Heat Pump Pressure Trip Recalculation for Stable Heating Demand
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Solution Overview
Problem
Conventional heat pump systems experience undesirable fluctuations in heating demand and frequent shutdowns due to excessive compressor discharge pressure, leading to inefficient temperature control and potential service calls.
Innovation Solution
A controller system that adjusts the maximum heating demand based on trip signals from pressure sensors, recalculating the heating demand to prevent shutdowns by incrementally managing operational parameters such as fan and compressor speeds, thereby maintaining stable operation and avoiding excessive pressure limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heating demand is increased to achieve the temperature set-point faster, then the heating efficiency is improved, but the compressor discharge pressure exceeds the maximum pressure limit causing frequent shutdowns
Solution Approach 1:
The controller continuously monitors compressor discharge pressure and uses this feedback to dynamically adjust the heating demand. When pressure approaches the maximum limit, the controller reduces heating demand to prevent shutdowns, creating a closed-loop control system that balances heating efficiency with system reliability
Solution Approach 2:
The system transitions from static heating demand control to dynamic control where the heating demand percentage is continuously adjusted based on real-time pressure conditions. The controller modifies operational parameters such as fan and compressor speeds dynamically to maintain optimal performance within safety limits
2Reliability
If the compressor discharge pressure is reduced to prevent shutdowns, then the system reliability is improved, but the temperature control efficiency deteriorates
Solution Approach 1:
The controller applies partial action by adjusting operational parameters incrementally rather than making extreme changes. When pressure approaches limits, the controller makes gradual adjustments to fan and compressor speeds, maintaining sufficient heating capacity while preventing shutdowns, thus balancing reliability with temperature control efficiency
Solution Approach 2:
The system changes operational parameters (fan speed, compressor speed, heating demand percentage) based on pressure conditions. The controller monitors discharge pressure and dynamically adjusts these parameters to maintain system reliability while preserving adequate heating performance to meet temperature set-points
3Reliability
If the heating demand is frequently adjusted to prevent pressure exceedance, then the system reliability is improved, but the temperature control stability deteriorates due to fluctuations
Solution Approach 1:
The controller implements periodic monitoring of compressor discharge pressure and makes rhythmic adjustments to heating demand. This periodic control approach prevents chaotic fluctuations by systematically adjusting parameters at regular intervals based on pressure trends, thereby maintaining both reliability and temperature stability
Solution Approach 2:
The closed-loop feedback system continuously monitors both pressure and temperature, adjusting heating demand based on integrated feedback from both parameters. This dual-feedback mechanism ensures that temperature control stability is maintained while preventing pressure-related shutdowns, as the controller considers both parameters in its decision-making process
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 controller system reduces the frequency of shutdowns and maintains stable heating demand, ensuring consistent temperature control and reducing the need for service calls by incrementally adjusting operational parameters in response to pressure fluctuations.
Implementation Method 1
During the winter, a HP system transfers heat from the outdoor air heat exchanger to an indoor heat exchanger where the heat is used to heat the interior of the residence or building
Implementation Method 2
A refrigerant high pressure sensor located on the refrigerant tubing and is configured to provide a trip pressure signal of the refrigerant system
Implementation Method 3
an outdoor fan/heat exchanger and compressor (OD) system
Data Source
AI summary
One aspect presents an controller that comprises a control board, a microprocessor located on and electrically coupled to the control board, and a memory coupled to the microprocessor and located on and electrically coupled to the control board. The controller is configured to receive a trip signal from a refrigerant high pressure sensor and set a maximum heating % demand of the heat pump system based on the trip signal, recalculate a heating % demand based on at least one of the recalculated heating % demand or the maximum heating % demand.