Absorption chillers play a crucial role in providing efficient cooling in industrial and commercial applications. One of the essential factors that influence their performance is the solution flow configuration, which can be either parallel or serial. BROAD uses parallel solution flow in its absorption chillers, which has specific advantages and disadvantages.
A. Working Principle of BROAD Parallel Solution Flow
In a parallel solution flow, two solution circuits are employed: one goes to the High-Temperature Generator (HTG) and the other to the Low-Temperature Generator (LTG). The concentrated solution in the HTG operates at:
- Temperature: 148℃
- Concentration: 61%
- Solution Volume: Higher amount of solution used
Advantages:
- Reduced Crystallization Risk: The crystallization temperature in parallel flow is 27℃ under a 61% concentration, which rarely occurs in chillers, significantly reducing the risk of crystallization.
- Reliable Operation: The use of two solution pumps enhances the reliability of the chiller’s operation, ensuring continuous performance without interruption.
- Increased Thermal Efficiency: Parallel solution flow is well-suited for Plate Heat Exchanger (PHE) applications, leading to improved thermal efficiency.
Disadvantages:
- Higher Solution Demand: This configuration requires more solution, which can increase operational costs.
- Additional Solution Pump: The need for an extra solution pump adds to the system’s complexity and cost.
B. Working Principle of Conventional Serial Solution Flow
In a conventional serial solution flow, the solution first goes to the HTG and then flows to the LTG. The solution temperature is higher in this configuration to maximize vapor production:
- Temperature: 155℃
- Solution Handling: Generates vapor as much as possible with less solution
Advantages:
- Reduced Solution Demand: Serial flow requires less solution, making it more cost-effective due to the high cost of the solution.
Disadvantages:
- Higher Crystallization Risk: The crystallization temperature is 38℃ under a 63% concentration, which can be easily reached when the cooling water temperature is low or in the event of a sudden power outage. Overheating the solution to generate sufficient vapor leads to higher concentrations, increasing the risk of crystallization.
- Difficult De-crystallization: With only one solution loop, it becomes challenging to de-crystallize since there is no effective way to increase the temperature or dilute the solution.
- Limited PHE Application: The higher risk of crystallization makes it difficult to utilize PHE, which requires stable and lower concentration levels to operate effectively.
C. BROAD Unique Technology for Crystallization Prevention
To prevent crystallization issues, BROAD using parallel solution flow in absorption chiller. This configuration ensures safer and more reliable operation by minimizing the risk of crystallization. BROAD using Auto Decrystallization System that can automatically resolve crystallization issues. This system operates as follows:
- Temperature Difference: Ensures a temperature difference greater than 20℃.
- PLC Control: Bypasses the refrigerant into the solution to reduce concentration.
- Intermittent Operation: Starts and stops the solution pump and heat source intermittently to increase the temperature in the plate heat exchanger and solution pipe for de-crystallization.
With this advanced technology, crystallization issues do not affect BROAD customers, ensuring seamless operation of the absorption chiller.
Conclusion
BROAD’s Parallel Solution Flow offers several compelling benefits for absorption chillers:
- Lower Crystallization Risk: Significantly minimizes the likelihood of crystallization.
- Higher Thermal Efficiency: Optimized for PHE applications.
- Reliable Operation: Dual pump system enhances operational reliability.
- Increased Costs: Requires more solution and an additional pump, raising the production cost of BROAD chillers.
By understanding and implementing the appropriate solution flow configuration, operators can enhance the performance and longevity of their absorption chillers, ensuring efficient and reliable cooling.