Journal articles: 'HVAC'

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Hussain, Abadal Salam T., F. Malek, S. Faiz Ahmed, Taha A. Taha, Shouket A. Ahmed, Mardianaliza Othman, Muhammad Irwanto Misrun, Gomesh Nair Shasidharan, and Mohd Irwan Yusoff. "Operational Optimization of High Voltage Power Station Based Fuzzy Logic Intelligent Controller." Applied Mechanics and Materials 793 (September 2015): 100–104. http://dx.doi.org/10.4028/www.scientific.net/amm.793.100.

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This paper discusses the use of the intelligent microcontroller and also discusses the results from the simulation application of fuzzy logic theory to the control of the high voltage direct and alternation current (HVDC)& (HVAC) power station systems. The application considered their implementation in both low and high level control systems in HVDC& HVAC power station systems. The results for the fuzzy logic based controller shows many improvements compared to the conventional HVDC& HVAC control system. The fuzzy logic based controller concept was further successfully extended to high level control of optimization problems such as the power swings. Based on simulation results, HVDC and HVAC breaker design are online protection against unwanted incidents happening to the system.

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Javed, Umar, Neelam Mughees, Muhammad Jawad, Omar Azeem, Ghulam Abbas, Nasim Ullah, Md Shahariar Chowdhury, Kuaanan Techato, Khurram Shabih Zaidi, and Umair Tahir. "A Systematic Review of Key Challenges in Hybrid HVAC–HVDC Grids." Energies 14, no. 17 (September 1, 2021): 5451. http://dx.doi.org/10.3390/en14175451.

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The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC–HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC–HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC–HVDC grids, current developments, and future research directions and prospects, which have led to the evolution of this field. Therefore, the motivation, novelty, and the main contribution of the survey is to comprehensively analyze the integration challenges, implemented control algorithms, employed optimization algorithms, and major security challenges of hybrid HVAC–HVDC systems. Moreover, future research prospects are identified, such as security algorithms’ constraints, dynamic contingency modeling, and cost-effective and reliable operation.

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Yang, Wen Qing, Wei Cao, Jian Kun Wu, and Lin Chen. "Research on the Technology of Converting the Existing AC Lines to DC Lines." Advanced Materials Research 614-615 (December 2012): 1394–400. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.1394.

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Power transmission is a key link in power system. As the increase of power supply, the transmission capacity of the lines should be enlarged too. In the developed area, the right-of-way for transmission line is hard to be obtained. And converting the existing HVAC overhead transmission lines using HVDC technology could enhance the transmission capability. There are three possible plans for different HVAC transmission lines: single-pole HVDC, bi-pole HVDC and tri-pole HVDC.

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Narayan, R. S., S. Mohan, and K. Sunitha. "Simulative Study into the Development of a Hybrid HVDC System Through a Comparative Research with HVAC: a Futuristic Approach." Engineering, Technology & Applied Science Research 7, no. 3 (June 12, 2017): 1600–1604. http://dx.doi.org/10.48084/etasr.1192.

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High Voltage Direct Current Transmission (HVDC) is considered a better solution for bulk long distance transmissions. The increased use of HVDC is a result of its advantages over the HVAC systems and especially of its fault stability nature. A better solution is proposed by using a Voltage Source Controlled–HVDC as one of the infeed for the Multi-Infeed HVDC (MIDC or MI-HVDC) systems. The main advantage with the VSC converter is its flexible power control which enhances the stability of the MIDC systems. In this paper, the behavior of an HVDC system is compared with that of an HVAC during faults. A Hybrid HVDC system that includes a LCC as a rectifier unit and a VSC converter as the inverter is being proposed. It is considered suitable for MIDC systems and particularly for supplying a weak AC system. The performance of the system during steady state and transient conditions for all the proposed topologies including HVDC, HVAC and Hybrid HVDC are studied in MATLAB/SIMULINK. All of the proposed control strategies are evaluated via a series of simulation case studies.

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Bidadfar, Ali, Oscar Saborío-Romano, Jayachandra Naidu Sakamuri, Vladislav Akhmatov, Nicolaos Antonio Cutululis, and Poul Ejnar Sørensen. "Coordinated Control of HVDC and HVAC Power Transmission Systems Integrating a Large Offshore Wind Farm." Energies 12, no. 18 (September 6, 2019): 3435. http://dx.doi.org/10.3390/en12183435.

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The development of efficient and reliable offshore electrical transmission infrastructure is a key factor in the proliferation of offshore wind farms (OWFs). Traditionally, high-voltage AC (HVAC) transmission has been used for OWFs. Recently, voltage-source-converter-based (VSC-based) high-voltage DC (VSC-HVDC) transmission technologies have also been considered due to their grid-forming capabilities. Diode-rectifier-based (DR-based) HVDC (DR-HVDC) transmission is also getting attention due to its increased reliability and reduced offshore platform footprint. Parallel operation of transmission systems using such technologies can be expected in the near future as new OWFs are planned in the vicinity of existing ones, with connections to more than one onshore AC system. This work addresses the control and parallel operation of three transmission links: VSC-HVDC, DR-HVDC, and HVAC, connecting a large OWF (cluster) to three different onshore AC systems. The HVAC link forms the offshore AC grid, while the diode rectifier and the wind farm are synchronized to this grid voltage. The offshore HVDC converter can operate in grid-following or grid-forming mode, depending on the requirement. The contributions of this paper are threefold. (1) Novel DR- and VSC-HVDC control methods are proposed for the parallel operation of the three transmission systems. (2) An effective control method for the offshore converter of VSC-HVDC is proposed such that it can effectively operate as either a grid-following or a grid-forming converter. (3) A novel phase-locked loop (PLL) control for VSC-HVDC is proposed for the easy transition from the grid-following to the grid-forming converter in case the HVAC link trips. Dynamic simulations in PSCAD validate the ability of the proposed controllers to ride through faults and transition between grid-following and grid-forming operation.

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Wu, Yuan Kang, Ching Yin Lee, Dong Jing Lee, and Yung Ching Huang. "Comparative Analysis of HVAC, HVDC and Hybrid HVAC-HVDC Transmission System Based Offshore Wind Farm." Advanced Materials Research 953-954 (June 2014): 342–47. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.342.

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Taiwan is developing the renewable energy actively, in which the wind energy is seen as one of important resources. However, the suitable locations for wind farm constructions are less and less on the shore, and the trend of wind farm development in the future will toward to offshore where the installation capacity of the wind farm could reach hundreds of megawatts. As the installation capacity of the wind farm increases, the effects on the interconnected AC grid are also more notable. In this paper, the off-peak system in Taiwan is used as a studied system in which the Penghu area and Taiwan grid is connected by submarine cables. This study explores the wind farm transmission system including HVAC, HVDC, and hybrid HVAC-HVDC systems and compares the differences of their impact on the system.

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Siregar, Yulianta, and Credo Pardede. "Study of Hybrid Transmission HVAC/HVDC by Particle Swarm Optimization (PSO)." Energies 15, no. 20 (October 16, 2022): 7638. http://dx.doi.org/10.3390/en15207638.

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There are considerable power losses in Indonesia’s SUMBAGUT 150 kV transmission High Voltage Alternating Current Network (HVAC) system. These power losses and the voltage profile are critical problems in the transmission network system. This research provides one possible way to reduce power losses involving the use of a High Voltage Direct Current (HVDC) network system. Determining the location to convert HVAC into HVDC is very important. The authors of the current study used Particle Swarm Optimization (PSO) to determine the optimal location on the 150 kV SUMBAGUT HVAC transmission network system. The study results show that, before using the HVDC network system, the power loss was 68.41 MW. On the other hand, power loss with the conversion of one transmission line to HVDC was 57.31 MW for “Paya Pasir–Paya Geli” (efficiency 16.22%), 51.79 MW for “Paya Pasir–Sei Rotan” (efficiency 24.29%), and 60.8 MW for “Renun–Sisikalang” (efficiency 110.12%). The power loss with the conversion of two transmission lines to HVDC was 45.7 MW for “Paya Pasir–Paya Geli” and “Paya Pasir–Sei Rotan” (efficiency 33.19%), 44.95 MW for “Paya Pasir–Paya Geli” and “Renun–Sidikalang” (efficiency 26.98%), and 44.69 MW for “Paya Pasir–Sei Rotan” and “Renun–Sidikalang” (efficiency 34.67%). The power loss with the conversion of three transmission lines to HVDC was 38.71 MW for “Paya Pasir–Paya Geli,” “Paya Pasir–Sei Rotan,” and “Renun–Sidikalang” (efficiency 41.41%).

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Jovcic, D., N. Pahalawaththa, and M. Zavahir. "Analytical modelling of HVDC-HVAC systems." IEEE Transactions on Power Delivery 14, no. 2 (April 1999): 506–11. http://dx.doi.org/10.1109/61.754095.

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Zhang, Jian, Xin Long Zheng, Guo Zhi Chen, Zhi Gang Zhang, and Bei Bei Xu. "Economic Comparison of VSC-HVDC and HVAC Systems for Connections of Offshore Wind Farms." Applied Mechanics and Materials 672-674 (October 2014): 325–30. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.325.

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Large-scale offshore wind power has been developed in recent years, and two possibilities are considered for the transmission system between the offshore wind farms and the onshore grid: VSC-HVDC and HVAC. The paper aims to compare both systems for 300MW offshore wind farms, 25 km, 50km and 75km from the Point of Common Coupling on an economic basis using a DCF(discounted cash flow) analysis. A linear fit to the net present values has been made, obtaining the break-even distance of 47km. When the transmission distance is shorter than 47km, the HVAC system is more economic, otherwise the VSC-HVDC system is a more cost-efficient option.

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Choopum, Cattareya, and Boonchai Techaumnat. "Numerical Investigation on the Effects of Wind and Shielding Conductor on the Ion Flow Fields of HVDC Transmission Lines." Energies 16, no. 1 (December 24, 2022): 198. http://dx.doi.org/10.3390/en16010198.

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Ion flow field is an important aspect of high voltage direct current (HVDC) transmission lines. In this paper, we apply the upwind finite volume method for solving the ion flow field of three HVDC configurations to clarify the effect of the wind and the role of shielding conductors. For the monopolar configuration installation, the ground current distribution with underbuilt shield wires was studied numerically and experimentally. For the ±250 kV bipolar configuration, the calculated peak electric field and current density are verified with the values in a reference. The ±500 kV bipolar configuration is used to investigate the change in electric field and ion current within the same corridors of the existing HVAC lines. We analyze the ion flow field with and without the dedicated metallic return conductor (DMRC). In the absence of wind, the maximum of the electric field is lower than that of the HVAC lines and the current density is very low on the ground. In the presence of wind, the electric field and the current distribution become unsymmetrical on the ground level. The peak current density increases significantly on the downwind side. The HVDC line without DMRC has the electric field peak higher than that of the HVAC lines. With the higher wind shear coefficient, the peak of the electric field and the current density increases on the downwind side. Overall investigations summarize that DMRC can effectively reduce the peak of the electric field to be lower than that of the existing 500 kV HVAC lines under all wind conditions.

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Ramirez-Vazquez, Isaias, Fermin Pascual Espino-Cortes, and Carlos Gómez-Yáñez. "Direct Current Inclined Plane Testing on Silicone Rubber Composites Reinforced with Silica Nano Particles." Journal of Nano Research 71 (January 25, 2022): 135–49. http://dx.doi.org/10.4028/www.scientific.net/jnanor.71.135.

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Polymer insulators traditionally used in HVAC (High Voltage Alternating Current) are used in HVDC (High Voltage Direct Current) transmission lines. For these polymer insulators, silicone insulating rubber, based on Polydimethylsiloxane (PDMS), is used in industry to manufacture high voltage insulators for power lines. Silicone rubber material ages due to pollution and environmental factors such as UV (ultraviolet light), rain, and temperature. Moreover, no international standard is available to standardize its functional characteristics to ensure its best performance in HVDC regime. Standards usually define the testing procedures to measure the resistance of the materials to these conditions. One of the tests used to evaluate the performance in AC (alternating current) of the housing material of polymeric insulators is the inclined plane test (IPT). This test has the purpose of assessing the tracking and erosion resistance of housing materials. However, for the IPT, no consensus is reached yet for this testing in Direct Current (DC) voltage. In addition, there are no indications whether the formulations that have been successfully used for HVAC work fine; also, in HVDC regime, or not. In this paper, an investigation of the tracking and erosion resistance under positive DC IPT is presented. In this way, the study was carried out on skirts of an HVAC commercial insulator and samples of a new outstanding composite silicone rubber formulation filled with micro and nano particles. The results show that HVAC silicone rubber formulations could not be suitable for HVDC applications under highly polluted conditions. In the case of the new enhanced composite, it is shown how nano particles used in this material significantly enhance the performance during DC tracking and erosion testing well above other materials tested in previous works. Also, thermogravimetric analysis (TGA) of the composites is used to correlate thermal stability with the DC IPT performance.

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Zhou, Xia, Cangbi Ding, Jianfeng Dai, Zhaowei Li, Yang Hu, Zhaohui Qie, and Feng Xue. "An Active Power Coordination Control Strategy for AC/DC Transmission Systems to Mitigate Subsequent Commutation Failures in HVDC Systems." Electronics 10, no. 23 (December 6, 2021): 3044. http://dx.doi.org/10.3390/electronics10233044.

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Subsequent commutation failures (CFs) in HVDC systems will cause large-scale power flow transfer in AC/DC transmission systems and lead to overload risk in HVAC systems. In order to cope with these effects, a power coordination control strategy for the AC/DC transmission system with high-proportion wind power is proposed. Firstly, a model of the AC/DC transmission system considering the large-scale wind farms access is established by analyzing the power transmission characteristics of the AC/DC transmission system with high-proportion wind power, and the power transmission characteristics are analyzed after subsequent CFs. Secondly, the HVDC subsequent CFs can be mitigated by adjusting DC power transmission, while the active power output of the sending-end AC system is reduced by active control of wind turbine generators (WTGs) to reduce the overload risk of the HVAC system. Finally, the proposed power coordination control strategy is simulated and verified based on the established simulation model and actual power grid, and the results show that this strategy can effectively mitigate HVDC’s subsequent CFs and reduce the overload risk in HVAC systems.

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Masullo, Massimiliano, Katsuya Yamauchi, Minori Dan, Federico Cioffi, and Luigi Maffei. "Intercultural Differences in the Perception of HVAC Sound Quality in Car Cabins: From Conventional to Electric Vehicles." Applied Sciences 11, no. 23 (December 2, 2021): 11431. http://dx.doi.org/10.3390/app112311431.

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In electric-powered cars, the production of which is increasing, the HVAC system is responsible for most of the noise inside the car’s cabin, causing significant discomfort for passengers. Moreover, the noise produced by the HVAC affects the perceptible sound inside the car cabin, significantly impacting the perceived quality of the vehicle. It is thus essential to investigate and quantify people’s preferences concerning HVAC noise. Our previous research revealed differences in the HVAC noise between hybrid electric (HEV) and internal combustion engine (ICEV) vehicles. A subsequent factor analysis revealed that the adjectives used to describe the sounds can be grouped into two main dimensions: Aesthetic and Loudness. The present paper highlights the results of a listening test that aimed to identify possible differences in the perception of HVACs’ sound quality between Italian and Japanese subject groups, for ICEV and HEV, in different functioning conditions. Results revealed that the most remarkable difference emerges at high air flow rates, where the Japanese group perceived the quality of sound and annoyance, respectively, to be significantly lower and significantly higher than the Italian group.

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Sung, Wen Pei, Tzai Tang Tsai, Hsien Jung Wang, and Ming Der Chen. "Improved Energy Performance of Air-Conditioning System Using Variable Primary Flow Chilled Water Systems in an Office Building." Applied Mechanics and Materials 71-78 (July 2011): 1973–77. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1973.

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The main objective of this on-site study is to use a full-scale HVAC (Heating, Ventilating and Air-Conditioning) system installed in an office building in Taiwan for comparing the power consumption, energy-saving, and CO2reduction by variable primary flow (VPF) chilled water systems for controlling the HVAC. The on-site experimental results indicate that average power consumptions are 44,935 kWh for the constant volume (CV) chilled water systems, and 39,025 kWh for the VPF system. Approximately 19% of the maximum energy-saving rate can be achieved if the HVAC system is operated as a VPF system. Additionally, the reduced quantity of accumulated CO2emission varies from 0 to 44,186 kg with 0.623 kg-CO2kwh-1emission factor during the office hours of 08:00 (a.m.) to 20:00 (p.m.). The results demonstrate that switching the operation of an office building HVAC system from CV to VPF will significantly enhance energy savings and CO2reduction. This study is will offer useful information for evaluating an indoor environmental policy with respect to energy savings and CO2emission reduction for office HVACs used in subtropical regions.

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Oni, Oluwafemi Emmanuel, Kamati I. Mbangula, and Innocent Davidson E. Davidson. "Dynamic Voltage Stability Studies using a Modified IEEE 30-Bus System." Transactions on Environment and Electrical Engineering 1, no. 3 (September 1, 2016): 9. http://dx.doi.org/10.22149/teee.v1i3.30.

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Power System stability is an essential study in the planning and operation of an efficient, economic, reliable and secure electric power system because it encompasses all the facet of power systems operations, from planning, to conceptual design stages of the project as well as during the systems operating life span. This paper presents different scenario of power system stability studies on a modified IEEE 30-bus system which is subjected to different faults conditions. A scenario whereby the longest high voltage alternating current (HVAC) line is replaced with a high voltage direct current (HVDC) line was implemented. The results obtained show that the HVDC line enhances system stability more compared to the contemporary HVAC line. Dynamic analysis using RMS simulation tool was used on DigSILENT PowerFactory.

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Jovcic, D., N. Pahalawaththa, and M. Zavahir. "Small signal analysis of HVDC-HVAC interactions." IEEE Transactions on Power Delivery 14, no. 2 (April 1999): 525–30. http://dx.doi.org/10.1109/61.754098.

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Goel, Supriya, Michael Rosenberg, Juan Gonzalez, and Jérémy Lerond. "Total System Performance Ratio—A Systems Based Approach for Evaluating HVAC System Efficiency." Energies 14, no. 16 (August 19, 2021): 5108. http://dx.doi.org/10.3390/en14165108.

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The prescriptive path is the most widely used approach for commercial code compliance in the United States. Though easy to implement, prescriptive approaches do not typically discriminate between minimally compliant, high-performing and poorly performing HVAC system configurations. Hence, to meet aggressive energy and carbon reduction goals, it is clear that energy codes will need to transition from prescriptive to performance-based approaches, a transition that is riddled with several challenges. This paper discusses a new HVAC system-based performance approach (HVAC System Performance) which provides a simpler solution to HVAV system evaluation compared to whole building performance, while keeping tradeoffs limited to specific building systems. The Total System Performance Ratio (TSPR) is a metric for evaluation of overall system efficiency instead of individual component efficiency, a solution which could also eventually facilitate the transition to a 100% performance-based code structure. TSPR is a ratio that compares the annual heating and cooling load of a building to the annual energy consumed by the building’s HVAC system. A calculation software tool has been developed for determining a building’s TSPR. Already incorporated into the 2018 Washington State Energy Code, this approach is also being evaluated by ASHRAE Standard 90.l Project Committee and has the potential to provide a comprehensive performance-based approach for HVAC system evaluation and analysis.

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Swaminathan, Siva, Ximan Wang, Bingyu Zhou, and Simone Baldi. "A University Building Test Case for Occupancy-Based Building Automation." Energies 11, no. 11 (November 14, 2018): 3145. http://dx.doi.org/10.3390/en11113145.

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Heating, ventilation and air-conditioning (HVAC) units in buildings form a system-of-subsystems entity that must be accurately integrated and controlled by the building automation system to ensure the occupants’ comfort with reduced energy consumption. As control of HVACs involves a standardized hierarchy of high-level set-point control and low-level Proportional-Integral-Derivative (PID) controls, there is a need for overcoming current control fragmentation without disrupting the standard hierarchy. In this work, we propose a model-based approach to achieve these goals. In particular: the set-point control is based on a predictive HVAC thermal model, and aims at optimizing thermal comfort with reduced energy consumption; the standard low-level PID controllers are auto-tuned based on simulations of the HVAC thermal model, and aims at good tracking of the set points. One benefit of such control structure is that the PID dynamics are included in the predictive optimization: in this way, we are able to account for tracking transients, which are particularly useful if the HVAC is switched on and off depending on occupancy patterns. Experimental and simulation validation via a three-room test case at the Delft University of Technology shows the potential for a high degree of comfort while also reducing energy consumption.

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Reed, Liza, M. Granger Morgan, Parth Vaishnav, and Daniel Erian Armanios. "Converting existing transmission corridors to HVDC is an overlooked option for increasing transmission capacity." Proceedings of the National Academy of Sciences 116, no. 28 (June 20, 2019): 13879–84. http://dx.doi.org/10.1073/pnas.1905656116.

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A changing generation mix and growing demand for carbon-free electricity will almost certainly require dramatic changes in the infrastructure and topology of the electricity system. Rather than build new lines, one way to minimize social opposition and regulatory obstacles is to increase the capacity of existing transmission corridors. In addition to upgrading the capacity of high-voltage alternating current (HVAC) lines, we identify a number of situations in which conversion from HVAC to high-voltage direct current (HVDC) is the least-cost strategy to increase the capacity of the corridor. If restricted to the existing right-of-way (ROW), we find DC conversion to be the least-cost, and in some cases the only, option for distances of >200 km or for increases of >50% capacity. Across all configurations analyzed, we assess HVDC conversion to be the lower-cost option at >350 km and >50% capacity increases. While we recognize that capacity expansion through HVDC conversion may be the optimal solution in only some situations, with future improvements in the cost and performance of solid-state power electronics, conversion to HVDC could be attractive in a growing set of circumstances.

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Kalair, A., N. Abas, and N. Khan. "Comparative study of HVAC and HVDC transmission systems." Renewable and Sustainable Energy Reviews 59 (June 2016): 1653–75. http://dx.doi.org/10.1016/j.rser.2015.12.288.

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Rahman, Syed, Irfan Khan, Hend I. Alkhammash, and Muhammad Faisal Nadeem. "A Comparison Review on Transmission Mode for Onshore Integration of Offshore Wind Farms: HVDC or HVAC." Electronics 10, no. 12 (June 20, 2021): 1489. http://dx.doi.org/10.3390/electronics10121489.

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The development of offshore wind farms (WF) is inevitable as they have exceptional resistance against climate change and produce clean energy without hazardous wastes. The offshore WF usually has a bigger generation capacity with less environmental impacts, and it is more reliable too due to stronger and consistent sea winds. The early offshore WF installations are located near the shore, whereas most modern installations are located far away from shore, generating higher power. This paradigm shift has forced the researchers and industry personnel to look deeper into transmission options, namely, high voltage AC transmission (HVAC) and high voltage DC transmission (HVDC). This evaluation can be both in terms of power carrying capability as well as cost comparisons. Additionally, different performance requirements such as power rating, onshore grid requirements, reactive power compensation, etc., must be considered for evaluation. This paper elaborately reviews and explains the offshore wind farm structure and performance requirements for bulk offshore power transfer. Based on the structure and performance requirements, both HVDC and HVAC transmission modes are compared and analyzed critically. Finally, a criterion for selection and increasing popularity of HVDC transmission is established.

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Do, Huyen, and Kristen S. Cetin. "Data-Driven Evaluation of Residential HVAC System Efficiency Using Energy and Environmental Data." Energies 12, no. 1 (January 8, 2019): 188. http://dx.doi.org/10.3390/en12010188.

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In the U.S., the heating, ventilation, and air conditioning (HVAC) system is generally the largest electricity-consuming end-use in a residential building. However, homeowners are less likely to have their HVAC system serviced regularly, thus inefficiencies in operation are also more likely to occur. To address this challenge, this research works towards a non-intrusive data-driven assessment method using building assessors’ data, HVAC electricity demand data, and outdoor environmental data. Building assessors’ data is first used to estimate the HVAC system size, then estimate the electricity demand curve of the HVAC system. A comparison of the proposed electricity demand curve development method demonstrates strong agreement with physics-based HVAC model results. An HVAC efficiency rating is then proposed, which compares the model-predicted and actual performance data to define whether an HVAC system is operating as expected. As a case study, detailed data for 39 occupied, conditioned residential buildings in Austin, Texas, was used demonstrating the identification of the presence of potential HVAC inefficiencies. The results prove beneficial for utilities to help target residential HVAC systems in need of service or energy efficiency upgrades, as well as for homeowners as a continuous assessment tool for HVAC performance.

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Hussein, Israa Ismael, Sirine Essallah, and Adel Khedher. "Improvement of the Iraqi Super Grid Performance Using HVDC/HVAC Links by the Integration of Large-Scale Renewable Energy Sources." Energies 15, no. 3 (February 3, 2022): 1142. http://dx.doi.org/10.3390/en15031142.

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The increasing use of renewable energy sources (RES) and their integration into transmission systems requires extensive studies to get more benefits from these sources. Stability analysis is one of the most crucial issues in these systems, and therefore needs to be studied in depth. In this paper, an analytical study was conducted for the stability assessment of the Iraqi super grid after adding a solar power plant with a capacity of 1000 MW using both HVAC and HVDC links for comparison purposes. Thus, the objective of this study was to determine the best way to integrate RES into the power grid while improving its performance. The system’s stability was evaluated for two types of faults: line and bus disturbances. The strength of the grid and its ability to absorb the newly added energy was also studied. The simulations were performed with the PSS/E software using the Newton-Raphson method for a 500 km transmission line length. The results showed that the HVDC link outperforms the HVAC link in improving the overall performance of the power system.

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Abbas, Samar, Abu Bakar, Yasra Chandio, Khadija Hafeez, Ayesha Ali, Tariq M. Jadoon, and Muhammad Hamad Alizai. "Inverted HVAC." ACM Transactions on Sensor Networks 14, no. 3-4 (December 20, 2018): 1–26. http://dx.doi.org/10.1145/3229063.

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Betts, Richard. "HVAC: Maintaining HVAC equipment with air intake filters." Filtration + Separation 50, no. 4 (July 2013): 32–35. http://dx.doi.org/10.1016/s0015-1882(13)70167-8.

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Iggland, Emil, Roger Wiget, Spyridon Chatzivasileiadis, and Goran Anderson. "Multi-Area DC-OPF for HVAC and HVDC Grids." IEEE Transactions on Power Systems 30, no. 5 (September 2015): 2450–59. http://dx.doi.org/10.1109/tpwrs.2014.2365724.

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Rizki Aulia Nanda, Agus Supriyanto, Karyadi, Fathan Mubina Dewadi, Ramadhan Ronggo Jati, and Laurentinus Agus Kurniawan. "PERANCANGAN DAN PERAKITAN ELEKTRONIKA MIKROKONTROLER BERBASIS IOT UNTUK STUDI PENGUKURAN SISTEM HVAC." BUANA ILMU 7, no. 1 (November 3, 2022): 43–55. http://dx.doi.org/10.36805/bi.v7i1.3015.

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Sistem HVAC merupakan sistem pengkondisian udara (heating, ventilating and air conditioning) dimana proses yang terjadi yaitu pemanas, sirkulasi udara dan pendigin. Dari sistem tersebut diperlukan proses pengukuran suhu dan tekanan udara untuk melihat studi parameter pada sistem HVAC. Dengan adanya studi parameter sistem HVAC tersebut maka tujuan penelitian ini adalah merancang sistem elektrikal untuk sensor pengukuran suhu dan tekanan udara pada sistem HVAC berbasis IOT untuk memudahkan melihat nilai pengukuran suhu dan tekanan udara sistem HVAC secara jarak jauh. Batasan penelitian ini hanya pada perancangan dan pembuatan sensor, tidak dengan studi parameter kinerja sistem HVAC. Metode penelitian mencangkup perancangan sistem elektrikal, pembuatan alat, pengujian sistem elektronika, pengujian pengukuran dan pengujian sistem hasil pengukuran berbasis IOT. Dari pengujian tersebut menghasilkan kapasitas tegangan tertinggi ada pada Arduino namu arus tertinggi ada pada esp32 wifi. Dengan pengukuran tersebut menghasilkan nilai resistansi atau tahanan dengan rata-rata 0,87 ohm dan tergolong sistem elektrikal tegangan rendah yang aman dan terdistribusi sistem listrik yang merata. Jadi sistem alat ukur untuk HVAC aman digunakan dengan hasil pengukuran tekanan udara sebesar 11 kPa dengan suhu sebesar 38 derajat Celsius. Peninjauan pengukuran sistem IOT juga berhasil pada website ThingSpeak. Dengan kesimpulan bahwa alat ukur untuk studi parameter sistem HVAC berhasil dengan nilai yang valid. Kata Kunci: Sistem Elektrikal, HVAC, Sensor, Mikrokontroler

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Hou, Lianjian. "Discussion on Energy-Saving Design Measures of HVAC." World Construction 4, no. 3 (September 20, 2015): 15. http://dx.doi.org/10.18686/wcj.v4i3.4.

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<p>With continual increase of people's living quality requirements, the demand for buildings with HVAC systems is growing. As energy shortage intensifies today, EEBs (Energy-efficient Buildings) are becoming the main trend of future developments in the construction industry. Therefore, further improving HVAC energy-saving measures is a particularly important task and is the key issue being examined by current HVAC designers. This study starts with analyzing existing problems in energy-saving design of HVAC, and proposes some views and recommendations for HVAC energy-saving design method, as well as reasonable choices of parameters for HVAC systems such as energy-saving design of cooling and heating ventilation, energy-saving design of hot and cold water systems, and optimum heat recovery design of HVAC systems, in order to reduce buildings’ energy consumption and to improve energy efficiency for energy-saving purposes. </p>

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Hou, Lianjian. "Discussion on Energy-Saving Design Measures of HVAC." World Construction 4, no. 3 (September 20, 2015): 15. http://dx.doi.org/10.18686/wc.v4i3.4.

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<p>With continual increase of people's living quality requirements, the demand for buildings with HVAC systems is growing. As energy shortage intensifies today, EEBs (Energy-efficient Buildings) are becoming the main trend of future developments in the construction industry. Therefore, further improving HVAC energy-saving measures is a particularly important task and is the key issue being examined by current HVAC designers. This study starts with analyzing existing problems in energy-saving design of HVAC, and proposes some views and recommendations for HVAC energy-saving design method, as well as reasonable choices of parameters for HVAC systems such as energy-saving design of cooling and heating ventilation, energy-saving design of hot and cold water systems, and optimum heat recovery design of HVAC systems, in order to reduce buildings’ energy consumption and to improve energy efficiency for energy-saving purposes. </p>

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SERRANO GONZALEZ, JAVIER, JESUS RIQUELME SANTOS, and ANGEL ARCOS VARGAS. "HVDC POWER TRANSMISSION. THE TECHNOLOGICAL RESURGENCE OF DIRECT CURRENT." DYNA 97, no. 3 (May 1, 2022): 226–28. http://dx.doi.org/10.6036/10479.

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This article provides an overview of high voltage direct current (HVDC) and high voltage alternating current (HVAC) power transmission alternatives. The use of HVDC systems currently represents an efficient alternative under certain conditions, mainly due to reduced converter costs, improved power system flexibility and higher economic efficiency for long distances and, in particular, when it is relevant for power transmission over submarine or subway cables. Therefore, this paper describes the overview of the two alternatives, both from a technical and economic point of view

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Pfeiffer, Martin, Soren Hedtke, and Christian M. Franck. "Corona Current Coupling in Bipolar HVDC and Hybrid HVAC/HVDC Overhead Lines." IEEE Transactions on Power Delivery 33, no. 1 (February 2018): 393–402. http://dx.doi.org/10.1109/tpwrd.2017.2713603.

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Zhao, Jing Bo. "The Application of the Green Energy in HVAC." Advanced Materials Research 860-863 (December 2013): 663–66. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.663.

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With the rapid development of Chinese economy, making the energy consumption of HVAC increase sharply, HVAC energy saving has been an increasingly urgent event. This paper points out that the development of green energy is the need of energy saving and environmental protection, this paper introduces the application of green energy in the HVAC, how to develop new technology in HVAC and puts forward some opinions.

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Kharal, Kumail, Chang-Hwan Kim, Chulwon Park, Jae-Hyun Lee, Chang-Gi Park, Se Lee, and Sang-Bong Rhee. "A Study for the Measurement of the Minimum Clearance Distance between the 500 kV DC Transmission Line and Vegetation." Energies 11, no. 10 (September 30, 2018): 2606. http://dx.doi.org/10.3390/en11102606.

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High voltage direct current (HVDC) transmission is being widely implemented for long-distance electrical power transmission due to its specific benefits over high voltage alternating current (HVAC) transmission. Most transmission lines pass through forests. Around the HVDC lines, an arc to a nearby tree may be produced. Thus, there should be a minimum possible clearance distance between a live conductor and a nearby tree, named the minimum vegetation clearance distance (MVCD), to avoid short-circuiting. Measurement of minimum clearance distance between the conductor and trees is a significant challenge for a transmission system. In the case of HVAC transmission, a large amount of research has been undertaken in the form of the Gallet equation for the measurement of this distance, whereas for HVDC transmission no substantial work has been done. An equivalent AC voltage value can be derived from the DC voltage value in order to use the Gallet equation. This paper presents an experimental measurement technique for determining the MVCD at 500 kV to verify the results obtained from the Gallet equation in the case of DC voltage. Performing the experiment with a 500 kV DC line is not possible in the laboratory due to safety concerns. Therefore, an experiment up to 60 kV is conducted to measure the MVCD for DC voltage. The measured results achieved from the experiment are then extrapolated to calculate the MVCD at 500 kV.

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Grainge, Zoe. "HVAC efficiency: Can filter selection reduce HVAC energy costs?" Filtration & Separation 44, no. 1 (January 2007): 20–22. http://dx.doi.org/10.1016/s0015-1882(07)70021-6.

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Ryndzionek, Roland, and Łukasz Sienkiewicz. "Evolution of the HVDC Link Connecting Offshore Wind Farms to Onshore Power Systems." Energies 13, no. 8 (April 14, 2020): 1914. http://dx.doi.org/10.3390/en13081914.

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This paper presents an overview of the DC link development and evolution dedicated to HVDC structure for connecting offshore wind power plants to onshore power systems. The growing demand for the green energy has forced investors in power industry to look for resources further out at sea. Hence, the development of power electronics and industrial engineering has enabled offshore wind farms to be situated further from the shore and in deeper waters. However, their development will require, among other technologies, DC-DC conversion systems. The advantages of HVDC over HVAC technology in relation to transmission distance are given. The different HVDC configurations and topologies of HVDC converters are elucidated. In this context, the HVDC grids are a promising alternative for the expansion of the existing AC grid.

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Mariita, Richard M., James H. Davis, Michelle M. Lottridge, Rajul V. Randive, Hauke Witting, and Johannes Yu. "Towards a Healthy Car: UVC LEDs in an Automobile’s HVAC Demonstrates Effective Disinfection of Cabin Air." Atmosphere 13, no. 11 (November 18, 2022): 1926. http://dx.doi.org/10.3390/atmos13111926.

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Vehicle Heating, ventilation, and air conditioning (HVAC) systems can accumulate and recirculate highly infectious respiratory diseases via aerosols. Integrating Ultraviolet Subtype C (UVC) light-emitting diodes (LEDs) to complement automobile HVAC systems can protect occupants from developing allergies, experiencing inflammatory problems, or acquiring respiratory infectious diseases by inactivating pathogenic organisms. UVC can add little to no static pressure with minimal space, unlike mercury lamps which are larger and heavier. Additionally, UVC LEDs are effective at low voltage and have no mercury or glass. While previous experiments have shown UVC LED technology can reduce bacteriophage Phi6 concentrations by 1 log in 5 min (selected as the average time to clean the cabin air), those studies had not positioned LED within the HVAC itself or studied the susceptibility of the surrogate at the specific wavelength. This study aimed to assess the disinfection performance of UVC LEDs in automotive HVAC systems and determine the dose–response curve for bacteriophage Phi6, a SARS-CoV-2 surrogate. To achieve this, UVC LEDs were installed in a car HVAC system. To determine inactivation efficacy, a model chamber of 3.5 m3, replicating the typical volume of a car, containing the modified automobile HVAC system was filled with bacteriophage Phi6, and the HVAC was turned on with and without the UVC LEDs being turned on. The results revealed that HVAC complemented with UVC reduced bacteriophage Phi6 levels significantly more than the HVAC alone and reduced the viral concentration in the cabin by more than 90% viral reduction in less than 5 min. The performance after 5 min is expected to be significantly better against SARS-CoV-2 because of its higher sensitivity to UVC, especially at lower wavelengths (below 270 nm). HVAC alone could not achieve a 90% viral reduction of bacteriophage Phi6 in 15 min. Applying UVC LEDs inside an HVAC system is an effective means of quickly reducing the number of aerosolized viral particles in the chamber, by inactivating microorganisms leading to improved cabin air quality.

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Chen, Yimin, Guanjing Lin, Eliot Crowe, and Jessica Granderson. "Development of a Unified Taxonomy for HVAC System Faults." Energies 14, no. 17 (September 6, 2021): 5581. http://dx.doi.org/10.3390/en14175581.

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Detecting and diagnosing HVAC faults is critical for maintaining building operation performance, reducing energy waste, and ensuring indoor comfort. An increasing deployment of commercial fault detection and diagnostics (FDD) software tools in commercial buildings in the past decade has significantly increased buildings’ operational reliability and reduced energy consumption. A massive amount of data has been generated by the FDD software tools. However, efficiently utilizing FDD data for ‘big data’ analytics, algorithm improvement, and other data-driven applications is challenging because the format and naming conventions of those data are very customized, unstructured, and hard to interpret. This paper presents the development of a unified taxonomy for HVAC faults. A taxonomy is an orderly classification of HVAC faults according to their characteristics and causal relations. The taxonomy includes fault categorization, physical hierarchy, fault library, relation model, and naming/tagging scheme. The taxonomy employs both a physical hierarchy of HVAC equipment and a cause-effect relationship model to reveal the root causes of faults in HVAC systems. A structured and standardized vocabulary library is developed to increase data representability and interpretability. The developed fault taxonomy can be used for HVAC system ‘big data’ analytics such as HVAC system fault prevalence analysis or the development of an HVAC FDD software standard. A common type of HVAC equipment-packaged rooftop unit (RTU) is used as an example to demonstrate the application of the developed fault taxonomy. Two RTU FDD software tools are used to show that after mapping FDD data according to the taxonomy, the meta-analysis of the multiple FDD reports is possible and efficient.

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Zhang, Jiawen. "Design and Technical Analysis of HVAC Ventilation System in Green Building." E3S Web of Conferences 261 (2021): 03039. http://dx.doi.org/10.1051/e3sconf/202126103039.

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In recent years, the construction industry has developed rapidly, and there are more and more urban construction projects. The corresponding design requirements for HVAC systems are also getting higher and higher. HVAC has been widely used in all kinds of buildings. While providing convenience for people, environmental pollution has gradually become a topic of concern for people. Therefore, when designing the HVAC system, HVAC not only meets the needs of customers, but also uses green energy saving technology to reduce energy consumption as far as possible. Reduce environmental pollution, so that the HVAC ventilation system of tall buildings can be in a stable and efficient operation state. Improve the operation effect of air conditioning, while reducing energy consumption.

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Jang, Hyeonwoo, Byeongkwan Kang, Keonhee Cho, Kyu hee Jang, and Sehyun Park. "Design and Implementation of IoT-based HVAC and Lighting System for Energy Saving." MATEC Web of Conferences 260 (2019): 02012. http://dx.doi.org/10.1051/matecconf/201926002012.

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Building Energy Management System(BEMS) technology is under study as one of the various solutions to environmental problems such as depletion of energy resources, global warming, and climate change. Solving the energy problems of the future BEMS is not the only goal. Occupants must be guaranteed a comfortable environment. HVAC systems and lighting systems are a large part of building energy consumption, which also means that it is an important part of energy conservation. In this paper, we propose IoT-based HVAC and Lighting(I-HVAC&L) system for HVAC system and lighting system management. With I-HVAC&L System, you can save energy efficiency without compromising the convenience of residents’.

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Asim, Nilofar, Marzieh Badiei, Masita Mohammad, Halim Razali, Armin Rajabi, Lim Chin Haw, and Mariyam Jameelah Ghazali. "Sustainability of Heating, Ventilation and Air-Conditioning (HVAC) Systems in Buildings—An Overview." International Journal of Environmental Research and Public Health 19, no. 2 (January 17, 2022): 1016. http://dx.doi.org/10.3390/ijerph19021016.

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Increasing demand on heating, ventilation, and air-conditioning (HVAC) systems and their importance, as the respiratory system of buildings, in developing and spreading various microbial contaminations and diseases with their huge global energy consumption share have forced researchers, industries, and policymakers to focus on improving the sustainability of HVAC systems. Understanding and considering various parameters related to the sustainability of new and existing HVAC systems as the respiratory system of buildings are vital to providing healthy, energy-efficient, and economical options for various building types. However, the greatest opportunities for improving the sustainability of HVAC systems exist at the design stage of new facilities and the retrofitting of existing equipment. Considering the high available percentage of existing HVAC systems globally reveals the importance of their retrofitting. The attempt has been made to gather all important parameters that affect decision-making to select the optimum HVAC system development considerations among the various opportunities that are available for sustainability improvement.

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Sun, Jian Min, and Chun Dong Zhang. "Development and Analysis on Energy Conservation Equipment and Control Technology of HVAC." Advanced Materials Research 424-425 (January 2012): 852–56. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.852.

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In building, the energy consumption of heating, ventilation and air conditioning (HVAC) is the largest, which accounts for forty to sixty percent of the total building consumption. So it is a key research to reduce the energy consumption of the HVAC system for saving building energy. This article describes a variety of energy conservation equipment of HVAC, and describes in detail the principles of each type of equipment. This article also analyzes the growing advanced control technologies for the HVAC system. In conclusion, HVAC equipment is developing in the direction of clean energy and energy efficient; intelligent control technology is more applicable to the varying parameters of complex system such as air conditioning, is more energy conservation and will become the leading direction of research and application

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Martis, Radu, Florin Pop-Piglesan, Sorin Cosman, and Claudia Martis. "Considerations on design, development and testing of Electrical Machines for automotive HVAC." MATEC Web of Conferences 322 (2020): 01042. http://dx.doi.org/10.1051/matecconf/202032201042.

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HVAC represents one of the highest energy consumer in a vehicle and for full electric vehicles, the design of HVAC and the dimensioning of its driving system is of utmost importance in order to avoid the limitation of driving range. Due to its advantages, especially when it comes to power density, PMSM is one of the most used electrical machines for a wide range of automotive applications, including HVAC systems. The paper presents the generation of the requirements, design, analysis and HiL testing of a PMSM for HVAC applications. The challenge is to develop a machine answering to the requirements for an electric vehicle HVAC at low- voltage. An experimental model of the machine was tested using a test- bench, based on HiL techniques.

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Clerici, A., L. Paris, and P. Danfors. "HVDC conversion of HVAC lines to provide substantial power upgrading." IEEE Transactions on Power Delivery 6, no. 1 (1991): 324–33. http://dx.doi.org/10.1109/61.103755.

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Clerici, A., L. Paris, and P. Danfors. "HVDC Conversion of HVAC Lines to Provide Substantial Power Upgrading." IEEE Power Engineering Review 11, no. 1 (January 1991): 59. http://dx.doi.org/10.1109/mper.1991.88673.

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Conceição, Eusébio, António Sousa, João Gomes, and António Ruano. "HVAC Systems Applied in University Buildings with Control Based on PMV and aPMV Indexes." Inventions 4, no. 1 (January 15, 2019): 3. http://dx.doi.org/10.3390/inventions4010003.

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In this work, HVAC (Heating, Ventilation and Air Conditioning) systems applied in university buildings with control based on PMV (Predicted Mean Vote) and aPMV (adaptive Predicted Mean Vote) indexes are discussed. The building’s thermal behavior with complex topology, in transient thermal conditions, for summer and winter conditions is simulated by software. The university building is divided into 124 spaces, on two levels with an area of 5931 m2, and is composed of 201 transparent surfaces and 1740 opaque surfaces. There are 86 compartments equipped with HVAC systems. The simulation considers the actual occupation and ventilation cycles, the external environmental variables, the internal HVAC system and the occupants’ and building’s characteristics. In this work, a new HVAC control system, designed to simultaneously obtain better occupants’ thermal comfort levels according to category C of ISO 7730 with less energy consumption, is presented. This new HVAC system with aPMV index control is numerically implemented, and its performance is compared with the performance of the same HVAC system with the usual PMV index control. Both HVAC control systems turn on only when the PMV index or the aPMV index reaches values below −0.7, in winter conditions, and when the PMV index or the aPMV index reaches values above +0.7, in summer conditions. In accordance with the results obtained, the HVAC system guarantees negative PMV and aPMV indexes in winter conditions and positive PMV and aPMV indexes in summer conditions. The energy consumption level is higher in winter conditions than in summer conditions for compartments with shading, and it is lower in winter conditions than in summer conditions for compartments exposed to direct solar radiation. The consumption level is higher using the PMV control than with the aPMV control. Air temperature, in accordance with Portuguese standards, is higher than 20 °C in winter conditions and lower than 27 °C in summer conditions. In Mediterranean climates, the HVAC systems with aPMV control provide better occupants’ thermal comfort levels and less energy consumption than the HVAC system with PMV control.

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Toub, Mohamed, Chethan R. Reddy, Rush D. Robinett, and Mahdi Shahbakhti. "Integration and Optimal Control of MicroCSP with Building HVAC Systems: Review and Future Directions." Energies 14, no. 3 (January 30, 2021): 730. http://dx.doi.org/10.3390/en14030730.

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Heating, ventilation, and air-conditioning (HVAC) systems are omnipresent in modern buildings and are responsible for a considerable share of consumed energy and the electricity bill in buildings. On the other hand, solar energy is abundant and could be used to support the building HVAC system through cogeneration of electricity and heat. Micro-scale concentrated solar power (MicroCSP) is a propitious solution for such applications that can be integrated into the building HVAC system to optimally provide both electricity and heat, on-demand via application of optimal control techniques. The use of thermal energy storage (TES) in MicroCSP adds dispatching capabilities to the MicroCSP energy production that will assist in optimal energy management in buildings. This work presents a review of the existing contributions on the combination of MicroCSP and HVAC systems in buildings and how it compares to other thermal-assisted HVAC applications. Different topologies and architectures for the integration of MicroCSP and building HVAC systems are proposed, and the components of standard MicroCSP systems with their control-oriented models are explained. Furthermore, this paper details the different control strategies to optimally manage the energy flow, both electrical and thermal, from the solar field to the building HVAC system to minimize energy consumption and/or operational cost.

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Alavi, Hamidreza, and Nuria Forcada. "User-Centric BIM-Based Framework for HVAC Root-Cause Detection." Energies 15, no. 10 (May 17, 2022): 3674. http://dx.doi.org/10.3390/en15103674.

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In the building operation phase, the Heating, Ventilation, and Air-Conditioning (HVAC) equipment are the main contributors to excessive energy consumption unless proper design and maintenance is carried out. Moreover, HVAC problems might have an impact on occupants’ discomfort in thermal comfort. Hence, the identification of the root cause of HVAC problems is imperative for facility managers to plan preventive and corrective maintenance actions. However, due to the complex interaction between various equipment and the lack of data integration among Facility Management (FM) systems, they fail to provide necessary information to identify the root cause of HVAC problems. Building Information Modelling (BIM) is a potential solution for maintenance activities to address the challenges of information reliability and interoperability. Therefore, this paper presents a novel conceptual model and user-centric framework to determine the causes of HVAC problems implemented in BIM for its visualization. CMMS and BMS data were integrated into BIM and utilized by the framework to analyze the root cause of HVAC problems. A case study in a university building was used to demonstrate the applicability of the approach. This framework assists the FM team to determine the most probable cause of an HVAC problem, reducing the time to detect equipment faults, and providing potential actions to solve them.

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Xu, Dongsheng. "Learning Efficient Dynamic Controller for HVAC System." Mobile Information Systems 2022 (May 13, 2022): 1–7. http://dx.doi.org/10.1155/2022/4157511.

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People employ a variety of devices to achieve comfort in various aspects of their lives; for example, numerous types of air conditioners are used to maintain a pleasant indoor temperature. The wide applications of heating, ventilation, and air conditioning (HVAC) systems have significantly improved the comfort level of the indoor environment for commercial buildings. However, air conditioners have their own set of issues, the most significant of which is the increased energy usage. Besides the fact that HVAC is a recent move toward the indoor temperature adjustment, the energy cost that arose from the HVAC system is still high, which takes up over 40% of the total energy. How to develop an energy-eﬀicient HVAC system has become one of the challenging topics that need further investigation. This paper addresses this problem with the aid of deep learning (DL) algorithms. Furthermore, this study proposes an energy-eﬀicient controller and improvement schemes for HVAC systems based on deep reinforcement learning algorithms. To reduce the implementation cost of the proposed design, this study utilizes neural network pruning techniques to develop a low-complexity HVAC controller. The experimental results show that the algorithm proposed in this study not only retains a high energy-saving rate but also reduces the implementation cost of the HVAC control algorithm.

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Zhong, Xuyang, Zhiang Zhang, Ruijun Zhang, and Chenlu Zhang. "End-to-End Deep Reinforcement Learning Control for HVAC Systems in Office Buildings." Designs 6, no. 3 (June 4, 2022): 52. http://dx.doi.org/10.3390/designs6030052.

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The heating, ventilation, and air conditioning (HVAC) system is a major energy consumer in office buildings, and its operation is critical for indoor thermal comfort. While previous studies have indicated that reinforcement learning control can improve HVAC energy efficiency, they did not provide enough information about end-to-end control (i.e., from raw observations to ready-to-implement control signals) for centralized HVAC systems in multizone buildings due to the limitations of reinforcement learning methods or the test buildings being single zones with independent HVAC systems. This study developed a model-free end-to-end dynamic HVAC control method based on a recently proposed deep reinforcement learning framework to control the centralized HVAC system of a multizone office building. By using the deep neural network, the proposed control method could directly take measurable parameters, including weather and indoor environment conditions, as inputs and control indoor temperature setpoints at a supervisory level. In some test cases, the proposed control method could successfully learn a dynamic control policy to reduce HVAC energy consumption by 12.8% compared with the baseline case using conventional control methods, without compromising thermal comfort. However, an over-fitting problem was noted, indicating that future work should first focus on the generalization of deep reinforcement learning.

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Totaro, Michele, Anna Costa, Beatrice Casini, Sara Profeti, Antonio Gallo, Lorenzo Frendo, Andrea Porretta, Paola Valentini, Gaetano Privitera, and Angelo Baggiani. "Microbiological Air Quality in Heating, Ventilation and Air Conditioning Systems of Surgical and Intensive Care Areas: The Application of a Disinfection Procedure for Dehumidification Devices." Pathogens 8, no. 1 (January 15, 2019): 8. http://dx.doi.org/10.3390/pathogens8010008.

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International literature data report that the increase of infectious risk may be due to heating, ventilation and air conditioning (HVAC) systems contaminated by airborne pathogens. Moreover, the presence of complex rotating dehumidification wheels (RDWs) may complicate the cleaning and disinfection procedures of the HVAC systems. We evaluated the efficacy of a disinfection strategy applied to the RDW of two hospitals’ HVAC systems. Hospitals have four RDW systems related to the surgical areas (SA1 and SA2) and to the intensive and sub-intensive care (IC and sIC) units. Microbiological air and surface analyses were performed in HVAC systems, before and after the disinfection treatment. Hydrogen peroxide (12%) with silver ions (10 mg/L) was aerosolized in all the air sampling points, located close to the RDW device. After the air disinfection procedure, reductions of total microbial counts at 22 °C and molds were achieved in SA2 and IC HVAC systems. An Aspergillus fumigatus contamination (6 CFU/500 L), detected in one air sample collected in the IC HVAC system, was eradicated after the disinfection. The surface samples proved to be of good microbiological quality. The results suggest the need for a disinfection procedure to improve the microbiological quality of the complex HVAC systems, mostly in surgical and intensive care areas.

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Journal articles on the topic 'HVAC'

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