Internal heat pump, method for operating an internal heat pump, and control unit for such a heat pump
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Solution Overview
Problem
Existing indoor heat pumps using flammable refrigerants pose a safety risk due to the potential formation of dangerous gas mixtures with ambient air in case of refrigerant leaks, especially with limited ambient air volumes indoors.
Innovation Solution
An indoor heat pump system equipped with a vent pipe and fan for outdoor discharge, a gas detector for leak detection, and a safety card control unit that activates the fan and performs recurring functional tests to ensure safe operation and prevent refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flammable refrigerants are used to meet low GWP requirements, then environmental compliance is improved, but safety risk increases due to potential formation of dangerous gas mixtures with ambient air
Solution Approach 1:
The patent extracts the harmful refrigerant gas from the indoor environment by implementing a vent pipe system that actively evacuates leaked refrigerant to the outside of the building, separating the hazard from the occupied space
Solution Approach 2:
The system performs preliminary actions by continuously monitoring refrigerant concentration with gas detectors and pre-activating the venting system before dangerous gas mixtures can form, preventing the harmful condition rather than just responding to it
2Object-affected harmful factors
If a vent pipe with fan is activated upon refrigerant leak detection, then safety is improved by evacuating the housing, but energy consumption increases
Solution Approach 1:
The system uses periodic action by triggering the fan only when refrigerant leakage is detected by the gas detector, rather than operating continuously, thus minimizing energy consumption while maintaining safety
Solution Approach 2:
The system implements feedback control where the gas detector continuously monitors refrigerant concentration and provides signal to the control unit, which then activates the fan only when leakage is detected, creating a closed-loop safety system that consumes energy only when needed
3Reliability
If recurring functional tests are performed by activating the fan, then reliability is improved by verifying leak prevention, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the control unit: it combines the safety monitoring, functional test initiation, fan control, and differential pressure evaluation into a single integrated control unit, reducing overall system complexity while maintaining reliability
Solution Approach 2:
The control unit serves multiple functions: it monitors gas detector signals, initiates functional tests, controls fan operation, and evaluates differential pressure readings, making it a multi-functional device that manages both safety operations and testing
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 manages refrigerant leaks by evacuating the housing and preventing further refrigerant release, ensuring safe operation and compliance with low global warming potential requirements.
Implementation Method 1
a vent pipe with a fan arranged in the vent pipe... upon activation of the fan, it discharges air from inside the housing to the outside
Implementation Method 2
The differential pressure sensor compares a pressure detected inside the housing and a pressure corresponding to the ambient pressure detected outside the heat pump housing
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to an indoor heat pump (1) configured to be installed inside a building, the heat pump (1) comprising: - a housing (2) accommodating a heat pump circuit (4), - a flammable refrigerant contained in the heat pump circuit (4), - a ventilation pipe (8) and a fan (10) fluidly connected to the ventilation pipe (8), - a gas detector (12) located in the housing (2), and - an electrical control unit (14) referred to as a safety card (14'), the ventilation pipe (8) being arranged to convey air from the interior of the housing (2) to the outside of the building (2) upon activation of the fan (10), the safety card (14') being configured to receive a leak detection signal (LS) from the gas detector (12) and to activate the fan (10) in response to receiving the leak detection signal (LS).The indoor heat pump (1) further comprises a differential pressure sensor (16) configured to detect a pressure difference (DF) between the inside and the outside of the housing (2), wherein the safety card (14') is configured to trigger recurring functional tests (FT) by activating the fan (10) and evaluating a developing pressure difference (DF) measured by the differential pressure sensor (16), wherein the functional test (FT) is passed if the developing pressure difference (DF), in particular depicted as a negative differential pressure, exceeds a predetermined pressure threshold.