Search Results (1,091)

This study evaluates the thermal and energy performance of building envelopes incorporating phase change materials (PCM) compared with traditional resistive thermal insulation, considering future climate scenarios. Using EnergyPlus simulations, the study analyzes a medium office building with varying envelope compositions in two distinct Brazilian climates—Curitiba and Rio de Janeiro—representing bioclimatic zones 1 and 8, respectively. The PCM used, SP24E, aligns with the HVAC system setpoints, and climate projections for 2050 and 2080 are integrated using the Climate Change World Weather File Generator (CCWorldWeatherGen) based on the A2 emissions scenario. Results indicate that in mild climates like Curitiba, PCM significantly improves energy efficiency, reducing annual Energy Use Intensity (EUI) by 8.2% in 2050 and 10% in 2080 compared with resistive insulation. Conversely, in hotter climates like Rio de Janeiro, PCM increases EUI by 12.1% in 2050 and 20.7% in 2080 compared with resistive insulation. This study highlights the varying effectiveness of PCM in different climatic conditions and its implications for future building energy performance. Full article

As the penetration rate of renewable energy in the power grid increases, the imbalance between power supply and demand has become one of the key issues. Buildings and their heating, ventilation, and air conditioning (HVAC) systems are considered excellent flexible demand response (DR) resources that can reduce peak loads to alleviate operational pressures on the power grid. Centralized chiller plants are regarded as flexible resources with large capacity and rapid adjustability. The direct load control of chiller plants can respond to the power grid within minutes, making them highly suitable for participation in emergency DR. However, existing studies are generally based on simulations and lack experimental research in actual large-scale buildings to demonstrate the effectiveness of this method and provide related lessons learned. This study conducted field experiments on a centralized chiller plant within an industrial building in Guangdong, China. The results indicate that the strategy of shutting down chiller plants is an effective DR measure. It can complete the load reduction process within 15 min, rapidly decreasing the system power by 380~459 kW, with a maximum duration of up to 50 min, without significantly affecting the thermal comfort of indoor occupants. Additionally, the impact of existing control logic on the participation of chiller plants in the DR process is also discussed. Full article

This paper provides a comprehensive comparative analysis of smart building solution providers within Europe, emphasizing the technological advancements and market strategies employed by companies selected for the study. As energy efficiency becomes a critical focus due to rising global energy demands and climate change concerns, smart building technologies have emerged as pivotal in optimizing energy use and enhancing occupant comfort. This study examines 19 products from 15 prominent manufacturers, categorized into six product categories: smart thermostats, smart valves, HVAC control, data acquisition and energy management software, smart home ecosystems, and home energy management systems. Using a comparative assessment matrix and SWOT analysis, the paper evaluates these products across five key areas: service impacts, market penetration, investment topics, business models, and value propositions. Findings highlight a strong focus of manufacturers in energy efficiency and comfort services, while identifying opportunities for improvement in energy flexibility and health integration. This analysis aims to guide stakeholders in strategic planning and decision-making, offering insights into the current and future landscape of the smart building solutions market. Full article

Faults of heating, ventilation, and air-conditioning (HVAC) systems can cause significant consequences, such as negatively affecting thermal comfort of occupants, energy demand, indoor air quality, etc. Several methods of fault detection and diagnosis (FDD) in building energy systems have been proposed since the late 1980s in order to reduce the consequences of faults in heating, ventilation, and air-conditioning (HVAC) systems. All the proposed FDD methods require laboratory data, or simulated data, or field data. Furthermore, the majority of the recently proposed FDD methods require labelled faulty and normal data to be developed. Thus, providing reliable ground truth data of HVAC systems with different technical characteristics is of great importance for advances in FDD methods for HVAC units. The primary objective of this study is to examine the operational behaviour of a typical single-duct dual-fan constant air volume air-handling unit (AHU) in both faulty and fault-free conditions. The investigation encompasses a series of experiments conducted under Mediterranean climatic conditions in southern Italy during summer and winter. This study investigates the performance of the AHU by artificially introducing seven distinct typical faults: (1) return air damper kept always closed (stuck at 0%); (2) fresh air damper kept always closed (stuck at 0%); (3) fresh air damper kept always opened (stuck at 100%); (4) exhaust air damper kept always closed (stuck at 0%); (5) supply air filter partially clogged at 50%; (6) fresh air filter partially clogged at 50%; and (7) return air filter partially clogged at 50%. The collected data from the faulty scenarios are compared to the corresponding data obtained from fault-free performance measurements conducted under similar boundary conditions. Indoor thermo-hygrometric conditions, electrical power and energy consumption, operation time of AHU components, and all key operating parameters are measured for all the aforementioned faulty tests and their corresponding normal tests. In particular, the experimental results demonstrated that the exhaust air damper stuck at 0% significantly reduces the percentage of time with indoor air relative humidity kept within the defined deadbands by about 29% (together with a reduction in the percentage of time with indoor air temperature kept within the defined deadbands by 7.2%) and increases electric energy consumption by about 13% during winter. Moreover, the measured data underlined that the effects on electrical energy demand and indoor thermo-hygrometric conditions are minimal (with deviations not exceeding 5.6% during both summer and winter) in the cases of 50% clogging of supply air filter, fresh air filter, and return air filter. The results of this study can be exploited by researchers, facility managers, and building operators to better recognize root causes of faulty evidences in AHUs and also to develop and test new FDD tools. Full article

Metal–organic frameworks (MOFs) have garnered significant attention in recent years for their potential to revolutionize heat exchanger performance, thanks to their high surface area, tunable porosity, and exceptional adsorption capabilities. This review focuses on the integration of MOFs into heat exchangers to enhance heat transfer efficiency, improve moisture management, and reduce energy consumption in Heating, Ventilation and Air Conditioning (HVAC) and related systems. Recent studies demonstrate that MOF-based coatings can outperform traditional materials like silica gel, achieving superior water adsorption and desorption rates, which is crucial for applications in air conditioning and dehumidification. Innovations in synthesis techniques, such as microwave-assisted and surface functionalization methods, have enabled more cost-effective and scalable production of MOFs, while also enhancing their thermal stability and mechanical strength. However, challenges related to the high costs of MOF synthesis, stability under industrial conditions, and large-scale integration remain significant barriers. Future developments in hybrid nanocomposites and collaborative efforts between academia and industry will be key to advancing the practical adoption of MOFs in heat exchanger technologies. This review aims to provide a comprehensive understanding of current advancements, challenges, and opportunities, with the goal of guiding future research toward more sustainable and efficient thermal management solutions. Full article

This systematic literature review (SLR) focuses on indoor environmental quality (IEQ) in passenger transport vehicles within tropical and subtropical regions. It specifically examines indoor air quality (IAQ), thermal comfort (TC), acoustic comfort (AC), and visual comfort (VC) of passenger vehicle cabins (PVCs) in auto rickshaws, sedans, trucks, bus rapid transits (BRTs), buses, trains, trams, metro systems, aircraft and ferries of tropical and subtropical regions. The SLR used the PRISMA approach to identify and review scientific studies between 2000 and 2024 on the IEQ of PVCs in the tropics. Studies reviewed were found in SCOPUS, Web of Science, Science Direct, and EBSCO databases including relevant citation references. Findings reveal a significant geographical imbalance in research, with most studies concentrated in tropical Asia (78.2%), while sub-Saharan Africa (8.2%), South America (11.8%), and Oceania (1.8%) are considerably underrepresented. In 113 studies, most addressed IAQ and TC but limited attention to AC and VC. Moreover, fewer studies have jointly addressed all the IEQ parameters, highlighting the need for a more comprehensive approach to IEQ for tropical PVCs. Several studies alluded to in-cabin commuter risk linked to PM2.5, PM10, carbon monoxide (CO), and volatile organic compounds (VOCs). These risks are exacerbated by traffic hotspots, poor ventilation, ambient pollution, overcrowding, and poor vehicle conditions. Additionally, thermal discomfort is compounded by extreme heat loads, inefficient HVAC systems, and high vehicle occupancy. Common gaps include a paucity of IEQ studies and inadequate IEQ regulations or adapted standards in developing tropics. Infrastructural and regulatory deficiencies have been identified, along with strategies for mitigation. Recommendations are for more holistic IEQ studies in the tropics, including exposure studies for emerging gaps in new indoor pollutants, integration of AI and IoT for sustainable ventilation strategies, and development of effective regulatory frameworks considering region-specific conditions. Finally, Policymakers are encouraged to establish localized IEQ standards, enforce regulations, and prioritize upgrades to transport infrastructure. The SLR findings emphasize the urgent need for targeted interventions in developing tropical regions to address disparities in IEQ, ensuring healthier and more sustainable transport environments that could be replicated across transport systems worldwide. Full article

Offshore wind farms are increasingly being commissioned farther from shore, and high voltage alternating current (HVAC) transmission systems are preferred because of their maturity and reliability. However, as cable length increases, ensuring system stability becomes more challenging, making it essential to investigate shunt reactor compensation configurations and converter control strategies. This study examines three different shunt reactor compensation arrangements and two control strategies, grid-forming (GFM) and grid-following (GFL), across three cable lengths (80 km, 120 km, and 150 km). The systems were evaluated based on small-signal stability using disk margins for different active power operating points, and later for different short-circuit ratios (SCR) and X/R. The results demonstrate that the GFM is preferable for longer cables and enhanced stability. The most robust configuration includes a shunt reactor placed in the mid-cable with additional reactors at both ends of the cable, followed by an arrangement with reactors at the beginning and end. The GFM converter control maintained stability across all operating points, cable lengths, and configurations, whereas the stability of the GFL unit was highly dependent on active power injection and struggled under weaker grid conditions. Thus, for longer HVAC cables, it is necessary to employ GFM control units, and it is recommended to use shunt reactors at the cable start and end, as well as at mid-cable, for optimal stability. Full article

Although different investigations have been carried out on the analysis of adaptive thermal comfort in naturally ventilated buildings, fewer have focused on mixed mode operation. Moreover, there is limited research as for the implementation of adaptive comfort models into the control system of buildings. Therefore, this paper investigates how the application of a setpoint based on adaptive comfort control (ACC) would affect occupants’ comfort considering mixed mode operation and based on the results of a longitudinal field study in an academic office building of a tertiary educational institution in southern Spain. The manuscript analyses the Thermal Preference Vote over 12 months in a mixed mode room with an HVAC system whose setpoint is adjusted with a previously calculated adaptive algorithm for the building. For that, a thorough analysis was conducted in which users identified situations regarding thermal comfort and the operation of the conditioning system was collected. The results indicate that it is possible to develop adaptive comfort models that ensure the thermal well-being of occupants. Moreover, this study highlights the need for further research to assess the implications of ACC in terms of comfort and energy consumption as well as addressing the future improvements and the limitations of the work carried out. Full article

The paper presents a number of tests of the carbon monoxide concentration in a single-car garage equipped with exhaust ventilation, while the combustion engine of a parked passenger car is operating. The main source of carbon monoxide in the garage is the internal combustion engine of a passenger car. Single-car garages are characterized by a relatively small volume, which causes a rapid accumulation of carbon monoxide inside the garage. The aim of this publication is to present the results of research on carbon monoxide concentration in a single-family building garage with the combustion engine in a passenger car running and at various air exchanges in the garage. The test results showed that the permissible values (WHO, NAAQS) of carbon monoxide concentrations were significantly exceeded, both with the exhaust ventilation switched on and off. The highest carbon monoxide concentration values (2253 ppm) in the garage were observed when the exhaust ventilation was turned off. The study also developed two one-dimensional models of carbon monoxide concentrations in a garage with the combustion engine of a passenger car turned on, with the exhaust ventilation turned on and off. The models developed can be used in ventilation design to estimate the carbon monoxide concentrations in garages, based on the type of car and the number of air changes. Full article

The European Union (EU) has introduced a range of policies to promote energy efficiency, including setting specific targets for energy-efficient renovations across the EU building stock. This study provides a comprehensive environmental and economic assessment of energy-efficient renovation scenarios in a large-scale multifamily building project that is district-heated, considering both the building and the broader urban energy system. A systematic framework was developed for this assessment and applied to a real case in Sweden, where emission factors from energy production are significantly lower than the EU average: 114 g CO₂e/kWh for district heating and 37 g CO₂e/kWh for electricity. The project involved the renovation of four similar district-heated multifamily buildings with comparable energy efficiency measures. The primary distinction between the measures lies in the type of HVAC system installed: (1) exhaust ventilation with air pressure control, (2) mechanical ventilation with heat recovery, (3) exhaust ventilation with an exhaust air heat pump, and (4) exhaust ventilation with an exhaust air heat pump combined with photovoltaic (PV) panels. The study’s findings show that the building with an exhaust air heat pump which operates intermittently with PV panels achieves the best environmental performance from both perspectives. A key challenge identified for future research is balancing the reduced electricity production from Combined Heat and Power (CHP) plants within the energy system. Full article

Recently, there has been a growing interest in understanding how respiratory particles spread within passenger cars, especially in light of ongoing challenges posed by infectious diseases. This study experimentally investigates dispersion patterns of respiratory airborne particles (<1 µm) within these confined spaces. The main objective is to introduce a manikin-based method for studying particle dispersion and assessing in-cabin air quality. To achieve this, a respiratory manikin as a particle source has been developed and tested under various use-cases, including variations in source emission (breathing vs. speaking), the HVAC ventilation mode (fresh and recirculation), and the blower level of the HVAC system (low and high). The findings reveal that for an infection source on the first row of the vehicle when cabin airflow originates from the front panel, the seat directly behind the particle source is associated with the highest particle exposure, while the seat adjacent to the source offers the lowest exposure. Among the tested configurations, the recirculation mode with an active HEPA filter and high blower level shows the lowest particle concentration at recipients’ breath levels during both breathing and speaking. These findings can be used to enhance the design of passenger cars to reduce the transmission of potentially pathogen-laden particles. Full article

The paper analyses multi-variant energy simulations carried out in IDA ICE 4.8 software for a newly designed single-family building within the framework of the 4E Idea. This idea assumes the use of energy-saving, ecological, ergonomic, and economic solutions in construction and building operation. Energy simulations were conducted to evaluate the annual energy-saving potential of the developed architectural house concept, which incorporates ergonomic analyses and cost-effective construction solutions. Analyses were conducted to optimise the non-renewable primary energy index by selecting mechanical ventilation system (CAV or VAV) with heat recovery; the configuration of photovoltaic module installation in terms of their location and orientation; the exposure and type of solar thermal collectors (flat and vacuum); and the use of two types of heat pumps (air- and ground-source). The most favourable energy performance of the building was achieved with an HVAC system equipped with a VAV mechanical ventilation system with heat recovery, an on-grid photovoltaic installation, vacuum solar thermal collectors, and a ground-source heat pump with a horizontal heat exchanger. This configuration resulted in a primary energy index value of 2 kWh/m²/year. The results of the analyses carried out for the 4E building concept may serve as a reference point for future energy-efficient building designs aspiring to meet higher standards of sustainable development. Full article

This study presents a comprehensive framework for the sustainable selection of manufacturers in variable refrigerant flow (VRF) air conditioning systems by integrating environmental impact considerations with traditional technical and economic criteria using multi-criteria decision-making (MCDM) methods. This research addresses the growing need for sustainable HVAC solutions while acknowledging the complexity decision-makers face when evaluating multiple manufacturers across environmental, technical, and economic dimensions. Unlike previous studies that focus solely on technical performance or evaluate brands individually, this research introduces a novel approach by grouping manufacturers according to their country of origin (Japan, South Korea, China, Germany, Italy, and France) and assessing them through a sustainability lens. This study employs a three-tier methodology: first, utilizing the Analytic Hierarchy Process (AHP) to determine criteria weights with particular emphasis on environmental factors; second, developing a consensus decision matrix through expert evaluations; and third, applying VIKOR and EDAS methods for comprehensive ranking. The analysis encompasses environmental criteria, including energy efficiency, carbon footprint, and refrigerant global warming potential, alongside traditional technical, marketing, financial, and network considerations. The results indicate that while Japanese manufacturers maintain strong technical leadership, European manufacturers, particularly German ones, demonstrate superior environmental performance. These findings suggest that manufacturers can enhance their market position by balancing environmental sustainability with traditional performance metrics, particularly through improved energy efficiency, sustainable refrigerant selection, and circular economy practices. This research contributes to the growing body of knowledge on sustainable manufacturer selection in the HVAC industry and provides practical guidelines for decision-makers prioritizing environmental sustainability alongside technical performance. Full article

This study evaluates the energy consumption and embodied carbon emissions of various heat pump systems for an office building in Chicago, IL, U.S., over a 50-year lifespan, including the operation, manufacturing, and construction phases. The analyzed systems include air source heat pumps (ASHP) in Air to Air and Air to Water configurations, and ground source heat pumps (GSHP) in Soil to Air and Soil to Water configurations. A traditional HVAC system serves as the baseline for comparison. Advanced simulation tools, including Rhino, Grasshopper, TRACE 700, and One Click LCA, were used to identify the optimal HVAC system for sustainable building operations. Unlike prior studies focusing on GSHP versus traditional HVAC systems, this research directly compares GSHP and ASHP configurations, addressing a significant gap in the sustainable HVAC system design literature. The GSHP (Soil to Water) system demonstrated the lowest energy intensity at 100.8 kWh/m²·yr, a 41.8% improvement over the baseline, and the lowest total embodied carbon emissions at 3,882,164 kg CO₂e. In contrast, the ASHP (Air to Air) system, while reducing energy consumption relative to the baseline, exhibited the highest embodied carbon emissions among the heat pump configurations due to its higher operational energy demands. The study highlights the significance of the operating phase in embodied carbon contributions. These findings emphasize the importance of a holistic design approach that considers both operational and embodied impacts to achieve sustainable building designs. Full article

This paper addresses the challenge of decarbonizing residential energy consumption by developing an advanced energy management system (EMS) optimized for cost reduction and energy efficiency. By leveraging the thermal inertia of building envelopes as a form of thermal energy storage (TES), the proposed EMS dynamically balances energy inputs from the electrical grid, photovoltaic (PV) systems, and battery storage, while regulating HVAC operations. Employing model predictive control (MPC) and integrating real-time data on energy prices, weather conditions, and consumption patterns, the system minimizes energy costs, while maintaining indoor thermal comfort. Simulations conducted for both summer and winter scenarios demonstrate significant reductions in energy costs. Laboratory and real-world testing confirm the EMS’s efficacy in enhancing energy efficiency, increasing PV self-consumption, and reducing reliance on grid energy, marking a step forward in sustainable energy solutions for residential applications. Full article