Multi-effect Adsorption Desalination System for Low-Cost Freshwater
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Solution Overview
Problem
Existing adsorption desalination systems are inefficient in producing freshwater from seawater due to reliance on fossil energy for hot water supply, leading to increased operation costs and reduced system efficiency, and they require separate chilled water for cooling.
Innovation Solution
An adsorption desalination system utilizing a multi-effect evaporator apparatus that produces high-pressure and low-pressure vapor, with multiple sequential evaporators and three adsorption and desorption beds, allowing for selective vapor and water supply to optimize the coefficient of performance (COP) and produce chilled water for cooling, while using latent heat exchange to maximize freshwater yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fossil energy is used for hot water supply in adsorption desalination systems, then the system can maintain operation, but operation costs increase and system efficiency decreases
Solution Approach 1:
The system uses self-generated high-pressure vapor from the multi-effect evaporator to provide both heating and cooling functions. The high-pressure vapor drives the adsorption process and generates chilled water through heat exchange, eliminating the need for external fossil energy input and reducing operation costs while maintaining reliable system operation
Solution Approach 2:
The system changes the energy parameter by using high-pressure vapor instead of thermal energy from fossil fuels. The multi-effect evaporator generates vapor at different pressures that are utilized for different purposes: high-pressure vapor for adsorption heating and low-pressure vapor for cooling, fundamentally changing how energy is supplied to the system
2Temperature
If separate chilled water is required for cooling, then cooling function can be provided, but system complexity increases and energy consumption increases
Solution Approach 1:
The high-pressure vapor generated by the multi-effect evaporator serves multiple functions simultaneously: it provides heating for the adsorption process, generates chilled water through heat exchange with cold water, and can be used for cooling purposes. This multi-functionality eliminates the need for separate chilled water systems, reducing both complexity and energy consumption while maintaining effective cooling
3Productivity
If multi-effect evaporator with sequential evaporators is used, then freshwater production efficiency increases, but device complexity increases
Solution Approach 1:
The evaporator system is segmented into multiple sequential evaporators that process vapor at different stages. Each evaporator handles a specific portion of the vapor flow, allowing efficient heat exchange and freshwater production. The segmentation enables the system to maximize freshwater yield by utilizing heat at multiple temperature levels simultaneously
Solution Approach 2:
The sequential evaporators are arranged in a nested configuration where vapor from one evaporator becomes the heating medium for the next evaporator in the sequence. This nested arrangement allows compact integration of multiple evaporation stages within a single system structure, achieving high productivity without proportionally increasing overall system complexity
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
The system enhances freshwater production efficiency, utilizes chilled water as a by-product for cooling, and produces condensate water as additional freshwater, thereby improving COP and reducing energy consumption.
Implementation Method 1
a multi-effect evaporator apparatus that produces high-pressure vapor and low-pressure vapor
Implementation Method 2
using latent heat exchange to maximize freshwater yield
Implementation Method 3
an adsorbent that adsorbs or desorbs moisture from the high-pressure vapor and low-pressure vapor
Implementation Method 4
a heat exchange tube that can transfer heat to the adsorbent through chilled water or hot water
Implementation Method 5
a condenser configured to condense vapor containing moisture desorbed from the adsorbents of the reaction units so that the vapor can be collected as freshwater
Data Source
AI summary
This application relates to an adsorption desalination system using a multi-effect evaporator apparatus. In one aspect, the system includes a multi-effect evaporator apparatus producing high-pressure vapor and low-pressure vapor, a plurality of reaction units including an adsorbent adsorbing or desorbing moisture from the high-pressure vapor and low-pressure vapor and a heat exchange tube transferring heat to the adsorbent. The system may also include a condenser condensing vapor containing moisture desorbed from the adsorbents, and cold-hot water lines selectively supplying chilled water and hot water to the heat exchange tubes. The system may further include vapor lines connecting the multi-effect evaporator apparatus and the reaction units, and the reaction units and the condenser, respectively, valves disposed in the vapor lines, and a valve controller controlling operation of the valves to selectively supply chilled water or hot water supplied to the heat exchange tubes from the cold-hot water lines.