Split Heat Pump with Indoor Compressor for Noise Reduction

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Solution Overview

Problem

Heat pumps generate noise due to the operation of compressors and fans, which can be a nuisance, and existing solutions do not effectively address this issue while maintaining energy efficiency and ease of maintenance.

Innovation Solution

A split heat pump design with the compressor located in the indoor unit, equipped with control electronics cooled by a first heat exchanger and a variable-speed compressor, along with a second heat exchanger to prevent condensate pan freezing, and an intermediate heat exchanger for refrigerant expansion, allowing for efficient noise reduction and improved maintenance access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the compressor is located in the outdoor unit, then the heat pump can operate efficiently, but noise emissions increase and become a nuisance

Engineering Contradiction:
Improvestandard heat pump configurationVSAvoidnoise emissions
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The compressor is extracted from the outdoor unit and relocated to the indoor unit, separating the noise-generating component from the outdoor environment. This allows the outdoor unit to function as a silent heat exchanger while the indoor unit houses the compressor, effectively removing the noise nuisance from the outdoor area.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The heat pump system is segmented into two functionally distinct units: an outdoor unit containing only heat exchangers (evaporator and condenser) and an indoor unit containing the compressor and control electronics. This segmentation allows each unit to be optimized for its specific function, with the outdoor unit being noise-free and the indoor unit being easily accessible for maintenance.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If the compressor is moved to the indoor unit, then noise emissions are reduced, but maintenance access and installation complexity change

Engineering Contradiction:
Improvenoise emissionsVSAvoidinstallation complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The compressor is extracted from the traditional outdoor unit configuration and placed in the indoor unit, which simplifies the outdoor unit to a basic heat exchanger assembly. This extraction reduces installation complexity at the outdoor location while allowing the indoor unit to serve as a centralized housing for all mechanical components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If a variable-speed compressor is used, then energy efficiency is improved, but the compressor generates more heat requiring additional cooling

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcompressor heat generation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The cooling function for the compressor is merged with the existing refrigerant circulation system. The refrigerant, after absorbing heat in the evaporator, is routed through the compressor to absorb the heat generated during compression. This eliminates the need for separate cooling mechanisms and efficiently manages the thermal load of the variable-speed compressor.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The refrigerant circulation system is given multiple functions: it not only transfers heat from the outdoor environment to the indoor space but also cools the compressor during operation. This multi-functionality is achieved by routing the cold refrigerant through the compressor housing, allowing the same system to perform both heat transfer and compressor cooling.

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

4Productivity

If the control electronics are cooled by the refrigerant, then energy efficiency is improved, but the system requires additional heat exchanger integration

Engineering Contradiction:
Improveenergy efficiencyVSAvoidheat exchanger integration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cooling of control electronics is merged with the compressor cooling function. A single heat exchanger integrates both the compressor cooling channel and the control electronics cooling channel, allowing the refrigerant to cool both components simultaneously. This eliminates the need for separate cooling systems for each component.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchanger is designed with multi-functionality, serving as both the compressor cooler and the control electronics cooler. The refrigerant flows through integrated channels that contact both the compressor housing and the control electronics housing, providing universal cooling for all heat-generating components within the indoor unit.

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

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

Significantly reduces noise emissions, enables the use of a variable-speed compressor, and simplifies maintenance by placing the compressor indoors, while maintaining energy efficiency and preventing condensate freezing.

Implementation Method 1

a first heat exchanger (12) integrated into the refrigerant circuit for cooling the control electronics by means of the refrigerant

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a second heat exchanger (14) integrated into the refrigerant circuit for heating the condensate pan by means of the refrigerant

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

The compressor compresses the refrigerant, increasing its pressure

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

At least part of the refrigerant condenses in the condenser, giving off heat in the process

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

a throttle, which reduces the pressure of the refrigerant

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Implementation Method 6

the pressure-reduced refrigerant evaporates in the evaporator and heat energy in the evaporator and thus from the environment of the evaporator absorbs

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2500676B1Heat pump
Publication Date: 2019.07.03 STIEBEL ELTRON GMBH & CO KG
  • EP2500676B1 patent drawingFigure 1
  • EP2500676B1 patent drawingFigure 2
  • EP2500676B1 patent drawingFigure 3

AI summary

The heat pump (100) has a refrigerant circuit with a refrigerant and a compressor (1) for compressing the refrigerant or for increasing the pressure the refrigerant. A condenser is provided for liquefying the refrigerant and a throttle (17) reduces the pressure of the refrigerant. An evaporator (18) evaporates the refrigerant. An internal unit (101) is installed in a building to be heated and for receiving the condenser.