Detailed Energy Audit Research Articles

Audit Energi Pemakaian Air Conditioning (AC) Di Gedung Dinas Pekerjaan Umum Kab. Ketapang Propinsi Kalimantan Barat

Abstract–Goverment Building Pekerjaan Umum Office of Ketapang District, West Kalimantan is one of government office buildings into categorized of office buildings that use air conditioning. To implement one of the government's policy that is to save electricity energy consumption in government building, it must be known Intensity of Energy Consumption in the building, Preliminary Energy Audit Result in Public Service Office Building of Kab. Ketapang shows the value of Energy Consumption Intensity (IKE) of 198.13 kWH / (m ^ 2.year) and belongs to the category of government building with air conditioning with energy efficient enough.To improve the category of energy saving savings, a Detailed Energy Audit should be performed. Detailed Energy Audit Result, through the measurement data analysis step, the search for energy saving opportunities analysis of energy saving opportunities resulted some recommendations that must be done by the Office of Public Works of Kab. Ketapang in order to improve the category of energy-efficient usage. The results of the Detailed Energy Audit improve the category of energy use in Public Works Office to be efficient with the value of Energy Consumption Intensity (IKE) 156.83 kWH / (m2.year)And savings programs that are made include in energy savings program at no cost and with low cost.

The role of energy in health facilities: A conceptual framework and complementary data assessment in Malawi.

BackgroundModern energy enables health service delivery. Access to electricity is, however, unreliable in many health facilities in developing countries. Little research has explored the relationships between energy and service delivery.MethodsBased on extensive literature searches and iterative discussions within the research team, we first develop a conceptual framework of the role of energy in health facilities. We then use this framework to explore how characteristics of electricity supply affect distinct energy uses in health facilities (e.g. lighting), and how functional or non-functional lighting affects the provision of night-time care services in Malawi. To do so we apply descriptive statistics and conduct logistic and multinomial regressions using data from the Service Provision Assessment (SPA) of the Demographic and Health Surveys (DHS) for all health facilities in Malawi in 2013/2014.ResultsThe conceptual framework depicts the pathways from different energy types and their characteristics, through to distinct energy uses in health facilities (e.g. medical devices) and health-relevant service outputs (e.g. safe medical equipment). These outputs can improve outcomes for patients (e.g. infection control), facilities (e.g. efficiency) and staff (e.g. working conditions) at facilities level and, ultimately, contribute to better population health outcomes. Our exploratory analysis suggests that energy uses were less likely to be functional in facilities with lower-quality electricity supply. Descriptive statistics revealed a critical lack of functional lighting in facilities offering child delivery and night-time care; surprisingly, the provision of night-time care was not associated with whether facilities had functional lighting. Overall, the DHS SPA dataset is not well-suited for assessing the relationships depicted within the framework.ConclusionThe framework conceptualizes the role of energy in health facilities in a comprehensive manner. Over time, it should be empirically validated through a combination of different research approaches, including tracking of indicators, detailed energy audits, qualitative and intervention studies.

Evaluating approaches for district-wide energy model calibration considering the Urban Heat Island effect

Over the past decade, the building energy research community has increasingly focused on urban-scale models. The shortcomings of analyzing isolated buildings in an urban context are well-known and far from negligible, mainly due to the inability to account for Urban Heat Island (UHI), shading from neighboring obstructions, and obstructed wind flow. The aim of this paper is to evaluate the impact of the urban context via urban-scale modelling and inverse parameter estimation (calibration) using metered building energy consumption. We describe an automated calibration process for modelling 56 buildings in a representative district in downtown Abu Dhabi (UAE), where a detailed energy audit was conducted with data from 2008 to 2010. Since the urban ambient air temperature could differ significantly from the reference rural air temperature used in most building simulations, the calibration procedure will also consider this UHI effect. Two main approaches of district-wide energy model calibration are proposed using a genetic algorithm and compared to a baseline case where UHI is not considered. The first approach estimates seven building-related parameters together with four microclimate-related variables (describing annual average and seasonal variation of the UHI effect on both air temperature and humidity). The second one uses the Urban Weather Generator (UWG) to pre-process the urban EPW file, thereby reducing the number of the parameters to be estimated. In addition, two approaches are investigated for the calculation of the ASHRAE Guideline 14 calibration error metrics (CvRMSE and NMBE). One approach is to look at the whole district as one aggregate building, while the other, introduced for the first time herein, consists in deriving the weighted-average of the error of each building. The main contribution of this study is to provide simultaneous calibration for multiple buildings in the same district—and subject to the same UHI intensity. Hence, the UHI intensity (urban-rural temperature/humidity differential) is estimated alongside other calibration parameters. For the weighted average approach, CvRMSE found is between 19.09% and 19.40%, while NMBE is between 16.24% and 16.39%. For the aggregated building, CvRMSE is between 2.71% and 4.04%, while NMBE is between 1.95% and 2.35%.

Study on Energy Consumption Ration for Office Buildings

Energy management of public buildings is the key point for energy efficiency in China. Energy consumption ration (ECR) serving as an energy benchmark is one of the useful baselines to promote building energy efficiency diagnosis, and how to determine reasonable ECRs is an issue of the utmost importance. In this paper, the mean value method, the factor normalization method and the cumulative frequency distribution method were proposed firstly to determine ECR. In the factor normalization method, ECR is defined as the maximum value of energy use intensity by regulating the value of each explanatory factor within its scope. Twenty office buildings in Shanghai were selected for case study. Detailed energy audits and on-site surveys were conducted to obtain building information, operation and energy use data. Based on the survey data, the ECRs under the proposed three methods were compared, and the ECR determined by the factor normalization method is approved to be reasonable and practicable. In addition, it is found that three dependent variables, i.e. gross floor area, building usage rate and having data center or not, play a big role in the office building energy consumption. The ECR for office buildings in Shanghai is determined to be 60.3 kgce/(m2.a), and only 20% of the samples have higher energy use intensities than the fixed ration. It is suggested to use the factor normalization method as an efficient method to determine ECR, which can also shed some lights on the determination of ECRs for other buildings.

A new procedure of energy audit and cost analysis for the transformation of a school into a nearly zero-energy building

The article presents the fundamental steps of building refurbishment toward the nZEB target; it is based on a detailed energy audit and on a financial analysis. The methodology starts from the set-up of a numerical model of the building, calibrated through actual data on operation, climate and energy consumption. Then, a cost-optimisation procedure is applied to identify the energy efficiency measures that determine the minimum global cost in 30 years lifetime. Finally, the measures are improved as to comply with the nZEB requirements and to be cost-effective as well. The methodology was applied to a high school in Torino.

Macro-economic benefit analysis of large scale building energy efficiency programs in Qatar

Abstract This paper evaluates the economic, environmental, and social benefits of large-scale energy efficiency programs for new and existing buildings in Qatar. Using data obtained from detailed energy audits, several proven energy efficiency measures have been analyzed through optimized based analysis to assess their impact on the energy performance for both new and existing buildings in Qatar. Moreover, a bottom-up analysis approach is considered to quantify the multiple benefits for implementing large-scale building energy efficiency programs for the building stock in Qatar. In particular, a more stringent energy efficiency code for the new constructions and three energy retrofit levels for the existing buildings are considered in the analysis. A novel macro-economic analysis using the concept of energy productivity is used to assess the cost-benefit of large-scale energy efficiency programs in Qatar. It is determined that the implementation of a government funded large-scale energy retrofit program for the existing building stock is highly cost-effective in Qatar. In particular, it is found that a large-scale energy efficiency retrofit program of existing buildings can provide a reduction of 11,000 GWh in annual electricity consumption and 2500 MW in peak demand as well as over 5400 kilo-ton per year in carbon emissions. In addition, over 4000 jobs per year can be created when this large-scale energy retrofit program is implemented over 10-year period.

Inverse estimation of the urban heat island using district-scale building energy calibration

Over the past decade, building energy modelling research has increasingly focused on urban-scale models. The shortcomings of analyzing urban buildings in isolation are well known and far from negligible (mainly, the inability to account for urban heat island and shading from neighboring obstructions). The aim of this paper is to assess the impact of the urban context via urban-scale modelling and inverse parameter estimation (calibration) using metered energy consumption of each building. We describe an automated calibration method for 58 buildings in a representative downtown district of Abu Dhabi. This district has undergone a detailed energy audit and a large amount of data about the building envelopes, cooling loads and electricity consumption has been collected from 2008 to 2010. In our models, buildings are subdivided in up to three use types documented in the audit (Residential, Office and Retail). Since it is well known that, due to the urban heat island effect, the urban ambient air temperature can differ significantly from the reference rural air temperature used in most building simulations, the calibration procedure will also estimate this differential together with unknown building parameters. The main contribution of the paper is to demonstrate that the proposed district-scale calibration is, in average, more accurate than individual building calibration and informs not only on buildings but also on the outdoor environment. The calibration was performed using Genetic Algorithm, reaching an average building MAPE of 25.24%. For the district as a whole, a MAPE of 12.01% was achieved. The estimation of Urban Heat Island intensity revealed a daily maximum of 5.6°C and an average daily differential of 3°C for a typical day, showing the relevance to consider it for any building energy simulation.

Mapping failures in energy and environmental performance of buildings

Buildings regularly fail to perform at optimum levels and often do not meet design predictions. These failures impact energy efficiency, provision of adequate indoor environmental quality (IEQ) and occupant satisfaction. Detailed energy audits of 33 office buildings in Brazil are used to map and categorise the performance issues which lead to energy inefficiency and inadequate IEQ. Four buildings use occupant satisfaction questionnaires to complement the audit and evaluate the impact of failures on users. A total of 333 failures are identified and categorised in 51 separate modes. The causes of failures are identified as errors in building design and construction (D&C) or operations and maintenance (O&M). Some issues require retrofit procedures, but most can be corrected by adapting O&M procedures. Small- and medium-sized offices generally repeat the same failure modes; automated procedures or checklists and training could optimise performance in these buildings. Large offices are likely to require commissioning expertise in newer buildings, while older buildings require automation systems or full retrofits. The effects of O&M and building management are seen to have greater impacts on performance and occupant satisfaction than factors such as design, year of construction or building HVAC system.

Implementation of Energy Efficiency Strategies in Cooling Towers—A Techno-Economic Analysis

This paper depicts the results of a detailed energy audit, analysis, and implementation of energy efficient operations and maintenance strategies in a large commercial mall in Kuwait. Initially, the cooling towers (CTs) operated only at high speed, and on a typical summer day, nearly one-fourth of the make-up water was used for self-cooling of air. The study based on measured data and analysis, for a period of one year, revealed that the use of variable frequency drive (VFD) could reduce the water wastage for self-cooling of air by as much as 75% and overall water consumption by 18.6% while keeping the cooling system performance at the design level. An optimization model was developed, suitable exclusively for arid climatic conditions. Implementation of various energy efficient operation and maintenance strategies (EEO&MS) with ventilation and air-conditioning (VAC), and lighting systems obtained an overall reduction of 9879 MWh/y, equivalent to a percentage reduction of 11.7% in the annual energy consumption and a 345 kW in peak power demand. The study estimated an economical benefit of 19,958 KD/y for the owners and to the Ministry of Electricity and Water, in addition to a considerable environmental benefit of deduction in CO2 emissions by 6990 t/y.

Impact of building characteristics and occupants’ behaviour on the electricity consumption of households in Abu Dhabi (UAE)

The per capita consumption of electricity in Abu Dhabi is one of the highest in the world. Air cooling (AC) in the residential sector is responsible for much of this consumption. A preliminary energy survey of 36 residential units (18 villas and 18 flats) was carried out in Abu Dhabi, followed by a more detailed energy audit of 15 villas owned and occupied by Emirati citizens. The mean per capita use of electricity in villas was 16,874±4421kWh/ca/yr and the mean energy intensity was 349.1±102.6kWh/m2. AC and domestic water heating (DWH) systems operate 24h/day in most rooms of 12 villas, including times of no occupancy, and at least 9–14h/day in most rooms of the other three dwellings. Building characteristics of the villas audited do not meet minimum Estidama Pearl 1 requirements, and their orientation often maximizes exposure to solar radiation. Model simulations provided estimates of the large energy savings achievable by increasing the AC thermostat temperature to 24°C, by switching off AC and DWH when these are not needed and by retrofitting villas with roof insulation. These results highlight the importance of occupants’ behaviour for energy conservation in the residential sector of Abu Dhabi.

Energy Audit Analysis Enhancing Energy Conservation in Foundry Industries by Minimizing Heat Losses in Induction Furnaces

Objectives: Implementing energy conservation in foundries, identification of energy losses from induction furnace in the form of conduction and radiation heat losses. Method/Approach of Energy Audit: The energy audit in this work consists of two phases and this piece of work focuses on the second phase which consists of identification and determination of conduction and radiation heat losses from induction furnace. A comparison for different values of furnace lining thickness shows conduction losses for each value of furnace lining thickness. The radiation losses are identified and the combined total losses are calculated. Findings/Observations: The conduction losses remain practically the same for all the operating temperatures of the furnace for a given thickness of furnace lining. The conduction losses are different for different values of furnace lining thickness. They increase as the lining thickness of furnace is increased. Radiation losses remain practically the same for all values of lining thickness for the entire operating temperature range. Radiation losses occur from the furnace opening and increases as the temperature of the furnace is increased. Thus, for the original thickness of 63 mm, the maximum and minimum heat efficiency is 93.1% at 1200°C and 86.27% at 1500°C respectively. The furnace does operate at an overall average heat efficiency of about 90% with a deviation of about ±3% for a given value of thickness. Application/Improvements: A good energy management is the key towards energy conservation and it starts with an energy audit. The detailed energy audit analysis reveals good amount of energy saving in foundry and allied industries.

A regression-based approach to estimating retrofit savings using the Building Performance Database

Retrofitting building systems is known to provide cost-effective energy savings. However, prioritizing retrofits and computing their expected energy savings and cost/benefits can be a complicated, costly, and an uncertain effort. Prioritizing retrofits for a portfolio of buildings can be even more difficult if the owner must determine different investment strategies for each of the buildings. Meanwhile, we are seeing greater availability of data on building energy use, characteristics, and equipment. These data provide opportunities for the development of algorithms that link building characteristics and retrofits empirically. In this paper we explore the potential of using such data for predicting the expected energy savings from equipment retrofits for a large number of buildings. We show that building data with statistical algorithms can provide savings estimates when detailed energy audits and physics-based simulations are not cost- or time-feasible. We develop a multivariate linear regression model with numerical predictors (e.g., operating hours, occupant density) and categorical indicator variables (e.g., climate zone, heating system type) to predict energy use intensity. The model quantifies the contribution of building characteristics and systems to energy use, and we use it to infer the expected savings when modifying particular equipment. We verify the model using residual analysis and cross-validation. We demonstrate the retrofit analysis by providing a probabilistic estimate of energy savings for several hypothetical building retrofits. We discuss the ways understanding the risk associated with retrofit investments can inform decision making. The contributions of this work are the development of a statistical model for estimating energy savings, its application to a large empirical building dataset, and a discussion of its use in informing building retrofit decisions.

The outdoor microclimate benefits and energy saving resulting from green roofs retrofits

This paper focuses on the benefits on the local microclimate and the building energy saving resulting from green roof retrofits. The research investigates a case study located in a university campus in Toronto, Canada. After completing a detailed energy audit of the building, an assessment of the benefits resulting from the installation of an extensive green roof was performed. A virtual model validated using multiyear data of a local network of different weather stations was used to simulate the effects of the green roof retrofit over the outdoor microclimate. Then, a building energy model was used to compare the energy saving of several green roof designs. Results indicate that increasing the leaf area index (LAI) would lead to an increased cooling effect of the air temperature up to 0.4°C during the day at pedestrian level, while a more significant temperature reduction would be obtained only at the rooftop level. This confirms the potential of green roofs as urban heat island mitigation strategy. The adoption of a green roof retrofit resulted in a building energy demand reduction by 3%, and in significantly improved indoor comfort levels in the floor below the green roof. Finally, the parametric analysis of different green roof options showed that for building energy savings, increasing the soil depth is more important than increasing the LAI.

Low-Investment Energy Retrofit Framework for Small and Medium Office Buildings

Small and medium office buildings consume a significant parcel of the U.S. building stock energy consumption. Still, owners lack resources and experience to conduct detailed energy audits and retrofit analysis. We present an eight-steps framework for an energy retrofit assessment in small and medium office buildings. Through a bottom-up approach and a web-based retrofit toolkit tested on a case study in Arizona, this methodology was able to save about 50% of the total energy consumed by the case study building, depending on the adopted measures and invested capital. While the case study presented is a deep energy retrofit, the proposed framework is effective in guiding the decision-making process that precedes any energy retrofit, deep or light.

Accelerating the energy retrofit of commercial buildings using a database of energy efficiency performance

Small and medium-sized commercial buildings can be retrofitted to significantly reduce their energy use, however it is a huge challenge as owners usually lack of the expertise and resources to conduct detailed on-site energy audit to identify and evaluate cost-effective energy technologies. This study presents a DEEP (database of energy efficiency performance) that provides a direct resource for quick retrofit analysis of commercial buildings. DEEP, compiled from the results of about ten million EnergyPlus simulations, enables an easy screening of ECMs (energy conservation measures) and retrofit analysis. The simulations utilize prototype models representative of small and mid-size offices and retails in California climates. In the formulation of DEEP, large scale EnergyPlus simulations were conducted on high performance computing clusters to evaluate hundreds of individual and packaged ECMs covering envelope, lighting, heating, ventilation, air-conditioning, plug-loads, and service hot water. The architecture and simulation environment to create DEEP is flexible and can expand to cover additional building types, additional climates, and new ECMs. In this study DEEP is integrated into a web-based retrofit toolkit, the Commercial Building Energy Saver, which provides a platform for energy retrofit decision making by querying DEEP and unearthing recommended ECMs, their estimated energy savings and financial payback.

Energy audit in small wastewater treatment plants: methodology, energy consumption indicators, and lessons learned.

Energy audits in wastewater treatment plants (WWTPs) reveal large differences in the energy consumption in the various stages, depending also on the indicators used in the audits. This work is aimed at formulating a suitable methodology to perform audits in WWTPs and identifying the most suitable key energy consumption indicators for comparison among different plants and benchmarking. Hydraulic-based stages, stages based on chemical oxygen demand, sludge-based stages and building stages were distinguished in WWTPs and analysed with different energy indicators. Detailed energy audits were carried out on five small WWTPs treating less than 10,000 population equivalent and using continuous data for 2 years. The plants have in common a low designed capacity utilization (52% on average) and equipment oversizing which leads to waste of energy in the absence of controls and inverters (a common situation in small plants). The study confirms that there are several opportunities for reducing energy consumption in small WWTPs: in addition to the pumping of influent wastewater and aeration, small plants demonstrate low energy efficiency in recirculation of settled sludge and in aerobic stabilization. Denitrification above 75% is ensured through intermittent aeration and without recirculation of mixed liquor. Automation in place of manual controls is mandatory in illumination and electrical heating.

Reducing Auxiliary Power of Induced Draft Fans in Coal Fired Thermal Power Plants by Energy Audit

This paper describes the various opportunities for reducing the auxiliary power of induced draft fans in coal fired thermal power plants. The auxiliary power used by induced draft fans forms about 0.9 to 1.18 % of the total gross energy generation for 210 MW to 800 MW power plants. ID fans are the second largest (in rating) motor in a thermal power plant after Boiler Feed Pump (BFP). The detailed energy audit of auxiliary equipment in various thermal power stations, operational optimization and appropriate control system had shown ample scope for improving the energy efficiency of induced draft fans. The implementation of energy conservation measures reduce the average auxiliary power used by ID fans for 210 MW plant from average value of 1.18 % to 0.90 % of gross energy generation and the energy conservation schemes are economically attractive with a payback period of 1 to 5 years.

Energy Audit Methodology of Sponge Iron Manufacturing Units Using DRI Process

Conducting complete energy audit (both process and utility) of a sponge iron unit is challenging as there is no laid down procedure to audit the process side. Further, the average heat to power ratio (kWth/kWe) of sponge iron plants ranges from (25:1) to (31:1). This shows that the manufacturing process mostly uses thermal energy and application of electrical energy is insignificant. The main & only source of thermal energy is coal and the entire coal is fed to the rotary kiln. Therefore we find that “Kiln” is the “Black-Box” of this industry and the success of energy efficiency is hidden in the kiln process chemistry. This article tries to establish detailed energy audit methodology of sponge iron manufacturing process or kiln operation with a view to finding out major energy saving potential of the unit. In the research work we find that it is the incomplete reaction of coal that causes the major energy inefficiency in the process. Substantial amount of un-reacted carbon comes out with the char (by-product) which has virtually zero commercial value. The article also puts a question mark on the justification of using high-grade imported coal in such energy inefficient industries.

Prospects of energy savings in the national meat processing factory

This investigation is conducted to examine potential opportunities of energy savings in the meat processing industry. It demonstrates that energy saving can be considered as a major factor to increase profit and competition within this sector. Detailed energy audits were carried out for meat processing equipment in the national factory. This work shows that there are large opportunities of savings which can be achieved by installing the economiser; using compressed air leakage points in the distribution air network, increasing the suction temperature of the high stage compressors as well as recovering of heat in blow down by preheating feed water which will save even more energy. It was found that the refrigeration systems consume more electricity compared to other departments. However, modification of the water pumping system will save an extra amount of energy. Finally, valuable recommendations to factory management are proposed and required additional research, analysis, and data collection are identified.

Energy efficiency in membrane bioreactors

Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters. The aim of this project was to understand how the energy is consumed in MBR facilities and under which operating conditions, in order to finally provide guidelines and recommended practices for optimisation of MBR operation and design to reduce energy consumption and environmental impacts.