he current emphasis
of the Energy Efficiency program is to develop improved energy
recovery ventilators. The program is funded by the
California Energy
Commission,
Energy
Innovations Small Grant Program. Our progress reports are located
here.
WHAT ARE ENERGY RECOVERY VENTILATORS?
Modern, energy efficient homes and office buildings are well-insulated from the
environment to prevent heat loss or gain. Such well-sealed buildings also
prevent air exchange. Poor air quality in well-insulated buildings can result
in "Sick Building Syndrome". If windows are opened to provide air exchange
with the outdoors, the building may lose or gain a considerable amount of heat
depending on the outside conditions.
To prevent heat loss (or gain), heat recovery ventilators (HRV) or energy
recovery ventilators (ERV) use air-to-air heat exchangers to retain building
heat (or cold). HRV's only transfer sensible energy (heat) while ERV's are
total heat devices which transfer sensible energy and moisture.
REQUIREMENTS FOR INDOOR AIR QUALITY (IAQ)
According to the American Society of Heating, Refrigeration, and Air
Conditioning Engineers (ASHRAE), the current guideline for fresh air
ventilation is 0.35 air changes per hour (ACH). This works out to 8.4 air
changes over a 24 hour period.
The R-2000 program in
Canada certifies homes to meet efficiency and health criteria. All R-2000
homes use an HRV or ERV to provide a minimum of approximately 8 air exchanges
per day. Some states in the U.S. are beginning to adopt the Canadian R-2000
standards.
CURRENT TECHNOLOGY
Current HRV/ERV costs for home use (approx 200 CFM) are in the $900 to $1600
price range and use 100 to 200 Watts of power to operate. A typical 2000 sq ft
home needs about 120 CFM of flow to provide 8.4 air changes per day.
Click here to see: How an ERV works in a home
OUR RESEARCH
We seek to improve the heat exchanger effectiveness in an HRV by using a high
conductivity porous media. See the advantages of using porous media in heat
exchanger applications here: --Link to Porous Media section of this site--
By using a porous media to enhance heat transfer, we hope to show that:
- porous media can be engineered at the microstructural level to optimize
heat transfer
- porous media heat exchangers improve on current technology
- porous media can reduce the cost of current technology devices
OUR EXPERIMENT
The simple process loop has an easily removable test article section for
flexibility in testing different types of porous media.
Click to view a larger image:
Sources of porous media:
Photos:
