ZNE Project Archive

Energy demands in developed economies continue to dominate the world energy requirements. This trend of increasing energy use, which depends heavily on fossil fuels, is expected to continue to rise as other economies continue to develop. Through the project-based, hands-on Path to Zero Net Energy course, PIET addresses energy efficiency, renewable energy issues in the stationary and transportation sectors in the particular context of UC Davis campus and medical center, the former: a model of a small city with complete infrastructure; the latter: an energy-intensive hospital and research facility.

Recent Path to Zero Net Energy projects are described below. Please refer to the library for earlier projects.

Projects of Spring 2017:


  • Steam-to-hot water investment proposal, University of California, Davis

Project devised an investment strategy for fast-tracking the steam to hot water conversion at the University of California, Davis (UCD), utilizing external investment funds. The total capital investment of $172M (40% by UCD and 60% by investor) will be allocated in 3 phases over 4 years (2018-2021), with net benefits beginning in 2022, and providing a return of 9.7% to the external investor over 10 years and 6.5% to UCD over 20 years. Returns for the external investor can vary from 7% to 12.8% based on sensitivity to development costs, construction contingency allocation, and heating system energy losses. Pitch Deck: S-HW Proposal



  • Energy analysis of walnut production in California

Project sought to understand the magnitude of energy expenditure in the drying process of the walnut industry in California, in order to inform innovation in drying technology. Based on surveys conducted through the project duration and a review of historical published data, the largest energy use is due to transportation at 59% (out of the 13 MJ/kg of walnut produced in 2009), due to concentrated walnut processing in California’s Central Valley which required subsequent distribution to consumers elsewhere. Drying accounts for 1.1 MJ/kg in 2009, a significant reduction from 21 MJ/kg in 1980 due to energy efficient technologies. Report: Walnut energy  ;  Poster: Walnut energy



  • HVAC and lighting retrofit at the Rifle Range, University of California, Davis

Project quantified the energy reduction of 1) variable refrigerant flow heat pump system with dedicated outside air relative to a conventional rooftop air conditioning with gas furnace heating and of 2) Ethernet-powered LED lighting relative to a conventional fluorescent lighting in an office building by performing the following tasks: analyzing monitored data across a limited time-frame (winter season) and estimating the building performance across the year using eQuest simulation. The energy use intensity (EUI) of the building with the implemented systems was estimated at 16.8 kBTU/ft2relative to the baseline EUI of 33.7 kBTU/ft2Report: Rifle Range VRF ; Poster: Rifle Range VRF



  • Pathways to ZNE at LBE Cooperative, King City

Project entailed an energy assessment of a low-income housing cooperative and feasibility studies of energy efficiency and renewable energy opportunities. Of the total estimated energy use of 114 MWh, the top three end uses are attributed to lighting, refrigeration and plug loads (62%, 16% and 10% respectively). An LED lighting retrofit can reduce the annual energy cost by $3,392 for an estimated implementation cost of $3,000. Adoption of a CARE rate schedule across the community can reduce the annual energy cost by $480. Report: LBE ZNE ; Poster: LBE ZNE



  • Carbon footprint analysis at Russell Ranch, University of California, Davis

Project analyzed the carbon emissions (CO2 equivalent) of corn and tomato farming at a campus-affiliated research farm. Utilizing monitored data and literature references, analysis accounts for the following: on-site fertilizer, pesticide, fuel and electrical energy usage; fertilizer production, distribution and leeching/run-off; tillage losses and carbon sequestration. The total estimated carbon emissions of conventional corn & tomato farming is 1.6 tons/year.  By comparison, the estimated emissions of corn & tomato with cover crops farming is 1.5 tons/year. In both cases, electricity use due to irrigation pumping and tillage losses constitutes the two largest portions of total emissions. Report: Russell carbon ; Poster: Russell carbon



  • Solar PV alternatives at Russell Ranch, University of California, Davis

Project evaluated three solar photovoltaic (PV) alternatives with low land use impact for use at a campus-affiliated research farm to meet the electrical energy load of two well water pumps. The three alternatives are: 1) the solar tower which consists of vertically stacked PV panels, 2) the mobile bench, which includes PV panels mounted on a repurposed mobile shaded bench, and 3) the solar greenhouse, which utilizes semi-transparent thin PV as the fenestration material in a conventional greenhouse structure. The mobile bench, at $303,000, was estimated to cost the least expensive to implement. The solar tower, requiring the least area, at 551 ft2, was estimated to be the most expensive. Report: Russell PV ; Poster: Russell PV


Projects of Spring 2016:

  • Financing the conversion of steam district heating to hot water at UC Davis

This project contrasted the estimated cost of steam-to-hot water conversion to the business-as-usual case, considering maintenance and energy use. The conversion includes implementation of heat recovery chillers for cogeneration of cooling and heating. Over a 30-year analysis period and based on justifiable assumptions used in the financial model, the conversion has an NPV of $21M and MIRR of 8%. Financing options include public-private joint venture, energy savings performance contracts, energy services agreements, student fees and revolving loan funds.

Poster: Steam-to-Hot Water Conversion, Financing



  • Building level analysis of steam heating vs hot water heating

This project evaluated the potential energy savings at the building level due to conversion from steam to a hot water heating system. Two buildings were selected: Student Community Center (SCC) containing space heating and domestic hot water (DHW) loads and Robbins Hall containing space heating, DHW and process (laboratory) loads. Calculations suggests savings of 20% and 48% over the baseline for Robbins Hall and SCC, respectively, which are primarily due to lower distribution losses and virtually negligible condensate loss.

Poster: Steam-to-Hot Water Conversion, Building Analysis



  • Commuting emissions of UC Davis Medical Center in Sacramento

This project evaluates the effectiveness of the Green Commuting Program on commuting emissions reductions implemented at the UCD Sacramento Medical Center. The Program promotes commuting by ZipCar, campus shuttles, bike, walk and vehicle pooling. Fuel economy of personal transport was obtained from a sample of 200 vehicles at the UCDMC parking lots. MapQuest data was used to obtain driving distances from the UCDMC to the zip codes of residences. Total communitng emissions reductions due to the program was estimated at 2.5% of the baseline of 27 Mkg CO2. Additional recommendations for further actions includes increasing the cost of personal transport parking and increasing bike posts and the number of shuttle stops.

Poster: UCD Medical Center Commuting Emissions



  • Comparative performance of radiant versus fan coil cooling systems at Sproul Hall

This project evaluates the occupant comfort and energy use of radiant cooling and heating systems over convention fan coils in Sproul Hall at UC Davis. Monitored equipment data from eight rooms (half with radiant and half with fan coils) and surveys from occupants were collected and analyzed. The radiant system was found to provide a comparable level of comfort to the fan coils. Further work includes collection of humidity and equipment power draw data in order to provide better insight into energy uses of the each system.

Poster: Sproul Hall Radiant Heating and Cooling



  • Modeling campus sustainability alternatives using EnergyPRO

This project evaluated three renewable energy alternatives for UC Davis utilizing the modeling program EnergyPRO. Alternatives includes 1) displacing heating supply by natural gas boilers with solar thermal, 2) displacing heating and cooling supply by natural gas boilers and electric chillers with heat recovery chillers for thermal cogeneration, 3) displacing electricity use using a biomass power plant. Results suggest that solar thermal should be considered in the near future since it can reduce natural gas use for heating by 54-89%.

Poster: Renewable Alternatives at UCD



  • Financing strategies for University of California carbon neutrality

This project aimed at creating a tool and associated strategies for financing the UC Davis climate action plan projects with a focus towards building a sustainable green revolving fund. Funding sources includes endowments, donations and grants, utility rebates, capital budgets, cost savings from efficiency projects and student fees. Recommended action includes the establishment of a green revolving fund with staff, guidelines and approval process for projects.

Poster: Financing Strategies for Climate Projects