Heat Pump Compressor Control for Simultaneous Hot Water and Heating
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Solution Overview
Problem
Conventional heat-pump water heaters and room heaters face efficiency deterioration when simultaneously performing hot water supply and room heating, leading to impaired comfortability due to reduced coefficient of performance (COP) during maximum operation.
Innovation Solution
The heat-pump equipment calculates hot water supply time based on outdoor and indoor temperature differences, adjusting compressor rotation speed to efficiently reach a preset water temperature, combining maximum and high-efficiency operation modes to balance energy saving and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heat-pump apparatus operates at maximum capacity to complete hot water supply quickly, then the hot water supply speed is improved, but the coefficient of performance (COP) deteriorates and energy efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the compressor rotation speed adjustable rather than fixed. The controller dynamically changes the compressor speed based on operational conditions - operating at high speed when only hot water supply is needed, and at reduced speed when room heating is also required, thereby adapting the system performance to different demand scenarios
Solution Approach 2:
The patent changes the operational parameters of the heat-pump apparatus by adjusting the compressor rotation speed according to the operational mode. When simultaneous hot water supply and room heating are required, the system reduces the compressor speed from maximum to an optimized level, changing the operational parameters to balance between hot water supply speed and energy efficiency
2Adaptability or versatility
If heat quantity is distributed to both hot water supply and room heating, then both functions are provided, but the room heating capacity decreases compared to single room heating operation
Solution Approach 1:
The system dynamically adjusts the compressor rotation speed based on whether room heating is simultaneously required. When dual function operation is needed, the compressor speed is reduced to a level that maintains adequate room heating capacity while still providing hot water supply, rather than operating at maximum capacity which would prioritize hot water at the expense of room heating
3Loss of energy
If the compressor rotation speed is reduced to improve energy efficiency, then the COP increases, but the hot water supply time increases and may impair room comfort
Solution Approach 1:
The patent changes the compressor rotation speed parameter based on operational context. When simultaneous room heating is required, the system operates at reduced compressor speeds (e.g., 60-80% of maximum) to maintain energy efficiency. The controller monitors operational conditions and adjusts the speed parameter accordingly, balancing energy consumption with hot water supply timing requirements
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 allows for energy-saving hot water supply without compromising room comfort during simultaneous hot water and room heating requests, optimizing energy usage and comfort levels.
Implementation Method 1
a heat exchanger as a heat source and exchanges heat between refrigerant and a heat medium such as water flowing inside
Implementation Method 2
a heat-pump apparatus having a heat-pump apparatus of a variable operation capacity type
Data Source
Figure 1
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Figure 4~6
AI summary
When hot water supply and room heating are requested simultaneously, a hot water supply operation, by which energy saving is achieved without impairing the comfortability in a room, is performed. A heat-pump apparatus 100 of a variable operation capacity type, a primary water circuit 25, a hot water tank 22, a room heater 300, and a controller 400 are provided. The controller 400 sets a hot water supply operation completion target time t4 in the case of a requests for a simultaneous hot water supply and room heating operation, based on a temperature difference between the outdoor air temperature and the indoor temperature, and determines the rotation speed of the compressor 11 in the hot water supply operation completion target time t4 set.