Spillover Tank Refrigerant Level Control for Flooded Evaporators
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Solution Overview
Problem
HVAC systems face challenges in accurately managing refrigerant levels in evaporators and oil return to compressors, leading to inefficiencies in heat exchange and lubrication, respectively, due to difficulties in measuring refrigerant levels within the evaporators and ensuring proper oil concentration.
Innovation Solution
Incorporating a spill over tank with a fluid level sensor and a heat exchanger to regulate refrigerant levels and oil return, using a fluid flow regulating device to control the flow rate, and implementing methods to adjust refrigerant charges based on measured levels and flow rates to maintain optimal operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flooded evaporator is used to maximize heat exchange, then heat exchange efficiency is improved, but refrigerant level measurement becomes difficult
Solution Approach 1:
A spill over tank is introduced as an intermediary device between the evaporator and the rest of the refrigeration circuit. This tank receives refrigerant from the evaporator and provides a separate, accessible location for fluid level sensing, thereby enabling measurement without interfering with the flooded evaporator's heat exchange performance
Solution Approach 2:
The refrigeration system is segmented into separate functional zones: the flooded evaporator for heat exchange and the spill over tank for refrigerant level management and measurement. This segmentation allows each component to optimize its specific function without compromising the other
2Reliability
If refrigerant is circulated with oil in the refrigeration circuit, then lubrication is provided, but oil return to compressor becomes difficult to control
Solution Approach 1:
A fluid level sensor in the spill over tank provides feedback on refrigerant and oil levels. This feedback enables the control system to regulate refrigerant charging and expansion device operation to ensure proper oil return to the compressor, maintaining reliable lubrication while improving controllability
Solution Approach 2:
The spill over tank acts as an intermediary that separates oil management from the main refrigeration circuit. By concentrating oil and refrigerant mixture in this separate tank, the system can better control and monitor oil return to the compressor
3Ease of operation
If expansion device is used to control refrigerant level, then refrigerant distribution is improved, but precise level control becomes difficult
Solution Approach 1:
The fluid level sensor provides continuous feedback on refrigerant level in the spill over tank, enabling precise control of refrigerant charging and expansion device operation to maintain optimal levels
Solution Approach 2:
The manual or mechanical refrigerant level control through the expansion device is supplemented or replaced by an automated control system using fluid level sensor feedback, transitioning from purely mechanical control to a sensor-based precision control system
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 refrigerant level management in evaporators, enhancing heat exchange efficiency and ensures proper lubrication of compressors by accurately controlling refrigerant and oil levels, thereby increasing the overall performance and efficiency of HVAC systems.
Implementation Method 1
the refrigerant flowing out of the spill over tank may be directed into a heat exchanger that is configured to vaporize some or most of the refrigerant portion by exchanging heat between the refrigerant flowing out of the spill over tank and a heat source
Implementation Method 2
vaporize some or most of the refrigerant portion by exchanging heat between the refrigerant flowing out of the spill over tank and a heat source
Implementation Method 3
the spill over tank may include a fluid level sensor configured to measure the spill over refrigerant level in the spill over tank
Data Source
AI summary
A system for managing fluid level in an HVAC system includes a spill over tank for an evaporator of the HVAC system. The spill over tank may be configured to receive a refrigerant directed out of the evaporator. The spill over tank may be configured to include an outlet directing refrigerant into the spill over tank, out of the spill over tank and flowing back to a compressor of the HVAC system. The spill over tank may be equipped with a refrigerant level sensor measuring a refrigerant level in the spill over tank. The measured refrigerant level in the spill over tank may be used to control and/or maintain a refrigerant level in the evaporator, and/or to control a return refrigerant flow into the compressor of the HVAC system so as to manage an oil return to the compressor.