Energy Design of Buildings using Thermal Mass Cement Association of Canada July 2006

Buildings Energy Consumption and Environmental Impact Worldwide buildings consume 40% of total energy available Heating, cooling and ventilation represent 50% of consumed energy Shortfalls of Building Energy Codes in North America: do not address some parameters that affect building energy performance, including: building shape orientation layout and compactness thermal storage effects of building mass (ASHRAE gives limited recognition) Minimum building energy performance (kWh / m 2 year) for different building categories already exist in some European countries

Massive old structures Benefits of “mass” to moderate indoor climate known for centuries Examples found in many hot climate countries (ex. adobe housing) Buildings used heavy wall construction (stone, masonry)

Principles of Thermal Mass Design in Modern Buildings Acts as a heat sink, absorbing heat gains, stores and releases heat back to interior space Reduces and delays peak load demands Helps reduce heating and cooling energy demands Effects on HVAC design recognized by ASRAE

LEED and Energy Credits Points awarded for percentage reduction in design energy cost relative to MNECB and ASRAE 90.1 – New Buildings To achieve higher level energy performance and reduce environmental impact from excessive energy use Design based on either : Model National Energy Code ( Canada) or ASRAE / IESNA 90.1 ( USA) LEED calculations include energy consumption for HVAC, hot water use and interior lighting

Annual“Free Run” Temperature Profile of a Building with different Mass FRT simulation illustrates building’s passive response to its local climate Shows natural inside temperature fluctuation without active heat gains FRT simulation demonstrates the effect of passive components (mass) on building thermal response

Solar Radiation and the Building Envelope Summer surface temperature of dark tinted glass in downtown Vancouver – Terasen Building Summer surface temperature of a concrete wall in downtown Vancouver – Macmillan Bloedell Building

Passive Solar Design Concept of the 1980 th “Passive solar” house provides cooling and heating without mechanical equipment Design parameters include site selection and building orientation, construction materials and building features to capture solar heat Direct Gain design utilizes building’s thermal mass elements to store heat from sunlight

Cement Association of Canada Sustainable Design and Thermal Mass Study Guide to Sustainable Design with Concrete – based on new LEED Canada document Energy efficient design forms a major component in sustainable design of buildings (reflected in point system in LEED) Study focused on the effects of thermal mass on energy consumption in buildings in Canada

Thermal Mass study objective: To examine the effects of varying levels of thermal mass on energy consumption of a “model” commercial building Light mass constructionMedium mass constructionHeavy mass construction Three levels of building mass used in the model:

Study –Phase 1 Consultants: Stantec Consultants (formerly KEEN Engineering) Building input parameters and modeling assumptions Computer modeling assumed “passive” contribution of thermal mass

Phase 1 - Results Results presented in terms of: Thermal mass contribution to energy use or reduction in heating and cooling loads ( energy measured in kWh/m 2 and annual utility costs in $ / m 2 ) Thermal mass contribution to LEED Energy and Atmosphere credit points earned (as measured by % of energy reduction over a benchmark energy use)

Operating Cost Savings Annual Energy Use for a Small Office Building in Vancouver, BC

Thermal mass and energy use example -Vancouver

LEED points versus building thermal mass

Study –Phase 2 Consultants: Cobalt Engineering Study parameters:

Phase 2 - additional parameters studied Thermal mass location and distribution

Phase 2 Study - Results Report Executive summary: “The study results demonstrate that with the addition of thermal mass to the building envelope and structure: 90% of all simulated cases experienced reduced annual space heating energy requirements 60% of all simulated cases experienced reduced annual space cooling energy requirements 93% of all simulated cases experienced reduced peak space heating demand 92% of all simulated cases experienced reduced peak space cooling demand “

Space Heating Energy Requirements -Results

Space Cooling Energy Requirements -Results

Thermal Mass Monitoring of UBC ICICS Building ( Institute for Computing, Information and Cognitive Systems) New ICICS building designed to use 48% less energy in accordance with CBIP criteria 6 story concrete building completed in 2004 Mechanical design use chilled/heating slab system Ongoing monitoring program in place to evaluate actual energy consumption as well as to evaluate occupants comfort Interim results indicate that thermal comfort of occupants has been achieved

Indoor temperature reading over a period of 10 days in July 2006

*1.Total building energy use Dec12/05-Aug2/06: ICICS average bldg energy use per hour over this period: *2.ICICS average energy use per square meter per year: Total CICSR energy use Feb8/05-Jan25/06: CICSR average bldg energy use per hour over this period: *3.CICSR average energy use per square meter per year: Per square meter, the ICICS building uses 51% as much electricity as the CICSR building Electricity use in ICICS and CICSR (control) buildings – 6 months usage Energy used for cooling and ventilation (chillers), lights and computers ICICS building not yet fully occupied.

Project examples where Thermal Mass design is used Mountain Co-op, Montreal Manitoba Hydro new office, Winnipeg Life Sciences Building, UBC Gleneagles Community Center, West Vancouver