Low-power absorption refrigeration machine
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Solution Overview
Problem
Current absorption refrigeration machines require indirect systems for cold transportation, leading to increased electricity consumption and water contamination issues, especially in dry climates, due to the need for impeller pumps and fan coils in air-conditioning applications.
Innovation Solution
A low-power absorption refrigeration machine design that uses LiBr/H2O, H2O/NH3, or LiNO3/NH3 solutions, featuring a separated evaporation unit and an air-air configuration, eliminating the need for impeller pumps and fan coils by directly producing cold within the enclosure through a split-type system with an exterior unit and an interior unit connected by ducts, utilizing a refrigerant generator, heat recuperator, and direct expansion evaporator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an indirect cold transportation system is used with impeller pumps and fan coils, then cold can be transported to feeding points inside the building, but electricity consumption increases and water contamination issues occur
Solution Approach 1:
The patent extracts and eliminates the impeller pump and fan coil components from the traditional indirect cold transportation system. By using a direct expansion evaporator that directly contacts the air in the conditioned space, the system removes the intermediary cooling circuits, thereby eliminating the electricity consumption associated with pumps and fans while maintaining effective cold transportation.
Solution Approach 2:
The patent introduces air as an intermediary medium for heat transfer. Instead of using water-based cooling circuits with pumps, the system uses air circulation through the evaporator to directly absorb heat from the conditioned space, eliminating the need for liquid-based intermediary systems and their associated energy consumption.
2Temperature
If water-based cooling towers are used for condensation, then heat rejection is effective, but water consumption increases and Legionella contamination occurs
Solution Approach 1:
The patent replaces the water-based cooling tower system with an air-cooled condensation system. By using air flow across the condenser surfaces to reject heat, the system eliminates the mechanical water circulation system and associated contamination risks, while maintaining effective heat rejection through enhanced air convection and radiation.
Solution Approach 2:
The patent uses air as an inert cooling medium instead of water. Air circulation through the condenser provides effective heat rejection without the biological contamination risks associated with water systems, creating a cleaner, maintenance-free cooling environment that eliminates Legionella concerns.
3Adaptability or versatility
If lithium bromide/water solution is used as working fluid, then absorption refrigeration can operate, but the machine cannot operate at temperatures below 0°C and crystallisation occurs
Solution Approach 1:
The patent changes the working fluid parameters by using alternative absorption pairs such as water/ammonia or lithium nitrate/ammonia instead of lithium bromide/water. These alternative fluids have different thermodynamic properties that allow operation at sub-zero temperatures without crystallisation, expanding the temperature range while maintaining absorption refrigeration functionality.
4Temperature
If water/ammonia solution is used as working fluid, then operation below 0°C is possible, but a rectification column is required to separate water from ammonia
Solution Approach 1:
The patent extracts and eliminates the rectification column from the water/ammonia absorption system. By carefully controlling the ammonia concentration in the absorbent and using direct expansion evaporation, the system achieves effective refrigeration without requiring complex rectification equipment, thereby simplifying the overall device while maintaining sub-zero operating capability.
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 design reduces electricity consumption and water usage by directly producing cold within the air-conditioned space, enhancing efficiency and reducing operational costs while avoiding water contamination, suitable for climate control installations with output power less than 15 kW.
Implementation Method 1
an exchanger that can use the heat produced by a solar collector field, by a biomass boiler, by a biodiesel boiler, by a bioethanol boiler, by a conventional fossil fuel boiler or by the residual heat of engine exhaust gases, batteries or fuel cells
Implementation Method 2
the refrigerant generator comprises at least one heating chamber that houses a heat exchanger... so as to facilitate heat transfer to the lithium bromide/water solution
Implementation Method 3
an absorber capable of maintaining a low pressure and low evaporation temperature when the outside temperature is high
Implementation Method 4
a heat recuperator... which transfers the heat of the hot concentrated solution that flows out of the generator to the diluted cold solution that flows out of the absorber, preheating it
Data Source
AI summary
The present invention relates to a low-power absorption refrigeration machine that enables the use of air as a refrigerant and has an evaporation unit that is separated from the rest of the absorption refrigeration machine and works with LiBr/H2O, H2O/NH3, LiNO3/NH3 or similar solutions, configuring an air-air machine wherein cold is produced directly in the enclosure to be air conditioned without need for impeller pumps and fan coils.