Refrigerant transfer control in multi mode air conditioner with hot water generator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-purpose HVAC systems face inefficiencies and potential system cessation due to increased discharge pressure during water heating operations, requiring effective control methods without additional expensive components like thermostatic expansion valves and storage tanks.
Innovation Solution
A method and system utilizing a controller and flow control valves to manage discharge pressure by isolating the indoor unit from the outdoor unit and water heating module, directing high-pressure refrigerant to the indoor unit when necessary, and employing a four-way valve and electronic expansion valve to regulate refrigerant flow and superheat, thereby avoiding the need for additional pressure relief devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermostatic expansion valve is used to control discharge pressure during water heating operation, then the evaporator superheat can be held constant and the evaporator remains active, but additional expensive components (valves, expansion tanks, accumulators) are required to relieve pressure throughout the system
Solution Approach 1:
The existing flow control valve in the water heating module is made to serve dual functions: its original function of controlling refrigerant flow to the water heater heat exchanger, and the additional function of controlling discharge pressure by directing high-pressure refrigerant to the indoor unit. This eliminates the need for separate pressure relief devices, accumulators, and additional valves, resolving the contradiction between reliable evaporator operation and system complexity
Solution Approach 2:
The patent combines the discharge pressure control function with the existing water heating flow control valve and indoor unit, merging multiple functions into existing components. The flow control valve is used to divert refrigerant flow, and the indoor unit serves as both a heat exchanger and a pressure relief destination, eliminating the need for separate pressure management components
2Device complexity
If the outdoor heat pump operates in water heating mode without pressure control, then the system can maintain simple operation, but the discharge pressure increases to levels that make the water heating cycle inefficient or may cease operation
Solution Approach 1:
The system dynamically adjusts refrigerant flow based on discharge pressure conditions. The controller monitors discharge pressure and dynamically opens the flow control valve to divert high-pressure refrigerant to the indoor unit when pressure exceeds the predetermined threshold, and closes it when pressure is within acceptable ranges. This dynamic adjustment maintains water heating efficiency while keeping the system operationally simple
3Reliability
If additional valves and accumulators are added to relieve pressure during water heating mode, then optimal system performance can be maintained, but the system requires expensive additional components
Solution Approach 1:
The system uses its existing components to serve the additional function of pressure relief. The flow control valve and indoor unit, which are already part of the system, are utilized to manage discharge pressure during water heating operation. This self-service approach eliminates the need for separate pressure relief devices and accumulators, maintaining reliable system performance while avoiding additional manufacturing costs
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 effectively controls discharge pressure, maintains system performance, and optimizes refrigerant management across various operational modes without requiring separate storage tanks or accumulators, enhancing the efficiency and reliability of the HVAC system during water heating cycles.
Implementation Method 1
a compressor and a controller
Implementation Method 2
the water heater module including a heat exchanger
Implementation Method 3
a thermostatic expansion valve is used to regulate the refrigerant flow into the evaporator
Implementation Method 4
uses a fan and evaporator to pull heat from air surrounding the heat pump water heater in order to heat the refrigerant
Data Source
AI summary
A method for controlling an operating discharge pressure in a multi-purpose HVAC system including an outdoor unit, and an indoor unit, the HVAC system including a plurality of flow control valves configured to isolate the indoor unit from the multi-purpose HVAC system, a compressor and a controller, operably coupled to a water heater module, the water heater module including at least one valve, the controller executing a method including operating the multi-purpose HVAC system in a water heating mode, monitoring the operating discharge pressure from the compressor; and generating a signal commanding at least one of the plurality of control valves to isolate the indoor unit from the outdoor unit and water heating module and direct high pressure refrigerant to the indoor unit when the operating discharge pressure is greater than or equal to a predetermined pressure value.