Fluid management in a HVAC system
Find Innovative SolutionsGenerate Solutions
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 evaporator and ensuring proper oil distribution.
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 to maintain optimal operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flooded evaporator with tube bundle is used to maximize heat exchange, then heat exchange efficiency is improved, but refrigerant level measurement becomes difficult
Solution Approach 1:
The patent introduces a spill over tank as an intermediary device between the evaporator and the rest of the system. This tank provides a separate, accessible location for refrigerant level measurement using a float sensor, while the evaporator itself maintains its flooded design for optimal heat exchange. The spill over tank mediates between the conflicting requirements by decoupling the measurement function from the heat exchange function.
2Measurement precision
If refrigerant is allowed to spill over from the evaporator, then refrigerant level can be monitored in a spill over tank, but oil return to the compressor may be compromised
Solution Approach 1:
The patent implements a feedback control system where the float sensor in the spill over tank detects refrigerant level and provides feedback to a controller. The controller adjusts the expansion valve to maintain proper refrigerant levels, ensuring that oil-containing refrigerant spills over appropriately to the compressor while preventing excessive refrigerant accumulation that would compromise system reliability.
Solution Approach 2:
The spill over tank serves multiple functions simultaneously: it enables refrigerant level monitoring, facilitates oil return to the compressor, and provides a control point for maintaining optimal evaporator refrigerant levels. This multi-functionality resolves the contradiction by making the same component beneficial for both measurement precision and system reliability.
3Ease of manufacture
If the tube bundle is stacked up from the bottom of the evaporator, then manufacturing is simplified, but refrigerant distribution and heat exchange uniformity deteriorate
Solution Approach 1:
The patent applies local quality by ensuring the evaporator is flooded with refrigerant to a specific level that uniformly covers the tube bundle surfaces. The spill over tank maintains a consistent refrigerant level in the evaporator, creating uniform local conditions across all heat exchange surfaces. This uniform flooding compensates for the simplified bottom-up assembly approach, maintaining stable and uniform refrigerant distribution despite the manufacturing simplification.
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 flow rates, thereby optimizing HVAC system performance.
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
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 spill over tank for an evaporator of a HVAC system may be configured to receive a refrigerant spilled over from the evaporator. The spill over tank may be configured to have an outlet that directs the refrigerant in the spill over tank out of the spill over tank. The refrigerant may flow through the outlet back to a compressor of the HVAC system. The spill over tank may be equipped with a refrigerant level sensor configured to measure 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 may be used to control a return refrigerant flow into the compressor of the HVAC system so as to manage an oil return to the compressor.