Increase the first hour rating of a water heater by 15-30% without violating any of the competition restrictions.
A.O. Smith Call for Innovation
INCREASING THERMAL ENERGY STORAGE IN A RESIDENTIAL GAS OR ELECTRIC WATER HEATER WITHOUT INCREASING ITS SIZE
Recent increases in minimum energy efficiency standards for WH’s implemented on April 16th 2015 (known as NAECA III) essentially mandated the use of more expensive heat pumps for electric WH’s and condensing technology for gas WH’s for tanks with a volume >55 gallons.
Technologies such as phase change materials (PCM) have the ability to store and subsequently release large amounts of thermal energy. It is hypothesized that PCM’s can be used to increase the first-hour rating (FHR, as defined in 10 CFR Part 430, Subpart B, Appendix E), of a residential natural gas or electric WH without increasing either the current dimensional footprint or the water storage temperature. However successful cost-effective application of this technology for use in residential WH’s has proved largely unsuccessful to date.
The challenge is to use innovative methods (such as PCM) to deliver as much hot water as a 65 or 80 gallon tank from a 50 gallon one, representing an increase in FHR of between 15-30%, without increasing water storage temperature. Proposed solutions would be subject to the following restrictions:
- must not increase the storage temperature
- must stay within the existing dimensional footprint of 50 gallon units (diameter and height)
- must not negatively impact the EF as defined in 10 CFR Part 430, Subpart B, Appendix E
- must not negatively impact the service life of the water heater
- must not negatively impact the safety aspects of the water heater
- must increase the manufacturing cost by no more than $150 at high volume
For example, prior to NAECA III, standard 65 and 80 gallon electric WH’s had FHR’s of about 75 and 90 gallons respectively. The goal would be to achieve these same FHR’s in the footprint of a current compliant 50 gallon WH (EF of 0.95), meaning an increase in FHR of 20-30%.
A cash award of $5,000 will be sponsored by A.O. Smith for the top selected technology submission. The idea submitter will also be invited to discuss future collaboration with A.O. Smith and ORNL technical experts. Depending on the needs identified:
- ORNL may provide in-kind technical support of $10,000 - $20,000 to enable ORNL staff to providing prototype development, testing, 3rd party validation, or other defined needs.
- Participation in the DOE Small Business Voucher (SBV) pilot will also be discussed; ORNL may provide in-kind technical support of up to $300K through the SBV program, if the SBV is approved.
Idea Submission Deadline
Idea Submission Period Ends: Friday, April 8, 2016 at 11:59 PM EST
The challenge is to increase the First Hour Rating (FHR) of a small water heater by ~15-30% without decreasing the energy factor or service life and without increasing the cost or footprint.
The challenge is to use innovative methods to increase the thermal capacity of WH without increasing the size of tank and increase in FHR of between 15-30%, without increasing water storage temperature.
Typical solar thermal systems historically are not effective because they are too expensive and too complex. The very best solar water heaters are up to 75% efficient, requiring full backup.
Adding PCM to increase first hour capacity of hot water tank
The challenge is to deliver a simple and cost effective PCM solution in residential WHs that will increase the FHR by 15-30%, without increasing the footprint or water storage temperature.
add a recirculating unit in HW tank that captures heat from first tankful via heating oil or salt solution. As new water is added the the tank, it gains heat from these pipes for a faster recovery.
Delivering more hot water in the first hour delivery measurement of gallons delivered before the temperature drops below a reference temperature.
Pebble rock installed in water heater to increase first rating would be too expensive because of shipping and installation costs.
Transitions between desired temperature states result in "unusable water" during warming or cooling of the effluent.
An increase in the first hour rating is needed for HPWH to more closely match the performance of a electric resistance water heater.
Hot water tanks are typically insulated with fiberglass for conductive insulating properties. However, big box stores such as Lowe's and Home Depot sell kits for additional insulation. Why? To save heat loss, of course. Fiberglass has limited insulative characteristics and generally does not contain radiant heat, unless a reflective surface is applied.
Using complex chemicals for phase change results in a high risk of contaminating potable water. Using bromine or other salts can result in crystallization which requires extreme heat to get the solid to return back to a liquid. I have heard numerous horror stories of having to de-crystallize lithium bromide HVAC chillers that got "off" from their normal cycle. One hundred percent of the electrical energy become heat within ...more »
Supplying hot water throughout a home from a central location requires heating the path to the usage.
This heating from ambient for the pipes to "hot" is normally lost energy once demand stops and it cools down again.
And, the warming water is not "usable", so gallonage lost along with its heat.