With the development of urban district heating industry, plate heat exchanger has been better used. Compared with other heat exchangers, plate heat exchanger has the characteristics of high application efficiency, small area and less material consumption. Therefore, plate heat exchanger is widely used in chemical industry, petroleum industry and heating industry. But the selection process of plate heat exchanger is very complicated and the heating system needs to be optimized. Therefore, this paper mainly analyzes the specific application methods of energy-saving design in the plate heat exchanger heating system, and respectively the working principle of the heating system, the existing problems in the system design and the optimization design method of the heating system are analyzed.
Analysis of the working principle of the plate heat exchanger heating system
Plate heat exchanger is mainly composed of multiple plates, and each plate has a certain gap. When the fluid passes through the plate, the gap between the plates can play the role of heat and cold exchange. As the flow passage space is very small, the speed of the fluid flowing through the plate is fast, and it is easy to form turbulence, and large ripples will be formed between turbulence. The influence of turbulent ripple greatly improves the heat transfer performance of plate heat exchanger. Compared with the general heat exchanger, its heat transfer performance is better than the general heat exchanger, which is one of the important reasons that the plate heat exchanger can replace the general heat exchanger. In addition, turbulent ripples also enhance the stiffness of the plate. When two kinds of fluids flow through the holes at the four corners of the plate, they will form a flow channel in the plate heat exchanger, and finally form a flow in the direction or reverse. At this time, the plate can be used as the circulation medium to realize the heat exchange, and then complete the heating link of the plate heat exchanger. The analysis of plate heat exchanger heating system can further understand its existing problems, such as plate bearing capacity, flow arrangement can be changed, turbulence ripple can be effectively applied and so on. According to the above analysis, we should continuously optimize the design related to the plate heat exchanger structure, so as to improve the heat transfer performance of the heat exchanger heating system.
Two, plate heat exchanger heating system existing problems
1 Matching problem of heat transfer and depressurization
For plate heat exchanger, the heat transfer coefficient is directly proportional to the flow rate of the fluid in the channel, that is, when the speed of the fluid in the channel is faster, the heat transfer coefficient will increase, and the speed of the flow rate will lead to the constant increase of the resistance of the fluid, and then increase the fluid pressure loss. Therefore, we should choose the appropriate flow rate or seek the balance between pressure loss and heat transfer coefficient, so as to continuously improve the comprehensive performance of the plate heat exchanger heating system.
2 Not enough research
The start of plate heat exchanger is late and the study time is short in our country, which restricts the development of heating system to some extent, and then, this influenced the energy saving design of heating system. In addition, the research of plate heat exchanger is not deep enough in our country and lacks the technical patent. Therefore, the relevant departments should increase the capital investment, purchase the corresponding patent.
3 Limited application area problem
Plate heat exchanger has unique advantages, but there are some problems. As far as the design of the current heating system is concerned, there are many defects, such as the application of energy-saving design in the heating system is limited, mainly manifested in the heat exchanger is difficult to operate in the high temperature and high pressure environment. This is because the core component of plate heat exchanger is relatively thin sheet metal, and its ability to withstand pressure is limited, and plate heat exchanger is often used in heavy industry production, which requires the plate heat exchanger to have a strong ability to withstand pressure. It can be seen that for the plate heat exchanger heating system, one of the basic conditions for energy saving design is to break through the limitations of previous applications.
Iii. Optimization method of energy saving design of heating system
After the analysis of the working principle of plate heat exchanger, in-depth understanding of the factors affecting the heat transfer performance, such as sheet corrugated, flow rate, heat transfer coefficient, flow channel arrangement. For the energy-saving design of plate heat exchanger heating system, we should fully consider its influencing factors and optimize each subsystem continuously.
1Constantly optimize the overall design
For the whole plate heat exchanger heating system, energy saving design is not only in the design of the heating system need to consider the problem, in the heat exchanger also need to consider the problem. Therefore, the structure and function of plate heat exchanger should be optimized while optimizing the heating system plates, so as to realize the energy saving optimization of the heating system as a whole, so as to realize the energy saving design of the heating system. In addition, the optimization method and coefficient should be selected reasonably for different application requirements and occasions
1 Continuous optimization of plate design
In the plate heat exchanger heating system, plate optimization is a very key link, mainly including the following two steps:
① The ability of the plate to withstand pressure has a great impact on the performance of the heating system of the plate heat exchanger. Therefore, it is necessary to develop some production materials with good performance, which is one of the main research directions of the heat exchanger development.
② Optimize the strength of the sheet and its surface corrugation. The type, height and Angle of corrugation should be carefully analyzed. The energy saving design of plate heat exchanger system can be realized only by optimizing the plate design reasonably.
1 Match heat transfer coefficient and pressure drop
The matching of heat transfer coefficient and pressure drop mainly refers to the pressure loss and heat transfer coefficient of the equilibrium fluid. Under normal circumstances, can use the heat transfer unit number method, logarithmic average temperature difference method and unilateral maximum pressure drop utilization method. The main purpose of this is to effectively analyze the maximum pressure drop that the plate can bear or the most appropriate pressure drop, so as to accurately calculate the pressure drop and flow rate of the fluid when it flows through the channel, so as to find a design method of the maximum pressure drop value, and find a more appropriate heat transfer coefficient matching with the pressure drop, so as to enhance the pressure bearing capacity of the plate.
1 Reasonable arrangement of flow channels
The rationality of flow channel arrangement is directly related to the performance of plate heat exchanger heating system. There are great differences in the flow channel arrangement of series type and mixed type. For example, when there is a big gap between the heat transfer coefficient and the pressure drop, it is necessary to apply the flow channel arrangement of mixed type process. Therefore, for the energy-saving design of plate heat exchanger heating system, we should not only consider the application of plate heat exchanger, but also consider the pressure and fluid flow rate it can withstand. Only through continuous comprehensive analysis of various factors, can we design a better heat exchanger heating system, that is, the most energy-saving plate heat exchanger heating system.
In a word, when optimizing the design method of the plate heat exchanger heating system, the designer should make clear the goal and direction of optimization, so as to realize the energy-saving design of the heating system, and start from the specific method of the heating system design, on the basis of the overall optimization design. Only in this way, can we really design the plate heat exchanger heating system in line with people's needs.
