Improving Energy Performance of Water Allocation Networks Through Appropriate Stream Merging

Water-using operations in the process industry have demands for water usually both on water quality and temperature, and the existing mathematical models of heat exchange networks cannot guarantee the energy performance of a water network optimal. In this paper, the effects of non-isothermal merging on energy performance of water allocation networks are analyzed, which include utility consumption, total heat exchange load, and number of heat exchange matches. Three principles are proposed to express the effects of non-isothermal merging on energy performance of water allocation networks. A rule of non-isothermal merging without increasing utility consumption is deduced. And an approach to improve energy performance of water allocation network is presented. A case study is given to demonstrate the method.

Energy Performance Contracting—Business opportunities would be infinite if the “two obstacles” were cracked

Energy Performance Contracting was introduced into China in the mid 1990s. Since western energy service companies came to China, their management pattern has undergone major changes. Why did such changes occur? Mainly because these companies encountered two difficulties in China: tax and financing.

A CONCEPTUAL FRAMEWORK FOR DELIVERING SUSTAINABLE BUILDING ENERGY EFFICENCY RETROFIT USING THE ENERGY PERFORMANCE CONTRACTING(EPC)IN CHINA

Sustainable building has become a future development trend in the building sector.Building Energy Efficiency Retrofit(BEER)provides excellent opportunities to reduce energy consumption in existing buildings,and to promote environmental protection,the rational use of resources,occupants’health,all of which helps to improve the sustainability of existing buildings.Energy Performance Contracting(EPC)provided by Energy Service Companies(ESCOs)is a market mechanism to provide financial and technological support for energy efficiency projects.This paper aims to develop a sustainability promotion framework for BEER projects under the EPC mechanism to link the sustainable performance of BEER with the success factors of this EPC mechanism.Different types of building have different energy consumption characteristics.This research focuses on hotel buildings in China.The paper develops a framework for sustainable BEER through an EPC mechanism in hotel buildings based on the EFQM Excellence Model for business quality management.Interviews were conducted with experts from the hotel industry,from energy service companies and with academics.Based on the developed framework,the study has identified 11 performance indicators for sustainable BEER and 28 success factors of an EPC mechanism.This provides significant groundwork for future study in developing an assessment model to evaluate the sustainability of BEER projects.

RISK FRAMEWORK FOR ENERGY PERFORMANCE CONTRACTING BUILDING RETROFITS

Energy performance contracting(EPC)has emerged as a useful project financ-ing and delivery tool for building retrofits,particularly among building owner-ships which have experienced reduced funding for capital projects.Through EPC,a contractor(called the EPC contractor or the energy service company)guaran-tees minimum energy savings performance and enables the building owner to finance the project using utility savings over the length of the project(which is typically 12-15 years,or longer).Despite its growing use,there is a dearth of lit-erature regarding a contractor’s risks related to the delivery and execution of EPC building retrofits.This is particularly important as the performance guarantee effec-tively transfers project performance risk from the owner to the EPC contractor.This research proposes a project factors-based risk framework for EPC building retrofits,initially developed through a comprehensive review of relevant literature and project documents and refined through the elicited expertise of 19 highly expe-rienced EPC contracting professionals.A Delphi technique-based expertise elici-tation strategy was used to confirm the findings of the a priori(literature-based)framework and provide additional analysis related to risk causes and control mea-sures as well as relative risk importance.This information was used to construct a refined risk framework which provides insight into the lengthy project performance period during the earliest phases of the project’s life cycle.This has the advantage of providing rapid screening of the project factors that can potentially lead to the greatest project performance risks.

Energy performance assessment on central air-conditioning system of commercial building: A case study in China

Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipment is necessary. But it is difficult to evaluate it reasonably and comprehensively due to its complexity. A "holistic" approach was discussed to evaluate the energy performance of central air-conditioning system for an extra-large commercial building in a subtropical city. All procedures were described in detail, including field investigation method, field measurement instruments, data processing and data analyzing. The main factors affecting energy consumption of air-conditioning system were analyzed and the annual cooling-energy use intensity of this building was calculated and also compared with other shopping malls and other types of buildings in Guangzhou. And COP(coefficient of performance) of chiller, water transfer factor of chilled water system and cooling water system were taken into consideration. At last, the thermal comfort and indoor air quality issues were addressed. The results show that the chilled water pumps are over-sized and the indoor environmental quality should be improved. The purpose of this work is to provide reference for energy performance assessment method for air-conditioning system.

Energy Performance and Condensation Risk of DCDV System in Subtropical Hong Kong

The combined use of dry cooling(DC) system and dedicated ventilation(DV) system to decouple cooling and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its application in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment performance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54% in comparison with the conventional system(constant air volume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of condensation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parameters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed.

Climate change and building ageing impact on building energy performance and mitigation measures application:A case study in Turin, northern Italy

This study uses a building energy performance simulation to investigate the impact of predicted climate warming and the additional issue of building ageing on the energy performance for a library in Turin,Italy.The climate and ageing factors were modelled individually and then integrated together for several decades.Results from the climate-only simulation showed a decrease in thebuilding heating energy usage which outweighed the increase in the on-site cooling energy demand occurring in a warming scenario.The study revealed a high sensitivity of energy performance to building ageing,in particular due to HVAC(Heating,Ventilation and Air Conditioning) equipment efficiency degradation.Building ageing was seen to negatively affect the energy performance as it induced a further increase of the cooling energy usage in a warming climate,while it also counteracted the reduction of the heating energy usage resulting from warming.Simulations on the combination of mitigation techniques showed a number of potentially retrofit measures that would be beneficial for buildings to avoid an increase in the cooling energy usage due to climate warming.The combination of these retrofit techniques showed a potential decrease of 87.3% in the final cooling energy usage for the considered building.

The Energy Performance in the Italian Public Administration： State of the Art and Future Prospects

The commitment to improve energy and environmental performance in public administration is essential for the success of development models geared towards lasting sustainability. The Public Administration （PA） in Italy, in particular, plays a key role to affn-m models of development oriented towards energy and environmental sustainability, thanks to a wider and more innovative vision. The PA has a dual consumer/user role, public heritage and decision maker/planner, in promoting energy efficiency at local level, in the light of specific problems and peculiarities. For several decades, initiatives have been launched at various levels to improve energy and environmental performance in the public administration. The aim of this study is to outline from a critical perspective, the state of the art of policy makers in Italy concerning energy efficiency measures in public administration. There are however many cultural, value-related, financial, technological, institutional, and operational issues in the PA sector that limit investments in energy efficiency. It should be noted that if on one hand the PA shows a lack of knowledge and is unwilling to adopt practices and systemic tools for monitoring and control, on the other, in terms of bureaucracy, the system appears to be far too complicated and costly. The multiple benefits linked to improved energy performance would therefore require that the PA rethink their organizational and functional models, put in place more flexible and less bureaucratic forms of management and a more dynamic, pervasive, and proactive approach towards initiatives that promote energy efficiency. The research is a contribution towards identifying the driving forces behind potential systems and tools for energy efficiency in the PA, highlighting both critical elements and opportunities and, in particular, the limits deriving from the technological, managerial, and organizational options available for energy eff^ciency enhancement in the sector of the Italian PA.

Modelling of Chillers for Energy Performance Assessment of HVAC Systems

The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.

AN INVESTIGATION BY THE BEP-TR METHOD OF THE EFFECT OF OBSTRUCTION ANGLE PARAMETER ON LIGHTING ENERGY PERFORMANCE AND DAYLIGHT SUPPLY

Following the EN 15193,2008 Energy Performance in Buildings Regulation in the European Union Member States,a comprehensive calculation can be made on lighting energy performance and daylight effect.This improved model accounts for Turkey’s“BEP-TR”(“Regulation on Energy Performance in Buildings”).In the present study,the effect of the obstruction angle parameter of buildings on light-ing energy consumption and daylight provided is examined through a sample hotel project by the BEP-TR calculation method.This study investigates the effect of day-light on lighting energy performance alternatives that were produced according to the height,building distance variations(causing obstruction angle),and the correlation between annual lighting consumption values,daylight supply factor,and obstruction parameters.Accordingly,the current study aims to develop a method to assist zoning regulations,building intervals,and height decisions by determining specific ratios between obstruction parameters,daylight supply factor and lighting energy consump-tion values.Results of this study clearly show that obstruction parameter variables affect both the daylight supply factor and annual lighting energy significantly.

Early Stage CAD-Compliant Energy Performance Assessment Method

A simple calculator for early stage energy performance assessment in residential buildings was developed and partially validated in this study. The calculator is based on the correlation of heat loss and energy need for heating and has fixed internal heat gains as intended for compliance assessment. With the calculator, the effect of any parameter implemented can be immediately seen on delivered and primary energy. Because of simple equations, it is suitable for implementation into CAD （computer aided design） design tools including basic BIM （building information modeling） data. Results showed that the accuracy of the correlation for the cases with practical relevance was not worse than 14% of the energy need of space heating. This applies for passive house insulation level; for less insulated building envelopes, the deviations were smaller. This 14% equals to only 3 kWh/（m2.a）, i.e., the percentage difference in the total delivered and primary energy was much lower because of other components in the energy balance. The deviations determined were implemented in the calculator as safety margin. Results prove that simple energy performance assessment based on specific heat loss coefficient is well justified for early stage energy analyses as well as for compliance assessment implemented in Estonian regulation.

Energy Performance versus Indoor Environment QualitymNon-traditional Form of Elementary Schools Renovation in Terms of Slovak Republic

The content of contribution is to analyse suggested renovation of school building in term of energy performance and indoor environment quality. There were three selected variants of possible reno ration of school building. At first, it was installation of equipment for heat recovery into existing mechanical ventilation system. There were further evaluated possibilities how to use glass atrium or ground air-heat exchanger in mechanical ventilation system. These suggested variants were analysed in field of energy performance, namely in term of impacts on heat demand for space heating in order to keep required parameters of indoor environment quality according to standard STN EN 15251 （operative temperature, relative air humidity, air change rate）. The analysis was elaborated by using energy simulation tool Design Builder in order to evaluate yearlong operation of buildings.

RISK MODEL FOR ENERGY PERFORMANCE CONTRACTING IN CORRECTIONAL FACILITIES

Energy performance contracting provides guaranteed minimum energy savings to building owners,enabling them to finance project costs using utility savings over the duration of the project.This has been an attractive project delivery method for organizations with reduced budgets for capital projects,particularly among correctional facilities which frequently have lengthy periods of deferred maintenance and ongoing building operations and maintenance concerns.This research builds on a previously developed project factors risk framework for energy service companies undertaking building retrofits.This paper proposes a risk analysis and evaluation model that includes quantitative,expert-based,and probabilistically derived information.Expected cost was used to evaluate risks over lengthy project life cycles and a new metric was developed for use in the model-expected life cycle value.Model results reveal that the most critical risk factors relate to the reduced availability of“low-hanging fruit”energy conservation measures,work scopes based on traditional design-bid-build procurement,unavailable or inaccurate facility information,facility age and current code requirements,and conducting the investment grade audit too quickly.The life cycle cost-based risk model employed in this paper is proposed as an advancement over traditional risk management methods,and it is expected to be applicable,with modification,across other municipal and state government subdomains,especially high security projects.

Deep Learning for Multivariate Prediction of Building Energy Performance of Residential Buildings

In the quest to minimize energy waste,the energy performance of buildings(EPB)has been a focus because building appliances,such as heating,ventilation,and air conditioning,consume the highest energy.Therefore,effective design and planning for estimating heating load(HL)and cooling load(CL)for energy saving have become paramount.In this vein,efforts have been made to predict the HL and CL using a univariate approach.However,this approach necessitates two models for learning HL and CL,requiring more computational time.Moreover,the one-dimensional(1D)convolutional neural network(CNN)has gained popularity due to its nominal computa-tional complexity,high performance,and low-cost hardware requirement.In this paper,we formulate the prediction as a multivariate regression problem in which the HL and CL are simultaneously predicted using the 1D CNN.Considering the building shape characteristics,one kernel size is adopted to create the receptive fields of the 1D CNN to extract the feature maps,a dense layer to interpret the maps,and an output layer with two neurons to predict the two real-valued responses,HL and CL.As the 1D data are not affected by excessive parameters,the pooling layer is not applied in this implementation.Besides,the use of pooling has been questioned by recent studies.The performance of the proposed model displays a comparative advantage over existing models in terms of the mean squared error(MSE).Thus,the proposed model is effective for EPB prediction because it reduces computational time and significantly lowers the MSE.

Energy performance analysis of multi-chiller cooling systems for data centers concerning progressive loading throughout the lifecycle under typical climates

The increasing demand for cooling energy in data centers has become a global concern.Existing studies lack a comprehensive analysis of the energy performance of widely used multi-chiller cooling systems in air-cooled data centers throughout their lifecycle,especially concerning progressive loading.To bridge this gap,this study conducts a thorough assessment of the energy performance of multi-chiller cooling systems throughout the entire lifecycle.Additionally,the impact of climate conditions on the energy efficiency of the cooling systems is analyzed,considering design variations for typical climates.Multi-chiller cooling system models are developed using the test data of cooling equipment and typical control algorithms.The energy performance of the cooling system is thoroughly analyzed under full-range cooling loads and climate conditions.Results show that free cooling time could differ up to 1442 hours at different part load ratios in the same location.Furthermore,the cooling system’s coefficient of performance(COP)varies significantly,by up to 6,at different part load ratios,corresponding to a difference in power usage effectiveness(PUE)up to 0.14.Notably,the average cooling system COP throughout the lifecycle loading is found to be only 11.7,2.9 lower than the design system COP.

Optimizing building retrofit through data analytics:A study of multi-objective optimization and surrogate models derived from energy performance certificates

The building stock is responsible for a large share of global energy consumption and greenhouse gas emissions,therefore,it is critical to promote building retrofit to achieve the proposed carbon and energy neutrality goals.One of the policies implemented in recent years was the Energy Performance Certificate(EPC)policy,which proposes building stock benchmarking to identify buildings that require rehabilitation.However,research shows that these mechanisms fail to engage stakeholders in the retrofit process because it is widely seen as a mandatory and complex bureaucracy.This study makes use of an EPC database to integrate machine learning techniques with multi-objective optimization and develop an interface capable of(1)predicting a building’s,or household’s,energy needs;and(2)providing the user with optimum retrofit solutions,costs,and return on investment.The goal is to provide an open-source,easy-to-use interface that guides the user in the building retrofit process.The energy and EPC prediction models show a coefficient of determination(R2)of 0.84 and 0.79,and the optimization results for one case study EPC with a 2000€budget limit inÉvora,Portugal,show decreases of up to 60%in energy needs and return on investments of up to 7 in 3 years.

Multi-objective optimization of thermochromic glazing based on daylight and energy performance evaluation

Many efforts have been detected to investigate thermochromic(TC)glazing for improving building energy saving,while only a few approaches for daylight performance analysis.In this study,the performance of TC glazing is investigated based on multi-objective optimization for minimizing energy demand while maximizing daylight availability.The effects of five parameters including transition temperature,solar transmittance in clear state,solar transmittance modulation ability,luminous transmittance in clear state,and luminous modulation ability on the building energy consumption and useful daylighting illuminance(UDI_(300-3000))are examined.Linear Programming Technique for Multi-dimensional Analysis of Preference(LINMAP)is used for the decision-making of Pareto frontier.This research aims to explore the ideal thermochromic glazing by considering the daylight and energy performance of a typical office room,taking the weather condition of Xiamen,China as an example.Although it is impossible to achieve both optimal values of energy consumption and UDI_(300-3000)simultaneously,the proposed multi-objective optimization method could still provide low energy consumption with sufficient daylight.The non-dominated sorting of Pareto optimal solution(POS)demonstrated that the optimum building energy consumption and UDI_(300-3000)for single glazed windows are 46.64 kWh/m^(2)and 70.92%,respectively,while the values for double glazed windows are 44.40 kWh/m^(2)and 71.88%,respectively.The selected hypothetical TC windows can improve the building energy and daylighting performance simultaneously when compared with traditional clear single and double glazed windows.The presented framework provides a multi-objective optimization method to determine the most suitable TC glazing technologies for designers and architects during the design and retrofit procedure.

Evaluating diverse patterns of occupant behavior regarding control-based activities in energy performance simulation

Simulation is recognized as an effective tool for building energy performance assessment during design or retrofit processes. Nevertheless, simulation models yield deviating outcomes from the actual building performance and a significant portion of this deviation originates from the dynamic nature of occupant behavior. Literature on occupant behavior indicates that occupant behavior is not integrated into building energy performance assessment procedures with appropriate resolution, instead they are accepted as assumed and fixed data sets that usually represent the presence of occupants. This study attempts to evaluate the effect of diverse patterns of occupant behavior on energy performance simulation for office buildings. Diverse levels of sensitivity of occupant behavior on control-based activities such as using lighting apparatus, adjusting thermostat settings, and presence in space are employed through three diverse occupant behavior patterns. These occupancy patterns are correlated with three identical office spaces simulated within a conceptual office building. EDSL Tas is used to run building energy performance simulations. Effects of occupant behavior patterns on simulation outcomes are compared for five sample winter and summer workdays, with respect to heating and cooling loads. Results present findings on how diversity of occupancy profiles influences the consumption outcomes.

Method for rating energy performance of public buildings

This paper discussed a comparative study of several state-of-art methods for determining building energy consumption benchmark. A new approach, which combined the idea of ＂building benchmark＂ and ＂operational benchmark＂ in its rating system, was proposed. A case study was conducted which applied the proposed approach to benchmarking an existing office building in Tianjin. Besides, the calculation of benchmarks of the reference building model and real building model using the rating method in eQUEST was also considered. Furthermore, the simulation results of the reference building model were taken as the baseline to divide real office buildings into different energy performance grades.

PERFORMANCE INDICATORS FOR ENERGY EFFICIENCY RETROFITTING IN MULTIFAMILY RESIDENTIAL BUILDINGS

The energy performance of an existing building is the amount of energy consumed to meet various needs associated with the standardized use of a building and is reflected in one or more indicators known as Building Energy Performance Indicators(EnPIs).These indicators are distributed amongst six main factors influencing energy consumption:climate,building envelope,building services and energy systems,building operation and maintenance,occupants’activities and behaviour,and indoor environmental quality.Any improvement made to either the existing structure or the physical and operational upgrade of a building system that enhances energy performance is considered an energy efficiency retrofit.The main goal of this research is to support the implementation of multifamily residential building energy retrofits through expert knowledge consensus on EnPIs for energy efficiency retrofit planning.The research methodology consists of a comprehensive literature review which has identified 35 EnPIs for assessing performance of existing residential buildings,followed by a ranking questionnaire survey of experts in the built-environment to arrive at a priority listing of indicators based on mean rank.This was followed by concordance analysis and measure of standard deviation.A total of 280 experts were contacted globally for the survey,and 106 completed responses were received resulting in a 37.85%response rate.The respondents were divided into two groups for analysis:academician/researchers and industry practitioners.The primary outcome of the research is a priority listing of EnPIs based on the quantitative data from the knowledge-base of experts from these two groups.It is the outcome of their perceptions of retrofitting factors and corresponding indicators.A retrofit strategy consists of five phases for retrofitting planning in which the second phase comprises an energy audit and performance assessment and diagnostics.This research substantiates the performance assessment process through the identification of EnPIs.