Compressor Crankcase Heating Control Based on Temperature and Time
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Solution Overview
Problem
Compressors face issues with 'cold starting' and 'liquid flood-back' due to lubricant viscosity changes at low temperatures, leading to bearing wear and decreased performance, and existing crankcase heaters consume excessive energy by running continuously or at constant power levels, which is inefficient and not aligned with regulatory requirements.
Innovation Solution
A crankcase heating control system that selectively applies power to a heater based on compressor temperature, ambient temperature, current date, and time, disabling the heater when not necessary to conserve energy and prevent unnecessary heating, using a data receiving module and power control module to manage heating during off-states and seasonal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crankcase heater runs continuously or at constant power levels, then the lubricant temperature is maintained, but excessive energy is consumed
Solution Approach 1:
The patent applies dynamics by transitioning from constant power operation to variable power operation. The heater power level is dynamically adjusted based on real-time monitoring of compressor off-time duration and crankcase temperature conditions. The controller selectively applies different power levels (first, second, and third power levels) depending on the operational state, thereby optimizing energy consumption while maintaining reliable compressor operation when needed.
Solution Approach 2:
The patent changes the power parameter of the heater based on operational conditions. Instead of maintaining a fixed power level, the system modifies the power parameter dynamically - using higher power levels when the compressor has been off for extended periods and lower power levels when the compressor is frequently running or when ambient temperatures are favorable, thus resolving the contradiction between reliability and energy consumption.
2Reliability
If the crankcase heater is always on, then lubricant viscosity is controlled, but unnecessary heating occurs when not needed
Solution Approach 1:
The patent implements feedback control by continuously monitoring the crankcase temperature and compressor operational status, then using this information to control heater operation. The controller receives temperature data and operational state information, processes this feedback, and adjusts the heater power accordingly - turning the heater off or reducing power when temperatures are already adequate, thus preventing unnecessary heating while ensuring bearing protection when needed.
Solution Approach 2:
The heater operates periodically rather than continuously, with power application timed based on compressor off-periods and temperature conditions. The system activates the heater during specific periods when the compressor is off and temperatures drop below thresholds, and deactivates it during periods when the compressor is running or temperatures are sufficient, thereby eliminating wasted heating energy while maintaining bearing protection.
3Temperature
If the heater power is increased to ensure adequate heating, then lubricant temperature is maintained, but energy consumption increases
Solution Approach 1:
The patent applies partial action by using different power levels appropriate to different conditions rather than always applying maximum power. The controller selectively applies a first higher power level only when the compressor has been off for an extended period and temperatures are low, while using lower power levels (second and third power levels) for shorter off-periods or milder conditions, thus achieving adequate temperature maintenance with reduced overall energy consumption.
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
This solution improves compressor performance by maintaining optimal lubricant viscosity, reduces energy consumption by optimizing heating periods, and aligns with regulatory requirements by adjusting power usage based on seasonal and temporal factors.
Implementation Method 1
A crankcase heating control system selectively applies power to a heater of a crankcase
Data Source
AI summary
A crankcase heating control system for a heat pump system includes a data receiving module and a power control module. The data receiving module receives data indicative of a temperature of a compressor of the heat pump system, data indicative of an ambient temperature, and data indicative of a current date and a current time. The power control module selectively applies power to a heater of a crankcase of the compressor and selectively disables the heater based on the temperature of the compressor, the ambient temperature, the current date, and the current time.