Heat Pump Hot Water Control Using Learned Demand and Compressor Frequency
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Solution Overview
Problem
Existing combined air-conditioning and hot water supply systems face inefficiencies in hot water supply operations due to high compressor operating frequencies, leading to poor energy savings and operational inefficiencies, as they often prioritize hot water availability over efficiency.
Innovation Solution
A refrigeration cycle apparatus that computes the minimum required hot water supply capacity based on past user heat consumption, using a controller to adjust the compressor frequency according to the calculated heat storage and supply, ensuring efficient operation during both hot water supply and air-conditioning modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor operating frequency is increased to ensure hot water supply capacity, then hot water availability is improved, but operation efficiency deteriorates
Solution Approach 1:
The system performs preliminary learning of user heat usage patterns in advance to predict future hot water demands. By storing and analyzing past usage data, the controller can pre-determine optimal compressor operation schedules that ensure hot water availability while avoiding excessive energy consumption, thus resolving the contradiction between reliability and energy efficiency.
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors actual heat usage, compares it with learned patterns, and adjusts compressor frequency accordingly. This closed-loop control ensures hot water supply capacity is maintained while optimizing operation efficiency by avoiding both over-compression and under-supply scenarios.
2Reliability
If the compressor operating frequency is controlled to high frequency to prevent hot water shortage, then hot water availability is improved, but energy saving performance deteriorates
Solution Approach 1:
The controller performs preliminary learning of user heat usage patterns and stores this data for future reference. By analyzing past usage in advance, the system can determine optimal compression schedules that prevent hot water shortages while minimizing energy waste, thus resolving the contradiction between reliability and energy saving performance.
Solution Approach 2:
The system dynamically changes compressor operating parameters (frequency, duration) based on learned usage patterns and current system state. By adjusting these parameters optimally rather than maintaining constant high frequency, the system prevents hot water shortages while significantly improving energy saving performance.
3Reliability
If the system prioritizes hot water supply capacity over efficiency, then hot water availability is improved, but operation efficiency deteriorates
Solution Approach 1:
The system performs preliminary learning of usage patterns to predict future demands before they occur. This advance preparation enables the controller to optimize compressor operation schedules that ensure hot water availability while maintaining high operation efficiency, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The controller uses feedback from actual usage data to continuously refine its predictions and adjust compressor operation. This ensures hot water supply capacity is maintained while optimizing operation efficiency by avoiding both excessive compression and insufficient supply, thus resolving the contradiction between reliability and productivity.
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 high operation efficiency in hot water supply while preventing shortages, by optimizing compressor frequency based on actual usage patterns, thereby enhancing energy savings and operational efficiency.
Implementation Method 1
a refrigerant circuit formed by connecting a hot water supply unit (hot water supply device) to a heat source unit (outdoor unit) by pipes
Implementation Method 2
a refrigerant circuit formed by connecting a use unit (indoor unit) by pipes in addition to a hot water supply unit, thereby enabling simultaneous execution of an air-conditioning operation and a hot water supply operation
Implementation Method 3
the hot water supply device of a hot water storage tank type described in Patent Literature 1 achieves improved energy saving performance by boiling up water in accordance with the heat usage condition
Implementation Method 4
waste heat generated in cooling to be used as hot water supply operation
Data Source
Figure 1
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AI summary
A combined air-conditioning and hot water supply system 100 includes a refrigeration cycle mechanism, a hot water storage tank that stores heat based on heated hot water, and a controller 110. The refrigeration cycle mechanism has a compressor 1 whose operating frequency can be controlled, a plate water-heat exchanger 17 that heats water into hot water, a hot water supply pressure-reducing mechanism 20, and an outdoor heat exchanger 3. The controller 110 includes a clock section, a computing section, a memory section, and a controlling section. The clock section measures time. The computing section calculates the actual hot water supply load, which represents the quantity of heat that has been supplied to the load side per unit time, and the heat stored in the hot water storage tank. The memory section stores information related to the hot water supply load calculated by the computing section. The controlling section controls the operating frequency of the compressor 1 on the basis of the quantity of heat storage, the hot water supply load, and a preset hot water supply time. The control by the controller makes it possible to perform a hot water supply operation with high operation efficiency, and also avoid running out of hot water.