THE ENERGY SAVINGS POTENTIAL OF OPTIMIZED SLAB-ON-GRADE FOUNDATION INSULATION RETROFITS

2015 ◽  
Vol 10 (3) ◽  
pp. 116-136
Author(s):  
Louise F. Goldberg ◽  
Garrett Mosiman

A recently developed 3-dimensional earth contact simulation program that operates as a subroutine of the EnergyPlus whole building energy simulation program was used to evaluate the energy performance and cost-effectiveness of retrofit slab-on-grade (SOG) foundation insulation. An optimized retrofit insulation design utilizing hydro-vacuum excavation was developed that generated 8.4 % larger metered (or site) energy savings at a $428 lower cost than the IECC 2012 requirement in a Minneapolis, MN climate for a 400 ft2 test building. The energy performance and cost effectiveness of single and multi-family buildings was assessed for climate Zones 4 – 7. With reference to the Building America B10 benchmark, the highest site energy savings of 5 % was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 % for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. Thus it is likely that larger energy savings of 10% or more with concomitantly reduced simple paybacks can only be realized in well-insulated buildings.

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 749
Author(s):  
John H. Scofield ◽  
Susannah Brodnitz ◽  
Jakob Cornell ◽  
Tian Liang ◽  
Thomas Scofield

In this work, we present results from the largest study of measured, whole-building energy performance for commercial LEED-certified buildings, using 2016 energy use data that were obtained for 4417 commercial office buildings (114 million m2) from municipal energy benchmarking disclosures for 10 major U.S. cities. The properties included 551 buildings (31 million m2) that we identified as LEED-certified. Annual energy use and greenhouse gas (GHG) emission were compared between LEED and non-LEED offices on a city-by-city basis and in aggregate. In aggregate, LEED offices demonstrated 11% site energy savings but only 7% savings in source energy and GHG emission. LEED offices saved 26% in non-electric energy but demonstrated no significant savings in electric energy. LEED savings in GHG and source energy increased to 10% when compared with newer, non-LEED offices. We also compared the measured energy savings for individual buildings with their projected savings, as determined by LEED points awarded for energy optimization. This analysis uncovered minimal correlation, i.e., an R2 < 1% for New Construction (NC) and Core and Shell (CS), and 8% for Existing Euildings (EB). The total measured site energy savings for LEED-NC and LEED-CS was 11% lower than projected while the total measured source energy savings for LEED-EB was 81% lower than projected. Only LEED offices certified at the gold level demonstrated statistically significant savings in source energy and greenhouse gas emissions as compared with non-LEED offices.


Author(s):  
El Hassan Ridouane ◽  
Marcus V. A. Bianchi

Uninsulated wall assemblies are typical in older homes, as many were built before building codes required insulation. Building engineers need to understand the thermal performance of these assemblies as they consider home energy upgrades if they are to properly predict pre-upgrade performance and, consequently, prospective energy savings from the upgrade. Most whole-building energy simulation tools currently use simplified, 1D characterizations of building envelopes and assume a fixed thermal resistance that does not vary over a building’s temperature range. This study describes a detailed 3D computational fluid dynamics model that evaluates the thermal performance of uninsulated wall assemblies. It accounts for conduction through framing, convection, and radiation and allows for material property variations with temperature. Parameters that were varied include ambient outdoor temperature and cavity surface emissivity. The results may serve as input for building energy simulation tools that model the temperature-dependent energy performance of homes with uninsulated walls.


2020 ◽  
Vol 13 (1) ◽  
pp. 235
Author(s):  
Fernando Martín-Consuegra ◽  
Fernando de Frutos ◽  
Ignacio Oteiza ◽  
Carmen Alonso ◽  
Borja Frutos

This study quantified the improvement in energy efficiency following passive renovation of the thermal envelope in highly inefficient residential complexes on the outskirts of the city of Madrid. A case study was conducted of a single-family terrace housing, representative of the smallest size subsidized dwellings built in Spain for workers in the nineteen fifties and sixties. Two units of similar characteristics, one in its original state and the other renovated, were analyzed in detail against their urban setting with an experimental method proposed hereunder for simplified, minimal monitoring. The dwellings were compared on the grounds of indoor environment quality parameters recorded over a period covering both winter and summer months. That information was supplemented with an analysis of the energy consumption metered. The result was a low-cost, reasonably accurate measure of the improvements gained in the renovated unit. The monitoring output data were entered in a theoretical energy efficiency model for the entire neighborhood to obtain an estimate of the potential for energy savings if the entire urban complex were renovated.


Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 94
Author(s):  
Tara L. Cavalline ◽  
Jorge Gallegos ◽  
Reid W. Castrodale ◽  
Charles Freeman ◽  
Jerry Liner ◽  
...  

Due to their porous nature, lightweight aggregates have been shown to exhibit thermal properties that are advantageous when used in building materials such as lightweight concrete, grout, mortar, and concrete masonry units. Limited data exist on the thermal properties of materials that incorporate lightweight aggregate where the pore system has not been altered, and very few studies have been performed to quantify the building energy performance of structures constructed using lightweight building materials in commonly utilized structural and building envelope components. In this study, several lightweight concrete and masonry building materials were tested to determine the thermal properties of the bulk materials, providing more accurate inputs to building energy simulation than have previously been used. These properties were used in EnergyPlus building energy simulation models for several types of commercial structures for which materials containing lightweight aggregates are an alternative commonly considered for economic and aesthetic reasons. In a simple model, use of sand lightweight concrete resulted in prediction of 15–17% heating energy savings and 10% cooling energy savings, while use of all lightweight concrete resulted in prediction of approximately 35–40% heating energy savings and 30% cooling energy savings. In more complex EnergyPlus reference models, results indicated superior thermal performance of lightweight aggregate building materials in 48 of 50 building energy simulations. Predicted energy savings for the five models ranged from 0.2% to 6.4%.


Author(s):  
Heangwoo Lee ◽  
Xiaolong Zhao ◽  
Janghoo Seo

Recent studies on light shelves found that building energy efficiency could be maximized by applying photovoltaic (PV) modules to light shelf reflectors. Although PV modules generate a substantial amount of heat and change the consumption of indoor heating and cooling energy, performance evaluations carried out thus far have not considered these factors. This study validated the effectiveness of PV module light shelves and determined optimal specifications while considering heating and cooling energy savings. A full-scale testbed was built to evaluate performance according to light shelf variables. The uniformity ratio was found to improve according to the light shelf angle value and decreased as the PV module installation area increased. It was determined that PV modules should be considered in the design of light shelves as their daylighting and concentration efficiency change according to their angles. PV modules installed on light shelves were also found to change the indoor cooling and heating environment; the degree of such change increased as the area of the PV module increased. Lastly, light shelf specifications for reducing building energy, including heating and cooling energy, were not found to apply to PV modules since PV modules on light shelf reflectors increase building energy consumption.


2021 ◽  
Vol 6 ◽  
Author(s):  
Mario Frei ◽  
Chirag Deb ◽  
Zoltan Nagy ◽  
Illias Hischier ◽  
Arno Schlueter

In the building and construction sector, the mismatch between predicted and measured energy consumption is a well-known phenomenon called the performance gap. A promising approach to reduce the performance gap and thus improve the current building energy performance assessments are methods based on in-situ measurements. In this work, we present a building assessment process based on a novel, easily deployable wireless sensor kit. The basic sensor kit for building energy assessment presented in this study consists of a heating energy input node, several indoor temperature nodes, an outdoor temperature node, and a heat flux sensor. Specifically, the study outlines a medium-scale deployment of the sensor kit in eight occupied single-family homes in Switzerland and identifies the benefits of such an approach in the estimation of the overall heat loss coefficient and U-values. The findings of this study suggest that such sensor kits could be effectively used for rapid building performance assessment, and the paper concludes by outlining the potential benefits and implementation challenges of a larger scale study.


2019 ◽  
Vol 14 (4) ◽  
pp. 533-542
Author(s):  
Yuanda Hong ◽  
Wu Deng ◽  
Collins I Ezeh ◽  
Zhen Peng

Abstract Attaining sustainability in high-rise office buildings necessitates determining the major elements and their associating impacts on the energy performance of this building typology. This study investigates the impact of architectural and engineering features on the energy performance of high-rise office buildings within a warm-summer-cold-winter climate. A rectangular building plan form with a 1:1.44 plan ratio, vertical split core position and central atrium presented the best building performance. The plan form, core position and atrium effect accounted for 59, 30 and 11%, respectively, of an estimated 20.6% building energy savings. Furthermore, exploiting passive strategies founded on the climate and building features as defined by `PassivHaus’ standards further reduced the building energy usage.


Sign in / Sign up

Export Citation Format

Share Document