Heat Pump Dual-Compressor Control for Cold-Climate Heating Capacity
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Solution Overview
Problem
Conventional air-source heat pumps experience significant performance degradation and efficiency loss in cold climates, requiring supplemental heat sources and reducing their heating seasonal performance factor (HSPF), as compressors fail to operate properly at low ambient temperatures.
Innovation Solution
A method and device that control air-source heat pumps by determining the working mode and operating either one or both compressors based on ambient temperature, with a second compressor being activated in parallel only when the temperature falls below a certain threshold, and using a two-stage thermostat and electronic expansion valve to optimize operation across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional air-source heat pumps operate in cold climate, then heating demand increases, but heating capacity and efficiency decrease significantly
Solution Approach 1:
The heat pump system is segmented into two independent compressors (first compressor and second compressor) that can operate independently or in parallel. This segmentation allows the system to adapt to different ambient temperature conditions by activating only the necessary compressor(s), thereby maintaining heating capacity across a wide temperature range from 47°F down to -30°F.
Solution Approach 2:
The control system dynamically adjusts compressor operation based on real-time ambient temperature measurements. When ambient temperature is above the first predetermined temperature, only the first compressor operates. When ambient temperature falls below the first predetermined temperature, both compressors operate in parallel. This dynamic adaptation resolves the contradiction between maintaining heating capacity and operating efficiency across varying temperature conditions.
2Use of energy by moving object
If conventional air-source heat pumps operate below critical temperature, then heating demand increases, but system efficiency and HSPF reduce
Solution Approach 1:
The system changes operational parameters (compressor configuration) based on ambient temperature thresholds. By switching from single-compressor operation to dual-compressor parallel operation when temperature drops below the first predetermined temperature, the system maintains optimal heating efficiency and HSPF across varying thermal conditions.
3Productivity
If dual compressors operate in parallel, then heating capacity is maintained at low temperature, but device complexity increases
Solution Approach 1:
The two compressors are designed with identical or similar specifications, allowing either compressor to serve multiple functions. This universality simplifies the overall system design compared to using compressors of different types, while still enabling the system to maintain heating capacity across wide temperature ranges through parallel operation when needed.
Data Source
AI summary
A method for controlling a heat pump is provided. A working mode of the heat pump is determined. Based on a determination that the working mode of the heat pump is a heating mode, an ambient temperature of the heat pump is determined. Based on a determination that the ambient temperature of the heat pump is higher than a first predetermined temperature, a first compressor of the heat pump is operated. Based on a determination that the ambient temperature of the heat pump is lower than the first predetermined temperature, both the first compressor and a second compressor of the heat pump are enabled to operate, in response to a two-stage thermostat. The first compressor and the second compressor are coupled in parallel. The method allows the heat pump to be suitable for a cold climate.