1. Planning a carbon-neutral district heating system for UC Davis July 2018

2. campus carbon footprint
Existing Steam System
27 miles
of underground pipe
50+
years old
32%
campus carbon footprint 8M
square feet
served

3. Davis Main Campus CY 2017 Energy Use
Additional Context
Davis Main Campus CY 2017 Energy Use
UC Policy Drivers:
Climate Protection:
Reduce GHG emissions to 1990 levels by 2020
Climate neutrality by 2025 for business operations
Climate neutrality by 2050 or sooner for commuting & business air travel
Clean Energy:
100% clean electricity by 2025, to be met through a campus-determined mix of on-site and off-site renewables;
implementation of energy efficiency actions to reduce the campus’ energy use intensity by an average of at least 2 percent annually; and
by 2025, at least 40% of the natural gas combusted on-site at each location will be biogas.
Commodity
Units
Annual Use
Total Electricity
GWh
227.2
Solar Farm
29.2
Other Renewable
1.3
Total Gas
MM Therm
10.3
CHCP
8.3
Chilled Water
MM Ton-hr
39.1
Steam
MM lb
763.1

4. Heating System Impact on Campus Climate Goals
Camille to present

5. Heating System Analysis
Demand
Heat Recovery Potential
Cooling Demand
Diverse campus activities necessitate some heating and cooling year-round

6. Steam Heating: A Losing Proposition
Aging system, needs extensive repairs/renewal
Expensive to operate & maintain, safety concerns
Over 30% energy loss in distribution piping
Will require additional capacity in next 5 years
$141M total on map

7. Heating System Analysis
Goals for Heating System Investment:
Leverage advantages of district systems
Provide infrastructure modernization and renewal
Provide a safe and reliable heating system
Lowest life cycle cost (capital, energy, & maintenance)
Help campus reach sustainability and carbon goals

8. Heating System Analysis
The Process:
Incorporates large Stakeholder group and smaller Working Group
Big Sky ideation charrette
Qualitative (criteria and weighting) short listing of options
Quantitative (approx. 80 assumptions and inputs)
Cost
Carbon
Energy
Water
Sensitivity analysis on assumptions and inputs

9. Heating System Analysis
Life Cycle Cost Modeling
60 year horizon
Costs included:
Capital (initial & future)
Operational (maint., energy & carbon)
Evaluated existing system vs 5 alternatives
Included escalation and sensitivity analysis
Most of campus heating can be met w/ heat recovery
Can reduce operational costs by 90%
Can reduce distribution energy losses by 80%
Existing steam system is the most expensive
Hot water with heat recovery is the lowest cost
Centralized heat recovery is less expensive than distributed

10. Heating System Analysis
Findings:
New distribution system would address both renewal and capacity needs
Comparable capital investment would replace entire steam system with innovative hot water system and operational savings
Provides a pathway to carbon neutrality via full electrification
Most of campus heating can be met w/ heat recovery
Can reduce operational costs by 90%
Can reduce distribution energy losses by 80%
Existing steam system is the most expensive
Hot water with heat recovery is the lowest cost
Centralized heat recovery is less expensive than distributed

11. Central Combined Heating and Cooling (CHC) with Building Heat Recovery (HR) is the lowest NPC option for 82% of the sensitivity testing.

12. Central Combined Heating and Cooling
Recommendation
Central Combined Heating and Cooling
Least cost option, yet sustainable, innovative & resilient
Potential for incremental investment to full electrification and carbon neutrality by 2025
Campus districts identified for conversion plan
Tercero District already operational since 2010
Building on experience from similar projects on other campuses (ie, Stanford, UBC Vancouver, Ball State, Univ of Rochester, UVA)

13. 1 good (meets emission standards) 1 okay (requires emissions upgrades)
Existing Steam
Heating
NG fired steam boilers
1 good (meets emission standards)
1 okay (requires emissions upgrades)
2 at end of life (require replacement)
Aging steam distribution
Core distribution requires near-term replacement
Steam to Water HX in building level mechanical rooms
Cooling
Central, conventional chillers
Chilled water TES (5M gal.)

14. Central CHC +HW Dist. +Boiler +Heat Recovery +Heat Pump System
Future Enhancement
Full electrification

15. Existing District Steam Boundary
Chilled Water & Steam Plant
Chilled Water TES Plant
1 MILE

16. Campus Districts for Implementation

19. 45% of Waste Cooling Heat can Provide 60% of Heating Capacity

20. Recommended Option Cooling Demand: 45% CHC 55% Conventional
15% False Cooling
Recommended Option
Heating Demand:
60% CHC
20% Building Airside Heat Recovery
20% Boiler Heating (Replaced by geo-exchange/air-source heat pump system with future enhancement)

21. Proposed Hutchison-Quad District Hot Water Conversion
Cost effective solution to address the Quad underground steam piping deficiencies
Convert 2.8M sf (30%) of campus buildings from steam to hot water (40 buildings)
New underground hot water distribution
New building heat exchangers for domestic and industrial water and the building heating system
Allows for LRDP growth/expansion

22. Hutch - Quad Hot Water Conversion
Quad Steam Renewal
Hutch - Quad Hot Water Conversion

23. Achieving Our Goals: Heating System Analysis
Leverage advantages of district systems
Provide infrastructure modernization and renewal
Provide a safe and reliable heating system
Lowest life cycle cost (capital, energy, & maintenance)
Help campus reach sustainability and carbon goals
Implement in groups to align with available funding

24. Lessons Learned Understand your system: data gathering is a big effort
Acknowledge the importance of process to help build consensus among stakeholders
Fluently know the various assumptions in your model; be able to explain them to leadership and stakeholders
Go where it leads you: be open to surprising results
agenda

25. Discussion Presenters:
Michael BOVE, Affiliated Engineers, Inc.,
Camille KIRK, UC Davis, Office of Sustainability,
Joshua MOREJOHN, UC Davis, Facilities Management,