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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]

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]

This paper outlines the benefits of large scale energy efficiency programs for new and existing buildings in Oman. In particular, an energy productivity analysis for these programs is carried out to encompass their overall impact for Oman’s economy. Over 75% of the total electricity consumed in Oman is attributed to buildings with almost 50% is due to household. First, a comprehensive optimization analysis is carried out using whole-building energy simulation to determine the best energy efficiency measures suitable to improve the energy performance of buildings in Oman. The economic and environmental benefits of a wide range of energy efficiency technologies are then evaluated. In particular, the impacts of different energy efficiency retrofit levels of existing buildings are the estimated on the energy productivity indicators for the building sector of Oman. The results of the analysis indicate that the implementation of a government funded large scale energy retrofit program for the existing residential building stock is highly cost-effective. In particular, it is found that a basic large scale energy efficiency retrofit program can provide a reduction of 957 GWh in annual electricity consumption and 214 MW in peak demand as well as over 660 k-ton per year in carbon emissions. [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 performance of PV-integrated dynamic overhangs is evaluated when applied to windows for a prototypical home located in various US climates. The analysis includes both the shading effects on heating and cooling thermal loads as well as the electricity generated by the PV arrays. The dynamic overhangs can slide and rotate to maximize both their shading impacts and their PV generation levels. Various control strategies are investigated to operate the PV-integrated dynamic overhangs to minimize annual net energy demand for US home. A series of analyses are conducted to assess the impact of the design features of the overhangs, operation strategies, as well as the climatic conditions. The series of analyses indicate that the PV-integrated dynamic overhangs can provide significant benefits both for managing the shading effects and for generating electricity. Specifically, PV-integrated dynamic overhangs can achieve 57.8% savings in total annual energy demand for a home located in San Francisco, CA, due to the window shading effects of the overhangs and the PV electricity generation. Moreover, several design features can be optimized to enhance the performance of PV-integrated dynamic overhangs such as their geometry as well as the size and the orientation of the windows. • A novel rotating and sliding overhang is evaluated for US residential buildings. • Hourly, daily, and monthly settings are considered for the dynamic overhangs. • Optimal control strategies are identified to operate the dynamic overhangs. • The proposed dynamic overhangs can reduce by up to 50% the energy use for homes. [ABSTRACT FROM AUTHOR]

• A novel sliding/rotating overhangs is presented and evaluated for US residential buildings. • Both energy efficiency and environmental impacts of the dynamic overhangs are evaluated. • PV-integrated control strategies are considered to operate the dynamic overhangs. • The PV-integrated dynamic overhangs can result in net-zero building designs. The paper evaluates the benefits of integrating PV arrays with sliding and rotating overhangs to both generate electricity and reduce heating and cooling thermal loads for housing units in US apartment buildings. Optimal controls to operate the sliding-rotating overhangs are considered to minimize annual net energy demands with and without the integrated PV arrays. A series of sensitivity analyses is performed to assess the impact of design and operating conditions on the energy performance as well as the environmental impacts of the sliding-rotating overhangs. The analysis results clearly indicate that when integrated with PV modules, sliding overhangs can significantly reduce the energy demand for US housing units especially when they are set at the optimal angles specific to the building location to maximize their electricity generation and solar shading effects. Specifically, it is found that sliding overhangs can not only reduce energy demand but also can achieve net-zero energy conditions for US apartment units with large windows and located in mild climates even when monthly adjustments are applied to operate the shading systems. For instance, 9.2% of the total energy use of an apartment housing unit located in Boulder, CO, can be reduced using the sliding-rotating overhang with no-PV. In San Francisco, CA, more than 100% of the apartment housing unit energy demand can be avoided using PV-integrated sliding-rotating overhangs. To minimize design and operation complexities, it is recommended to consider sliding-only overhangs set at the latitude of the location to reduce both heating and cooling demand as well as increase PV array output. For instance, it is found that sliding overhang set at the latitude angle can be sufficient to achieve net-zero status and even a carbon-neutral operation for an apartment housing unit located in San Francisco, CA, even when adjusted on a monthly basis. [ABSTRACT FROM AUTHOR]

In this paper, a systematic review analysis of fully enforced stay at home orders and government lockdowns is presented. The main goal of the analysis is to identify the impacts of stay home living patterns on energy consumption of residential buildings. Specifically, metered data collected from various reported sources are reviewed and analyzed to assess the changes in overall electricity demand for various countries and US states. Weather adjusted time series data of electricity demand before and after COVID-19 lockdowns are used to determine the magnitude of changes in electricity demand and residential energy use patterns. The analysis results indicate that while overall electricity demand is lower because of lockdowns that impact commercial buildings and manufacturing sectors, the energy consumption for the housing sector has increased by as much as 30% during the full 2020 lockdown period. Analysis of reported end-use data indicates that most of the increase in household energy demand is due to higher occupancy patterns during daytime hours, resulting in increased use of energy intensive systems such as heating, air conditioning, lighting, and appliances. Several energy efficiency and renewable energy solutions are presented to cost-effectively mitigate the increase in energy demands due to extended stayhome living patterns. • The impacts of lockdowns and stay home orders due to COVID-19 on global electricity demand are discussed. • Data for specific US regions and residential building stocks are obtained and analyzed. • Specific sets of recommendations to improve the indoor air quality and energy efficiency for existing homes are outlined. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential energy use and peak demand savings associated with optimal controls of switchable transparent insulation systems (STIS) applied to smart windows for US residential buildings. The optimal controls are developed based on Genetic Algorithm (GA) to identify the automatic settings of the dynamic shades. First, switchable insulation systems and their operation mechanisms are briefly described when combined with smart windows. Then, the GA-based optimization approach is outlined to operate switchable insulation systems applied to windows for a prototypical US residential building. The optimized controls are implemented to reduce heating and cooling energy end-uses for a house located four US locations, during three representative days of swing, summer, and winter seasons. The performance of optimal controller is compared to that obtained using simplified rule-based control sets to operate the dynamic insulation systems. The analysis results indicate that optimized controls of STISs can save up to 81.8% in daily thermal loads compared to the simplified rule-set especially when dwellings are located in hot climates such as that of Phoenix, AZ. Moreover, optimally controlled STISs can reduce electrical peak demand by up to 49.8% compared to the simplified rule-set, indicating significant energy efficiency and demand response potentials of the SIS technology when applied to US residential buildings. [ABSTRACT FROM AUTHOR]

Controlled Environment Agriculture (CEA) applications, such as vertical farms and plant factories, have the potential to shift food production to be close to urban centers helping meet demands of large populations as well as achieving global climate goals. Growing crops in controlled environments has proven to be feasible for several applications, however, most involve energy intensive processes. The review analysis presented in this paper seeks to overview current CEA practices as well as potential energy efficiency technologies that can enhance the sustainability and the profitability of the indoor farming industry. Specifically, the paper reviews various CEA techniques, optimal indoor growing environments, successful case studies, and recommended energy systems research. The review analysis indicates that changes to a facility's envelope, HVAC, lighting, and incorporation of distributed generation technology can reduce consumption of electricity up to 75% in several CEA case studies. Future research into controls, dehumidification, lighting, and crop variety are vital for a wider adoption of CEA applications. • Controlled environment agriculture or CEA can help in meeting the increasing global food needs. • This review evaluates the limited studies to enhance the energy performance of CEA facilities. • Research needs to design and operate energy efficient CEA facilities are discussed. [ABSTRACT FROM AUTHOR]

• The types and benefits of occupancy-based temperature controls for residential buildings are reviewed. • A systematic analysis approach is performed for a wide range of temperature controls specific to Saudi households. • Smart occupancy-controls can save on average 36% of annual energy consumption for a typical KSA household. The paper describes the potential energy efficiency and demand response benefits of occupancy-based temperature controls applicable to residential buildings for the Kingdom of Saudi Arabia (KSA). Specifically, various spatial and temporal temperature controls are evaluated to account for spatial and temporal occupancy patterns associated to typical living styles of Saudi households. The analysis results show that the benefits of occupancy-based temperature settings can be significant when at least two thermal zones controlled by different thermostats exist within the same housing unit. Specifically, occupancy-based thermostat settings can save up to 38.7% of total annual electricity consumption for a dwelling located in Riyadh. Moreover, when the indoor temperature settings are adjusted spatially, a reduction of up to 34.7% in peak demand can result for most KSA regions. Using a bottom-up analysis approach, it is found that when scaling up to the entire KSA housing stock, the adoption of smart thermostats has the potential to reduce annual electricity use by 48 TWh/year or over 30% of the national residential sector energy consumption. [ABSTRACT FROM AUTHOR]

This paper describes the development of a residential building stock model for the Kingdom of Saudi Arabia using an engineering bottom-up approach. The model is suitable for evaluating the impact of any energy efficiency or demand-side management program targeted for the residential building sector. The model accounts for the make-up and the characteristics of the existing Saudi housing stock using 54 prototypes representing KSA residential buildings including their type, vintage, and location. The model relies on a detailed building simulation tool to predict hourly energy consumption. The model predictions have been verified against actual reported data for energy consumption levels associated to main four Saudi regions. As an application of the building stock model, the benefits of a series of energy retrofit measures and programs are evaluated for both households and Saudi government. The analysis results clearly indicate that large-scale implementation of retrofit programs for existing KSA housing stock is cost-effective and has a wide range of economic, environmental, and social benefits. In particular, a full and targeted implementation of optimal retrofit programs can reduce the annual electricity consumption of the KSA residential sector by 50% in addition to similar decreases in carbon emissions and electricity generation capacities. The analysis results clearly indicate that for the retrofit program to be effective, the energy efficiency measures need to be tailored to the housing type, vintage, and location. Optimal sets of retrofit measures have been identified for the various categories of KSA housing stock as part of the based analysis carried out in this study. • A building stock model t represent energy performance of KSA existing housing units is developed. • The building stock model has been applied to evaluate the benefits of energy retrofit programs. • Over half of energy consumption can be saved through targeted energy retrofit programs of KSA housing stock. [ABSTRACT FROM AUTHOR]