Energy-intensive Building Research Articles

Health monitoring methodology based on exergetic analysis for building mechanical systems

Exergetic analysis is not often performed in the context of retrocommissioning (RCX); this research provides insight into the benefits of incorporating this approach. Data collected from a previously developed RCX test for an air handling unit (AHU) on a college campus are used in an advanced thermodynamic analysis. The operating data is analyzed using the first and second laws and retrofit design solutions are recommended for improved system performance; the second law analysis is particularly helpful because it requires few additional calculations or data collections. The thermodynamic methodology is extended to a building's cooling plant, which uses a vapor compression refrigeration cycle (VCRC) chiller. Existing chiller data collected for the design of automated fault detection and diagnosis methodology is used. As with the AHU analysis, the second law analysis locates irreversibilities that would not be determined from a first law analysis alone. Plant data representing both normal and faulty operation is used to develop a chiller model for assessing performance and health monitoring. Data is analyzed to determine the viability of health monitoring by performing an exergy analysis on existing data. Conclusions are drawn about the usefulness of exergetic analysis for improving system operations of energy intensive building mechanical systems.

Thermal characterization of portland cement-magnesia blends

Due to growing environmental concerns and the need to use less energy-intensive building products, alternatives and improvements to Portland cement (PC) are being actively researched worldwide. Use of supplementary materials is now a common practice where PC is the predominant component of inorganic building products. This study aims to investigate the potential of magnesia (MgO), derived from a naturally occurring raw material magnesite, as a supplementary material. Results from mortar samples prepared with 10 and 20% replacements of ordinary Portland cement (OPC) by MgO are presented. DTA-TG was used to study and characterise the hydration behaviour of MgO in OPC environment after 3, 7, 14, 28, 56 and 90 days of moist curing. Microstructural and compressive strength determinations providing additional information on the influence of hydrated phases are also reported.

Energy and Labor in the Construction Sector

An energy input-output model was used to investigate energy and employment in the construction industry. The model covered nearly 400 industrial sectors and was used to determine the impact of construction activities on total national energy consumption in 1967 and to study the patterns of total energy use and employment within various construction categories. For the construction of new buildings, total energy consumption could be reduced by 20 percent by selecting less energy-intensive building materials and assemblies for fixed programmatic requirements, by expending energy in construction to minimize the total lifetime energy cost of buildings, and by energy conservation in industries that supply direct and indirect inputs to the construction sector of the economy.