Bellows Compressor Vapor Recompression for Desalination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current desalination technologies, such as reverse osmosis, require high energy inputs and have significant capital and maintenance costs, making them inefficient and costly for large-scale water production.
Innovation Solution
A novel mechanical vapor recompression system with a bellows compressor and a thermally coupled evaporation and condensation unit, designed to minimize energy consumption by compressing water vapor along the saturated water line and maintaining a low thermal resistance between the condensation and evaporation chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If reverse osmosis is used for desalination, then energy requirement is reduced compared to thermal methods, but capital cost and maintenance cost increase significantly
Solution Approach 1:
The patent replaces the mechanical membrane-based reverse osmosis system with a thermal distillation system that uses phase change and heat transfer. This substitution eliminates the need for complex membrane structures and high-pressure pumping systems, thereby reducing capital and maintenance costs while maintaining reasonable energy requirements through thermal processes
Solution Approach 2:
The invention utilizes phase transitions (evaporation and condensation) as the core mechanism for desalination. Water evaporates from the saline solution and condenses on the cooler surface, leaving salt behind. This phase transition approach simplifies the system architecture compared to membrane-based methods while achieving effective separation
2Device complexity
If thermal methods such as MSF and MED are used, then capital cost and maintenance cost are reduced, but energy requirement increases significantly
Solution Approach 1:
The patent combines the evaporation and condensation processes into a single integrated unit where the condensation surface is directly coupled to the evaporation chamber. This merging eliminates the need for separate effectors and heat exchangers required in MSF and MED systems, reducing capital cost while improving thermal efficiency through direct heat transfer
Solution Approach 2:
The system uses the latent heat released during condensation to directly provide the heat required for evaporation through thermal coupling. This self-service heat recovery mechanism eliminates the need for external energy input for each cycle, significantly reducing overall energy requirements compared to conventional thermal methods
3Use of energy by moving object
If reverse osmosis is used, then energy requirement is reduced, but maintenance complexity and cost per cubic meter increase
Solution Approach 1:
The patent employs simple, inexpensive components such as bellows compressors and basic heat transfer surfaces that can be easily replaced or maintained. These components have no complex internal structures like membranes that require specialized cleaning and replacement procedures, making maintenance straightforward and cost-effective
4Productivity
If large-scale desalination is implemented using reverse osmosis, then water production capacity increases, but energy consumption becomes unsustainable for developing countries
Solution Approach 1:
The system recovers and reuses the latent heat from condensation to drive evaporation, creating a self-sustaining thermal cycle. This internal heat recovery mechanism dramatically reduces the external energy input required per unit of water produced, making large-scale deployment feasible in regions with limited energy infrastructure
Solution Approach 2:
The invention operates at atmospheric or near-atmospheric pressures using phase change at moderate temperatures, rather than requiring high pressures. This parameter change enables the use of simpler, less energy-intensive equipment and allows for scalable deployment from small to large capacities without proportionally increasing energy consumption
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 achieves a higher thermodynamic efficiency compared to reverse osmosis, with lower capital and maintenance costs, and reduces energy requirements for desalination, making it more viable for large-scale water production.
Implementation Method 1
compressing water vapor along the saturated water line
Implementation Method 2
evaporation and condensation unit
Implementation Method 3
condensation unit
Implementation Method 4
maintaining a low thermal resistance between the condensation and evaporation chambers
Data Source
AI summary
A novel mechanical vapor recompression system is proposed which offers improved energy efficiency. As opposed to a process using an adiabatic compression step, the proposed system recompresses the vapor with concurrent heat transfer back to the evaporation chamber. When the compression rate is slow relative to the heat transfer capacity between the evaporation and condensation chambers, the compression process initially follows the saturated vapor line as opposed to moving into the superheated vapor region, which results in a much lower enthalpy increase compared to an adiabatic compression step. For an identical recompression pressure, compressing saturated water vapor along the saturated vapor line has been shown to require approximately 78% less energy compared to a system employing adiabatic compression.