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This paper describes a novel optimization-based analysis framework to evaluate the cost benefits of retrofit programs of existing Saudi housing stocks with the main objective to reduce their electrical peak demands. The retrofit programs are developed to minimize the cost for peak demand reduction while maximizing energy use savings to select sets of energy efficiency and renewable energy technologies for various residential building prototypes prevalent in Saudi Arabia. The effectiveness of large-scale implementations of optimal retrofit packages is evaluated to assess their cost benefits as well as their effects on shaping Saudi electrical load profiles. It found that the optimal retrofits are more effective than the deployment of rooftop PV systems in reducing both peak demand and annual energy consumption for Saudi housing stock. In particular, the analysis indicates that retrofitting the housing stock with one energy efficiency measure reduces electrical peak demand at 779 USD/kW lower than that attributed to deploying rooftop PV systems. [ABSTRACT FROM AUTHOR]

Although the energy and cost benefits for retrofitting existing buildings are promising, several challenges remain for accurate measurement and verification (M&V) analysis to estimate these benefits. Due to the rapid development in advanced metering infrastructure (AMI), data-driven approaches are becoming more effective than deterministic methods in developing baseline energy models for existing buildings using historical energy consumption data. The literature review presented in this paper provides an extensive summary of data-driven approaches suitable for building energy consumption prediction needed for M&V applications. The presented literature review describes commonly used data-driven modeling approaches including linear regressions, decision trees, ensemble methods, support vector machine, deep learning, and kernel regressions. The advantages and limitations of each data-driven modeling approach and its variants are discussed, including their cited applications. Additionally, feature engineering methods used in building energy data-driven modeling are outlined and described based on reported case studies to outline commonly used building features as well as selection and processing techniques of the most relevant features. This review highlights the gap between the listed existing frameworks and recently reported case studies using data-driven models. As a conclusion, this review demonstrates the need for a flexible M&V analysis framework to identify the best data-driven methods and their associated features depending on the building type and retrofit measures. [ABSTRACT FROM AUTHOR]

In this paper, a review of the adoption status of energy efficiency and renewable energy technologies is presented, specific to US residential buildings. Various technologies are reviewed and categorized as either their relative "higher adoption" or "lower adoption" rates within the US housing stock. More importantly, the review analysis investigates the main factors associated with their high or low adoption rates. Specifically, the paper provides a background of the historical progression of energy efficiency programs as well as sustainability certifications and standards for buildings. The review then analyzes specific building energy efficiency and renewable energy technologies applied to US residential buildings and their adoption rates. The review analysis indicates that building technologies are more frequently adopted for multiple reasons including requirements by codes and standards, incentives through green certifications, low implementation costs, and acceptance and popularity by the public. In contrast, technologies with low adoption rates have higher payback periods, are not required or highly incentivized through codes and certifications, have limited promotion about their benefits, or are not compatible with existing systems. By determining the reasons for the high and low adoption rates, mitigation options can be identified to increase the application of sustainable energy technologies in designing and retrofitting buildings. [ABSTRACT FROM AUTHOR]

The energy benefits of integrating PV panels with dynamic overhangs are evaluated for US residential buildings. Various control strategies are investigated to operate the dynamic overhangs to minimize annual net energy demands to account for both building energy needs and PV electricity generation yields. The analysis results indicate that dynamic overhangs can reduce significantly the annual energy demand for US residences compared to no-overhang and static overhang options even when controlled on a monthly basis and without any PV panels. Specifically, it is found that dynamic overhangs applied to southern facing windows for houses located in Golden, CO, can save up to 6% when no-PV array is installed and more than 35% when integrated with PV panels using monthly adjustments. Even higher savings up to 90% can be achieved for houses located in warm climates and those with larger windows. Moreover, PV-integrated dynamic overhangs can provide energy savings for windows oriented in any direction especially when adjusted on daily basis. • PV-integrated rotating overhangs are evaluated for US residential buildings. • Optimal control strategies are determined for the dynamic PV-integrated overhangs. • The dynamic overhangs can reduce the annual energy demand up to 90% for US homes. [ABSTRACT FROM AUTHOR]

To meet the increasing energy demand and to shave the peak, the Kingdom of Saudi Arabia (KSA) is currently planning to invest more on renewable energy (RE) seeking diversity of energy resources. Through the integration of demand-side management measures and renewable energy distributed generation (DG) systems, the study outlined in this paper aims at investigating the potential of hybrid renewable energy systems in supplying energy demands for residential communities in an oil-rich country. The residential community considered in this study, located in the eastern region of KSA, has an annual electrical usage of 1174 GWh and an electrical peak load of 335 MW that are met solely by the grid. The results of the analyses indicated that the implementation of cost-effective energy efficiency measures (EEMs) reduced the electricity usage by 38% and peak demand by 51% as well as CO2 emissions by 38%. Although the analysis of the hybrid systems showed that purchasing electricity from the grid is the best option with a levelized cost of energy (LCOE) of $0.1/kWh based on the current renewable energy market and economic conditions of KSA, RE systems can be cost-effective to meet the loads of the residential communities under specific electricity prices and capital cost levels. [ABSTRACT FROM AUTHOR]

Due to the rapid development of Advanced Metering Infrastructure (AMI), data-driven approaches are becoming more effective and accurate for Measurement and Verification (M&V) baseline energy modeling of existing buildings using historical energy consumption data. This paper develops and applies a comprehensive analysis framework suitable for developing baseline data-driven models to estimate energy savings from building retrofits. The framework employs common data-driven modeling approaches for building energy prediction, necessary data processing tasks, and industry-used evaluation methods. The modeling approaches considered by the developed framework include linear regression, ensemble models, support vector regression, neural networks, and kernel regression. The developed framework is applied to two case studies with different sources of energy consumption data generated via a simulated office building model and actual measurements obtained from a publicly available dataset. The framework applications to data from 170 buildings with 1-year data result in energy use predictions with medians of Goodness-of-Fit (GOF) scores that are less than 25%. • A data-driven framework is proposed to automate baseline modeling for measurement and verification analysis. • The framework considers several data-driven modeling approaches and timestamp frequencies. • The framework is able to predict within 5.54%, the energy savings incurred by retrofitting an office building. [ABSTRACT FROM AUTHOR]

The paper provides a systematic evaluation of the optimal optical characteristics of smart windows to maximize their energy efficiency benefits when deployed for residential buildings. The evaluation accounts for a wide range of design specifications and operation conditions of housing units including building orientation, window sizes, and climatic zones. Using integrated analysis aimed to minimize energy use required to heat and cool housing units, the optimal design and control settings are determined for two types of smart windows including those that can switch between only clear and dark tint states and those that can transition to multiple intermediate tint levels. The results from a series of sensitivity analyses show that the required design optical specifications for the smart windows could depend on several variables including primarily climate characteristics and window features including size, orientation, and U-value. Significant energy savings can be achieved by smart windows relative to the code-compliant static fenestration systems ranging from 21% in cold climates to 5% in warm climates. These energy savings can be achieved using stepped controls to set the tint levels of the smart windows. Additional albeit slight savings can be obtained through gradual controls for those smart glazing that have the capabilities to transition to intermediate tint levels. • A new analysis approach is presented for selecting optical properties of smart glazing. • Optimal optical properties for smart glazing can be identified for any residential building. • Energy efficiency benefits of smart glazing are enhanced using optimal optical properties. • Over 20% energy use can be saved by smart glazing relative to code-compliant systems. [ABSTRACT FROM AUTHOR]

Abstract A new analysis framework is developed and applied to assess the benefits of building energy efficiency policies and programs. One of the main advantages of the new energy productivity analysis is that it accounts for both economic and energy performances of energy efficiency actions using only one metric. Specifically, the approach applies the concept of energy productivity to the building sector and accounts for both value added and energy savings of energy efficiency measures. Moreover, the proposed analysis accounts for all quantifiable benefits of energy efficiency programs including economic, environmental, and social. In this paper, the general guidelines for the energy productivity analysis are first described. Then, the analysis is applied to evaluate energy efficiency renewable energy programs for both existing and new buildings in the Gulf Cooperation Council (GCC) countries. The analysis results indicate that retrofitting the existing building stock can provide significant benefits and can improve the energy productivity of the building sector in all GCC countries and free up large energy volumes and investment potentials to the development of other economic sectors. In particular, the analysis indicates that reduction in energy consumption, peak demand, and carbon emissions due to deep retrofit programs for the existing building stock can double the energy productivity of the GCC region. Highlights • A new analysis approach is presented to evaluate building energy efficiency policies. • The analysis is used to assess energy efficiency programs for new and existing GCC building stocks. • Retrofit of the existing building stocks can double the energy productivity in all GCC countries. [ABSTRACT FROM AUTHOR]

In the United Arab Emirates (UAE), buildings consume almost 90% of the total electricity used in the country. This paper provides a comprehensive overview of recent trends in energy consumption in the building sector as well as current efforts in promoting energy efficiency within UAE. Moreover, the paper explores available opportunities to improve energy efficiency of the UAE building sector. In particular, the impacts of three levels of energy retrofits are quantified based on results from existing literature and an optimization-based bottom-up analysis for residential, commercial, and governmental buildings. The analysis indicates that any level of energy retrofit for the existing building stock can be effective in reducing energy consumption and peak power demand as well as in lowering carbon emissions for UAE. It is estimated that a basic energy retrofit program applied to existing UAE building stock could achieve savings of 7550 GWh/year in electricity consumption, 1400 MW in peak electricity demand and reduce carbon emissions by 4.5 million tons/year per year. The program would have an average payback period of less than six months for the UAE government and would generate almost 9000 job-years. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential heating and cooling energy use and cost savings associated with improved controls of dynamic insulation materials (DIMs) when used in multilayered wall assemblies for commercial office buildings. Using a genetic algorithm (GA) based optimization technique, optimum R-value settings are identified for the DIMs throughout the year. These optimal R-value settings are selected to maximize energy cost savings when compared to traditional static insulated wall systems. It is found that optimal control settings for DIMs depend on several factors including building design and operation strategies as well as climatic conditions. Moreover, the optimal settings were found to depend on the orientation of exterior walls and well as the climatic conditions. Specifically, the analysis results indicate that north-facing walls are more active and frequently have to change their R-value in order to minimize the office building energy use and cost. When optimally controlled, DIMs could save up to 17% of annual heating and cooling energy costs for US office buildings. [ABSTRACT FROM AUTHOR]

Optimal control strategies have been developed to enhance the performance of ventilated cavity walls (VCWs) with spray evaporative cooling systems. In particular, the spray system and three dampers are operated to regulate water usage and cavity air flow in order to maintain indoor thermal comfort, reduce water usage, prevent mold growth risk, and minimize cooling energy consumption. The control strategies have been obtained through multi-objective optimization analysis using genetic algorithm search technique. In particular, it is found that the spray droplet size can be used as a control variable to effectively operate the VCW systems. For residential buildings in Riyadh, it is found that 30 μm droplets provided the best compromise between indoor thermal comfort, water use, and mold growth potential. The optimal control strategies have been obtained through two approaches: (i) long-term (i.e., one season or one year) optimization based on both outdoor and indoor conditions with a fixed droplet size, and (ii) short-term (i.e., one hour or one-day) optimization that includes the droplet size as a control variable in addition to outdoor and indoor conditions. Using the first approach, the optimal control strategies of buildings equipped with VCWs are found to be able to reduce cooling energy consumption by 23% compared to that used by buildings having conventional concrete walls. The second optimization approach indicates that VCW system is able to provide 100% cooling energy savings compared to the conventional walls. Moreover, the optimum control strategies for VCWs have found to reduce water usage by 78% and mold growth by 98% while maintaining indoor thermal comfort when compared to uncontrolled VCW system. [ABSTRACT FROM AUTHOR]

In recent years there has been a widespread adoption of high reflectance (cool) roofing materials in hot climates to reduce a building's cooling load and energy use. While a cool roof can reduce the building's cooling load during warm months, it may regrettably increase the heating load in cool months thus reducing their overall effectiveness. One potential solution to preserving high cooling load savings without accruing a large heating load penalty is to implement a switchable roof reflectance technology; allowing a low reflectance roof during the heating season and a high reflectance roof during the cooling season. This paper organizes and summarizes the literature on cool roofs and switchable roofing materials as a tool for energy savings in buildings. It presents a review of material properties and advancements, energy savings and penalties, current codes, additional benefits and limitations, and recommendations for future research. Finally, the paper summarizes comparative analysis results of the energy performance for both static and switchable cool roofs. [ABSTRACT FROM AUTHOR]

In this paper, economic and environmental impacts of energy efficiency programs associated with new and existing buildings are evaluated for the Kingdom of Saudi Arabia (KSA). In particular, the analysis considers optimized designs for new buildings as well as different energy retrofit programs for existing buildings are considered in the bottom-up analysis using archetypical building energy models located in five sites representing a wide range of KSA climates. In particular, the analysis presented in this paper provides specific estimations to the extent of the energy and demand savings that could be achieved in the building sector even under highly subsidized energy prices. It is found that even a basic energy retrofit program using low-cost energy efficiency measures implemented to the existing building stock can provide significant economic and environmental benefits. Indeed, a level 1 energy efficiency retrofit program targeting only the existing residential building stock could reduce electricity consumption by 10,054 GWh/year and peak demand by 2290 MW and carbon emission by 7.611 million tons/year. [ABSTRACT FROM AUTHOR]

The paper evaluates the potential energy efficiency benefits for dynamic sliding exterior shades suitable for windows of both new and existing buildings. In particular, the analysis outlined in the paper summarizes the energy performance of dynamic sliding shades when applied to windows for apartment units located in various US climates. A series of sensitivity analyses is performed using a detailed whole-building simulation coupled with modeling techniques of dynamic envelope systems to determine the optimal positions for the dynamic sliding shades to minimize the annual demand for US housing units. Several operation strategies are evaluated using continuous and stepped settings of the positions for the dynamic sliding shades using monthly, daily, and hourly adjustment frequencies. The results of the analyses indicate that the dynamic shades have significant energy efficiency potential for all US climates and design conditions with annual savings in HVAC energy end-use of over 50% especially in hot and mild climates. The performance of the dynamic shades is even higher for large and single-pane windows indicating that these systems can serve as retrofit alternatives to window replacements. • New and low-cost dynamic and insulated shading systems are introduced. • Energy benefits of the dynamic shades are assessed for residential buildings. • Optimal controls for the dynamic shades are determined for US climates. • Dynamic shades achieve over 50% reduction in heating and cooling energy use. [ABSTRACT FROM AUTHOR]

The application of thermo-active foundation (TAF) systems to heat and cool residential buildings is evaluated in this paper. First, a transient three-dimensional finite difference numerical model is developed for the analysis of thermo-active foundations. The numerical model predictions are then validated against experimental data obtained from laboratory testing. Using the validated numerical model, G-functions for TAFs are generated and integrated into whole-building simulation analysis program, energyplus. A comparative analysis is carried out to evaluate TAF systems compared to conventional ground-source heat pumps (GSHPs) to provide heating and cooling for multifamily residential buildings. In particular, the analysis compares the cost-effectiveness of TAFs and GSHPs to meet heating and cooling needs for a prototypical multifamily building in three U.S. climates. Due to lower initial costs associated to the reduced excavation costs, it is found that TAFs offer a more cost-effectiveness than GSHP systems to heat and cool multifamily residential buildings. [ABSTRACT FROM AUTHOR]

This paper describes an experimental set-up used to validate predictions from a numerical model for ventilated wall cavity with spray evaporative cooling systems. The validation analysis results have indicated that the numerical model, developed and described in a companion paper, can accurately predict the outlet air temperatures and relative humidity levels achieved by a ventilated wall cavity with a spray evaporative cooling system utilized to air condition buildings in hot and dry climates. Air velocity predictions of the ventilated cavity have been also verified against results obtained from a detailed CFD analysis. Moreover, the experimental testing results indicate that the ventilated wall cavity with an evaporative cooling with 5 μm spray droplets can significantly reduce outdoor air temperatures. Specifically, the system was able to reduce air temperature from 45 °C to 25.5 °C. Moreover, the results of a parametric analysis obtained using the validated numerical solution suggest that there is a significant reduction potential in heat transfer through cavity walls while providing acceptable supply air temperature capable of maintaining indoor thermal comfort. In addition, the parametric analysis has evaluated the effect of climatic conditions (temperature and humidity) on the required distances for spray droplets to fully evaporate. The presented results could help in designing effective and energy efficient ventilated wall cavity with spray evaporative cooling systems to condition buildings in hot and dry climates. [ABSTRACT FROM AUTHOR]

Envelope systems are the main contributors to the energy consumption associated to cooling or heating buildings. There have been significant research efforts to improve the performance of building envelope systems by integrating passive cooling strategies to reduce cooling loads and maintain acceptable indoor thermal comfort. The ventilated wall cavity system is one of these passive-cooling strategies that have received considerable attention recently due to the significant benefits of reducing thermal loads of buildings. In particular, evaporative cooling inside ventilated wall cavities is an attractive passive cooling technique especially in hot and dry climates. This paper presents the initial findings of a current research study focusing on improving the ventilated wall cavity with spray evaporative cooling system that produce fine water droplets. Specifically, this paper describes a numerical modeling approach to evaluate the performance of the proposed passive cooling system to cool buildings in hot and dry climates. The simulation results suggest that a significant reduction in cooling loads can be achieved since the wall cavity can absorb heat from the indoor and outdoor while inducing acceptable supply air temperature capable of maintaining indoor thermal comfort within buildings. [ABSTRACT FROM AUTHOR]

• Combined design and control optimization is carried out for smart glazed office buildings. • Simultaneous optimization is conducted for both design specifications and control strategies. • Combined optimization of smart windows results in up to 18% total building energy cost savings. • Temperature-based controls are more effective that solar-based controls for smart windows. • When optimally designed and controlled, smart windows are cost-competitive at 350 USD/m2. The paper examines the benefits of simultaneous optimization of various design and control parameters for smart glazing windows of office buildings. The design variables include the window U-value, solar heat gain coefficient (SHGC), visible transmittance (Tvis), and window-to-wall ratio (WWR). The tint-switching control strategies reviewed include outdoor air temperature (OAT), indoor air temperature (IAT), incident total solar radiation (ITSR), and incident beam solar radiation (IBSR). These variables are optimized independently and simultaneously to determine the best specifications to minimize operating costs while maintained desired thermal and visual comfort levels. Specifically, electrochromic (EC) smart glazed windows are optimally designed and controlled when installed for a prototypical medium office building in Denver, Colorado. The optimization analysis results are considered to determine the breakeven installation costs required for smart glazing systems to be cost competitive compared to their static glazing counterparts. The analysis found that the annual energy cost savings from optimally designed and controlled smart glazed windows ranged from 11% − 18%. Of the design parameters, the U-value proved to be the most impactful on energy and cost reductions, followed by SHGC and WWR. Indoor and outdoor air temperature-based controls are determined the most effective operation strategies. Simultaneously optimizing for the design and control parameters provided the highest annual savings. [ABSTRACT FROM AUTHOR]

• Optimized designs for controlled environment agriculture (CEA) facilities are described. • The designs utilize life cycle cost analysis to achieve optimal energy performance. • Energy efficiency and renewable energy measures are part of optimized CEA designs. • Optimal savings of over 65% can be achieved compared to baseline CEA designs. The paper describes a systematic analysis approach to optimize the design of indoor farming facilities considering both energy efficiency and renewable energy systems. The design optimization is based on a life cycle cost (LCC) analysis to account for both capital and energy costs over the lifetime of the facilities. The analysis indicates that LCC-based optimal designs consistently reduce annual energy consumption of the indoor farming facilities compared to the baseline case reaching up to 65%. The most effective energy efficiency measures for indoor farming facilities include high performance heating and cooling systems as well as optimized operational controls. While the heating and cooling system depends on the climate, daylighting controls and temperature settings are found to be consistently suitable for optimized designs in all US locations. The optimization analysis indicates that net-zero energy (NZE) designs for indoor farming facilities, while technically feasible, are typically not cost-effective in most US climates. Only NZE facilities located in Sacramento, CA, can be achieved cost-effectively. [ABSTRACT FROM AUTHOR]

• The optimal energy benefits of switchable insulation systems (SIS) are evaluated for office buildings. • When combined with precooling, optimally operated SISs can provide significant energy and cost reductions. • Optimal and hybrid controls are developed to operate SIS-integrated roofs and precooling strategies. • Optimized controls for SIS and precooling can reduce by over 20% energy use and 30% peak demand. In this paper, optimized controls to enhance the energy efficiency and demand response benefits of roof-integrated switchable insulation system combined with precooling strategies are evaluated for office buildings. A wide range of optimal cost functions are investigated to evaluate the total building energy saving as well as electrical peak demand shedding and shifting potentials. The results indicate that roof-integrated switchable insulation systems provide modest reductions even when optimally controlled of up to 5% and 4% savings in total building's energy use and electrical peak demand during a peak day. However, when precooling strategies are integrated with roof switchable insulation systems, optimal controls can enhance the performance of office buildings by reducing total energy use by up to 19% and electrical peak demand by up to 34%. Moreover, the analysis presented in this study demonstrated that roof-integrated SIS combined with precooling strategies offer significant potential to shape the energy demand profiles for grid-interactive efficient building (GEB) applications when optimized controls are deployed. [ABSTRACT FROM AUTHOR]

This paper evaluates potential energy savings associated with variable reflectivity envelope systems (VRCs) including cool roofs associated the application of coatings that can change their reflective properties over time depending on outdoor conditions and desired controlled strategies. It is well known that static cool roofs can save energy use during cooling periods but may increase energy consumption during swing or heating seasons due to lower beneficial heat gains. In the analysis, a two-step control strategy is considered to modify the properties of the cool roof coatings based on the temperature difference between internal and external roof surfaces. Using a simulation environment capable of modeling variable properties of outer surface of building envelope, a comparative analysis is carried out to evaluate the impact of VRCs on the heating and cooling energy end-uses for commercial buildings in four US climates. It is observed that VRCs can save heating energy use compared to static cool roofs for all four US climates for both commercial buildings. In particular, it is found that VRCs have the potential to reduce annual energy use in commercial buildings up to 11% compared to the static cool roofs. [ABSTRACT FROM AUTHOR]

In this paper, passive cooling strategies have been investigated to evaluate their effectiveness in reducing cooling thermal loads and air conditioning energy consumption for residential buildings in Kingdom of Saudi Arabia (KSA). Specifically, three passive cooling techniques have been evaluated including natural ventilation, downdraft evaporative cooling, and earth tube cooling. These passive cooling systems are applied to a prototypical KSA residential villa model with an improved building envelope. The analysis has been carried using detailed simulation tool for several cities representing different climate conditions throughout KSA. The impact of the passive cooling systems is evaluated on both energy consumption and electrical peak demand for residential villas with and without improved building envelope for five cities, representatives of various climate conditions in KSA. It is found that both natural ventilation and evaporative cooling provide a significant reduction in cooling energy use and electrical peak demand for the prototypical villa located in dry KSA climates such as that of Riyadh and Tabuk. Natural ventilation alone has reduced the cooling energy end-use by 22%, while the evaporative cooling system has resulted in 64% savings in cooling energy end-use. Moreover, the natural ventilation is found to have a high potential in all KSA climates, while evaporative cooling can be suitable only in hot and dry climates such as Riyadh and Tabuk. Finally, the analysis showed that natural ventilation provided the lowest electrical peak demand when applied into the improved envelope residential buildings in all five cities in KSA. [ABSTRACT FROM AUTHOR]

In this paper, the impact of heavily subsidized energy prices is evaluated for the residential building sector in Kuwait. The analysis compares the impact on both the Kuwaiti government and households of the existing building Energy Conservation Code of Practice as well as of a more stringent energy efficiency code. The stringent code is developed using an optimized life cycle cost analysis approach based on a wide range of design and operating energy efficiency measures suitable for Kuwaiti residential buildings. Specific policies are suggested and discussed to improve the energy performance of residential buildings while reduce the financial burden associated with the high energy subsidies. The analysis indicates that both households and the government would benefit from a stringent energy efficiency codes even under the current highly subsidized energy prices. Moreover, it is found that by doubling the electricity prices relative to the current levels and establishing a rebate program to cover the implementation costs of the energy efficiency measures required by a more stringent building energy efficient code, both the Kuwaiti government and the households would benefit. The energy bills would be reduced by 21% for the households while the energy subsidies incurred by the Kuwaiti government would be lowered by 28% relative to the current policy. The expenses associated with financing the energy efficiency program can be recovered within 2 years due to the income from the increase in electricity prices. [ABSTRACT FROM AUTHOR]

This paper presents a simulation environment developed to assess the energy use specific to integrated radiant heating and cooling systems. The developed simulation environment combines a transient finite difference solution for the two-dimensional model of an integrated radiant slab heating and cooling system with a resistance capacitance (RC) thermal network model for a multifloor building. The developed model of the integrated radiant system is able to account for thermal bridge effects on the energy performance of multifloor buildings. The predictions of the developed simulation environment are verified against those obtained from a detailed whole-building energy simulation tool under specific conditions. The developed simulation environment is then used to investigate the impact of thermal bridge effects on the performance of an integrated radiant heating and cooling system. Thermal bridging can affect significantly the energy performance of the integrated radiant systems by up to 8%. Several insulation configurations have been evaluated to assess the performance of the integrated radiant systems during both heating and cooling seasons for three U.S. locations: Chicago, IL; Golden, CO; and San Francisco, CA. A combination of horizontal and edge insulations is the most effective regardless of the building location. The most effective insulation configuration achieves up to 30% in heating energy savings and 35% in cooling energy savings compared with the building with no insulation. [ABSTRACT FROM AUTHOR]

This paper presents an economic analysis to estimate the optimal insulation levels required for indoor ice rinks floors. The analysis is carried out using a thermal ice rink floor system model integrated into EnergyPlus to determine the energy performance of ice rink facilities under different design and operation conditions. Moreover, an ice rink facility is first simulated using a modified version of EnergyPlus that includes the developed ice rink floor system model. The ice rink facility simulation model is then calibrated using monthly utility data. The calibrated ice rink facility simulation model is used to determine economically optimal insulation levels to be placed beneath an ice rink floor in order to reduce energy use and cost for operating ice rink arenas in selected US climates. Finally, the results of sensitivity analyses are utilized to develop a simplified calculation method to determine optimal ice rink floor insulation level as a function of both climatic and economic parameters. [ABSTRACT FROM AUTHOR]

In this paper, an overview of the Kuwaiti energy sector characteristics is presented to include its generating capacity as well as its end-use consumption over the last two decades. Moreover, a detailed analysis of the total and end-use energy consumption attributed to various building types is provided. The paper presents the specific regulations of the building energy conservation code of practice using its original version of 1983 and its revised version of 2010. The code enforcement mechanism is also outlined. Based on a detailed review of the reported literature, the potential energy savings opportunities and their cost-effectiveness for Kuwaiti buildings are discussed. Using a comprehensive review for reported analyses, the paper summarizes the economical and environmental benefits of improving energy efficiency for both new and retrofitted buildings in Kuwait. It is found that the 2010 revised version of the energy conservation code of practice can provide an additional 23% savings compared to the original version of the code developed and implemented in 1983. The implementation of an energy efficiency program to achieve the energy savings level set by 2010 energy conservation code of practice can achieve. It is found that without a gradual reduction of energy subsidies, the establishment of a mandatory energy efficiency retrofit program in Kuwaiti through implementation of basic energy efficiency measures and improved operating strategies for the existing building stock can provide significant economical and environmental benefits to Kuwait as well as the creation of significant job opportunities. [ABSTRACT FROM AUTHOR]

This paper reviews applications of multi-objective optimization approaches for design, control, and the combination of both design and control of a single element or a set of integrated building systems using the current state of the art in building energy modeling and simulation tools. The review provides background on the simulation tools and applicable data-analysis methods currently available to the building industry for both design-oriented and control-oriented optimization approaches of various energy systems. In particular, the analysis presented in this paper reviews the capabilities of these toolsets, as well as their suitability for use by industry professionals, and academic researchers. Reviewed studies show significant annual energy savings and peak load shifting potential for integrated system optimization within buildings. However, the available toolsets and frameworks are not suitable to readily perform multi-objective combined optimizations that integrate a wide range of building energy systems at industry scale. To maximize the efficiency of these systems and mitigate greenhouse gas emissions by buildings in accordance with goals set forth by nations across the world, a comprehensive and easy-to-use combined design and control-oriented optimization tool that interfaces easily with geometric architectural design tools is needed for the building simulation industry. Moreover, optimization-based building energy modeling and simulation tools that consider utility driven demand response and peak load management, would be beneficial for designing and operating a built environment that is resilient and sustainable. The case studies reviewed in this paper confirm the limited studies of energy simulation optimizations that have simultaneously analyzed design and control elements of building energy systems prior to construction. This review concludes that there is a need for the development of a more advanced user-friendly tools that integrate both design and control-oriented optimizations of building energy systems to truly transition the building energy industry forward beyond the common code compliance designs. [Display omitted] • Optimization approaches for designing and controlling building systems are reviewed. • Current optimization analyses are specific to either design or control applications. • Simultaneous Optimization of design and control are required for building systems. [ABSTRACT FROM AUTHOR]

In both the US and French building sectors, significant efforts have been undertaken to reduce the environmental impacts of new constructions notably their fossil energy consumption and related carbon emissions. This paper summarizes the results of a comparative evaluation of optimal design specifications for office buildings for selected locations in both US and France using life cycle cost analysis approach. First, an overview of both the US and French approaches for developing building energy efficiency standards and design of high performance buildings is outlined. Then, a general approach for design optimization of energy efficient office buildings is presented. Finally, selected results of the optimal analysis are discussed. In particular, it is found that optimizing life cycle costs (LCC) resulted on average in 30% in primary energy savings for office buildings located in the US and 40% savings in France. However, it is found that LCC-based optimal building designs do not meet the French energy efficiency RT 2012 standard. When accounting for typical operating conditions, photovoltaic (PV) panels are needed in order to comply with the RT 2012 required thresholds for the total primary energy consumption of the office buildings located in the French cities considered in the analysis. [ABSTRACT FROM AUTHOR]

This paper summarizes the findings from a study that has been conducted to evaluate the feasibility of using renewable energy sources such as solar and wind in combination with the conventional power system; diesel systems in an isolated island of Masirah in Oman. The study has been conducted to determine the best sustainable generation system to meet the electrical load requirements for a small community of 500 residential buildings. A series of a simulation analyses have carried out to assess different distribution technologies including photovoltaics, wind and diesel for electrical generation in combination with storage batteries. It was found that the cost of energy could be reduced by as much as 48% compared to the cost under the idealized design currently used in the Masirah Island (i.e. Diesel Driven Generators). In particular, it was found that wind turbines in combination with storage batteries have a great impact in reducing the cost of generating electrical energy for the residential community. Moreover, solar PV panels were found unattractive at the current diesel price rates but could potentially become viable if the diesel prices increase. The paper outlines an optimal design for generating electricity for the community at lowest cost while minimizing carbon emissions. Other two options are also proposed to ensure a neutral carbon emission community with a cost of energy generation still more competitive than that of the currently used diesel generation system. [ABSTRACT FROM AUTHOR]

Thermal piles or thermo-active foundations utilize heat exchangers embedded within foundation footings to heat and/or cool buildings. In this paper, the impact of thermal piles on building foundation heat transfer is investigated. In particular, a simplified analysis method is developed to estimate the annual ground-coupled foundation heat transfer when buildings are equipped with thermal piles. First, a numerical analysis of the thermal performance of thermo-active building foundations is developed and used to assess the interactions between thermal piles and slab-on-grade building foundations. The impact of various design parameters and operating conditions is evaluated including foundation pile depth, building slab width, foundation insulation configuration, and soil thermal properties. Based on the results of a series of parametric analyses, a simplified analysis method is presented to assess the impact of the thermal piles on the annual heat fluxes toward or from the building foundations. A comparative evaluation of the predictions of the simplified analysis method and those obtained from the detailed numerical analysis indicated good agreement with prediction accuracy lower than 5%. Moreover, it is found that thermal piles can affect annual building foundation heat loss/gain by up to 30% depending on foundation size and insulation level. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive analysis study is presented in order to improve the energy performance of residential buildings in the Kingdom of Saudi Arabia (KSA) through optimizing the building envelope elements. The building envelope energy conservation measures included in the study are wall insulation, roof insulation, window area, window glazing, window shading, and thermal mass. The optimization process was based on life cycle cost and energy savings. Optimum packages of energy efficiency measures for a residential building located in five climate zones in KSA have been determined for subsidized and non-subsidized energy costs. The results showed optimal energy savings of 39.5%, 33.7%, 35%, 32.7% and 22.7% for Riyadh, Jeddah, Dhahran, Tabuk and Abha, respectively, can be obtained for the subsidized energy cost case. For the non-subsidized energy cost case, the optimal energy savings were 47.3%, 41.5%, 43.19%, 41.1% and 26% for Riyadh, Jeddah, Dhahran, Tabuk and Abha, respectively. Moreover, a sensitivity cost analysis indicated that the cost of energy has more influence on optimal energy savings and life cycle costs than the initial costs of the energy efficiency measures. Finally, this study concluded that substantial savings in annual energy costs subsidies can be achieved by the KSA government if it aggressively promotes, through investments and incentives, energy efficiency programs for both existing and new buildings. [ABSTRACT FROM AUTHOR]

A transient, three-dimensional finite volume method (FVM) numerical model was developed specifically for the purpose of modeling thermo-active foundations. Validation against a physical experiment was first carried out using measurements obtained from an experimental set-up of a thermo-active foundation. The model was then used to investigate three design parameters as they apply to thermo-active foundations including tube spacing, pier depth, and flow velocity. The model was also used to investigate the thermal interaction between the thermo-active foundation and the building above it using annual simulations based on hourly weather data for Boulder, CO. In particular, it is found that thermo-active foundation can increase a building's ground-coupled slab heat loss for 57% of hours during the heating season when compared to a standard foundation. A decrease in slab heat loss or increase in slab heat gain was seen for 32% of hours during the cooling season. [ABSTRACT FROM AUTHOR]

In this paper, a value-engineering based integrated design approach is presented to improve energy efficiency of residential buildings. The design approach is based on reducing construction costs from oversizing structural systems of the building to allow investing in energy efficiency measures. The integrated design utilizes optimized selection procedure to identify set of measures that can minimize life-cycle costs while maximizing energy consumption for the buildings without exceeding budget thresholds defined by the value engineering analysis. The integrated design approach is demonstrated and applied to design a prototypical villa in Kuwait considering both homeowner and government perspectives to optimize the selection of energy efficiency measures. The results indicate that significant reductions in construction costs can be achieved due to commonly practiced oversizing of the villa's structural systems. These cost reductions are more than sufficient to cover the incremental costs of implementing optimally identified energy efficiency measures with the benefits of lowering annual energy demand by 70% compared to the current design practices in Kuwait. [ABSTRACT FROM AUTHOR]

• A new design approach is presented for selecting smart glazing for office buildings. • Optimal optical properties for smart glazing are determined for office spaces. • Impacts of daylighting are considered to identify optimal optical properties. • Optimal smart glazing can achieve over 40% annual energy savings for office spaces. In this paper, a systematic analysis is presented to determine optimal optical properties of smart glazing to minimize energy demand for perimeter office spaces. The optimization analysis considers the impacts of design and operation conditions of commercial buildings including size and orientation of windows as well as the climate characteristics of the buildings. In addition, daylighting benefits are included in the analysis of smart glazing that can transition between clear and dark states as well as intermediate tint levels. The optimization analysis results confirm that smart glazing can provide substantial energy efficiency for office buildings when coupled with daylighting controls especially for cold climates and large windows. However, the analysis indicates that specific set of optical properties for both clear and dark states are required to achieve optimal energy efficiency benefits for smart glazing when applied to office spaces. Indeed, the presented analysis allows the identification of the optimal optical properties for smart glazing depending on several influencing factors including primarily the climate as well as the window size and orientation. Moreover, the magnitude of the annual energy savings achieved by the smart glazing depends largely on the optical properties of the static glazing type used as a reference. Using code-compliant static glazing as a reference, the energy savings incurred by smart glazing range from 1.2% to 13.3% depending on daylighting controls and climatic conditions. [ABSTRACT FROM AUTHOR]

This paper evaluates the energy performance of shallow ground source heat pumps using the state-of-art whole building energy simulation tool. In particular, the paper presents a systematic and easy to implement approach to model the energy performance of shallow and helical ground heat exchangers and assess their energy efficiency benefits to heat and cool buildings. The modeling approach is based on the implementation of G-functions, generated using a validated numerical model, in a state-of-art whole building energy simulation tool. Both the numerical model and the simulation tool are applied to assess the energy performance of various shallow geothermal systems designed to meet heating and cooling needs for detached single-family homes in California. Specifically, a series of sensitivity analyses is conducted to determine the energy performance of the shallow geothermal systems in 16 locations representing all California climate zones. It is found that the suitability and the efficiency of the shallow geothermal systems vary widely and depend on several factors including their design specifications as well as the climate conditions. Compared with conventional air-to-air heat pumps, the shallow ground source heat pumps can be more energy efficient in most climate zones in California except those locations with extreme weather conditions resulting in either heating or cooling only operation. Moreover, configurations of shallow ground source heat pumps with 16 boreholes with 6.7 m (22 ft) depth are found to be cost-effective in several California climate zones. [ABSTRACT FROM AUTHOR]

Highlights: [•] Five steady-state air infiltration heat recovery or IHR models are described and compared. [•] IHR models are incorporated within whole-building simulation analysis tool. [•] IHR can reduce the thermal loads of residential buildings by 5–30%. [Copyright &y& Elsevier]

This article summarizes the results from a feasibility study to design optimal distributed generation (DG) plants for three remote communities in Alaska. All three of these towns have isolated electrical grids and currently rely on diesel fuel for 100% of their electricity and heating requirements. This assessment included an analysis of each community's electrical and thermal load, a wind and solar resource evaluation, modeling and optimization of various DG systems using HOMER software, and an economic analysis of these systems. For all three of the communities, hybrid wind-diesel systems have the potential to provide reductions in the cost of energy. However, the economic feasibility of these systems is extremely site-specific. In addition to providing possible decreases in the cost of energy, these hybrid systems can also provide significant environmental benefits, such as reductions in diesel fuel use and CO2emissions. Future research should evaluate hybrid solar/wind generators with combined-heat-and- power (CHP) diesel engines. [ABSTRACT FROM AUTHOR]

The analysis presented in this paper evaluates the impact of both short-term and long-term stay home living on the energy consumption of Saudi residential building stock. The analysis combines monitored data obtained for a sample of housing units as well as the results from a validated Saudi residential building stock model. In particular, a bottom-up building stock modeling analysis approach is used to estimate the energy impact of the 2020 stay home order imposed due to COVID-19 in most of Saudi Arabia's regions between March 15 and June 15, 2020. Moreover, the potential influences of long-term stay home patterns on the cost-benefits of energy retrofit programs are investigated targeting Saudi existing housing stocks. The analysis results indicate that when normalized to weather, the 2020 lockdown has resulted in a 16 % increase in electricity consumption compared to the 2019 level specific to the entire Saudi housing stock. Most of this increase is associated with the higher energy end-use of lighting, appliances, and air conditioning associated with increased occupancy levels during daytime hours. For a transition to long-term stay home living, the results of the analysis show that the energy consumption of the Saudi housing stock is estimated to increase by 13.5 % compared to the current occupancy pattern. Moreover, the analysis indicates that the cost-benefits for energy efficiency retrofits are enhanced with long-term stay home living. • Households on average increased their energy demand during the COVID lockdown period. • Lighting and appliances are the main contributors to the energy consumption increase. • Energy consumption would increase by 13.5 % due to a yearlong home living pattern. • Retrofitting lighting and appliances are cost-effective options to curb energy demand. • Retrofitting AC units has beneficial effects on demand regardless of the living style. [ABSTRACT FROM AUTHOR]

• The energy benefits of switchable insulation systems (SISs) are evaluated. • When combined with precooling, SISs can provide significant peak demand reduction. • Using simplified rules, SISs can reduce cooling and heating energy uses by up to 60%. • When combined with precooling, SISs can reduce both energy use and peak demand. The energy efficiency and demand response benefits of switchable insulation systems (SISs) are evaluated for commercial buildings based on a comprehensive simulation analysis. In particular, switchable insulation systems, operated using temperature-based controls, are combined with precooling strategies to maximize the benefits from passive thermal storage of commercial buildings. The performance of switchable insulation system-based precooling strategies has been evaluated considering a wide range of design and operational control parameters. The simulation results indicate that switchable insulation system can achieve significant savings in annual heating and cooling energy end-uses reaching up to 65% and 25%, respectively, when considering deploying roof-integrated switchable insulation system during weekends in addition to weekdays for the various investigated climates. Moreover, the analysis found that when combined with precooling, the energy efficiency benefits from switchable insulation system are decreased. However, switchable insulation system-based precooling results in significant savings in electrical peak demand. For instance, operating switchable insulation system with precooling results in 18% savings in electrical peak demand when the building is located in Denver, CO. It has been demonstrated that precooling and switchable insulation system can provide both energy efficiency and demand response benefits for commercial buildings located in the US and other countries with diverse climates. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the results of a series of parametric analysis to investigate the factors that affect the effectiveness of using simultaneously building thermal capacitance and ice storage system to reduce total operating costs (including energy and demand costs) while maintaining adequate occupant comfort conditions in buildings. The analysis is based on a validated model-based simulation environment and includes several parameters including the optimization cost function, base chiller size, and ice storage tank capacity, and weather conditions. It found that the combined use of building thermal mass and active thermal energy storage system can save up to 40% of the total energy costs when integrated optimal control are considered to operate commercial buildings. [Copyright &y& Elsevier]