Methods and systems for supplemental flow control of working fluid through a climate control circuit
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Solution Overview
Problem
Current climate control systems for transport units face challenges in maintaining consistent temperature control and minimizing power consumption, particularly during start-stop cooling cycles, which can lead to hydraulic locking and inefficient compressor operation.
Innovation Solution
The implementation of supplemental flow control methods that stage the operation of valves in the transport climate control circuit relative to the compressor's start-stop cycles, utilizing an auxiliary suction port and main suction port, along with a discharge port, to optimize working fluid flow and reduce temperature fluctuations, while minimizing power consumption and preventing hydraulic locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor operates in conventional start-stop cooling cycles, then the climate control system can maintain cooling capacity, but temperature swing fluctuations increase and temperature control precision deteriorates
Solution Approach 1:
The liquid suction valve is opened in advance before the compressor starts and closed after the compressor stops, creating a buffer of liquid refrigerant that absorbs temperature fluctuations during compressor cycling, thereby maintaining more stable temperature control
Solution Approach 2:
The system dynamically controls the liquid suction valve timing based on compressor operation state, adjusting the valve opening and closing moments to optimize temperature stability during each compression cycle
2Use of energy by stationary object
If the compressor cycles ON and OFF frequently to maintain temperature, then the system responds to temperature changes, but power consumption increases and compressor reliability decreases
Solution Approach 1:
By opening the liquid suction valve before compressor start, the system prepares the refrigerant flow path in advance, enabling smoother compressor startup and reducing the frequency of complete stop-start cycles, thereby lowering power consumption and improving compressor reliability
Solution Approach 2:
The staged valve operation maintains continuous refrigerant flow through the system even during compressor cycling, eliminating idle periods and ensuring the cooling function operates continuously without complete interruption
3Ease of operation
If liquid working fluid flows freely into the compressor during startup, then the compressor can operate, but hydraulic locking occurs and compressor damage is caused
Solution Approach 1:
The liquid suction valve is opened before compressor startup to prepare the refrigerant path, but controlled timing ensures liquid flow is managed appropriately during the transition, preventing hydraulic locking while enabling smooth startup
Solution Approach 2:
The liquid suction valve acts as an intermediary device that mediates between the liquid refrigerant source and the compressor, controlling the timing and amount of liquid flow to prevent harmful hydraulic locking while enabling proper operation
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 approach enhances temperature control within the climate-controlled space, reduces compressor cycling, minimizes power consumption, and prevents hydraulic locking by optimizing compressor operation and reducing discharge pressure, thereby improving overall system efficiency.
Implementation Method 1
a compressor with an auxiliary or intermediate suction port (also referred to as an economizer port, a vapor injection port, etc.) in combination with a main suction port and a discharge port
Implementation Method 2
The embodiments described herein can be used with a fixed speed (e.g., two-speed compressor) or a variable speed compressor
Implementation Method 3
The embodiments described herein can reduce the flow of working fluid through the transport climate control circuit beyond what can be accomplished with a variable speed compressor
Implementation Method 4
The embodiments described herein can provide tighter temperature control within a climate controlled space of the transport unit
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method for providing supplemental flow control of working fluid through a transport climate control circuit during a start-stop cooling operation mode is provided. The method includes closing (305) a main liquid suction solenoid valve (236) disposed between a condenser and an evaporator of the transport climate control circuit when the compressor is OFF. The method also includes monitoring (310) a climate controlled space temperature within a climate controlled space. When the climate controlled space temperature is greater than or equal to a predetermined setpoint temperature (315), the method includes turning a compressor ON (320), and opening (335) the main liquid suction solenoid valve when a suction pressure at the suction port of the compressor is less than or equal to a predetermined suction pressure threshold. When the climate controlled space temperature is less than or equal to the predetermined setpoint temperature (340), the method includes turning the compressor OFF (350), and closing (355) the main liquid suction solenoid valve.