Heat Pump Hot Water Variable-Flow Control for Efficient Heating

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Solution Overview

Problem

Conventional heat pump hot water apparatuses suffer from poor heating efficiency due to a fixed circulation flow rate, leading to prolonged heating times and pressure issues when heating water in a hot water storing tank, regardless of the water temperature.

Innovation Solution

A heat pump hot water apparatus with a control system that adjusts the circulation amount of circulating water based on temperature differences between the radiator and the hot water storing tank, using a compressor, radiator, decompressing means, and evaporator, along with outlet, inlet, and tank temperature detectors to optimize heating efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed circulation flow rate is used to heat water in the hot water storing tank, then the system structure remains simple, but the heating efficiency deteriorates when the water temperature is low

Engineering Contradiction:
Improvecirculation system structureVSAvoidheating efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The circulation pump's flow rate is made variable rather than fixed. The control unit dynamically adjusts the circulation flow rate based on the temperature difference between the hot water in the storing tank and the circulating water, enabling the system to adapt to different heating conditions and improve heating efficiency

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a fixed circulation flow rate is used, then the pump operation is simple, but the heating time is prolonged when the supply-hot water temperature is low

Engineering Contradiction:
Improvepump operationVSAvoidheating time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

Temperature sensors continuously monitor the water temperature in the hot water storing tank and the circulating water temperature. The control unit uses this feedback information to calculate the temperature difference and adjust the circulation pump's flow rate accordingly, optimizing the heating process and reducing heating time

Inventive Principle:
Principle #23Feedback

3Device complexity

If a fixed circulation flow rate is used, then the system control is simple, but the pressure on the high pressure side of the heat pump cycle reaches allowable working pressure when the supply-hot water temperature is high

Engineering Contradiction:
Improvecontrol systemVSAvoidheat pump cycle pressure
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The circulation flow rate is dynamically adjusted based on real-time temperature conditions. When the supply-hot water temperature is high, the system reduces the circulation flow rate to prevent the high pressure side of the heat pump cycle from reaching allowable working pressure, thereby maintaining system reliability

Inventive Principle:
Principle #15Dynamics

4Device complexity

If a fixed circulation flow rate is used, then the system design is simple, but heating efficiency deteriorates due to repetitive heating operations with breaks

Engineering Contradiction:
Improvesystem designVSAvoidheating efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The control unit continuously monitors temperature conditions and adjusts the circulation pump operation accordingly. This feedback mechanism prevents the heat pump from needing to stop and restart repeatedly by maintaining optimal circulation flow rates, thereby improving heating efficiency and eliminating repetitive heating operations with breaks

Inventive Principle:
Principle #23Feedback

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 solution enhances heating efficiency by dynamically adjusting the circulation flow to match temperature differences, reducing the temperature gradient within the tank and improving overall heating performance, thus providing an energy-efficient heating process.

Implementation Method 1

a radiator that heats circulating water through heat exchange with the refrigerant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a hot water storing tank-dedicated heat exchanger that allows the circulating water heated at the radiator and water in the hot water storing tank to exchange heat with each other

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3115699B1Heat pump hot water apparatus
Publication Date: 2019.05.01 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3115699B1 patent drawingFigure 1~2
  • EP3115699B1 patent drawingFigure 3~4
  • EP3115699B1 patent drawingFigure 5

AI summary

A heat pump hot water apparatus of the present disclosure includes a heat pump cycle, a hot water storing tank, a hot water storing tank-dedicated heat exchanger, and a circulation pump. Further, the heat pump hot water apparatus includes outlet temperature detecting means for detecting a temperature of circulating water from a radiator, inlet temperature detecting means for detecting a temperature of the circulating water to the radiator, tank temperature detecting means for detecting a temperature of water in the hot water storing tank, and a control apparatus. In accordance with a reduction in a difference between a target heating temperature of the water in the hot water storing tank and the temperature detected by the tank temperature detecting means during a heating operation, the control apparatus adjusts a circulation amount of the circulating water so as to reduce a difference between the temperature detected by the outlet temperature detecting means and the temperature detected by the inlet temperature detecting means.