Zero Net Energy Retrofit Projects - The Domes Final Performance Assessment & Verification
In 2012, the University of California, Davis (UC Davis), Energy Institute initiated a project funded by the Emerging Technologies Program at the Pacific Gas and Electric Company (PG&E) to retrofit existing residential structures through energy efficiency improvements and with ground source heating and cooling systems to achieve zero net energy (ZNE) performance goals. The project team hoped to identify scalable, deployment-ready technologies that could hasten the transition to zero net energy homes in PG&E territory. In addition, it was a project goal that the technologies selected would be both leading-edge as well as readily available, reliable, and proven. This is exemplified in the selection of technologies such as LED lights, heat pumps, and basic envelope improvements.
Four out of the fourteen residences at The Domes project site have been retrofitted with the selected technologies. One of these four domes did not receive the HVAC retrofit and is a partial baseline. Energy monitoring equipment has been installed at these four retrofitted Domes along with two other “baseline” Domes that did not receive any retrofit to improved envelope, lighting, shared DHW system, and heating/cooling equipment. The performance of the retrofitted Domes was ultimately compared to the performance of the three “baseline” Domes.
NORESCO has collected a full twelve months of monitored performance data, spanning from February 2014-February 2015, which has provided insight into the performance of the heat pump technologies. It has also highlighted a number of potential performance issues. The heat pumps have proven to be effective at heating and cooling the retrofitted Domes and all three units are operating efficiently. However, the shared domestic hot water system is using significantly more energy than the existing baseline domestic water heaters and is causing the overall energy use of the retrofitted Domes to be much higher than the baseline.