Three-Pipe Heat Recovery Heat Pump for Dehumidification Without Overcooling
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Solution Overview
Problem
The complexity and cost of controlling heat recovery in multi-connected heat pump systems due to the need for multiple four-way valves to allocate refrigerant and recover discharged heat, which degrades thermal comfort and efficiency, especially in rainy and low-temperature environments.
Innovation Solution
A heat recovery variable-frequency multi-connected heat pump system design utilizing a four-way valve with an oil separator, electromagnetic valves, capillary, check valve, vapor-liquid separator, and electronic expansion valves to manage refrigerant flow across various operating conditions, allowing for flexible operation of indoor units for heating, refrigerating, or dehumidifying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple four-way valves are used to allocate refrigerant and recover discharged heat, then heat recovery function is achieved, but system complexity and control cost increase
Solution Approach 1:
The patent merges multiple four-way valves into a single four-way valve with multiple ports (A, B, C, D ends) that can control refrigerant flow to multiple indoor units. This consolidation reduces the number of valves from multiple to one, simplifying the system structure while maintaining the heat recovery function across multiple indoor units.
Solution Approach 2:
The single four-way valve is designed with multi-functionality to perform the roles of multiple valves. It can allocate refrigerant to different indoor units for both heating and cooling operations, and enable heat recovery between indoor units, making one component perform multiple functions that previously required several separate valves.
2Adaptability or versatility
If multiple four-way valves are used to allocate refrigerant and recover discharged heat, then heat recovery function is achieved, but control cost increases
Solution Approach 1:
By combining multiple valve functions into a single four-way valve with multiple ports, the patent reduces the total number of components that need to be manufactured and installed. This merging approach directly reduces control cost by eliminating redundant valves and their associated control mechanisms.
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
The system improves thermal comfort and efficiency by using three pipes with a four-way valve and two sets of electronic expansion valves and heat exchangers, enabling six operating conditions, including dehumidification without temperature lowering, thus enhancing refrigeration and heating capacity.
Implementation Method 1
the outdoor units are connected with the indoor units through the refrigerant pipe and the manifold pipe... heat in the system is recovered... enable the operating indoor units to refrigerate and heat concurrently
Implementation Method 2
two sets of electronic expansion valves... enabling the first electronic expansion valves (15) and the second electronic expansion valves (17) of the respective indoor units to throttle for lower pressure
Implementation Method 3
the outdoor heat exchanger (5)... the first indoor heat exchangers (16)... and the second indoor heat exchangers (18)... enable the operating indoor units to refrigerate and heat concurrently
Data Source
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AI summary
A heat recovery variable-frequency multi-split heat pump system and a control method thereof. The system comprises an outdoor unit and at least two indoor units. The system is a three-pipe heating recovery multi-split heat pump system designed on the basis of a four-way reversing valve, and one indoor unit thereof is provided with two electronic expansion valves and two heat exchangers so that any indoor unit in the system can operate independently under three working conditions of refrigeration, heating or heat recovery dehumidification. Under multi-split condition, the system can operate under six working conditions, namely, the full-refrigeration working condition, the full-heating working condition, the common-heat-recovery working condition, the common-heat-recovery-dehumidification working condition, the heat recovery dehumidification-refrigeration-combination working condition and the heat recovery dehumidification-heating-combination working condition. Under the heat recovery dehumidification condition, a lower outlet air temperature, during low-temperature dehumidification, is raised by means of heat removal of a condenser so as to achieve the purpose of dehumidification without temperature fall or temperature rise, so that the thermal comfort and efficiency of the system are improved, and the refrigerating capacity and heating capacity of the system are effectively improved.