Absorption Chiller Wet Lay-Up Freeze Protection Using Regenerator Heat
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Solution Overview
Problem
Absorption chillers with wet lay-up configurations face challenges in preventing freezing damage when temperatures drop, especially when heating functions are absent or not desired.
Innovation Solution
The absorption chiller incorporates a control system that introduces a heating medium into the cooling water and cold water circuits when temperatures approach freezing points, using communication valves and pumps to circulate the heating medium and dilute solutions to prevent freezing, even in the absence of a heating function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet lay-up is performed to prevent corrosion, then device reliability is improved, but freezing damage risk increases when temperature drops
Solution Approach 1:
The patent introduces a heating medium as an intermediary substance to transfer thermal energy from the regenerator to the cooling water pipes. This mediator enables indirect heating of the cooling water without requiring the chiller to operate in heating mode, thus preventing freezing while maintaining wet lay-up configuration.
Solution Approach 2:
The regenerator, originally designed solely for refrigerant regeneration, is made multi-functional by enabling it to also serve as a heat source for preventing freezing of cooling water. The heating medium circulates through the regenerator to absorb heat during refrigerant regeneration and then transfers this heat to the cooling water pipes, allowing one component to perform multiple functions.
2Object-affected harmful factors
If heating operation is performed to prevent freezing, then freezing damage is prevented, but energy consumption increases and heating function is required
Solution Approach 1:
The system uses its own operational characteristics to prevent freezing. During normal refrigeration operation, the regenerator absorbs heat from the dilute solution to evaporate refrigerant. The heating medium circulates through the regenerator during this process, capturing the heat that would otherwise be wasted and transferring it to the cooling water pipes, thereby preventing freezing using the system's own operational heat rather than external heating energy.
Solution Approach 2:
The patent converts the heat absorbed by the regenerator during refrigerant regeneration (which would normally be a loss or require additional heating energy) into a beneficial resource for preventing cooling water freezing. The heating medium acts as a carrier to redirect this thermal energy to where it is needed, turning a potential waste into a useful function.
3Object-affected harmful factors
If dry lay-up is performed to prevent freezing, then freezing damage is prevented, but corrosion damage increases due to metal rust
Solution Approach 1:
The heating medium serves as an intermediary that enables the system to maintain wet lay-up configuration (with cooling water in the pipes) while still preventing freezing. By transferring heat from the regenerator to the cooling water through the heating medium circulation system, the patent eliminates the need to drain the pipes (dry lay-up), thus preventing both freezing damage and the subsequent corrosion that would occur during dry storage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents freezing damage to the absorption chiller's components while maintaining a wet lay-up configuration, ensuring continuous operation and reducing repair time due to corrosion.
Implementation Method 1
a control means that causes a heating medium to be introduced into the first and second cooling water pipes when the detected temperature of cooling water is equal to or lower than the predetermined temperature
Implementation Method 2
an evaporator and an absorber connected in a closed circuit for conducting a refrigerant and an absorbent solution in an absorption refrigerant cycle, the absorber being arranged in the closed circuit to receive refrigerant vaporized in the evaporator
Implementation Method 3
the absorber being arranged in the closed circuit to receive refrigerant vaporized in the evaporator and to be supplied with absorbent solution for absorption of the vaporized refrigerant
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An absorption chiller (2) with a controller (30) configured to cause the dilute solution in the regenerator (11) to be heated by the heating medium and to cause an obtained concentrated solution to be supplied to the absorber (14) so as to perform a heat exchange with the cooling water in the cooling water pipe (12a, 14a), and to cause a vapor refrigerant generated by the heating of the dilute solution to perform the heat exchange with the cooling water of the cooling water pipe (12a, 14a) in the condenser (12), when the temperature detected by the cooling water temperature detector (31) is equal to or lower than a predetermined temperature, in a wet lay-up state including a state in which the cooling water inlet shut-off valve (V2) and the cooling water outlet shut-off valve (V3) are closed and the cooling water pipe (12a, 14a) is filled with the cooling water; and a first pressure relief valve (V9) provided on the cooling water pipe (12a, 14a), wherein the controller (3) is further configured to control the pressure relief valve to relieve an internal pressure in the cooling water pipe (12a, 14a) generated from the heat exchange.