Building Energy Use Research Articles

Investigating the Energy-Efficient Structures Using Building Energy Performance Simulations: A Case Study

The use of energy efficient structures in the local construction industry assists in promoting green building concepts, leading to economical and eco-friendly solutions for self-sustained structures. The main aim of this study was to examine and compare the energy performance of various local buildings. Detailed 3D building models (house, office, and warehouse buildings) were constructed and investigated for their cost and energy savings using building energy simulation tools (green building studio and insight). Moreover, the effects of various building materials for walls, window panels, and roof construction were explored, and a life-cycle cost analysis was performed. It was observed that the effect of the window-to-wall ratio was less severe in term of energy use in office buildings compared to normal houses due to the larger amount of space available for air circulation. Furthermore, the most efficient location for windows was found to be at the middle of the wall in comparison with the top and bottom positions. The effect of the orientation mainly depended on the symmetry of the building. More symmetric buildings, i.e., tested warehouse buildings (rectangular structure), showed an energy use difference of around 7 MJ/m2/year for a 360° orientation change. Tested house buildings exhibited an energy use difference of up to 25 MJ/m2/year. Three-pane glass windows also showed major improvements, and the total energy consumption for houses was reduced to 14%. Furthermore, wood walls showed comparable energy performance with brick walls without the use of insulation. According to US-LEED guidelines, the tested house, office, and warehouse buildings achieved 79, 89, and 88 points, respectively. The cost recovery period for house, office, and warehouse buildings was estimated to 54, 13, and 14 years, respectively, including running and maintenance costs. It can be argued that the Insight and Green Building Studio packages can assist construction stakeholders to determine the energy efficiency of the modeled building as well as to help in the selection of materials for optimized and improved design.

Influence of operating conditions on solar energy utilization efficiency of flat plate solar collector

For the last 20 years, solar collectors have been developing rapidly in the use of energy in buildings. Under experimental conditions, the solar energy utilization efficiency (SEUE) of flat plate solar collectors (FPSC) can reach more than 80%, but the engineering application of SEUE is low, and even the collector heating cannot meet the design requirements. In this paper, based on the existing thermal performance of FPSC, the influence of ambient meteorological parameters and hot water system operation parameters on SEUE is studied using experimental tests and analytical calculations. The results reflected that the collectors connected to the auxiliary heaters will affect SEUE, with series-connected systems having greater SEUE than parallel-connected systems. When the solar radiation intensity was low, the SEUE of parallel-connected systems was more likely to be negative. Under calculated conditions, when the water inlet temperature was 20, 30, 40, and 50 °C, the SEUE of the collector was 0%, and the corresponding solar radiation intensity was 113, 184, 225, and 328 W/m2, respectively. Reducing the average water temperature of the collector can reduce the heat loss in the energy conversion process between the collector and the air and increase the SEUE. When the solar radiation intensity was 500 W/m2, the collector inlet temperature decreases from 50 °C to 30 °C, and the SEUE increased from 20.9% to 38.5%. The research results can provide a parameter basis for the design of the FPSC system, especially the connection mode of collector and auxiliary heat device, and the design of system water temperature.

Experimental performance evaluation of a climate-responsive ventilated building façade

Enhancing building energy performance has become a focal point in reducing the environmental impacts of buildings to address climate change. Considering the high share of comfort-related energy use in buildings, and the importance of indoor environmental quality (IEQ), a balance between energy conservation and IEQ provision is required. Building façades are the primary boundary controlling mass and energy flow to and from buildings. Dynamic and climate-responsive façades are potential improvements to existing high-performance façades to enhance IEQ in buildings, as they change their functionality with time, in response to changing environmental loads. A multifunctional, integrated, climate-responsive, opaque, and ventilated building façade (MICRO-V) was designed to regulate the flow of heat, air, and moisture into buildings. The MICRO-V façade has a novel design to pre-condition the fresh air and regulate thermal loads in buildings on a daily and seasonal basis. The multiple components of this façade include phase change materials (PCMs), a bi-directional ventilation module and an adjustable insulation system. In this paper, the thermal performance of this façade was evaluated using long-term experimental tests. The real-scale prototype of the façade was constructed and installed in the full-scale BETOP test cell facility in Toronto, Canada. The results of different tests showed how the façade could pre-condition the fresh air acting as a decentralized ventilation module due to a high heat recovery efficiency of 81%. However, it was also shown that the significant impact of solar irradiance, which requires constant adjustment to the operation schedule of the ventilation fans in the façade.

The impact of urban vegetation morphology on urban building energy consumption during summer and winter seasons in Nanjing, China

Studies have shown that urban vegetation can be an effective strategy for reducing energy consumption in urban buildings by regulating the microclimate and shading solar radiation on building surfaces. However, an understanding of the potential energy savings of vegetation morphological planning at the urban scale is still lacking, particularly regarding the quantitative correlation between urban vegetation morphology and its impact on urban building energy use. The morphology of the metropolitan area in Nanjing, a typical hot summer/cold winter city in eastern China, was statistically analyzed, and 40 urban building-vegetation morphological prototypes were extracted. Using the proposed co-simulation technique for urban microclimate and urban building energy, the summer and winter building energy consumption of the prototypes were simulated. A quantitative analysis was conducted on the relationship between urban vegetation morphology indexes and building energy consumption. The results indicate that strategically planned urban vegetation morphology can significantly reduce urban building energy consumption. In the summer, vegetation close to the geometric center of the site, uniformly distributed and highly mixed with buildings, can significantly reduce the building energy consumption; in the winter, the opposite is true. The presented findings provide designers and planners with strategies for incorporating urban vegetation morphology design into the construction of energy efficient cities.

Estimating Space-Cooling Energy Consumption and Indoor PM2.5 Exposure across Hong Kong Using a City-Representative Housing Stock Model

High-quality data on building energy use and indoor pollution are critical to supporting government efforts to reduce carbon emissions and improve the population’s health. This study describes the development of a city-representative housing stock model used for estimating space-cooling energy use and indoor PM2.5 exposure across the Hong Kong housing stock. Archetypes representative of Hong Kong dwellings were developed based on geographically-referenced housing databases. Simulations of unique combinations of archetype, occupation, and environment were run using EnergyPlus, estimating the annual space-cooling energy consumption and annual average PM2.5 exposure concentrations under both non-retrofit and retrofit scenarios. Results show that modern village houses and top-floor flats in high-rise residential buildings, on average, used 19% more space-cooling energy than other archetypes. Dwellings in urban areas had lower exposure to outdoor-sourced PM2.5 and higher exposure to indoor-sourced PM2.5 compared to those in rural areas. The percentage decrease in space-cooling energy consumption caused by energy efficiency retrofits, including external wall insulation, low-e windows, and airtightening, varied significantly based on archetype. The implementation of external wall insulation in the housing stock led to an average decrease of 3.5% in indoor PM2.5 exposure, whilst airtightening and low-e windows resulted in 7.9% and 0.2% average increases in exposure, respectively.

Temporal Segmentation for the Estimation and Benchmarking of Heating and Cooling Energy in Commercial Buildings in Seoul, South Korea

The building sector is responsible for more than one-third of total global energy consumption; hence, increasingly efficient energy use in this sector will contribute to achieving carbon neutrality. Most existing building-energy-benchmarking methods evaluate building energy performance based on total energy use intensity; however, energy usage in buildings varies with the seasons, and as such, this approach renders the evaluation of cooling and heating energy difficult. In this study, an information gain-based temporal segmentation (IGTS) method was used to identify the seasonal transition times based on patterns of hourly weather and corresponding building energy use. Twelve commercial buildings were considered for the study and four seasons were identified using IGTS; base-load, cooling energy, and heating energy data were gathered. For the 12 buildings, the estimated and measured heating and cooling energy during the summer and winter periods showed a linear relationship (R2 = 0.976), and the average of those differences was 9.07 kWh/m2. In addition, differences in the benchmarking results based on these energies were marginal. The results indicated that the IGTS approach can be effectively used for determining the actual heating and cooling energy consumption in buildings, as well as for energy benchmarking. This can, in turn, improve building energy use, with positive implications for achieving carbon neutrality.

Numerical investigation of serpentine earth-to-air heat exchanger for passive building heating systems by recovery criteria

This paper investigates the performance of the earth-to-air heat exchanger (EAHE) system in the winter for Mashhad. A three-dimensional model of novel serpentine geometry for use in the passive building heating system is proposed. A new and visual method of recovery analysis is performed for regaining the soil energy by considering a period of time to stop the system. The thermal performance of the system is evaluated by analyzing the derating factor, knee point, and heat transfer evaluation criteria for a serpentine model of EAHE. Results demonstrate that the thermal conductivity of the soil and the duration of EAHE's continuous operation has a significant impact on its transient thermal performance. By employing soil thermal conductivities of 1, 2, and 4 W/m.K, the temperature of the outlet reduced 21 %, 12 %, and 6 %, respectively. Finally, the results indicate the highly better performance of the system in soils with higher thermal conductivity during long-term. The temperature of the outlet air in the 24-hours operation mode decreases compared with the 1-hour operation mode. A new method of recovery analysis is performed for regaining soil energy. This paper aims to develop a new model of EAHE system to maximize the energy use of buildings.

Large-scale statistical analysis and modelling of real and regulatory total energy use in existing single-family houses in Flanders

ABSTRACT Large-scale statistical studies on the gap between the real and regulatory energy use in residential buildings in Europe have shown that the regulatory calculation overestimated the real energy use, inflated true energy savings and undermined national energy policy making. Using data from 122,680 Flemish existing single-family houses, this research builds further on existing studies by contributing results for Flanders. The study also examines to what extent available aggregated variables explain the real annual total building energy use using statistical linear models and addresses the problem of multicollinearity and the importance of bootstrapped confidence intervals for model quality control. The overestimation of the real total energy use (and potential energy savings) by the Flemish regulatory method is exceedingly large compared to studies from other EU countries. The Flemish labels prove very poor indicators of the real energy use. Statistical linear models explain up to 46.6% of all variability and indicate that a significant extent of multicollinearity had to be corrected. Half of the variability has been left unexplained and has to be attributed to variables that were not available and the fact that the data were insufficiently accurate. Future analysis will explore whether more complex models identify more evidence.

Policy instruments for energy-efficient renovations at district level

IEA EBC Annex 75 aims to investigate, amongst other policy for reducing carbon emissions and energy use in buildings at district level, combining both energy efficiency measures and renewable energy measures. Particularly policy instruments deployed at the local level targeting owners and investors could increase residential building renovation and renewable energy systems to a district scale. A desk and empirical research using 38 expert interviews from 8 European countries was used to investigate the use and development of various types of policy instruments, including regulations, incentives, communication and facilitating instruments. The research confirms interest of frontrunners to use or develop specific policy instruments further, such as enforcement of energy standards and inspections, financial incentives for district stakeholders and for groups of homeowners, renovation services and energy desks, digital communication and network meetings in districts. It also finds that low relative advantage for some stakeholders, lack of good examples, an incompatible legal or national framework and high complexity are serious risks that can further hinder adoption of energy efficiency and renewable energy systems in districts. Renovations at district scale including energy efficiency and renewable energy can benefit from adapted or improved regulations, incentives, communication and facilitation to better support renovations at district scale including energy efficiency and renewable energy systems.

Cooling-related energy uses and adaptive behaviors in high-rise residential buildings in the subtropical climate: A case study in Hong Kong

The growing urban population has accelerated the development of high-density cities and high-rise buildings. Meanwhile, cooling energy use is expected to increase, especially in (sub)tropical areas, due to climate change, the rising ownership rate of air-conditioners, and working-from-home during the Covid-19 pandemic. Thus, reducing cooling energy use in high-rise residential buildings is essential for achieving net zero by 2050. However, limited empirical studies are available on cooling energy use of high-rise residential buildings. This study aims to investigate cooling-related energy uses and adaptive behaviors in high-rise residential buildings, particularly, the vertical variation of energy uses and relevant factors. A high-rise student residence in Hong Kong was examined. Four-year electricity meter records in 716 rooms were analyzed to check the statistical significance of the vertical cooling electricity use difference. Long-term in-situ monitoring was applied to obtain environmental and behavioral data with twenty-one residents. A validated building energy model was used to explain the vertical cooling energy use difference. Results show that the annual cooling electricity use declined averagely by 0.8% per floor, which could be mainly explained by the environmental and behavioral factors that changed with building height. The findings will facilitate decision-making on energy efficiency in high-rise residential buildings. • The monitored annual cooling electricity use declined vertically by 0.8% per floor. • The measured outdoor temperature lapse rate ranged from 1.5 to 11.7 K/km. • Fewer extremely hot hours were experienced by residents on higher floors in summer. • Residents on higher floors opened windows more often during the cooling season. • Behavior modes moderated the impact of environmental factors on cooling energy use.

Impact of a Warming Climate on Hospital Energy Use and Decarbonization: An Australian Building Simulation Study

The high energy use of hospitals and healthcare facilities globally contributes to greenhouse gas emissions. At the same time, a large percentage of this energy use is attributed to space heating, cooling and ventilation, and is hence correlated to the climate. While the energy performance of Australian hospitals at the design stage is evaluated using historical weather data, the impact of the warming climate on Australian hospitals into the future remains unknown. The research question addressed is: What is the impact of future climates on the energy use of Australian hospitals built with the current design conditions? Two archetype hospital models were developed (a small single-story healthcare facility and a large multi-story hospital). DesignBuilder was used to simulate the performance of these models in 10 locations, ranging from the tropics to cool temperate regions in Australia. Current (1990–2015) and future climate files (2030, 2050, 2070 and 2090) were used. The results show that with the warming climate, the heating demand decreased, while the cooling demand increased for both hospital models for all sites. Cooling dominated climates, such as Darwin and Brisbane, were significantly impacted by the changing climates due to a substantial increase in cooling energy use. Heating based climates, such as Hobart and Canberra, resulted in an overall small reduction in total building energy use. In addition, the single-story facility was more impacted by the change in climate (in terms of energy use intensity) than the multi-story facility. The study highlights the importance of future climate files in building simulation and decarbonization planning.

Investigating the performance of machine learning models combined with different feature selection methods to estimate the energy consumption of buildings

Machine learning is considered a promising method for developing building energy-benchmarking models. However, the high dimensionality of building energy datasets can reduce model accuracy and generalization but increase the computational cost. Meanwhile, the poor interpretability of machine learning models limits the understanding of insights and, in turn, hinders policymaking. Therefore, the first objective of this study was to investigate the benefits of feature selection on the performance of machine learning-based energy usage models. Three typical feature selection methods (filter, wrapper, and embedded) were selected, and the effect of each method was evaluated based on three tree-ensemble learning algorithms. Another objective was to analyze the interpretability of the machine learning model using the Shapley additive explanation method. The results were obtained using a city-scale energy consumption dataset consisting of 478 healthcare buildings in Chongqing, China. It was found that the wrapper method generally improved the accuracy of the machine learning models compared to that of the other two methods. In addition, the model developed using extreme gradient boosting combined with the wrapper method achieved the best accuracy. Moreover, the model interpretability analysis demonstrated important features and revealed how these features influence energy use for individual buildings.

Mandatory or voluntary approaches to green roof implementation: a comparative study among some global cities

Green roofs can deliver multiple environmental and social benefits by reducing the urban heat island effect, reducing building energy use and greenhouse gas emissions, improving air quality, providing habitat for biodiversity and access to the biophilia effect. Green roofs provide these benefits to differing degrees in different climate zones globally. Despite known benefits, uptake of green roofs has been slow. Different cities, globally, adopt various policies and programmes to increase their green roofs; the question is which approach is best? This research used an in-depth review, site visits and qualitative methods, to determine whether mandatory or voluntary approaches produced greater uptake. Green roof policies and practices from selected global cities, London, Toronto, Singapore, Rotterdam and Stockholm, Sydney and Melbourne were examined. Singapore’s voluntary approach led to the greater uptake of green roofs. The mandatory approach taken by Toronto, with financial grants provided meaningful outcomes. London and Rotterdam implemented useful voluntary programmes, and Stockholm required more time to evaluate the effectiveness of its voluntary approaches in increasing green roofs. A voluntary approach for retrofit and a mandatory approach for new build developments are suggested as recommendations for Australian cities. Given the increases in green roofs internationally, similar increases can occur in Melbourne and Sydney in Australia, and these findings may be transferable to other global cities investigating different approaches to the increased adoption of retrofitted green roofs.

Novel metal-organic framework (MOF) based phase change material composite and its impact on building energy consumption

Space cooling (including dehumidification) is the fastest-growing use of energy in buildings. Materials that have high thermal and moisture buffer capacities can passively mitigate indoor temperature and humidity fluctuations, thus reducing the demand for air conditioning and improving building energy efficiency. Here, we report a novel metal–organic framework (MOF) based microencapsulated phase change material (MPCM) composite. The new MOF-MPCM is a dual-function material that can simultaneously absorb/release heat and moisture from surrounding air and passively regulate the indoor hygrothermal environment. MIL-160(Al), a novel green and biomass-derived MOF material with excellent sorption performance and large-scale production potential, was prepared for moisture buffering. MPCM containing an n-octadecane core and polymethylmetracrylate shells were synthesized for temperature control. Physicochemical and hygrothermal properties of MOF-MPCM composite were characterized by SEM, XRD, DVS, DSC, and TGA techniques, etc. A HAM-Enthalpy model was developed to study the impact of MOF-MPCM on the indoor hygrothermal environment and building energy performance in different climates. Seven cities around the world (i.e., Singapore, Hong Kong, Phoenix, Denver, Barcelona, London, and Beijing) were selected as the representative climate locations. The simulation indicates that MOF-MPCM can effectively mitigate indoor temperature and moisture variations and cut down the energy consumption of air conditioning systems, especially in hot-dry, temperate, and continental climates with large diurnal air temperature and humidity variations. The maximum energy-saving potential could reach 35.2% in Phoenix. The study provides guidance for the further improvement and application of dual-function MOF-MPCM composite in different climates.

Use of Polar Heliostats to Improve Levels of Natural Lighting inside Buildings with Little Access to Sunlight.

The growing need to increase environmental and energy sustainability in buildings (housing, offices, warehouses, etc.) requires the use of solar radiation as a renewable source of energy that can help to lower carbon footprint, making buildings more efficient and thereby contributing to a more sustainable planet, while enhancing the health and wellbeing of its occupants. One of the technologies deployed in the use of solar energy in buildings is heliostats. In this context, this paper presents an analysis of the performance of a heliostat illuminator to improve illumination in a classroom at the Campus of Rabanales of the University of Cordoba (Spain). A design of a system in charge of monitoring and measuring daylighting variables using Arduino hardware technology and free software is shown. This equipment develops the communications, programming and collection of lighting data. In parallel, installation of an artificial lighting system complementary to the natural lighting system is implemented. Finally, an analysis of the impact of the proposed solution on the improvement of energy efficiency is presented. Specifically, it is estimated that up to 64% of savings in artificial lighting can be achieved in spaces with heliostatic illuminators compared to those without them.

An Assessment of External Wall Retrofitting Strategies Using GRC Materials in Hot Desert Regions

Due to urbanization, population growth, and the consequences of climate change, the usage of energy for cooling has increased considerably in recent years. Passive climate measures, on the other hand, could alleviate the situation by reducing energy use in buildings. This study examined the environmental and financial benefits of utilizing glass fiber-reinforced cement in the external walls of a communal social hub building in New Aswan city, taken an example of the hot desert region. Utilizing Design Builder software, the effect of various outside wall alternatives on cooling energy consumption was explored and analyzed. In addition, a cost–benefit analysis utilizing the simple payback period was conducted to aid decision-makers in selecting the most suitable exterior wall materials for public buildings in hot desert regions. Using cement plaster, cement brick, glass wool, and glass fiber-reinforced cement as an outside wall resulted in a significant improvement rate, according to the data. Compared to a typical wall (cement plaster, cement brick, and cement plaster), it can save up to 41% of energy. In addition, it has the lowest simple payback period value when compared to other examined solutions (10.86 years). In general, the results indicate that glass fiber-reinforced cement walls embedded in thermal insulation materials and incorporated into cement brick walls are more energy-efficient in terms of necessary cooling energy and economic viability.

Exploring Factors Influencing Renewable Energy Diffusion in Commercial Buildings in Nigeria: A Grounded Theory Approach

The adoption and integration of renewable energy technologies (RETs) into buildings is key to making the necessary transition to low-carbon and resilient built environments. However, such technologies have struggled to gain a firm foothold in countries within the sub-Saharan African (SSA) region. This is particularly the case in Nigeria, which suffers from severe energy poverty, despite its significant RE and conventional energy potential. In Nigeria, a significant proportion of the energy demand for offices is provided by self-powered off-grid fossil-fuel generators. The country is also one of the primary settings for increased construction activity. This, combined with its susceptibility to the effects of climate change, presents significant concerns relating to the resilience of its built environment. However, there has not yet been a comprehensive empirical study addressing this, as previous studies have been limited in their insight and perspectives. This study adopted a grounded theory method (GTM) aligned with Charmaz’s approach, to gain in-depth participant-driven insights into factors influencing sustainable energy use in commercial buildings, focusing on solar photovoltaics (PVs). This led to the development of a theory of the sustainability transition process of construction professionals (CPs). It provides relevant, reliable, and relatable points of reference that would be beneficial to policymakers in developing plans for actionable interventions for PV and broader sustainable measures toward green energy transition. Furthermore, it highlights the value of employing GTMs in construction management research beyond the developing context. This paper contributes theoretically, empirically, and methodologically to facilitate a better understanding of the situations (context) grounded in empirical data.

ASSESSING LAND SURFACE TEMPERATURE IN URBAN AREAS USING OPEN-SOURCE GEOSPATIAL TOOLS

Abstract. Land surface temperature (LST) in urban areas can be traditionally observed by thermal remote sensors. The increasing availability of 3D city models provides an alternative approach based on geospatial modeling. Using solar radiation tools and scripting in GRASS GIS, we have developed a physically-based LST model that can be used to estimate LST in urban areas represented by vector 3D city models. It uses standard input parameters such as solar irradiance, albedo or convection heat transfer coefficient for urban surfaces. The solar irradiance is estimated using the v.sun solar radiation add-on module in GRASS GIS. The LST values are calculated using map algebra operations using a Python script. The suggested methodology was applied to the study area in the city of Košice, Slovakia. Results indicate that urban morphology has a strong impact on spatial distribution of LST during the daylight hours. The accurate parameterization of urban surfaces can increase the accuracy of the model that can be used for urban planning, optimization of energy use in buildings or mitigation of urban heat island effects.

Relationships between building characteristics, urban form and building energy use in different local climate zone contexts: An empirical study in Seoul

The influence of building context on the relationship between building and its energy use has been attracting attention. However, most studies simply defined building contextual areas as within an arbitrary distance and measured their form with commonly used planning and design indicators. Such an approach often suffers from the lack of justifications on the context area size, confounding effects between indicators, and weak connection between those indicators and urban energy policy. This study uses the local climate zone (LCZ) as buildings’ thermal context area, and investigates the relationship between building characteristics, urban form, and residential building energy use in different LCZ contexts in Seoul, South Korea. A linear mixed model is employed to examine this relationship. Results show that LCZs as different contextual forms not only significantly influence building energy, but also impact the effects of building characteristics on building energy use. The results are further compared to another model with zoning classes, a widely used development control tool in planning, as contextual areas, and find the latter has much smaller influences. The findings suggest a promising application of the LCZ framework in understanding the form-energy relationship in complex urban environments and in energy-oriented urban planning.

Integrating building energy simulation with a machine learning algorithm for evaluating indoor living walls’ impacts on cooling energy use in commercial buildings

The environmental challenges of climate change increase the energy usage and peak demands of buildings. Most extant studies of greenery systems focus on exterior applications such as green façades and roofs, which indirectly affect the indoor environment. Few studies have focused on quantifying the influence of indoor greenery systems on building energy consumption. The cooling effects of indoor greenery systems such as living walls are largely accounted for by the evapotranspiration (ET) process, in which water is transferred to the ambient environment through the evaporation from and transpiration of plants. Current building energy simulation software such as EnergyPlus does not have a module for modeling indoor greenery systems.In this study, an ET model was created using a machine learning algorithm—Gaussian Mixture Regression (GMR) based on experimental data. An indoor living wall model quantifying sensible and latent loads from the ET process was integrated with the energy simulation software—EnergyPlus through the Python plugin feature. The U.S. Department of Energy (DOE) medium-sized office building reference model was modified and used in this study to evaluate indoor living walls’ impacts on cooling energy use. A parametric study on leaf to floor area ratios (LFAR), orientations, distances from windows, and climates was conducted to evaluate the influence of each factor on indoor living walls’ performance. Cooling effects of indoor living walls were evaluated in three ASHRAE climates with high cooling demands. Observable cooling energy savings were obtained for the south, east, and west perimeter zones while savings for the north perimeter zone was negligible in all three climates. With the consideration of extra electricity use from direct expansion (DX) dehumidification devices for humidity control, the maximum cooling electricity savings in Los Angeles, CA are 25.1 % when LFAR = 1.5 for the south perimeter zone, 14.4 % when LFAR = 0.5 for the east perimeter zone, 0.3 % when LFAR = 0.3 for the north perimeter zone, and 14.5 % when LFAR = 0.5 for the west perimeter zone on the design day.