- System Description
- Campus Context
- Goals and Targets
- Lessons Learned
- Future Learning
Image 11.1 Energy Exchange Diagram
11.1 System Overview
One of the most important goals of the CIRS project was to achieve net-positive energy performance. By harvesting renewable and waste energy, CIRS is able to supply not only its own energy needs but also a portion of the needs of an adjacent building. The end result is that the addition of a 4-storey, 5675 square meter building to the campus reduces UBC’s overall energy consumption by over 1 million kilowatt hours per year.
A high-performance building envelope, passive design strategies, provisions for inhabitant control of personal spaces and energy efficient equipment were used to minimize the building energy loads. Multiple systems work together to serve the different needs in the building and use energy efficiently. A heat recovery system captures waste heat in the exhaust ventilation from the fume hoods on the adjacent Earth and Ocean Sciences (EOS) building and transfers it to the heat pumps in CIRS. The heat pumps provide heating and cooling for the building through the radiant slabs and a displacement ventilation system. The energy exchange system returns excess heat from the CIRS heat pumps to EOS, which reduces its heat load and the demand on the campus steam system. The amount of energy in the heat transferred to EOS is greater than the total amount of energy consumed in CIRS. A ground source geo-exchange field supplements the waste heat recovery and provides heating and cooling to the pumps. An evacuated tube array on the roof that captures solar energy and an internal heat recovery system that captures waste heat from the building systems pre-heat the domestic hot water. Photovoltaic cells on the atrium roof and the window sunshades convert solar energy into electricity. Ongoing monitoring and research will study the energy consumption and effectiveness of the building systems in relation to inhabitants’ behaviour and help to optimize the operation of the building.
Image 11.2 CIRS Energy Systems Diagram
11.2 System Description
Mechanical Heating and Cooling
Heating and cooling (cooling is provided for the lecture theatre only) are provided by three water-to-water heat pumps, which are located in the basement mechanical room and attached to three different heat sources. The main heat source is heat recovery coils connected to the lab exhaust of the adjacent Earth and Ocean Sciences (EOS) Building. Based on site-measured data, the lab exhaust provides a continuous exhaust of 10,384 liters per second (623,000 liters per minute or 22,000 cubic feet per minute) and provides more heat annually than is required by CIRS. The excess heat is returned to preheat the makeup air in EOS. The second heating source for CIRS is a series of heat recovery coils located in the CIRS exhaust air stream, feeding heat back into the hot water loop. This heat source is available only when the ventilation system is running. The coils collect heat from the exhaust flows from the air handling units and the washrooms as well as heat from the heat pumps in mechanical and service rooms. The third heat source is a small ground source geo-exchange field. This supplements the heat recovery systems and when operated will allow more energy to be returned to the EOS building, increasing the net-positive energy balance of CIRS.
Tempered ventilation air and a radiant floor system provide heating and cooling of the interior spaces. The large lecture theatre is the only space supplied with mechanical heating and cooling, with tempered ventilated air delivered through the raised flooring. The office spaces are heated with ventilation air supplied through the under floor system and supplemented in certain areas by radiant baseboard heating. A radiant floor system, supplemented by tempered ventilation air in the café, provides heat to the atrium social spaces and cafe.
Image 11.3 Solar Energy Diagram
Domestic Hot Water
A 40 square meter evacuated tube array on the roof and the heat pumps provide heat for the domestic hot water in CIRS. The array provides a significant amount of heat annually (15,400 kilowatt-hours) resulting in an excess during the summer. In the future, waste heat from the solar hot water array could be captured and reused. Currently, it dissipates to the atmosphere.
A 25-kilowatt photovoltaic (PV) cell array supplies less than ten per cent of the building’s electrical consumption (22,148 kilowatt-hours per year). BC Hydro provides the rest through the campus electrical grid. Although an original design intention was to supply all of the energy needs of CIRS through renewable sources, such as solar energy or wind turbines, this was not feasible due to current technology capabilities and the local climate and site constraints. Photovoltaic cells are often removed from projects to reduce costs during the value-engineering phase, however this project secured their use by leveraging special funding arrangements. Research infrastructure grants from the Canadian Foundation for Innovation (CFI) and Sustainable Development Technology Canada (SDTC) funded the photovoltaic cells. The fixed external sunshades of the façades and on the roof of the atrium support the cells.
Image 11.4 CIRS EOS Energy Balance Diagram
Ongoing Energy Modeling
Stantec Consulting completed the energy model for CIRS using the eQUEST v3.61 and DOE2.2e software packages. The energy model projected a 63 per cent energy savings (including non-regulated energy and renewable energy savings) relative to the Model National Energy Code for Buildings (MNECB) reference building. In calculating the energy savings of the heat-recovery system between CIRS and the adjacent EOS building, the model projects that the amount of energy used by CIRS (including the EOS heat recovery system) to total 613,540 equivalent kilowatt-hours per year (ekWhr/yr). The energy model results also showed the amount of energy in the heat that can be accepted back by EOS to be 622,070 ekWh/yr making CIRS net-positive in energy performance. After taking into account actual equipment efficiency at the UBC Steam Plant and the distribution losses (60% overall efficiency) the total projected savings to the overall campus energy consumption is 1,036,780 ekWh/yr. Actual operational data will be compared to the energy model output after one year of data are available. The data is collected on a regular basis to inform operational adjustments and provide data for systems research.
|Energy Use||Energy Consumed/Reduced(ekWhr/yr)|
|CIRS + EOS pre-heat system||"613, 540|
|CIRS Heat Transfer to EOS||"-622, 070|
|Total Savings at the UBC Plant||"-1,036,783|
Table 11.1 Energy Model Summary
Image 11.5 Left: View of EOS Building from CIRS. Right: Pipes for the Energy Exchange System
Photographs by Martin Tessler
11.3 Campus Context
UBC Campus Plan
In order to accommodate planned future growth in a sustainable manner, the University is initiating an integrated planning approach to maximize the efficiency of existing systems, limit future demand and reduce carbon emission and costs. For energy planning, this approach operates on two scales: developing sustainable alternatives to campus wide systems and implementing sustainable strategies on individual projects. New projects are expected to integrate strategies to minimize energy consumption and use local sustainable options for electricity, space heating and hot water. New projects must also look for opportunities to utilize waste heat from any adjacent buildings. The waste heat recovery system used in CIRS is pioneering this approach. The University has identified other potential waste heat sources on campus and is siting new projects near them. (Vancouver Campus Plan map, pg 59) The knowledge and experience gained from CIRS will be incorporated into future applications.
UBC Climate Action Plan
The University Climate Action Plan has set goals for UBC to become a net-positive energy performance organization and to reduce UBC’s greenhouse gas emissions by 100 per cent by 2050. Multiple opportunities for carbon reduction have been identified in areas relating to campus development and infrastructure, food, travel and transportation and energy supply. Choosing energy systems for new projects that have low or no carbon emissions and finding synergies with existing buildings to help reduce those buildings’ carbon emissions contributes towards the University’s energy goals.
A number of policies within the UBC Climate Action Plan should lead to the targeted energy use reduction and lower carbon emissions:
- DV-01 Increase the energy efficiency of development on campus
- DV-02 Establish long term funding for energy efficiency for both new construction and existing buildings
- EN-01 Expand energy management activities on campus
- EN-07 Reduce energy consumption from laboratory and research activities
UBC Technical Guidelines, Divisions 15 & 16
Division 15 governs the design and construction of mechanical systems. Division 16 governs the design and construction of electrical systems. These guidelines include instructions on coordination with and approval from UBC Building operations for energy efficiency. UBC Technical Guidelines 2011 Edition, Division 15 & 16
Division 15 contains a number of strategies designed to increase the flexibility of buildings for low grade energy supply systems and heat recovery, to reduce the capital cost of the energy supply system and to reduce maintenance costs. UBC Technical Guidelines 2011 Edition, Division 15, Section 15710
The Building Management System (BMS) Design Guidelines specifies that UBC should provide an energy monitoring software facility in both the Campus Building Management System (CBMS) and Building Management System Network Data Server (NDS) to monitor and report electrical energy usage and instantaneous energy demand.
UBC Technical Guidelines 2011 Edition, Division 15. UBC Building Management Systems Design Guidelines
11.4 Goals and Targets
Table 11.2 lists the project goals and targets specifically related to the research of CIRS. For a complete list of all the goals and targets for CIRS, refer to Section 4.0 Goals & Targets.
|5 - SUPPLY SYSTEMS||Supply all building energy requirements from on-site sustainable and renewable energy sources.Achieve net positive energy performanceBe greenhouse gas emission neutral.||"Direct energy consumption target: Meet and exceed the best achieved to date for comparable uses: < 75kWh/m2/year overall, <15 kWh/m2/year for heating.Install PVs for 30% of building operation requirements.Reduce energy loads.Harvest and export energy exceeding the building needs.|
|6 - ENERGY REDUCTION HVAC||Design CIRS to be as passive and simple as possible.Demonstrate that all strategies have the lowest possible energy requirements.Design a high performance building envelope.||Building envelope thermal performance to average R20(3.5 RSI).|
|7 - ENERGY REDUCTION LIGHTING||CIRS will integrate daylight systems that provide 100% of the illumination required through the building during the day to minimize lighting power consumption at other times.|
|18 - SEAMLESS DESIGN & OPERATION||The building will seamlessly integrate the design and ongoing operations.|
Table 11.2 Goals and Targets for the Energy Systems
The energy systems used at CIRS benefits the project in the following ways:
Evaluates the Energy Modeling Process
The energy model will provide a valuable comparison for ongoing systems monitoring, optimization and research. As well, an evaluation of the energy model will provide feedback to the design team about the actual performance of various strategies.
The use of multiple energy systems is considered to be more robust and resilient than relying completely on one energy source. Multiple energy systems also provide more opportunities for research and systems testing.
Inspired a New Approach to Campus-Wide Energy Supply/Consumption
Inspired by the potential of the waste heat recovery system, UBC is looking for other synergies between new projects and buildings with excessive waste energy/heat. The campus is converting the district heating system from a natural gas-powered steam system to a biomass powered hot water system, further expanding the opportunities for waste heat recovery and other renewables such as solar hot water.
Reduces Heat Demand and Carbon Emissions at EOS
The Earth and Ocean Science (EOS) building is currently heated from the campus-wide natural gas-powered steam system. Reallocating surplus heat from CIRS to the EOS building reduces the amount of heat drawn from the steam system, thereby lowering the overall demand for natural gas and associated carbon emissions. The resulting greenhouse gas emissions reduction from this strategy is 185.6 tons carbon dioxide (CO2), with a campus-wide boiler efficiency of 60%.
Provides Opportunities for Continued Learning
Ongoing testing will investigate balancing human comfort and behaviour with energy consumption, highlighting occasions for further reducing demand and optimizing the systems. Lessons learned at CIRS will communicated widely to help improve the design of future buildings.
The energy systems used at CIRS were challenging to the project in the following ways:
Resolving Project Objectives with Project Realities: Wind
The site of UBC Point Grey campus is not adequate for the use of wind turbines large enough to provide a significant amount of power. Constraints include the abundance of large trees and height restrictions for airplane transit pathways to the nearby airport.
Producing the Highest Quality Energy Modeling
Most energy models compare a design to an energy code with a set of rules about what is included in the calculations. In order to reach a target of energy positive using multiple systems, the model for this project was extended to include extra loads and detailed profiles of energy usage.
There are many types of energy modeling programs, some more comprehensive and complicated than others and therefore the design team had to test different options to determine the best for this project.
Estimating Energy Consumption of the Loop Café
No data exists for the energy consumption of food services facilities on UBC campus. Therefore careful extrapolation has been undertaken in the energy consumption estimate for the Loop Café in CIRS. Monitoring of actual usage is required to obtain an accurate metric.
Utilizing all Sources of Waste Heat
Waste heat generated during the operation of building systems is a valuable resource. Many sources of waste heat have been identified and used in CIRS, however, some waste heat supplies were not acknowledged and have not been captured or utilized for gain. For example, the waste heat from the evacuation tubes for the solar hot water on the roof has not been harnessed.
11.7 Lessons Learned
The experiences gained through the energy systems used at CIRS provided valuable lessons to apply to future projects. Some of the key lessons are:
Set Challenging Goals
Establishing challenging goals, such as being approximately ten per cent energy positive, inspires design teams and stakeholders to look for creative, unconventional solutions.
Look for Synergies
Waste heat from nearby buildings and infrastructure, such as exhaust from fume hoods, may provide a beneficial resource or design solution to a new project.
Reduce Demand through Integration
Ensuring buildings and their systems are interconnected can reduce overall levels of consumption, emissions and waste.
Attach Funding to Building Components
Sourcing grants to fund specific building components ensures that they will remain in the project through the Value Engineering phase. If they are removed, the project loses money as well as identifiable association with prestigious funding agencies and organizations.
Capture all Waste Energy
Most building systems (such as solar hot water evacuation tubes) generate some waste or excess heat while operating, which is a valuable resource that can be included in a waste heat recovery system. This is one of the first post-completion projects of the operations phase of CIRS.
Additional lessons learned over the operational life of the building will be added at periodic intervals.