Refrigeration Circuit Return Line for Compressor Heat Recovery Heating
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Solution Overview
Problem
Heat management systems in electrified motor vehicles require electric heaters for rapid heating in cold conditions, which consume electrical energy and reduce energy efficiency.
Innovation Solution
A refrigeration circuit with a refrigerant compressor, condenser, chiller, and evaporator connected in series, featuring a return line and valve circuit that allows for thermal energy reuse, enabling faster start-up and reduced electric heater power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electric heaters are used for rapid heating in cold conditions, then heating speed is improved, but electrical energy consumption increases
Solution Approach 1:
The patent converts the waste heat generated by the refrigerant compressor into useful heating energy for the vehicle interior. The return line redirects compressed refrigerant containing thermal energy back to the evaporator, where this heat is transferred to the cabin air through the air conditioning device, eliminating the need for separate electric heaters.
Solution Approach 2:
The refrigeration circuit serves dual purposes: cooling when needed and heating when needed. The system uses its own compressor-generated thermal energy to provide cabin heating, making the system self-sufficient and eliminating dependence on external electric heaters for heating functions.
2Temperature
If the refrigeration circuit operates in cold ambient conditions with little waste heat, then heating capability is insufficient, but adding electric heaters reduces energy efficiency
Solution Approach 1:
The refrigeration circuit is designed to perform multiple functions: it can cool the cabin during hot conditions and heat the cabin during cold conditions. The return line and valve circuit enable the system to switch between cooling and heating modes by redirecting refrigerant flow, allowing one system to serve both thermal comfort needs.
Solution Approach 2:
Instead of discarding the thermal energy generated by the refrigerant compressor as waste heat, the system recovers this energy and redirects it through the return line to the evaporator for cabin heating. This recovery process converts what would be wasted energy into useful heating capability.
3Power
If thermal energy is dissipated in the main circuit, then heating power is reduced, but blocking the return line prevents rapid start-up
Solution Approach 1:
The valve circuit dynamically controls the refrigerant flow path based on operational requirements. During start-up, the valve directs refrigerant through the return line for rapid heating. During steady-state operation, the valve can redirect flow through the main circuit to the condenser and chiller, optimizing heating power and thermal management based on real-time conditions.
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 solution allows for quicker refrigeration circuit start-up and increased heating power without an additional electric heater, improving energy efficiency by utilizing thermal energy generated by the compressor for heating.
Implementation Method 1
a refrigerant compressor (11)
Implementation Method 2
a condenser (13), in particular a water-cooled condenser, for exchanging heat with a cooling circuit
Implementation Method 3
a chiller (15) for exchanging heat with the cooling circuit
Implementation Method 4
an evaporator (14) for controlling the temperature, in particular cooling, air in an air-conditioning device
Implementation Method 5
a return line (29), which branches off from the main circuit on a high-pressure side of the refrigerant compressor and leads into the main circuit on a low-pressure side of the refrigerant compressor
Data Source
AI summary
A refrigeration circuit for a motor vehicle includes a refrigerant compressor, a condenser for exchanging heat with a cooling circuit, a chiller for exchanging heat with the cooling circuit, and an evaporator for temperature control of air in an air-conditioning device. The evaporator being in parallel with the chiller, and, in a main circuit, the refrigerant compressor, the condenser, and the parallel circuit of chiller and evaporator being connected in series. The circuit also includes a return line that branches off from the main circuit on a high-pressure side of the refrigerant compressor and leads into the main circuit on a low-pressure side of the refrigerant compressor, and a valve circuit to block and release flow through the return line.