Heat Pump Heating Circuit With Accumulator-Based Subcooling

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Solution Overview

Problem

Existing heating installations inefficiently utilize surplus heat from heat pumps, leading to energy wastage and suboptimal operation, particularly in maintaining temperature stability and energy recovery.

Innovation Solution

Incorporating a third heat pump and an accumulator tank in the heating installation to facilitate efficient subcooling of the working medium and optimal energy recovery by utilizing surplus heat from the first heat pump, while ensuring temperature stability and efficient cooling before re-entering the heat exchanger.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the heat exchanger is used to transfer heat from the working medium of the first heat pump to the medium in the second circuit, then the efficiency of the first heat pump is improved by utilizing surplus heat, but the temperature of the medium in the second circuit may fluctuate rapidly

Engineering Contradiction:
Improveefficiency of the first heat pumpVSAvoidtemperature stability of the medium in the second circuit
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The accumulator tank is positioned in the circuit before the heat exchanger to pre-stabilize the medium temperature. By accumulating the medium and allowing thermal equilibrium to establish before the medium enters the heat exchanger, rapid temperature fluctuations are prevented while still enabling efficient heat transfer from the first heat pump's working medium.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If the second heat pump operates to absorb heat energy from the medium in the second circuit, then energy recovery is optimized, but the operation must be continuously adapted to maintain desired temperature reduction

Engineering Contradiction:
Improveenergy recovery efficiencyVSAvoidoperational complexity of the second heat pump
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The accumulator tank automatically performs temperature stabilization without requiring external control intervention. The thermal mass in the accumulator naturally buffers temperature changes, allowing the second heat pump to operate in a self-regulating manner where the system's thermal inertia maintains temperature within optimal ranges without continuous adaptation.

Inventive Principle:
Principle #25Self-service

3Productivity

If the medium is rapidly cooled in the heat exchanger, then subcooling efficiency is improved, but rapid temperature changes occur that affect system stability

Engineering Contradiction:
Improvesubcooling efficiencyVSAvoidtemperature stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The accumulator tank pre-cools and stabilizes the medium temperature before it enters the heat exchanger. This preliminary thermal conditioning allows the heat exchanger to operate at high subcooling efficiency while the accumulator's thermal mass prevents excessive temperature drops, maintaining overall system stability.

Inventive Principle:
Principle #10Preliminary action

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

Enhances the efficiency of the first heat pump by utilizing surplus heat, prevents rapid temperature changes, and optimizes energy recovery in the second heat pump, allowing for efficient subcooling and heating purposes.

Implementation Method 1

a heat exchanger which is arranged in the second circuit and which is connected between a condenser and an expansion valve of the first heat pump in order to transfer heat from a working medium of the first heat pump to the medium in the second circuit

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a second heat pump arranged for heating a medium by absorbing heat energy from the medium in the second circuit, wherein the second heat pump has its input side connected to the second circuit so that heat exchange between the medium in the second circuit and a working medium of the second heat pump is possible via an evaporator of the second heat pump

Methodology Applied
Scientific EffectHeat absorption: Conduction (thermal)

Implementation Method 3

a third heat pump arranged for heating a medium by absorbing heat energy from the medium in the second circuit. The first accumulator tank is connected to an evaporator of the third heat pump in order to allow medium to circulate between the first accumulator tank and the evaporator of the third heat pump so that heat exchange between the medium in the second circuit and a working medium of the third heat pump is possible via the evaporator of the third heat pump

Methodology Applied
Scientific EffectHeat absorption: Conduction (thermal)

Data Source

PatentEP3218650B1Heating installation
Publication Date: 2021.06.23 ENERGY MACHINES
  • EP3218650B1 patent drawingFigure 1
  • EP3218650B1 patent drawingFigure 2
  • EP3218650B1 patent drawingFigure 3

AI summary

A heating installation comprising: a first circuit (C1); a second circuit (C2); a first heat pump (4) for heating the medium in the first circuit; a heat exchanger (10) which is arranged in the second circuit and connected between a condenser (4b) and an expansion valve (4d) of the first heat pump; second and third heat pumps (11, 13) arranged for heating a medium by absorbing heat energy from the medium in the second circuit; and an accumulator tank (12) arranged in the second circuit downstream of the second heat pump (11). The accumulator tank is connected to an evaporator ( 13a) of the third heat pump (13) in order to allow medium to circulate between the accumulator tank and this evaporator so that heat exchange between the medium in the second circuit and a working medium of the third heat pump is possible via the evaporator of the third heat pump.