Method of operating an air conditioning system including reducing the energy consumed by the compressor crank case heaters
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Solution Overview
Problem
Current climate control systems for packaged air conditioning units consume substantial energy when compressors are idle for extended periods, as crank case heaters continuously operate to prevent refrigerant condensation, leading to inefficiencies.
Innovation Solution
Implementing a conservation mode that de-powers at least one compressor and its associated crank case heater, reducing energy consumption by only activating the heaters when necessary, such as during a 'winter mode' when compressors are inactive for seasonal periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crank case heaters are continuously operated to prevent refrigerant condensation in idle compressors, then compressor reliability is improved, but energy consumption increases substantially
Solution Approach 1:
The system implements periodic action by operating crank case heaters only during specific periods when compressors are idle for extended times (such as seasonal shutdowns), rather than continuously. The controller monitors compressor operation status and activates heaters only when idle time exceeds a threshold, thereby maintaining compressor reliability during critical periods while avoiding unnecessary energy consumption during shorter idle periods or when compressors are temporarily stopped.
2Use of energy by moving object
If crank case heaters are de-powered during conservation mode, then energy consumption is reduced, but refrigerant condensation risk increases
Solution Approach 1:
The system implements feedback by continuously monitoring compressor operation status, idle time duration, and environmental conditions. The controller uses this feedback to intelligently determine when to activate or deactivate crank case heaters, activating them only when the compressor has been idle long enough to pose a condensation risk, thereby balancing energy conservation with protection against refrigerant condensation.
Solution Approach 2:
The system changes operational parameters dynamically by adjusting heater power state based on idle time duration and environmental conditions. Rather than using a fixed on/off schedule, the controller modifies the operational parameters (heater activation) based on real-time system state, allowing the system to adapt to varying conditions and minimize both energy consumption and condensation risk.
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
Significant energy savings are achieved by selectively powering crank case heaters only when needed, minimizing unnecessary energy usage during periods of inactivity.
Implementation Method 1
Crank case heaters are utilized to boil off the refrigerant from the crank case and to prevent migration of the refrigerant thereto
Implementation Method 2
Each crank case heater of the two or more crank case heaters is associated with a compressor of the two or more compressors to prevent condensation of refrigerant in a compressor lubricant crank case
Data Source
AI summary
A method of operating an air conditioning system includes cooling a selected space with the air conditioning system. The air conditioning system includes two or more compressors and two or more crank case heaters. Each crank case heater of the two or more crank case heaters is operably connected to a compressor of the two or more compressors. Operation of the two or more compressors is stopped, thus initiating operation of the two or more crank case heaters. The air conditioning system is switched to a conservation mode, including de-powering at least one compressor of the two or more compressors and a connected at least one crank case heater or the two or more crank case heaters.