Heat Pump Dryer Air Conduit Layout to Reduce Condensate
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Solution Overview
Problem
Household dryers with heat pumps face challenges such as high manufacturing costs, long drying times, and environmental hazards from refrigerants, along with issues like condensate production and lint clogging, which existing solutions have not adequately addressed.
Innovation Solution
A household appliance design that combines first and second air conduits into a single exhaust conduit, utilizing secondary air to reduce condensate generation and eliminate the need for lint filtering, with a heat transfer device using a fluorinated hydrocarbon refrigerant like R152a to efficiently recover and manage heat, and incorporating a bypass conduit for ambient air to prevent ice formation and excessive condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat pump is used to recover heat from process air, then energy efficiency is improved, but condensate production increases causing clogging issues
Solution Approach 1:
The patent extracts the harmful condensate formation process by separating the heat extraction function from the process air stream. Instead of cooling process air directly in the heat pump evaporator, the system extracts heat from process air through a heat exchanger and uses that heat to drive the heat pump, which then transfers heat to the exhaust air. This extraction approach maintains energy recovery while avoiding the temperature conditions that cause condensate production.
Solution Approach 2:
The patent introduces an intermediary heat exchanger between the process air and the heat pump evaporator. This intermediary device allows heat transfer from process air to the refrigerant without direct contact or sufficient cooling to cause condensation. The heat exchanger acts as a mediator that enables energy recovery while preventing the harmful condensate formation that would occur with direct heat pump cooling of process air.
2Loss of substance
If process air is cooled to condense humidity, then humidity recovery is improved, but drying time increases
Solution Approach 1:
The patent converts the harmful effect of cooling process air (which causes condensate and lint clogging) into a beneficial process by redirecting the cooling function to exhaust air instead. The heat pump evaporator cools the exhaust air stream, condensing humidity from the exhaust rather than the process air. This converts what would be a harmful side effect into a useful humidity recovery mechanism that doesn't interfere with the drying process timing.
3Power
If heat transfer device uses traditional refrigerants, then heat transfer efficiency is improved, but environmental hazards increase
Solution Approach 1:
The patent changes the physical-chemical parameters of the heat transfer medium by using fluorinated hydrocarbon refrigerants (such as R152a) instead of traditional refrigerants. These alternative refrigerants have different thermodynamic properties including lower global warming potential and reduced ozone depletion potential, while maintaining adequate heat transfer efficiency for the application. This parameter change addresses environmental concerns while preserving the functional performance of the heat pump system.
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 design reduces condensate production, eliminates the need for lint filters, and enhances drying efficiency by balancing heat generation and dissipation, while using environmentally friendly refrigerants to minimize environmental impact and operational complexity.
Implementation Method 1
a heat sink for transferring heat into said heat pump
Implementation Method 2
cooling the process air, thereby extracting heat
Implementation Method 3
a heat transfer device to transfer heat from the heat sink to the heat source
Implementation Method 4
evaporating the heat transfer fluid in the heat sink by heat extracted from process air flowing through, subsequently compressing that heat transfer fluid and releasing heat from it back into the process air at the heat source
Implementation Method 5
a heat source coupled to said first air conduit for transferring heat from said heat pump into the process air
Implementation Method 6
evaporating the heat transfer fluid in the heat sink by heat extracted from process air flowing through
Implementation Method 7
releasing heat from it back into the process air at the heat source. That release of heat makes the gaseous heat transfer fluid condensate or liquefy
Data Source
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AI summary
The invention relates to a household appliance 1 comprising a housing 2, a drying chamber 3 for drying wet articles 6 therein, a first air conduit 7 for guiding process air drawn into said housing 2 to dry the articles 6 and a heat pump 12, 13, 14, 15, 16, 17, said heat pump 12, 13, 14, 15, 16, 17 comprising a heat sink 14 for transferring heat into said heat pump 12, 13, 14, 15, 16, 17, a heat source 13 coupled to said first air conduit 7 for transferring heat from said heat pump 12, 13, 14, 15, 16, 17 into the process air, and a heat transfer device 12, 15, 16, 17 for transferring heat from said heat sink 14 to said heat source 13. Said heat sink 14 is coupled to a second air conduit 18 for guiding secondary air drawn into said housing 2, for transferring heat from the secondary air into said heat pump 12, 13, 14, 15, 16, 17.