A Simplified Method to Estimate Cooling Energy Savings From Night Ventilation for Office Buildings

2007 ◽  
Author(s):  
Xiang Liu ◽  
Moncef Krarti
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Office Buildings ◽  
Analysis Method ◽  
Commercial Building ◽  
Volume Rate ◽  
Ventilation Duration ◽  
Night Ventilation ◽  
Simplified Calculation

This paper provides a simplified analysis method and to evaluate the potential of night ventilation to save cooling energy for office buildings. Specifically, impacts on cooling energy performance are investigated for various combinations of night ventilation flow rates and duration periods. The analysis results indicate that an increase of ventilation duration period and volume rate leads to greater night ventilation benefits for dwellings located in Denver, CO. However, an increase of the ventilation volume rate above 5 air changes per hour has a little impact on cooling energy savings. When the ventilation period is short (less than 10 hours), and the flow rate is high (more than 3 ACH), the cooling energy savings from night ventilation increase linearly with the ventilation duration period length. A simplified calculation method has been developed based on the results of a series of parametric simulation analyses. Commercial building designers and operators can use the proposed simplified calculation tool to assess the effectiveness of night ventilation in reducing cooling energy use.

scholarly journals Energy and Greenhouse Gas Savings for LEED-Certified U.S. Office Buildings

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 749
Author(s):  
John H. Scofield ◽  
Susannah Brodnitz ◽  
Jakob Cornell ◽  
Tian Liang ◽  
Thomas Scofield
Keyword(s):  
Greenhouse Gas ◽  
Energy Use ◽  
Energy Savings ◽  
Electric Energy ◽  
Building Energy ◽  
Energy Performance ◽  
Office Buildings ◽  
Ghg Emission ◽  
Site Energy ◽  
New Construction

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.

scholarly journals The Performance Gap in Energy-Efficient Office Buildings: How the Occupants Can Help?

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1480 ◽  
Author(s):  
Qadeer Ali ◽  
Muhammad Jamaluddin Thaheem ◽  
Fahim Ullah ◽  
Samad M. E. Sepasgozar
Keyword(s):  
Energy Efficient ◽  
Behavioral Interventions ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Office Buildings ◽  
Occupant Behavior ◽  
Energy Usage ◽  
Performance Gap ◽  
Energy Efficient Buildings

Rising demand and limited production of electricity are instrumental in spreading the awareness of cautious energy use, leading to the global demand for energy-efficient buildings. This compels the construction industry to smartly design and effectively construct these buildings to ensure energy performance as per design expectations. However, the research tells a different tale: energy-efficient buildings have performance issues. Among several reasons behind the energy performance gap, occupant behavior is critical. The occupant behavior is dynamic and changes over time under formal and informal influences, but the traditional energy simulation programs assume it as static throughout the occupancy. Effective behavioral interventions can lead to optimized energy use. To find out the energy-saving potential based on simulated modified behavior, this study gathers primary building and occupant data from three energy-efficient office buildings in major cities of Pakistan and categorizes the occupants into high, medium, and low energy consumers. Additionally, agent-based modeling simulates the change in occupant behavior under the direct and indirect interventions over a three-year period. Finally, energy savings are quantified to highlight a 25.4% potential over the simulation period. This is a unique attempt at quantifying the potential impact on energy usage due to behavior modification which will help facility managers to plan and execute necessary interventions and software experts to develop effective tools to model the dynamic usage behavior. This will also help policymakers in devising subtle but effective behavior training strategies to reduce energy usage. Such behavioral retrofitting comes at a much lower cost than the physical or technological retrofit options to achieve the same purpose and this study establishes the foundation for it.

scholarly journals Comparison Evaluations of VRF and RTU Systems Performance on Flexible Research Platform

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Je-hyeon Lee ◽  
Piljae Im ◽  
Jeffrey D. Munk ◽  
Mini Malhotra ◽  
Min-seok Kim ◽  
...  
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Thermal Conditions ◽  
The United States ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Part Load ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Load Conditions

The energy performance of a variable refrigerant flow (VRF) system was evaluated using an occupancy-emulated research building in the southeastern region of the United States. Full- and part-load performance of the VRF system in heating and cooling seasons was compared with a conventional rooftop unit (RTU) variable-air-volume system with electric resistance heating. During both the heating and cooling seasons, full- and part-load conditions (i.e., 100%, 75%, and 50% thermal loads) were maintained alternately for 2 to 3 days each, and the energy use, thermal conditions, and coefficient of performance (COP) for the RTU and VRF system were measured. During the cooling season, the VRF system had an average COP of 4.2, 3.9, and 3.7 compared with 3.1, 3.0, and 2.5 for the RTU system under 100%, 75%, and 50% load conditions and resulted in estimated energy savings of 30%, 37%, and 47%, respectively. During the heating season, the VRF system had an average COP ranging from 1.2 to 2.0, substantially higher than the COPs of the RTU system, and resulted in estimated energy savings of 51%, 47%, and 27% under the three load conditions, respectively.

Roof Cover Impact on Cooling Energy Use of Office Buildings

2014 ◽  
Author(s):  
Moncef Krarti
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Simulation Analysis ◽  
Calculation Model ◽  
Office Building ◽  
Climate Zones ◽  
Building Energy Use ◽  
Detailed Simulation ◽  
Simplified Calculation ◽  
The Impact

This paper analyzes the impact of roof covers on office building energy use for representative US climate zones. In particular, the study presented in the paper investigates the potential annual cooling energy use savings that roof covers could provide using whole-building simulation analysis to evaluate the performance of a 2-story office building in five US locations. Three parameters of the roof covers including their size, height, and transmittance, are considered in the analysis. The simulation results indicate that while roof covers had similar affects on buildings in all climate zones, their impact in reducing cooling energy usage is different and is more pronounced in cooler climates. Specifically, roof covers could potentially achieve cooling energy savings of up to: 25% in Houston, 33% in Atlanta, 31% in Nashville, 38% in Chicago, and 41% in Madison. Based on the detailed simulation analysis results, a simplified calculation model is developed to help the estimation of cooling energy savings as a function of the roof cover size, height, and transmittance.

Experimental Validation of the Laboratory Air Handling Unit System (LAHU): Part I — Winter Operation

Solar Energy ◽  
2005 ◽  
Author(s):  
Yujie Cui ◽  
Mingsheng Liu ◽  
Kirk Conger
Keyword(s):  
Pump Power ◽  
Heat Recovery ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Experimental Methodology ◽  
Air Handling Unit ◽  
Winter Operation ◽  
Air Control ◽  
Validation Experiments

The Laboratory Air Handling Unit (LAHU) system for laboratory buildings has been developed and optimized. Theoretical study has concluded that the LAHU with optimal outside air control and optimal heat recovery control significantly reduces thermal energy use, saves pump power consumption and improves office indoor air quality. This paper presents validation experiments of LAHU energy performance in a large university research building including detailed experimental methodology, procedures and preliminary experimental energy savings results. The experiments establish that the LAHU can reduce annual heating by over 30% and can reduce heat recovery pump power by over 50% for this typical laboratory building.

Analysis of Demand Side Management Measures for Residential Buildings

Solar Energy ◽  
2006 ◽  
Author(s):  
Jayme Dark ◽  
Moncef Krarti
Keyword(s):  
Energy Use ◽  
Residential Buildings ◽  
Energy Performance ◽  
Detailed Data ◽  
Analysis Method ◽  
Energy Audit ◽  
Peak Demand ◽  
Residential Homes ◽  
Management Measures ◽  
Efficiency Measures

As part of a utility program to explore implementation of demand charges and time of use utility rates for residential buildings, impact of commonly used energy efficiency measures on the reduction of electricity demand in residential homes are explored in this paper. The study presented in the paper focus on homes located in the Denver-Boulder area. Detailed energy audit and simulation analyses are conducted to obtain detailed data relevant to energy performance of 13 homes. Simplified analysis method is outlined to estimate the energy use of residential homes as well as electrical peak demand. Moreover, general guidelines are provided to effectively reduce peak demand for homes.

scholarly journals A Comparative Study: Energy Performance Analysis of Conventional Office Buildings at Lucknow

2020 ◽  
Vol 20 (1) ◽  
pp. 24-34
Author(s):  
Farheen Bano ◽  
Vandana Sehgal
Keyword(s):  
Energy Consumption ◽  
Time Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Building Envelope ◽  
Office Buildings ◽  
Energy Audit ◽  
Energy Usage ◽  
Factors Affecting ◽  
Using Data

In this study, the energy consumption of three government and three private office buildings in Lucknow was investigated, and the energy performance index (EPI) for each building was determined. The main purpose of this research was to assess the energy usage of the buildings and identify factors affecting the energy usage. An analysis was performed using data from an energy audit of government buildings, electricity bills of private office buildings, and an on-site visit to determine building envelope materials and its systems. The annual energy consumption of buildings has been evaluated through EPI. The EPI, measured in kilowatt hour per square meter per year, is annual energy consumption in kilowatt hours divided by the gross floor area of the building in square meters. In this study, the energy benchmark for day-time-use office buildings in composite climate specified by Energy Conservation Building Code (ECBC) has been compared with the energy consumption of the selected buildings. Consequently, it has been found that the average EPI of the selected buildings was close to the national energy benchmark indicated by ECBC. Moreover, factors causing inefficient energy consumption were determined, and solutions for consistent energy savings are suggested for buildings in composite climate.

scholarly journals Investigating the effect of summer night ventilation on the urban buildings’ thermal and energy performance using numerical approaches

2021 ◽  
Vol 899 (1) ◽  
pp. 012013
Author(s):  
S Tsoka
Keyword(s):  
Urban Areas ◽  
Energy Savings ◽  
Morphological Characteristics ◽  
Energy Performance ◽  
Thermostatic Control ◽  
Performance Simulation ◽  
Urban Buildings ◽  
Single Side ◽  
Simulation Results ◽  
Night Ventilation

Abstract The present study aims to evaluate by simulation means, the effect of different night ventilations rates on the thermal and energy performance of typical building units, located in dense urban areas in Thessaloniki, Greece, both under thermostatic control and free-floating conditions. The numerical assessment is conducted with the dynamic building energy performance simulation model EnergyPlus. A parametric analysis, involving 4 different air flow rates (i.e., 3 ACH, 5ACH, 10ACH, 15ACH) has been carried out for 8 typical building units, located in 4 different urban areas in the city of Thessaloniki, presenting different morphological characteristics. In all cases, single side ventilation has been considered rather than cross ventilation, to evaluate the less optimal, building configuration scenario. The obtained simulation results revealed the significant effect of night ventilation on improving the thermal and energy performance of all the examined building units. Still, the morphological characteristics of the case study areas in which the examined building units are located, also affected the obtained simulation results and the achieved cooling energy savings.

scholarly journals Attaining sustainable high-rise office buildings in warm-summer-cold-winter climates: a case study on Frankfurt

2019 ◽  
Vol 14 (4) ◽  
pp. 533-542
Author(s):  
Yuanda Hong ◽  
Wu Deng ◽  
Collins I Ezeh ◽  
Zhen Peng
Keyword(s):  
Energy Savings ◽  
Building Energy ◽  
Energy Performance ◽  
Major Elements ◽  
Office Buildings ◽  
Cold Winter ◽  
Winter Climate ◽  
High Rise ◽  
Warm Summer ◽  
The Impact

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.

A comparative meta-analysis of residential green building policies and their impact on overall energy consumption patterns

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Naim Jabbour
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Building ◽  
Green Building ◽  
Energy Performance ◽  
Residential Energy ◽  
Residential Energy Consumption ◽  
The Eu

Data shows residential energy consumption constituting a significant portion of the overall energy end use in the European Union (EU), ranging between 15% and 30%. Furthermore, the EU’s dependency on foreign fossil fuel-based energy imports has been steadily increasing since 1993, constituting approximately 60% of its primary energy. This paper provides an analytical re-view of diverse residential building/energy policies in targeted EU countries, to shed insight on the impact of such policies and measures on energy use and efficiency trends. Accordingly, the adoption of robust residential green and energy efficient building policies in the EU has increased in the past decade. Moreover, data from EU energy efficiency and consumption databases attributes 44% of total energy savings since 2000 to energy upgrades and improvements within the residential sector. Consequently, many EU countries and organizations are continuously evaluating residential building energy consumption patterns to increase the sec-tor’s overall energy performance. To that end, energy efficiency gains in EU households were measured at 1% in 2000 compared to 27.8% in 2016, a 2600% increase. Accordingly, 36 policies have been implemented successfully since 1991 across the EU targeting improvements in residential energy efficiency and reductions in energy use. Moreover, the adoption of National Energy Efficiency Actions Plans (NEEACP) across the EU have been a major driver of energy savings and energy efficiency. Most energy efficiency plans have followed a holistic multi-dimensional approach targeting the following areas, legislative actions, financial incentives, fiscal tax exemptions, and public education and awareness programs and campaigns. These measures and policy instruments have cumulatively generated significant energy savings and measurable improvements in energy performance across the EU since their inception. As a result, EU residential energy consumption trends show a consistent decrease over the past decade. The purpose of this analysis is to explore, examine, and compare the various green building and energy-related policies in the EU, highlighting some of the more robust and progressive aspects of such policies. The paper will also analyze the multiple policies and guidelines across targeted European nations. Lastly, the study will assess the status of green residential building policies in Lebanon, drawing from the comprehensive European measures, in order to recommend a comprehensive set of guidelines to advance energy policies and building practices in the country. Keywords: Building Policies; Residential Energy Patterns; Residential Energy Consumption; Energy Savings

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