External Heat Storage Charging Loop for Low-Pressure Hot Water Heating

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Solution Overview

Problem

Existing heat storage systems lack an efficient method to optimize hot water preparation, particularly in terms of automatic adjustment to system conditions and achieving desired temperatures without excessive energy consumption or pressure loss.

Innovation Solution

A heat storage system with a storage charging system outside the heat storage tank, utilizing a combination of an electrically operated instantaneous water heater and a circulating pump, along with a three-way valve or volume flow sensor, to heat and circulate the heat transfer medium within the system, allowing for adjustable temperature and volume flow management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a heating element is installed directly inside a storage tank, then the storage can be heated efficiently, but the system lacks flexibility in adjusting to system conditions and electricity price variations

Engineering Contradiction:
Improveenergy efficiencyVSAvoidadaptability to system conditions
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The heating system is divided into two independent parts: a storage tank with inlet/outlet connections and a separate external heating unit (instantaneous water heater or heat pump). This segmentation allows the heating unit to be controlled independently based on electricity prices and system conditions, while the storage tank provides thermal energy storage capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates dynamic control capabilities through a control unit that automatically adjusts operation based on electricity price signals, temperature sensors, and system demand. The charging pump and heating element can be switched on/off dynamically to optimize energy usage according to real-time conditions.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If an electrically operated compression heat pump is used, then heating efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improveheating efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The heating function is extracted from the storage tank and placed in a separate external unit. This allows the use of sophisticated heating technologies like heat pumps or instantaneous water heaters without increasing the complexity of the storage tank itself. The control unit manages the complexity of coordinating these components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system is designed to accommodate multiple types of heating units (heat pumps, instantaneous water heaters, or other heating devices). This multi-functionality allows the storage tank to work with different heating technologies depending on availability, cost, and system requirements, without requiring dedicated infrastructure for each type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Temperature

If the instantaneous water heater heats the hot water circulating between it and the heat accumulator, then the heat accumulator is heated efficiently, but pressure loss increases

Engineering Contradiction:
Improveheat accumulator temperatureVSAvoidpressure loss
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The instantaneous water heater is positioned to heat water locally at the point of need (the storage tank inlet), rather than heating water throughout the entire circulation loop. This localized heating approach minimizes the volume of water that needs to be circulated under pressure, thereby reducing overall pressure losses in the system.

Inventive Principle:
Principle #3Local quality

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 enables efficient heating of the heat accumulator, reduces pressure loss, and allows for flexible operation using surplus energy, achieving the desired outlet temperature while minimizing energy costs and optimizing hot water preparation.

Implementation Method 1

the instantaneous water heater being able to heat the hot water circulating between the instantaneous water heater and the heat accumulator

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

heat the hot water circulating between the instantaneous water heater and the heat accumulator and thus heat up the heat accumulator

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

a storage charging system outside the heat storage... utilizing a combination of an electrically operated instantaneous water heater and a circulating pump

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 4

A valve 1, for example a three-way switching valve or mixer valve, is switched in one embodiment variant in such a way that the water heated by the continuous-flow heater 3 is fed back into the reservoir 5

Methodology Applied
Scientific EffectValve flow control: Valve

Implementation Method 5

In a heat accumulator 5, heat is stored in a supply of hot water

Methodology Applied
Scientific EffectThermal energy storage: Thermal Energy Storage

Data Source

PatentEP3062027B1Heat storage system and method for its operation
Publication Date: 2018.06.06 VAILLANT GMBH(DE)
  • EP3062027B1 patent drawingFigure 1~2
  • EP3062027B1 patent drawingFigure 3~4
  • EP3062027B1 patent drawingFigure 5~6

AI summary

The invention relates to a heat storage system for storing heat. It includes a heat accumulator (5), an inlet (9) for cold water and an outlet (10) for removing hot water. According to the invention, the heat storage system comprises a storage charging system with an electrically operated flow heater (3) and a circulating pump (2). The heat accumulator (5), the continuous-flow heater (3) and the circulating pump (2) are arranged one behind the other in a closed hydraulic circuit (11) in the conveying direction of the circulating pump (2). The outlet (10) is arranged between the instantaneous water heater (3) and the circulation pump (2).