Passive Dwelling Ventilation Using Geothermal Air Separation
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Solution Overview
Problem
Existing air-conditioning systems for dwelling houses consume significant energy for heating and cooling, and current solutions fail to effectively utilize geothermal energy and maintain air quality by separating air flows.
Innovation Solution
A passive air-conditioning system incorporating a buried air intake pipe, an air/air heat exchanger, and controlled mechanical ventilation with a heat exchanger or heat pump, utilizing geothermal energy and ensuring air separation and quality by using a crawl space with a temperature control unit and bypass system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a passive air conditioning system uses a crawl space with geothermal energy exchange, then energy consumption is reduced, but air quality may deteriorate due to potential contamination from the crawl space
Solution Approach 1:
The air handling system is divided into separate channels: a first channel draws air directly from the crawl space for geothermal exchange, while a second channel draws fresh air from outside. This segmentation prevents contamination of the conditioned air while maintaining energy efficiency through geothermal utilization.
Solution Approach 2:
A heat exchanger is introduced as an intermediary device that transfers thermal energy between the crawl space air and the incoming fresh air without allowing direct mixing. This enables geothermal energy recovery while maintaining air quality separation.
2Loss of energy
If air is drawn directly from the crawl space for heat exchange, then geothermal energy is utilized effectively, but pathogens and contaminants present in the crawl space atmosphere may be introduced into the dwelling
Solution Approach 1:
The ventilation system uses completely separate air channels: the first channel handles crawl space air for geothermal exchange, while the second channel handles fresh outdoor air supply. This physical separation ensures that any pathogens in the crawl space remain isolated while still capturing the thermal energy benefits.
Solution Approach 2:
The heat exchanger acts as an intermediary that transfers thermal energy from the crawl space air to the incoming fresh air without allowing direct contact between the two air streams, thus preventing pathogen transmission while maintaining energy efficiency.
3Loss of energy
If insulation of walls in contact with the outside is reinforced, then energy losses are reduced, but the complexity of the construction increases
Solution Approach 1:
The crawl space is utilized as a self-service thermal buffer that passively provides heating in winter and cooling in summer through its thermal mass and geothermal connection, eliminating the need for additional active heating or cooling equipment and reducing construction complexity.
Solution Approach 2:
The crawl space serves multiple functions simultaneously: it acts as a thermal buffer for passive heating and cooling, a source of geothermal energy exchange, and a natural air intake for the ventilation system, thereby reducing the need for separate systems and simplifying construction.
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
The system reduces energy consumption by leveraging geothermal energy for heating and cooling, maintains air quality by separating air flows, and utilizes thermal inertia to maintain a moderate temperature, enhancing energy efficiency and air purity.
Implementation Method 1
at least one first air intake pipe, buried, forming a heat exchanger
Implementation Method 2
the air entering the crawl space is at a temperature close to that of the earth at the depth of the pipe
Implementation Method 3
an air/air heat exchanger installed in the technical room, the said exchanger comprising two air passageways separated in leaktight manner from each other by a heat exchange wall
Implementation Method 4
the first channel via its inlet orifice and its outlet orifice being in communication with the internal volume of the crawl space and comprising a fan to force air circulation along the exchange wall
Implementation Method 5
double-flow controlled mechanical ventilation integrating a heat exchanger, or a heat pump
Data Source
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AI summary
The house has a passive air-conditioning system comprising an air-to-air heat exchanger (9) that is installed in a technical room (1). The exchanger comprises air passage paths (90, 91) that are separated by a heat transfer wall (92). A double flow controlled mechanical ventilation (5) comprises air passage paths (50, 51), where one of the air passage paths is in communication with an inlet opening. An evacuation duct (6) is in communication with a by-pass primary (7) to direct air toward a space (2) or toward outside.