System and method of controlling a variable-capacity compressor
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Solution Overview
Problem
Current climate-control systems, such as heat-pump systems, face challenges in efficiently managing energy usage and comfort levels due to the inability to effectively vary compressor capacity and blower speed in response to changing indoor and outdoor conditions, particularly relative humidity and temperature.
Innovation Solution
A climate-control system incorporating a variable-capacity compressor and a variable-speed blower, controlled by a module that adjusts compressor capacity and blower speed based on indoor relative humidity, outdoor-air-temperature, and geographical region, using algorithms and lookup tables to optimize energy efficiency and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor operates in high-capacity mode to quickly cool or heat the space, then the cooling or heating speed is improved, but energy efficiency deteriorates
Solution Approach 1:
The compressor capacity is made variable through a variable-capacity compressor that can dynamically adjust between first and second capacity modes. The control module switches between these modes based on real-time conditions including temperature differential, humidity levels, and system runtime, allowing the system to optimize between speed and energy efficiency for each operating condition.
Solution Approach 2:
The system changes operational parameters by adjusting compressor capacity mode and blower speed based on multiple factors including temperature differential, humidity levels, and system runtime. This parameter adjustment allows the system to operate in high-capacity mode when rapid response is needed while switching to low-capacity mode for energy-efficient operation during maintenance phases.
2Use of energy by moving object
If the compressor operates in low-capacity mode to improve energy efficiency, then energy consumption is reduced, but the cooling or heating speed deteriorates
Solution Approach 1:
The system employs periodic action by alternating between high-capacity and low-capacity compressor modes in a cyclical pattern. The control module monitors system runtime and switches from first capacity mode to second capacity mode after a predetermined runtime period, enabling the system to achieve both rapid initial response and sustained energy-efficient operation.
Solution Approach 2:
The variable-capacity compressor dynamically adjusts between capacity modes based on real-time system conditions. The control module evaluates temperature differential, humidity levels, and runtime to determine the optimal capacity mode, allowing the system to transition from low-capacity energy-efficient operation to high-capacity speed-oriented operation when conditions require it.
3Ease of operation
If the blower operates at high speed to improve air circulation and comfort, then comfort level is improved, but energy consumption increases
Solution Approach 1:
The blower speed is made variable through a variable-speed blower that can dynamically adjust between first and second speeds. The control module switches between speeds based on real-time conditions including temperature differential, humidity levels, and compressor capacity mode, allowing the system to optimize the balance between comfort level and energy consumption for each operating condition.
Solution Approach 2:
The system changes blower speed parameters based on multiple factors including temperature differential, humidity levels, and compressor runtime. This parameter adjustment allows the blower to operate at high speed when comfort is prioritized while switching to low speed for energy-efficient operation during maintenance or mild conditions.
4Use of energy by moving object
If the blower operates at low speed to reduce energy consumption, then energy efficiency is improved, but air circulation and comfort level deteriorate
Solution Approach 1:
The system employs periodic action by alternating between high-speed and low-speed blower operation in a cyclical pattern synchronized with compressor capacity mode changes. The control module switches blower speed based on system runtime and environmental conditions, enabling the system to achieve both energy-efficient operation and periodic comfort enhancement.
Data Source
AI summary
A system includes a variable-capacity compressor operable in a first capacity mode and in a second capacity mode that is higher than the first capacity mode. A variable-speed blower is operable at a first speed and at a second speed that is higher than the first speed. A control module is configured to (i) receive indoor relative humidity data corresponding to an indoor relative humidity (ii) switch the variable-capacity compressor between the first capacity mode and the second capacity mode based on a demand signal from a thermostat and the indoor relative humidity and (iii) switch the variable-speed blower between the first speed and the second speed based on the demand signal from the thermostat and the indoor relative humidity.