Appropriate energy efficient building envelope technologies for social housing in the Irish climate
Extensive dynamic thermal simulation parametric analyses have been undertaken of energy efficient fabric alterations to social housing in Northern Ireland culminating in priorities for deployment. Five ȁ8basecaseȁ9 simulation models were used to represent the predominant characteristics of the existing social housing stock. The majority of technologies studied provided annual space-heating energy savings of more than 10%. The variation of energy savings and economic performance across the basecases highlights the value of a dwelling specific approach to selecting energy efficient building envelope technology solutions for energy rehabilitation programmes. The paper further outlines a framework for prioritising appropriate energy efficient building envelope technological solutions for a large regional building stock, i.e. existing social housing stock in Northern Ireland, highlighting influential parameters. An energy efficient building envelope inter-technology ranking approach provides a method of comparison across the various different dwellings in the regional housing stock. Airtightness ranked consistently highest across the dwellings studied with some solar technologies performing better than more technologically mature solutions such as insulation.
Evaluation of the thermal and structural performance of potential energy efficient wall systems for mid-rise wood-frame buildings
Abstract Approximately 30% of energy use in Canada is consumed in buildings, specifically space heating, which can be reduced by constructing thermally-resistant building envelopes. This study evaluates potential innovative energy-efficient wall systems for mid-rise (four to six storeys) wood-frame buildings in terms of thermal and structural performances. Regarding the thermal resistance performance, four wall systems are developed, installed in a full-scale test house, and examined, along with a baseline wall system, using the field data collected. The selection of the wall systems is based on current practice, structural analysis, pre-fabricability, and energy-efficiency. Several sensors are installed on each wall system to measure temperature, heat flow, and relative humidity. In addition, structural tests are conducted to determine the compressive loading capacity of the tested wall systems for both concentric and eccentric loads, where full-scale panels are constructed and tested in laboratory. As a general finding, all the tested wall systems achieved ASHRAE's minimum assembly R-value recommendation of RSI 3.45, where the I-joist wall system had the highest R-value, while the conventional wall system had the highest load-bearing capacity. This paper recommends I-Joist wall systems for their higher energy efficiency suggesting more future research on efficient end connections to achieve consistent structural performance.
Super-resolution of overlapped waves in time and frequency domain in a directional borehole radar measurement
The Multiple Signal Classification (MUSIC) algorithm is modified in order to resolve multiple waves and to estimate reflection points in 3-D space. This algorithm is suitable for directional borehole radar with a circular dipole array antenna. Making use of the spatial frequency difference of acquired array signals, the signals are decorrelated, and the 3-D MUSIC algorithm is applied. The time domain signals of the singlehole array-type borehole radar are used in order to form a measurement vector in the MUSIC algorithm. A computer simulation confirms that the proposed algorithm may estimate the directions of arrival (DOA) for three signals. Applying the proposed algorithm to field experiment data successfully estimates the DOA of a reflected wave from a fracture in rock.