Safety coil device for a heat pump
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Solution Overview
Problem
Residential heat pump systems using flammable and explosive refrigerants face challenges in safety design due to the difficulty in detecting critical concentrations, risk of explosion, and ensuring the refrigerant does not enter the ventilation circuit, while existing solutions have been complex, costly, and inefficient.
Innovation Solution
A heat pump system with a partial encapsulation design that includes a non-return valve and adjustable guide vanes to prevent refrigerant leakage into the ventilation system, combined with an exhaust air duct and automatic fire extinguishing agent to prevent ignition, ensuring safe operation and efficient flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If flammable and explosive refrigerants are used to replace safety refrigerants, then environmental harmlessness is improved, but safety risk increases due to explosion danger
Solution Approach 1:
The housing is divided into a first housing part containing the refrigeration circuit and a second housing part containing the ventilation circuit, with a hermetic seal between them. This segmentation prevents flammable refrigerant from mixing with ventilation air, eliminating explosion risk while maintaining environmental benefits of flammable refrigerants
Solution Approach 2:
A hermetic seal acts as an intermediary barrier between the refrigeration circuit containing flammable refrigerant and the ventilation circuit. This intermediary prevents direct contact between refrigerant and air, allowing safe use of environmentally friendly flammable refrigerants
2Reliability
If complex safety systems are integrated into the heat pump housing, then safety reliability is improved, but device complexity increases
Solution Approach 1:
The housing is segmented into refrigeration and ventilation parts with a hermetic seal, providing safety through simple structural division rather than complex safety systems. This reduces device complexity while maintaining high safety reliability
Solution Approach 2:
The ventilation circuit is extracted and separated from the refrigeration circuit into a distinct housing part. This extraction eliminates the need for complex safety systems by physically isolating the flammable refrigerant from potential ignition sources in the ventilation system
3Reliability
If the heat pump housing is completely sealed, then refrigerant leakage prevention is improved, but maintenance accessibility worsens
Solution Approach 1:
The hermetic seal is applied only at the interface between refrigeration and ventilation circuits, not throughout the entire housing. This segmented sealing approach prevents refrigerant leakage into the ventilation system while leaving other areas accessible for maintenance
Solution Approach 2:
The hermetic seal is applied locally only where refrigerant and air could mix (at the circuit interface), rather than sealing the entire housing. This local quality approach provides necessary leakage prevention while maintaining accessibility for maintenance in other areas
4Object-affected harmful factors
If flammable refrigerant escapes into the ventilation circuit, then explosion risk increases, but detection difficulty increases due to low concentration thresholds
Solution Approach 1:
The hermetic seal segments the refrigeration and ventilation circuits, preventing refrigerant escape into the ventilation system. This eliminates the detection problem by preventing the harmful situation from occurring in the first place
Solution Approach 2:
The hermetic seal acts as an intermediary barrier that prevents flammable refrigerant from reaching the ventilation circuit where it could form explosive mixtures. This eliminates the need for difficult detection of low-concentration refrigerant in ventilation air
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 effectively prevents refrigerant leakage into the ventilation circuit and ensures safe operation by diluting escaped refrigerant, preventing ignition, and maintaining energy efficiency, addressing the complexity and cost issues of previous solutions.
Implementation Method 1
with a partial encapsulation consisting of a lower part, an upper part, a middle part and a non-return valve
Implementation Method 2
one or more guide vanes are arranged in the air flow of the exhaust air before it reaches the wall opening
Implementation Method 3
a conveying fan for exhaust air
Implementation Method 4
automatic fire extinguishing agent to prevent ignition
Data Source
Figure 1
Figure 2
AI summary
Air-to-water heat pump with ventilation function for the safe operation of a counterclockwise thermodynamic cycle using a hazardous working fluid, which is circulated in a closed, hermetically sealed working fluid circuit, suitable for installation in a building (1), comprising a heat pump housing (2), at least one compressor (3) for working fluid, at least one expansion device (4) for working fluid, at least two heat exchangers (5, 6) for working fluid, each with at least two connections (7, 8) for heat transfer fluids, at least one fresh air duct for outside air (10) from the environment outside the building (1) into the housing (2), ducts (11) for exhaust air from the building (1) into the housing (2), a wall penetration (19) for exhaust air (12) to the environment outside the building (1), a conveying fan (13) for exhaust air (11), a heat exchanger fan (14) for conveying the exhaust air from the building (2), wherein a Partial encapsulation (18),consisting of a lower part (18a), an upper part (18b), a middle part (18c) and a non-return valve (18d), the lower part (18a) contains the compressor (3), the expansion device (4), one of the heat exchangers (6), the upper part (18b) contains the connections for outside air (10) and exhaust air (11), the middle part (18c) contains the other heat exchanger (5), the heat exchanger fan (14) and flow guide devices (23) for purge air (21, 22), the non-return valve (18d) is arranged so that backflow into the exhaust air system via the exhaust air (11) is prevented, and the partial encapsulation (18) is designed to be tightly sealed against the other components of the housing (2) of the heat pump.