Russell Richman

Hour‐By‐Hour Analysis for Increased Accuracy of Greenhouse Gas Emissions for a Low‐Energy Condominium Design

The seasonal and hourly variation of electricity grid emissions and building operational energy use are generally not accounted for in carbon footprint analyses of buildings. This work presents a technique for and results of such an analysis and quantifies the errors that can be encountered when these variations are not appropriately addressed. The study consists of an hour‐by‐hour analysis of the energy used by four different variations of a five‐story condominium building, with a gross floor area of approximately 9,290 square meters (m2), planned for construction in Markham, Ontario, Canada. The results of the case studied indicate that failure to account for variation can, for example, cause a 4% error in the carbon footprint of a building where ground source heat pumps are used and a 6% and 8% error in accounting for the carbon savings of wind and photovoltaic systems, respectively. After the building envelope was enhanced and sources of alternative energy were incorporated, the embodied greenhouse gas (GHG) emissions were more than 50% of the buildings operational emissions. This work illustrates the importance of short‐time‐scale GHG analysis for buildings.

More Sustainable Masonry Façades: Preheating Ventilation Air Using a Dynamic Buffer Zone:

During sunny conditions, surface temperatures on masonry façades can rise to over 40°C above the ambient temperatures. Conventional wall designs minimize the benefits of this solar heat through the use of thermal insulation. However, air that is drawn from the outdoors, between the façade and sheathing, can be used to recover heat from the masonry. The system, which utilizes a dynamic buffer zone (DBZ), acts as a solar air collector. This system can provide an effective way to preheat ventilation air at little to no extra cost, while not compromising the architectural features of the masonry wall system. A numerical model was developed to predict the amount of heat recovery possible using a DBZ. The numerical model was verified by comparing results with a commercial computational fluid dynamics software package and by conducting laboratory experiments. Preliminary results indicate that the DBZ as a solar air collector can achieve as high as 33% daily solar efficiency and seasonal solar efficiencies of up to 27%. Since this system is low-cost, yet effective, it may offer designers an opportunity to build more sustainable masonry wall systems.

Simulation of a convective loop for the Nested Thermal Envelope Design™ low-energy house

The Nested Thermal Envelope Design™ is an innovative low-energy house design that incorporates two thermal envelopes to create a core and perimeter zone. The perimeter acts as a thermal buffer zone, where heat loss from the core and solar gain in the perimeter are recovered to the core via an inter-zone heat pump. To optimize heat recovery from the perimeter and minimize temperature stratification, a complete loop is formed around the core living space, through which air may flow in a convective loop. A simplified convective loop was modelled with a commercial computational fluid dynamics software package. The results show that the convective loop distributes solar gains and reduces temperature stratification in the perimeter. The location of the heat pump in the convective loop was found to affect the heat pump’s coefficient of performance by up to 21%.

Laboratory dilatometry and field test to assess durability of masonry

This article analyses the use of dilatometry to assess the durability of load-bearing clay brick masonry in a century home in Toronto (Canada). The building had recently undergone the addition of medium density closed-cell polyurethane spray-applied foam insulation on all interior sides of the exterior clay brick load-bearing walls, increasing the insulating value in areas to RSI 7.9 m2K/W, on average, from the original RSI 0.5 m2K/W, on average. The critical moisture content (saturation degree) of representative samples from the building were compared with values obtained from frost dilatometry testing. The later indicate critical moisture content for freeze–thaw. The frost dilatometry method was furthered by studying three-dimensional testing, rather than the traditional two-dimensional approach. The results showed the brick masonry in the study building are at a relatively low risk of freeze–thaw damage thanks to good resistance of freeze–thaw of the subject brick masonry and low wetting potential of the brick masonry on site. This further strengthens the need for good water shedding characteristics.

The Reduced Gradient Approach (RGA): An Alternate Method to Optimizing Humidity Conditions in House Museums in Cold Climates

The modern approach to artifact preservation comprises an aggressive interior environment with high relative humidity levels. Maintaining high interior humidity coupled with typical interior temperatures in house museums has proved to be detrimental to their building envelopes. Such envelopes are typically un-insulated and often experience excessive, uncontrolled air leakage. Thus, the potential is high for interstitial condensation and the deleterious effects that typically accompany it. For house museums, solutions to mitigate this problem are limited because the degree of intrusiveness on original structure and associated costs are primary concerns. This article presents research on a simple, low-cost, non-destructive preservation control technique applicable to house museums and similar designated historical structures. The reduced gradient approach involves manipulation of the interior temperature regime to minimize the water vapor pressure differential across the building envelope throughout the year while maintaining the desired indoor relative humidity. Such an approach will minimize the amount of condensation due to air leakage. Two separate studies present the design and application of the reduced gradient approach when applied to a house museum in the cold climate of Toronto, Ontario, Canada. The results show that this approach as a successful preservation strategy for house museums with an interior environment that does not jeopardize artifacts nor the building structure.

Structural and durability analysis of a novel re-roofing concept

Metal roof decks in long-span light steel structures can become damaged and obsolete by corrosion should the roofing system become compromised. Re-roofing is conducted by either removing and replacing damaged areas (resulting in suspension of interior operations and lost revenue) or installing new decking directly over the damaged areas which can transfer corrosion to the new deck. This research conducts structural and durability analyses on a novel proposed re-roofing concept that installs a new metal roof deck over the existing deck by using a proprietary deck strap resulting in no interruption of interior processes. Preliminary structural analysis shows the proposed concept to be applicable to generic conditions around Southern Ontario. Recommendations for project specific structural analysis are made. Durability analysis demonstrates that the proposed concept system improves hygrothermal performance of the roof assembly in all cases except when insulation in the existing roof assembly is saturated. Saturated insulation should be removed prior to installing the re-roofing system.