Zero Net Energy Production Builder Demonstration: CHISPA (Greenfield, CA) Monitoring Report

Under the auspices of PG&E’s Zero Net Energy (ZNE) Production Builder Demonstration, CHISPA (Community Housing Improvement Systems and Planning Association, Inc.) built a 1,151 square foot ZNE home with ducts in conditioned space and a mini-split heat pump in Greenfield, CA. The attached reports include a Monitoring report, which describes the results from monitoring the occupied home for a full year, and a Design and Construction Report (added 7/30/2019).

The ZNE definition used for the design was based on Time Dependent Valuation (TDV) of energy, and the home met ZNE design requirements. However, TDV cannot be calculated from measured data. Therefore, this report assesses the ZNE performance of the home, based on site energy, and by comparing monitored site energy to modeled site energy. Actual site energy use was compared to two models: one using the Typical Meteorological Year (TMY) and the other using the Actual Meteorological Year (AMY) for Hollister, California during the monitoring period. Total monitored site energy use was approximately 56% more than modeled for both AMY and TMY. Actual solar production was 13% (TMY) and 5% (AMY) greater than modeled, which offset 72% of total site energy and 160% of site electricity. Models projected that PV production would offset 108% of the total site energy consumption based on AMY weather, and 199% of site electricity consumption. This is not commensurate with either prediction, indicating that the home meets the criteria for ZNE Design but not ZNE Performance.

Domestic hot water from the gas condensing tankless water heater represented the largest energy end use, at 35.2% of total household energy use. Non-cooking appliances, plug loads, cooking appliances, and space heating represented the next largest energy end uses, at 15.6%, 15.2%, 13.2%, and 10.5% of total energy consumption, respectively. Even though the overall energy consumption was much higher than modeled, the relative proportion accounted for by each end use was very similar to both the AMY and TMY models.

Attached are the design and monitoring reports, as well as a case study.

Five ZNE homes were designed and constructed in this Emerging Technologies project. The first set of reports detailed the design and construction process of a ZNE home in Stockton built by Habitat for Humanity of San Joaquin County. They can be found here at the ETCC website: Link

In addition detailed reports about the other 4 participating houses are available:

The combined report for all 6 projects can be found here: link