the choice of cold and heat source has attracted much attention, because it is related to primary investment and operation and management costs. For the cold and heat sources of industrial and civil buildings that use central air conditioning systems, the author believes that the use of chillers and oil (gas) hot water boilers is a very good cold and heat source solution. In summer, centrifugal (screw type) chillers are used to provide 7°C~12°C cold water, and in winter, oil (gas) hot water boilers are used to provide 50°C~60°C hot water. At present, there are many fuel (gas) hot water boilers, such as pressure hot water boilers, atmospheric pressure hot water boilers, vacuum hot water boilers, etc. Among them, vacuum hot water boilers are more concerned by users because of their safety.
2 Comparison of hot water boilers
2.1 Pressure hot water boiler
The pressurized hot water boiler is a boiler drum filled with water, which is directly burned and heated by the furnace to form hot water. Due to the high temperature of the boiler outlet water, the inlet and outlet water temperature of the pressure boiler is generally 95℃~70℃. However, the supply and return water temperature of the air-conditioning system is 50℃~60℃, so the system needs to set up another water-water heat exchanger. This makes the air conditioning hot water system must be equipped with two systems: primary water and secondary water. The system is complex and the area of the machine room is large.
2.2 Atmospheric pressure hot water boiler
Atmospheric pressure hot water boilers are also called large oil water heaters. The boiler burns to heat the heat medium water, and the heat exchange coil is immersed in the heat medium water. After the hot water is heated, the circulating water of the air conditioner in the coil is heated by the principle of water-water heat exchange. Since the heat medium water in the drum is connected to the atmosphere, the heat medium water is continuously evaporated, so it is necessary to supplement the heat medium water to reduce the water quality of the heat medium water. The surface of the water-water heat exchange coil is easy to scale, which reduces the heat exchange efficiency. In order to improve the water-water heat exchange efficiency, the internal circulation pump is used to force the flow of heat medium water, which increases the operating cost.
2.3 Vacuum hot water boiler
The vacuum hot water boiler uses the steam-water heat exchange (vacuum condensation heat exchange) under negative pressure to heat the air-conditioning circulating water in the heat exchange coil. In a closed space, the heat medium water is in the cycle of evaporation and condensation, so it will not decrease, and the water quality is unstable. In addition, the heat exchange is more efficient due to the steam-water heat exchange, and it is very safe and reliable because it operates under negative pressure.
3 Characteristics of vacuum hot water boiler
3.1 Safety and reliability: Since the vacuum boiler always operates under negative pressure, there is no danger of expansion and explosion, so it has the safety and reliability performance unmatched by atmospheric pressure boilers and pressure boilers.
3.2 Long service life: Because the vacuum boiler uses high-purity, special deoxidized heat medium water, no scale is formed in the furnace, and the furnace maintains a high vacuum and oxygen-free state, which greatly reduces the corrosion in the furnace. The unit is filled with heat medium water before leaving the factory. once. Because the heat medium water is repeatedly evaporated and condensed in the closed space, it generally does not need to be replaced during the service life, which is very convenient for users, avoids complicated boiler maintenance work, and makes the service life of the vacuum boiler more universal. According to relevant data, the service life of atmospheric hot water boilers is generally 8 to 10 years, while the service life of vacuum boilers is generally more than 15 years.
3.3 Multiple safety protection to ensure safe operation of vacuum boiler
3.4 Due to the steam-water heat exchange, the entire heat exchange coil is surrounded by negative pressure saturated steam, and is in the working state of the wet coil, and the heat exchange efficiency is much higher than that of the steam-water heat exchange. Therefore, the vacuum boiler is small in size and high in efficiency, which is more beneficial for places where the machine room is small. Moreover, due to the heat exchange of steam and water, the preheating time is shorter, which saves the running cost.
4 Working principle of vacuum hot water boiler
4.1 The vacuum hot water boiler uses the characteristics of different boiling temperatures of water under different pressures. For example, at one atmosphere (1 bar) the boiling temperature of water is 100°C. When the pressure is lower than 1 bar, the boiling point of water is lower than 100°C; at 0.7 bar, the boiling point is 90°C; at 0.3 bar, the boiling point is 70°C. The pressure was 0.1 bar and the boiling point was 40°C.
Jiangsu Kaitong Boiler and Pressure Vessel Co., Ltd. is mainly engaged in non-standard vessels, towers, condensers, chemical equipment, steam boilers, electric boilers, hot water boilers, heat exchangers, low nitrogen boilers, reactors, storage tanks, gas storage tanks , high-efficiency heat exchangers, etc. In line with the corporate philosophy of "creating green energy equipment for human beings and creating technological products for the industry", the company always adheres to the operation of "market-oriented, innovation-driven, quality-based survival, and development-oriented growth". The concept, will rely on the continuous innovation of science and technology and advanced modern management concepts, to produce high-quality, high-performance boiler and pressure vessel products, as well as good service to win the trust of the majority of users; willing to work together with the majority of users, mutual benefit, Work together to create a brilliant future for the enterprise.