Contiguous Condenser-Evaporator Layout to Prevent Heat Pump Icing
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Solution Overview
Problem
Reversible heat pump systems in vehicles and buildings face inefficiencies in heating mode when outside air temperatures are cold, as the external evaporator tends to freeze, leading to previous solutions requiring significant modifications or additional energy-consuming components.
Innovation Solution
The system incorporates a three-way valve configuration and a contiguous external condenser to reduce the risk of icing at the external evaporator by using the refrigerant from the internal condenser as a heat source, eliminating the need for additional heating devices and minimizing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the external evaporator is used in heating mode with cold outside air, then heat exchange with outside air is achieved, but the external evaporator freezes and operation is affected
Solution Approach 1:
The patent merges the external condenser and external evaporator into a single integrated heat exchanger assembly. The external condenser section provides heat to the external evaporator section through internal heat transfer, preventing freezing while maintaining heat exchange capability with outside air.
Solution Approach 2:
The patent uses the refrigerant in the external condenser as an intermediary heat source. The refrigerant condenses in the external condenser section, releasing heat that is transferred through the heat exchanger structure to prevent freezing in the external evaporator section, where the refrigerant then evaporates.
2Reliability
If ducts dedicated to defrosting with heat transfer fluid are added to the external evaporator, then defrosting capability is provided, but major modification of the external evaporator is required
Solution Approach 1:
The patent combines the heating and defrosting functions into a single integrated heat exchanger structure. The external condenser section serves dual purposes: normal heat rejection and defrosting heat source, eliminating the need for separate defrosting ducts and reducing structural complexity.
3Reliability
If an additional electric heater is used to heat the heat transfer fluid in the external evaporator, then defrosting is achieved, but additional bulky heating device and energy consumption are required
Solution Approach 1:
The patent implements a self-service defrosting system where the external condenser uses its own refrigerant heat to defrost the external evaporator section. This eliminates the need for additional electric heating devices and reduces energy consumption by utilizing waste heat from the refrigeration cycle.
Solution Approach 2:
The patent converts the cold refrigerant leaving the expansion valve, which would normally cause freezing, into a beneficial heat source for defrosting. The refrigerant absorbs heat from the external evaporator during evaporation, preventing ice accumulation, and the external condenser provides additional heat when needed.
4Temperature
If the external evaporator is installed in the same enclosure as the internal condenser, then heating by liquid refrigerant is achieved, but implementation is restrictive and overall performance is adversely affected
Solution Approach 1:
The patent merges the external condenser and external evaporator into a single integrated assembly with optimized internal heat transfer pathways. This allows the external condenser to heat the external evaporator through the heat exchanger structure without requiring separate enclosures, maintaining compact design while preserving system performance.
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 configuration enhances the refrigeration mode efficiency by reducing the probability of icing and maintaining performance without additional heating devices, especially in electric or hybrid systems, by utilizing the refrigerant heat to prevent freezing and optimizing energy consumption.
Implementation Method 1
The external condenser (CDE) is contiguous with the external evaporator (EE)... collect the refrigerant fluid... constitute a heat source for the adjoining external evaporator (EE)
Implementation Method 2
an external evaporator responsible, in heating mode, for heating the fluid refrigerant cooled and depressurized by exchange with so-called outside air
Implementation Method 3
a compressor (CP) responsible for heating and pressurizing a refrigerant which, in heating mode, comes from the external evaporator (EE)
Data Source
Figure 1~2
Figure 3
AI summary
A heating/air-conditioning installation (IC) comprises a compressor (CP) capable of heating and pressurizing a refrigerant, an internal condenser (CDI) capable, in heating mode, of contributing towards the heating of an air known as interior air by exchange with the refrigerant coming from the compressor (CP), an external pressure reducer (DTE) capable, in heating mode, of cooling the refrigerant, and an external evaporator (EE) capable, in heating mode, of heating up the refrigerant coming from the external pressure reducer (DTE) by exchange of heat with an air known as exterior air to feed into the compressor (CP). This installation (IC) further comprises an external condenser (CDE) contiguous with the external evaporator (EE) and capable, in heating mode, of collecting the refrigerant coming from the internal condenser (CDI) to feed the external pressure reducer (DTE) and constitute a heat source for the contiguous external evaporator (EE), so as to reduce the probability of the latter (EE) icing up in the presence of exterior air at a low temperature.