Adiabatic heat pump
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Solution Overview
Problem
Conventional vapor compression heat pump systems face limitations in operational efficiency, especially over a wide range of ambient temperatures, and are challenged by the need for environmentally friendly refrigerants that do not cause ozone depletion or global warming.
Innovation Solution
A heat transfer apparatus with a compressor-expander and separate fluidic loops for vapor and liquid portions, utilizing a working fluid that undergoes controlled phase changes to enhance efficiency and adaptability, allowing operation with a variety of environmentally friendly refrigerants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional vapor compression heat pump systems are used, then heat transfer function is achieved, but operational efficiency is limited especially over wide ambient temperature ranges
Solution Approach 1:
The system is divided into two separate fluidic loops: a liquid loop and a vapor loop. The liquid loop handles subcooled liquid working fluid between the compressor and liquid heat exchanger, while the vapor loop handles vapor working fluid between the expander and vapor heat exchanger. This segmentation allows each loop to be optimized for its specific phase, improving overall operational efficiency across wide temperature ranges.
Solution Approach 2:
The system utilizes an expander instead of a traditional throttle valve, enabling controlled expansion of the vapor working fluid. This parameter change allows for better control of pressure and temperature transitions, improving efficiency across varying ambient conditions. The expander recovers work during expansion, and the system can adapt to different temperature ranges by adjusting operating parameters.
2Productivity
If conventional refrigerants are used in heat pump systems, then heat transfer performance is achieved, but environmental harm occurs through ozone depletion and global warming
Solution Approach 1:
The system is designed to be compatible with various environmentally friendly refrigerants including hydrocarbons, ammonia, and carbon dioxide. The dual-loop configuration and use of an expander rather than a throttle valve provide universal functionality that accommodates different refrigerant types without sacrificing heat transfer performance, allowing selection of refrigerants with low environmental impact.
3Device complexity
If a single fluidic loop is used in heat pump systems, then system simplicity is maintained, but electrical power consumption is excessive
Solution Approach 1:
By segmenting the single loop into two separate loops (liquid and vapor), the system optimizes heat transfer in each phase independently. This reduces the temperature differences required for heat exchange, improving the coefficient of performance and reducing electrical power consumption, while adding only moderate complexity through the separation of fluid paths.
Solution Approach 2:
The system explicitly separates and handles liquid and vapor phases in different loops, utilizing phase transitions more efficiently. The liquid loop handles subcooled liquid compression and heating, while the vapor loop handles expansion and heat rejection. This phase-specific handling improves thermodynamic efficiency and reduces power 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 improved efficiency and wider operational temperature range, reducing electrical power consumption while accommodating a range of environmentally friendly refrigerants, thus addressing the limitations of conventional systems.
Implementation Method 1
expanding the first volume portion to reduce adiabatically the pressure therein, whereby the working fluid is cooled and at least a portion thereof is converted to vapor
Implementation Method 2
contracting the second volume portion to increase adiabatically the pressure therein above a target pressure set point, whereby any working fluid therein is heated
Implementation Method 3
The working fluid (either vapor or liquid) passes through the central tube, so that thermal energy is exchanged through the fins between the working fluid and the ambient atmosphere
Implementation Method 4
the fluid's ability to absorb and reject a large amount of heat energy quickly, in accordance with its critical behavior as a function of the temperature and pressure to which it is subjected. In most systems, the absorption and rejection of heat is heightened by using a working fluid that is repetitively transformed between the liquid and vapor states
Implementation Method 5
Each transformation is accompanied by the absorption or release of a relatively large amount of heat energy, termed the latent heat of evaporation
Data Source
AI summary
A heat transfer apparatus transfers heat from a heat source to a heat sink. The apparatus comprises a compressor-expander and a reservoir that are connected by two separate fluidic loops for the respective circulation principally of vapor and liquid portions of a working fluid. The loops may each contain a heat exchanger through which heat is respectively absorbed and rejected.