ASHRAE Journal - July 2023 - 30

FIRST PLACE 2023 ASHRAE TECHNOLOGY AWARDS
FIGURE 2 Measured monthly energy use versus energy production.
120,000
100,000
80,000
60,000
40,000
20,000
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
dry Santa Rosa, Calif., climate, the unit supply air
temperature can float as high as needed, as long as
the VAV diffuser setpoints are maintained. An allelectric
air source heat pump (ASHP) domestic water
heater and storage tank provide hot water to the
restrooms and the lavatories in the 95 exam rooms.
Lessons Learned
Building owner Kaiser Permanente likes to
implement a strict policy ensuring that their
buildings are fully commissioned prior to occupancy.
However, due to some scheduling issues, occupancy
of the Santa Rosa Medical Office Building 6 happened
prior to commissioning.
This situation caused serious thermal comfort issues
for many months after the building was occupied as
the commissioning agent, contractors and building
operators attempted to coordinate the work of getting
the systems functioning properly while the building
was occupied.
Operation & Maintenance
A life-cycle cost analysis was completed during the
schematic design phase of the project, indicating that
the TZHP/VAV diffuser strategy with ASHP domestic
hot water heaters saved approximately $1.2 million in
maintenance, replacement and operational cost over
30 years compared to the typical VAV reheat with gas
boilers baseline.
30
ASHRAE JOURNAL ashrae.o rg
J U LY 2023
Jul
CASE STUDY
Measured Energy
Use (Building)
Measured Energy
Production (Solar
PV System)
Aug
Sep
Cost Effectiveness
The TZHP and VAV diffuser strategy
with ASHP domestic hot water
heaters also saved over $1 million
in construction cost compared to
the typical VAV reheat with gas
boilers baseline. This savings was
predominantly due to eliminating
heating hot water piping inside the
building and natural gas piping both in
the building and on the site.
The project includes a 642 kW
photovoltaic (PV) array in several
parking lot canopies. The PV system
was provided through a power
purchase agreement (PPA) at zero first
cost of construction to the project. The
PPA contract is written such that Kaiser Permanente
pays less per kWh to the PPA provider for 100%
renewable energy than they would pay to the local
electrical utility company PG&E.
Environmental Impact
The Santa Rosa Medical Office Building 6 project
is an all-electric building. The parking lot PV array
produces more energy annually than the building
uses, including site lighting and electric car charging.
Therefore, the project is net zero energy and net
zero operational carbon. Figure 2 shows the modeled
versus measured performance of the building and PV
system.
Measured and verified annual consumption and
production data was compiled to achieve the LEED
Zero Energy and ILFI Zero Energy certifications.
This measured and verified data was collected from
utility bills provided by the owner from October
2018 through September 2019 and was not affected
by reduced building occupancy associated with the
COVID-19 pandemic.
Conclusion
Thanks in part to a simple yet innovative heat pump
strategy that saves energy and eliminates fossil
fuels, Kaiser Permanente Santa Rosa Medical Office
Building 6 is now the first medical building ever to be
certified net zero energy in the U.S.
kWh
ED DEAN
http://ashrae.org
ASHRAE Journal - July 2023

Table of Contents for the Digital Edition of ASHRAE Journal - July 2023
