Related Experiment Video
Updated: Jan 11, 2026
09:04
A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump
Published on: June 1, 2022
3.6K
Continuous tuning of ejector parameters via zeotropic component migration for optimising high-temperature heat pump
Zhengyong Li1,2,3, Youcai Liang4,5,6, Yan Zhu1,2,3
1School of Electric Power Engineering, South China University of Technology, Guangzhou, China.
Communications Engineering
|November 12, 2025
Summary
Heat pump performance improves by using ejectors to recover energy, overcoming throttling losses. Zeotropic refrigerants enable continuous adjustment of ejector parameters for optimal efficiency across varying conditions without mechanical changes.
Area of Science:
- Thermodynamics and Energy Systems
- Refrigeration and Heat Transfer
- Materials Science (Refrigerants)
Background:
- Heat pump efficiency decreases with increased temperature lift due to throttling losses in expansion valves.
- Ejectors offer a solution by recovering power during throttling but fixed-geometry designs perform poorly under off-design conditions.
- Zeotropic refrigerants possess component migration characteristics that can be leveraged for performance optimization.
Purpose of the Study:
- To propose and investigate a novel method for continuously adjusting ejector parameters using zeotropic refrigerants.
- To develop a vapor-injection heat pump cycle with a component-adjustable ejector.
- To demonstrate optimal performance of ejectors across variable operating conditions without mechanical modifications.
Main Methods:
- Developed a vapor-injection heat pump cycle with a component-adjustable ejector featuring three tunable parameters.
- Introduced the concept of equivalent ejector efficiency for performance evaluation.
- Investigated the adjustment capability of high-temperature refrigerant mixtures, including butane (R600)/R245fa and synthetic mixtures.
Main Results:
- The proposed system allows continuous adjustment of ejector parameters by modulating refrigerant quality.
- R600/R245fa mixtures demonstrated a lower adjustable limit of -5% compared to -2% for R1224yd(Z)/R1233zd(E) at 100 kW heating capacity.
- The study confirmed the feasibility of efficient operation for fixed-geometry ejectors under variable conditions.
Conclusions:
- Leveraging zeotropic refrigerant properties enables component-adjustable ejectors for enhanced heat pump performance.
- The proposed regulation strategy offers a viable alternative for industrial high-temperature heat pump applications.
- This approach enhances energy recovery and operational efficiency in variable-condition heat pump systems.
More Related Videos
10:36Author Spotlight: Optimization of Airflow Velocities in Battery Cooling Systems for Enhanced Thermal Performance and Reduced Energy Consumption
Published on: November 3, 2023
2.1K
11:11Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation
Published on: May 2, 2016
11.5K
Related Concept Videos
02:44Heating and Cooling Curves
26.5K
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves.
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
26.5K
01:07Refrigerators and Heat Pumps
2.9K
Refrigerators or heat pumps are heat engines operating in a reverse direction. For a refrigerator, the focus is on removing heat from a specific area, whereas, for a heat pump, the focus is on dumping heat into one particular area. A refrigerator (or heat pump) absorbs heat Qc from the cold reservoir at Kelvin temperature Tc and discards heat Qh to the hot reservoir at Kelvin temperature Th, while work W is done on the engine’s working substance.
A household refrigerator removes heat from...
A household refrigerator removes heat from...
2.9K
01:20Mechanisms of Heat Transfer II
4.2K
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
4.2K
01:14Mechanisms of Heat Transfer
1.6K
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
1.6K
01:27Thermal expansion and Thermal stress: Problem Solving
2.1K
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
2.1K
01:14Mechanisms of Heat Transfer I
5.9K
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
5.9K