Whether dealing with the harsh cold of winter or the blazing summer heat, all year round we rely on our homes and workplaces to keep us safe and comfortable. Not only does the ability of a building to maintain a comfortable internal temperature important for its occupants’ health, but it’s an important consideration in terms of environmental impact and operating costs! A well-insulated building uses less gas and electricity than one that constantly needs to be warmed up or cooled down.
Heat is transferred via conduction, convection, and radiation, and thermal energy will always move from warm areas into cold ones. This means that heated air naturally flows into colder areas of a home or other structure. Cold spots formed by gaps in insulation or draughts, for example, can lead to your home or business’ furnace working overtime to try to equalize the temperature inside and outside of a structure—an impossible job when it’s one appliance against the entirety of the great outdoors! To mitigate this issue, builders not only consider a building’s need for additional insulation, but the heat-insulating properties of the materials they use to build the exterior components of buildings.
To understand how well a building will function in terms of maintaining comfortable interior conditions, builders need to know a material’s “R-value”. In construction, the R-value (short for “Resistance Value”) is the measurement of a material’s capacity to resist heat transfer from one side to the other. In other words, R-values measure the effectiveness of insulation, and a higher number reflects a higher effectiveness in terms of providing insulation. The thermal resistance of a material is expressed as the temperature difference that will cause one unit of heat to pass through one unit of area over a period of time.
Historically, it has been difficult for builders to calculate the R-value of buildings with different exterior configurations. The current options available to the construction industry mostly involve builders making their best estimate, which can lead to inaccurate results, or the use of expensive and time-consuming numerical modelling.
Drs. Yuxiang Chen and Carlos Cruz-Noguez are working alongside the CIC on a project focused on developing physics- and statistics-based models to estimate the overall thermal resistance (or R-value) of different masonry wall systems. The outputs of their project will increase productivity in the design phase of construction, lower the cost of wall construction, and enhance the business competency of the construction industry.
To reduce the overall thermal resistance of buildings, designers require explicit guidelines and simple methods to predict the R-values of buildings with different exterior configurations. Currently, the options to calculate the R-values of walls consist of oversimplified assumptions that lead to inaccurate results, or findings based on expensive and time-consuming numerical modelling. The project team has been working closely with industry partner Dr. Mark Hagel from the Alberta Masonry Council to create 3D models of sections of different masonry walls. Based on the modeling results, the project team has developed design charts and R-value multipliers to enable fast and accurate calculation of the R-values of different wall configurations. Dr. Hagel is also using the results to provide R-value estimations to clients in a web-based catalogue format.
The ultimate goal of the project is to develop innovative tools and intuitive guidelines that are universal, easy to use, and cost-free for members of the construction industry. By improving on the existing guidelines and making it easier for builders to make accurate predictions regarding the R-values of various building configurations, people will be able to enjoy more comfortable homes and workplaces that consume less energy to heat and cool!
Looking for more details? Visit this project’s research page!