Dual-Circuit Heat Pump Control for High-Temperature Water Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional heat pump water heaters require an auxiliary heater and a refrigerant/water heat exchanger to achieve high-temperature hot water, leading to poor operating efficiency and inefficiencies in heating aqueous media.
Innovation Solution
A heat pump system with a heat-source-side and usage-side refrigerant circuit, featuring variable-capacity compressors and heat exchangers, where the discharge saturation temperatures are controlled to stabilize the refrigeration cycles, allowing for efficient heating of aqueous media without the need for an auxiliary heater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an auxiliary heater and refrigerant/water heat exchanger are used in combination to heat water, then high-temperature hot water can be supplied, but operating efficiency deteriorates
Solution Approach 1:
The system divides the heating function into two separate refrigerant circuits: a heat-source-side circuit that extracts heat from the environment, and a usage-side circuit that delivers heat to water. This segmentation allows each circuit to operate independently at optimized temperatures, eliminating the need for auxiliary heaters and improving overall operating efficiency while achieving high-temperature hot water supply.
2Temperature
If discharge pressure of the compressor is increased to supply high-temperature hot water, then hot water temperature increases, but operating efficiency deteriorates
Solution Approach 1:
The system employs variable-capacity compressors in both the heat-source-side and usage-side refrigerant circuits, allowing dynamic adjustment of compression ratios and discharge pressures. This enables the system to achieve high-temperature hot water supply without maintaining excessively high discharge pressures continuously, thereby reducing energy losses and improving operating efficiency through adaptive control.
3Device complexity
If a conventional heat pump cycle is used, then system simplicity is maintained, but the ability to produce stable high-temperature aqueous medium deteriorates
Solution Approach 1:
The control device monitors discharge saturation temperatures from both the heat-source-side and usage-side compressors and adjusts the variable-capacity compressors accordingly. This feedback control mechanism ensures stable operation of the refrigeration cycles, maintaining consistent high-temperature aqueous medium production while managing the increased system complexity through intelligent control.
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 achieves stable high-temperature aqueous media production with improved efficiency by controlling the compressors and heat exchangers, reducing the need for auxiliary heating and enhancing operational stability.
Implementation Method 1
the usage-side refrigerant circulating through the usage-side refrigerant circuit is heated in the first usage-side heat exchanger by radiation of the heat-source-side refrigerant circulating through the heat-source-side refrigerant circuit
Implementation Method 2
a high-temperature aqueous medium can be obtained by radiation of the usage-side refrigerant in the refrigerant/water heat exchanger
Implementation Method 3
The heat-source-side refrigerant circuit has a variable-capacity heat-source-side compressor for compressing a heat-source-side refrigerant
Implementation Method 4
The usage-side refrigerant circuit has a variable-capacity usage-side compressor for compressing usage-side refrigerant
Data Source
AI summary
A heat pump system includes: a heat-source-side refrigerant circuit having a heat-source-side compressor, a first usage-side heat exchanger operable as a radiator of heat-source-side refrigerant, and a heat-source-side heat exchanger operable as a radiator of heat-source-side refrigerant; and a usage-side refrigerant circuit having a usage-side compressor, a refrigerant/water heat exchanger operable as a radiator of usage-side refrigerant to heat an aqueous medium, and the first usage-side heat exchanger operable as an evaporator of usage-side refrigerant by radiation of heat-source-side refrigerant. The capacity of the heat-source-side compressor is controlled so that a saturation temperature corresponding to the pressure of the heat-source-side refrigerant in the discharge of the heat-source-side compressor becomes a target temperature; and the capacity of the usage-side compressor is controlled so that a saturation temperature corresponding to the pressure of the usage-side refrigerant in the discharge of the usage-side compressor becomes a target temperature.