Building Energy Demand Research Articles

Extreme Heat in the Caribbean: Impacts on Wellbeing and Buildings Energy Infrastructure—The 2023 Summer Case

Abstract The summer of 2023 in Puerto Rico and US Virgin Islands witnessed an unprecedented surge in extreme heat, surpassing historical norms prompting the analysis of the broader implications for the Caribbean region. This study presents the initial analysis of this remarkable heatwave, the broader context of global climate change, and its potential impacts on people's well-being and energy demand. Historical and 2023 summer daily maximum heat index (HI) are calculated using local stations and regional gridded data. The results show that summer 2023 exhibited a significant departure from the historical climate. For about 70% of summer days, HI values above 100 °F were recorded. It was found that the extreme summer is part of a broader regional pattern. The summer of 2023 recorded higher sea surface temperatures with anomalies above 2.07 °C and the weakening of the Azores High resulting in reduced wind speed in the region. This diminished the cooling effect associated with cooler maritime air aiding the stagnation of air masses over the region. The analysis sets a threshold of HI of 103 °F to assess human exposure. A significant portion of the region's population, especially in urban areas, was exposed to HI above this threshold. Concurrently, the intense heat led to increased energy demands, with about a 25% increase in peak energy demand in buildings. Per capita consumption exceeded 200 kWh/month for cooling and human comfort and anomalies adding around 15 kWh/month. The study is a step forward in developing adaptive strategies to safeguard vulnerable communities due to global warming-induced extreme events.

Impact of glazing type, window-to-wall ratio, and orientation on building energy savings quality: A parametric analysis in Algerian climatic conditions

Opaque surfaces, such as walls, are well-known for their significant contributions to heat loss and energy demands in buildings. However, transparent surfaces, such as windows, are equally critical to a building's energy performance. The design of these transparent elements requires a careful balance of various factors, including window size, glazing type, and orientation, each of which plays a pivotal role in enhancing energy efficiency. This study explores the optimization of these factors during the design process, emphasizing their impact on the overall building performance.This research evaluates the potential energy savings in a building archetype representative of the Algerian building stock. Utilizing the EnergyPlus simulation tool, the study conducted 1152 simulations on a baseline model to generate a comprehensive dataset detailing the building's energy demands for heating and cooling across various climatic conditions. The findings reveal that annual energy savings for this type of housing essentially depend on its climatic zone and can range from 6.92 % for a hot semi-arid climate (Bsh) to reach a maximum of 9.75 % in a cold semi-arid climate (Bsk), a window-to-wall ratio (WWR) of 60 % typically maximizes energy efficiency, low-E glazing proved most effective in most cases, although regions needing significant solar protection favored alternative glazing types. Optimal window orientation generally trends Eastward, except in regions where southern exposure better supports solar management, highlighting the complex relationship between architectural design choices and energy efficiency.

4E analysis of a new multi-generation geothermal system based on Allam cycle for providing energy demand of a sample residential building

4E analysis of a new multi-generation geothermal system based on Allam cycle for providing energy demand of a sample residential building

Thermos-economic performance of a novel CCHP system driven by low-grade thermal energy based on CO2 and organic fluids

A novel combined cooling, heating and power (CCHP) system is proposed based on mixture consisting of CO2 and organic fluids to meet the seasonal energy demand in buildings. Thermodynamic model was constructed based on the laws of thermodynamics, and seasonal operation modes were also established. Techno-economic performance was analyzed and the performance of mixture consisting of CO2 and organic fluids compared with CO2 and pure organic fluids. Results show that the temperature of the turbine inlet in trans-critical power cycle should be 10 °C lower than the heat source temperature, with the turbine inlet pressure being approximately 1.4 times as large as critical pressure. Turbine inlet temperature is negatively correlated to the payback period and levelized energy cost while turbine inlet pressure is positively correlated to the system economic performance. The carbon dioxide content is negatively correlated to net power output, thermal efficiency and exergy efficiency, while coefficient of performance will hit the bottom with the carbon dioxide content, except CO2/Propane. For the carbon dioxide content is between 5 % and 10 %, the system overall performance is also close to optimal value. In general, CO2/R134a (0.10/0.90) and CO2/R1234ze(E) (0.10/0.90) is recommendable.

Impact of urban form on building energy consumption in different climate zones of China

Despite numerous studies on the relationship between urban form and building energy demand, understanding the impact mechanisms of urban form is still insufficient. Here, we identified the direct and indirect influences of urban form on building energy demand. The direct influence includes the blocking of solar radiation. The indirect influence is exerted through the urban heat island (UHI) effect as different urban forms produce different UHI intensities. The UHI effect was calculated using the urban weather generator (UWG) tool. Then, the analysis of the direct and indirect influences on the building energy demand was carried out using building energy modeling (BEM) based on the output of UWG. Five cities in different building climate zones in China were investigated, and the corresponding direct and indirect influences were quantified based on the proposed UWG + BEM framework. Results show that warmer temperatures lead to an average increase in space cooling of 16 %–46 % while reduced space heating of 8 %–17 %. The shading of surrounding buildings allows an increase of 7 %–36 % in space heating and a decrease of 14 %–48 % in space cooling compared to that of an isolated building. In addition, direct influence due to shading is prominent in Shuangyashan, Xuzhou, and Fuzhou, accounting for 50 %, 80 %, and 57 % of variations in building energy consumption.

State-of-the-Art Review: Effects of Using Cool Building Cladding Materials on Roofs

Cool roofs are roofing systems designed to reflect significant solar radiation, reducing heat absorption and subsequent cooling energy demands in buildings. This paper provides a comprehensive review of cool roof technologies, covering performance standards, material options, energy-saving potential, and hygrothermal considerations. The review examines provisions in current codes and standards, which specify minimum requirements for solar reflectance, thermal emittance, and solar reflectance index (SRI) values. These criteria often vary based on factors like roof slope, climate zone, and building type. Different cool roof materials are explored, including reflective paints and coatings that can be applied to existing roofs as cost-effective solutions. Several studies have demonstrated the energy performance benefits of cool roofs, showing significant reductions in cooling loads, indoor air temperatures, peak cooling demand, and overall cooling energy consumption compared to traditional roofs. However, hygrothermal performance must be evaluated, especially in cold climates, to optimize insulation levels and avoid moisture accumulation risks, as reduced heat absorption can alter moisture migration patterns within the building envelope. While cool roofs provide substantial energy savings in hot climates, further research is needed to validate modeling approaches against real-world studies, investigate the impact of seasonality and green spaces on cool roof efficacy and urban heat island mitigation, and explore energy-saving potential, moisture control, and condensation risks in cold and humid environments.

Optimal design of renewable energy communities (RECs) in Italy: Influence of composition, market signals, buildings, location, and incentives

In Europe the concept of Renewable Energy Communities (RECs) renovates the need for decentralized energy generation among citizens and companies. The corresponding legal framework enables the creation of business models that shall support environmental, economic and social benefits, provided that adequate planning accounting for the local conditions is executed. The present work is focused on a thermal-electric co-simulation approach for the analysis of the energy exchanges within an Italian REC, aimed at sizing photovoltaics (PV) and energy storage systems. EnergyPlus is used to estimate the thermal and electric needs of the community, whose results are fed into the “EnergyCommunity.jl” tool for the design of the local power system. The influence of REC composition (prosumers/consumers), the building energy demands for heating, cooling, and appliances, the geography of the REC in Italian regions, the market data, and the total peak power of PV are examined. The self-consumed electricity, the energy shared among the community, and the social costs are evaluated in different scenarios, suggesting significant environmental and economic benefits for Energy Communities.

Reduction of Heating Energy Demand by Combining Infrared Heaters and Infrared Reflective Walls

We study the potential of infrared (IR) heaters in combination with IR reflective walls to reduce heating energy demand in buildings. Using IR heaters increases radiant temperature. Combined with IR reflective walls, less radiant heat is absorbed by the surrounding walls, and more is reflected to and absorbed by the occupants. This allows for lower air temperatures while maintaining constant thermal comfort. Lower air temperatures result in heating energy savings. In simulations, we examine the impact of four parameters on the thermal comfort indicator Predicted Mean Vote (PMV): wall temperature, inlet air temperature, IR heater power, and IR emissivity of the walls. To reduce the number of data points needed, we use a Central Composite Design for the layout of the simulation plan. The results show that the PMV can be changed from 0.15 to 1.16 only by lowering the emissivity of the surrounding walls from 0.9 to 0.1. At high IR heater power and at low wall temperature the impact of the emissivity on the PMV becomes larger. From the simulation data, we derive a response surface function to determine the required IR heating power for any given room conditions, which could be used for automated IR heater control.

TRNSYS Simulation of a Bi-Functional Solar-Thermal-Energy-Storage-Assisted Heat Pump System

The escalating energy demands in buildings, particularly for heating and cooling demands met by heat pumps, have placed a growing stress on energy resources. The bi-functional thermal diode tank (BTDT) is proposed as thermal energy storage to improve the heating and cooling performances of heat pumps in both summer and winter. The BTDT is an insulated water tank with a gravity heat pipe (GHP), which can harvest and store heat passively from sun radiation and the external environment during the daytime. In summer, it harvests and stores cold energy from the air and night sky during the daytime. The performance of the BTDT-assisted heat pump (BTDT-HP) system in Adelaide, Australia, during the 2021–2022 summer and winter seasons was evaluated by conducting a TRNSYS simulation. This study revealed that the BTDT-HP system outperformed the reference ASHP system, where up to 8% energy in heating and 39.75% energy in cooling could be saved. An overall reduction in the energy consumption of 18.89% was achieved. Increasing the BTDT volume and GHP panel area enabled the tank to store more thermal and cold energy across the winter and summer seasons, thereby improving the system’s performance. The maximum ESPs were found to be 31.6% and 41.2% for heating and cooling for the study case under optimal conditions. When the GHP panel area was fixed at 15 m2, the BTDT volume should be at least 28 m3 for the BTDT-HP system, boasting cooling and heating capacities of 40 kW and 43.2 kW, to achieve positive energy savings.

Energy demand and air quality in social housing buildings: A novel critical review

Social housing buildings, throughout Europe, represent a consistent share of the existing building stock. Due to the increasing levels of urbanization, the social housing population in the cities has risen and, after the economic crisis following the subprime mortgage crisis and the pandemic, low-income families as well. The greatest part of social dwellings, those built in the previous century, is usually sub-standard from an energy and environmental point of view. This study reviews the existing literature documenting indoor environmental conditions and energy refurbishment interventions or programs to improve the energy efficiency of existing social buildings. By considering the high risk of energy poverty in social contexts, and the socio-economic conditions of tenants, the economic implications deriving from the energy retrofit were also evidenced. Relevant papers published between 2010 and 2024 were reviewed and were divided according to the reference scale, namely the building or the district scale. The review shows the need to improve the energy performances of social dwellings, both to reduce their energy demand and to improve the indoor microclimatic conditions and quality of life of tenants. Through a critical literature review approach, this study provides a contribution to the in-depth understanding of the role of social housing in the contemporary context, providing meaningful insights for formulating more effective and inclusive housing policies for the next future.

Heating and ventilation efficiencies of a solar chimney integrated system in a low-energy office building

Mechanical air conditioning systems have a significant share of energy consumption in the building sector. Passive solar systems, such as solar chimneys, can reduce building energy demand by supplying space heating, cooling, and ventilation, significantly decreasing greenhouse gas emissions. Therefore, this study aimed to evaluate the heating and ventilation efficiencies of a solar chimney integrated system, including a roof solar chimney coupled with an air channel, for a two-story office building in Tehran, Iran. The studied system's conditions are switchable from heating to cooling by changing the opening positions. Computational Fluid Dynamics was employed to numerically investigate the heating and ventilation efficiencies of the proposed solar system. The results confirmed that the system could be utilized for pre-heating purposes during working hours but that the building should be ventilated only for 35% of this time with an air change rate of 0.8 during the year's coldest month. The arrangement could provide thermal and ventilation comfort for the occupied space only at solar intensity and ambient temperature higher than 550 W/m2 and 10 °C, respectively. In addition, the solar system could reduce 32% of the annual heating demand (918 kWh), which is equal to a reduction of 1865 kg of CO2 emissions during working hours.

Microclimatic models and their implications on the energy requirements of buildings in warm dry urban areas

Understanding the parameters that amplify or mitigate temperature increases in the built environment is crucial to reducing the energy demand of buildings and achieving urban resilience. This research examines how microclimate scenarios can affect building energy performance forecasts in cities with temperate and dry climates. The aim is to calculate the variation in building energy requirements resulting from using different weather files and urban parameters using the UBEM tool. To achieve this, UWG and Energy Plus software were used to create urban and building models. The study analysed four microclimatic scenarios in the city of Mendoza, Argentina. The scenarios used as a weather file input the annual format of a specific year (AMY files) or long-term (TMY file), whilst also considering the specific urban parameters of the assessed area. The study found that an incorrect weather file can cause a 36% error in energy usage assessments for cooling buildings during summer months. The contribution of this study is the development of a methodology for obtaining a weather file that accurately reflects the microclimate characteristics of the urban area of interest.

A Morris sensitivity analysis of an office building's thermal design parameters under climate change in sub-Saharan Africa

Sub-Saharan Africa faces severe overheating problems during hot periods due to substandardly constructed buildings and high-priced energy services. Global warming is expected to aggravate the situation. Although literature addresses the effects of climate change on buildings in different world regions, how it will impact the Sub-Saharan region is still being determined, particularly in terms of design parameters and how they will vary. This study assesses the influence of design parameters on the cooling energy demand of a small-scale office building in Lagos and Kano, Nigeria. A Morris sensitivity analysis was carried out to rank and compare the influence of different design parameters on energy consumption, determined using EnergyPlus for present-day typical weather and the SSP5-8.5 scenario. The future scenario was generated using the Future Weather Generator, a morphing tool. The results show that, in 2080, the cooling load will increase from 1551 kWh/a to 2612 kWh/a (68.4 %) in Kano and from 1931 kWh/a to 3093 kWh/a (60.1 %) in Lagos. The cooling load in Lagos will generally be higher than in Kano by 18.4 % (596 kWh/a). The results indicate that reductions in the thermal conductivity of the east wall and decreases in the solar absorptance of the east wall, roof, and west wall elements will be the most significant factors affecting cooling in Kano. In Lagos, reductions in the thermal conductivity of the east wall and decreases in solar absorptance of both the east wall and roof elements will be the most influential.

Spatial distribution of energy consumption: Integrating climate and macro-statistics for insights from clustering and sensitivity analysis

Limited comprehensive methods exist for studying spatial energy consumption distribution, integrating statistical and energy data. This paper introduces a novel approach for analyzing residential heating and cooling energy demand distribution. It employs clustering algorithms to study climate variables’ impact on energy demand distribution and assesses building energy demand intensity regionally, taking China as a case study. Initially compiling a dataset comprising climate characteristics, socioeconomic factors, and energy demand through data collection and simulation, the study compares clustering algorithms, highlighting the effectiveness of K-means in clustering high-dimensional climate-energy datasets. K-means analysis reveals temperature-based daily methods significantly affect building energy intensity, alongside factors like radiation intensity and humidity impacting regional energy demand variably. Additionally, climate’s influence on residential building energy consumption intensity varies regionally, with total energy demand influenced by population and economic factors. This paper offers insights for energy management and policy formulation.

Integration of solar thermal collectors and heat pumps with thermal energy storage systems for building energy demand reduction: A comprehensive review

Solar energy, coupled with innovative technologies, holds the promise of propelling buildings towards net-zero and carbon neutrality. In this regard, this review explores the integration of solar technologies, heat pumps, and thermal energy storage systems to reduce building energy demand. It thoroughly examines various types of solar thermal collectors (STCs), including both concentrating devices like compound parabolic concentrators and parabolic troughs, as well as non-concentrating designs such as flat plate and evacuated tube collectors. It examines innovative strategies for enhancing STC performance, such as alternative profiles for compound parabolic concentrators and the insertion of thermal fins in absorber tubes. Furthermore, the review categorizes solar-assisted heat pumps (SAHPs) into indirect expansion (IDX) and direct expansion (DX) systems, describing their advantages and limitations. It performs a comparison between IDX-SAHPs and DX-SAHPs, explaining their effectiveness and applicability. Eventually, the review explores thermal energy storage materials, categorizing them into sensible heat storage, latent heat storage, and thermochemical heat storage (TCHS). It discusses the advantages and disadvantages of each category, as well as notable materials within them. A comparative examination between open and closed systems for TCHS further enriches the discussion. Throughout the review, recent advancements and key findings from relevant studies are summarized in separate tables, offering valuable information into practical strategies for sustainable building energy systems. Regarding the provided sections, this review plays a crucial role in introducing scholars to practical methods employed in recent years to integrate the STCs with heat pumps and thermal energy storage systems.

The Impact of the Location of a Passive Frame House on Its Energy Demand for the Purpose of Heating—A Case Study

The reduction of energy demand in buildings is one of the key challenges in contemporary construction. To this end, the application of structural and material partitioning solutions that provide a high level of thermal insulation and the employment of technical installations with high energy performance have become widespread. However, there are a number of other factors that can reduce energy demand. These include the optimal use of heat gains from solar radiation. An aspect that is often discussed in the literature is the overheating of buildings due to excessive heat gains from solar radiation. This article is a case study showing the impact of the orientation of a single-family passive house on its heating energy demand. The building under consideration is located in Central Europe. External climate parameters measured directly at the site during experimental examinations were used for the calculations. This paper adopts six calculation options, considering the different orientations of the glazed façade. As the simulations showed, the effect of solar radiation on the energy demand between two extreme options of glazing orientation, that is south and north-facing orientation, reached 4.7% of the annual energy demand for heating, while for the option corresponding to the actual location of the building and the option involving south-facing windows, the difference was 0.3%, respectively.

Virtual wall: Numerical model on interaction between trees and building façade to quantify heat exchange and microclimate in urban context

When simulating a building's energy demand, the tree surroundings should be accounted in their shade and reshaping microclimate, just representing an envelope layer as a virtual wall. This study delves into the effects of such tree-induced virtual walls on building energy dynamics, with a dataset derived from 24 distinct samples of building façades and adjacent trees within a campus environment. An experiment was designed to validate microclimate simulation that captures variations in sheltered radiation and temperature reductions. The study introduces and calculates the dynamic and static equivalent heat transfer coefficients and thermal resistances for the virtual wall. The findings reveal significant correlations between the calculated coefficients and resistances, and various factors such as seasonality, weather conditions, and façade orientation. The equivalent thermal resistance value for south façade is highest on sunny days, reaching up to 3.7 m2·K/W, and on cloudy days, east façade has the highest equivalent heat transfer coefficient and thermal resistance values, at around 8.5 W/m2·K and 10.3 m2·K/W, respectively. Moreover, the study reveals that the tree's impact is primarily determined by its height and canopy area, with the equivalent heat transfer coefficient negatively correlated with tree height and canopy area, and positively correlated with building height.

Net Zero Energy Building technologies – Reversible Heat Pump/Organic Rankine Cycle coupled with Solar Collectors and combined Heat Pump/Photovoltaics – Case study of a Chilean mid-rise residential building

In the following years, the building sector will have to considerably reduce its final energy demand and emissions by adopting new technologies.This paper introduces two innovative technologies capable of reducing the final energy demand of residential buildings: A Heat Pump/Organic Rankine Cycle system coupled to solar thermal collectors (HP/ORC-COL), and a Heat Pump coupled with Photovoltaic panels (HP-PV). The HP/ORC-COL system alternates between generating either heat or electricity, whereas the HP-PV system produces them separately. The goal is to compare both systems through their Seasonal Performance Factor (SPF), equivalent emissions, operational cost, and Net Zero Energy Building (NZEB) potential. Additionally, the impact on the heating demand of retrofitting existing buildings with the Passivhaus Standard is studied.The heating, domestic hot water, and electricity demands are determined by considering the climate conditions of three polluted Chilean cities: Santiago, Concepción, and Temuco. The proposed systems are evaluated through numerical models developed in Python and validated with data from manufacturer catalogues. The validation of the models allows to enhance the result accuracy of the integrated overall model by closely aligning outputs with real conditions, and therefore increases the reliability of the prediction on the potential of the building to reach net zero energy.Results show that applying the Passivhaus standard allows to reduce heating requirements by up to 30% in all cities. The SPF and electricity production of the HP-PV system is better than the HP/ORC-COL, reaching a NZEB potential of 76.3% in Santiago, 66.6% in Concepción and 60.4% in Temuco. The average cost reduction of the HP/ORC-COL system compared to oil, natural gas, and wood pellet boilers is 82.7%, 90.4%, and 72.3%, whereas for the HP-PV system is 93.3%, 96.3%, and 89.2% respectively. On the CO2 emissions, the HP/ORC-COL system presents an average reduction of 63.6% and 59.7% compared to an oil and natural gas boiler, while the HP-PV system has an average reduction of 72.5% and 69.5% respectively.

Data-Driven and Domain Adaption Framework for Optimizing Energy Usage Forecasting in Smart Buildings Using ARIMA Model

Building energy demand and energy system supply are increasingly balanced by energy storage and short-term DSM. This is necessary due to fluctuating renewable energy supplies and rising building power use. Worldwide, structures utilize tons of energy. Greenhouse gas emissions and operational expenses decrease with construction energy efficiency. Forecasting and optimization algorithms can solve challenges, including supply chains (inventory optimization), traffic, and sustainable energy system battery/load/production scheduling for carbon-free energy generation. We often solve optimization problems that need forecasting due to uncertain future values. Predicting and optimizing are challenging; therefore, little research has been done. Our method uses building energy modeling professionals' data to forecast neighboring building types for new or unknown building types. After training, we utilize the models to estimate energy usage for the k-closest building types and combine the predictions using a weighted average. We used time-series decomposition to detect uncertainty and a hybrid model to close this gap: The concepts encode static features and predictable patterns in time-series simulation results. The model learns latent performance differences and calibrates output using outcomes and history records. Historical data predicts public building energy ARIMA use. Our method covers data processing, training, validation, and forecasting. We measured our method. Mixed integer linear optimization and ARIMA projected most accurately.

Multi-aspect analysis of measures to reduce the building's energy demand

Issues related to reducing the energy demand of residential buildings are still relevant in the light of the energy transition and ongoing climate change. A single-family house from the early 1990s with a heated area of approximately 177 m2, located in the north-eastern part of Poland, was used as a case study. The article contains the results of nine years of measurements that included energy consumption for heating and domestic hot water preparation. It was estimated that the annual final energy consumption was 128.2 kWh/m2 [462 MJ/m2]. After insulating the building envelope and replacing the windows with triple-glazed ones, this value reduced to 68.2 kWh/m2 [246 MJ/m2]. The measurement results were used to build a statistical model, based on multiple regression, to calculate the energy demand of a similar building to the one analysed in this article in any given location. The article presents the second, more advanced, energy simulations model made in the DesignBuilder environment, which enabled additional analysis of the operation of the heating and ventilation system. The scope of this study also included a multi-variant economic analysis of the building energy renovation, in which the Life Cycle Cost (LCC), Net Present Value (NPV) and Internal Rate of Return (IRR) values were determined.