Heat pump installation
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Solution Overview
Problem
Heat pump systems face reliability and safety issues due to unforeseen influences leading to refrigerant freezing in heat exchangers, causing internal leakage and safety risks, especially with flammable refrigerants, as existing solutions do not adequately prevent freezing and rely on software-driven pressure sensors that may malfunction.
Innovation Solution
A low-pressure switch is strategically placed on the first heat exchanger, configured to switch off the compressor when a certain low pressure is reached, creating an independent safety mechanism that prevents freezing by isolating the heat pump system from unsafe operating conditions, thus ensuring reliable and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor integrated into software control is used to monitor refrigerant pressure, then the system can detect pressure changes, but the measurement reliability deteriorates due to software malfunctions and sensor deterioration
Solution Approach 1:
The patent replaces the software-based electronic pressure sensor with a mechanical low-pressure switch that directly senses pressure through a membrane or diaphragm. This mechanical system provides reliable pressure detection without software intervention, eliminating the reliability issues associated with software control and sensor deterioration.
Solution Approach 2:
The low-pressure switch is designed as a simple, inexpensive mechanical device that can be easily replaced if needed. Its straightforward construction with a membrane, spring, and electrical contact makes it more reliable than complex electronic sensors while being cost-effective.
2Reliability
If the low-pressure switch is arranged upstream of the compressor in the suction line, then the compressor can be protected, but the freezing protection of the heat exchanger becomes insufficient
Solution Approach 1:
The patent places the low-pressure switch directly on the heat exchanger (evaporator) rather than in the suction line. This localized positioning allows the switch to specifically monitor and protect the heat exchanger from freezing conditions, while the compressor protection function is maintained through the system's overall pressure monitoring.
Solution Approach 2:
The low-pressure switch acts as an intermediary safety device between the heat exchanger and the control system. It directly senses pressure conditions at the heat exchanger and provides immediate mechanical switching action to prevent freezing, independent of software control delays.
3Device complexity
If software-based pressure monitoring is used, then the system can operate with fewer hardware components, but the safety against freezing deteriorates due to response delays and malfunctions
Solution Approach 1:
The patent replaces software-based pressure monitoring with a mechanical low-pressure switch that provides immediate, reliable pressure sensing and switching action. This mechanical system eliminates software delays and malfunctions, providing superior freezing protection safety despite adding a dedicated hardware component.
Solution Approach 2:
The low-pressure switch is a self-contained mechanical device that automatically senses pressure conditions and triggers the safety shutdown without requiring software processing. The membrane directly responds to pressure changes and mechanically actuates the electrical contact, providing fail-safe operation independent of control software.
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 effectively prevents freezing by automatically shutting down the compressor when low pressure is detected, enhancing the safety and reliability of the heat pump system, particularly in defrosting and cooling modes, and reducing the risk of refrigerant leakage into occupied areas.
Implementation Method 1
a low-pressure switch, wherein the low-pressure switch is arranged and configured on the first heat exchanger, in particular on a low-pressure side thereof
Implementation Method 2
a first heat exchanger (in particular refrigerant-liquid heat exchanger and/or plate heat exchanger)
Implementation Method 3
the compressor (compressor), a refrigerant is brought from a low pressure level to a higher pressure level
Data Source
Figure 1
AI summary
The invention relates to a heat pump system for heating and/or cooling, in particular of a building or part of a building, comprising a first heat exchanger (11), in particular a plate heat exchanger, a second heat exchanger (12), and a low-pressure switch (15), wherein the low-pressure switch (15) is arranged on the first heat exchanger (11) and is configured to switch off the heat pump system, in particular a compressor (10) thereof, when a certain cut-off low pressure is reached or falls below a certain threshold.