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Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC)

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A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Energy Science and Technology".

Deadline for manuscript submissions: closed (31 January 2021) | Viewed by 22855

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Special Issue Editor

Prof. Dr. Demis Pandelidis

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Guest Editor

Department of Mechanical and Power Engineering, Wroclaw University of Technology, 50-370 Wroclaw, Poland
Interests: renewable energy; new energy technologies; heat and mass transfer; numerical modeling; fluid mechanics; engineering thermodynamics; heating ventilation and air conditioning systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Heating, ventilation, and air conditioning systems (HVAC) are a critical component of modern buildings. The world needs radical change in the energy efficiency of HVAC technologies, one that can effectively offset global energy demand while improving the quality of life and health of users. The growing need for energy to provide comfortable indoor conditions has become a global concern. Due to this, new and innovative technologies need to be developed in order to face this challenge. This Issue is dedicated to new, advanced solutions in all of the fields of heating, ventilation and air conditioning systems which can significantly improve the energy efficiency of buildings.

This Special Issue is open to all contributors in the field of heating, ventilation, and air conditioning systems (HVAC). We invite submissions of novel and original papers and reviews to this Special Issue that extend and advance our scientific/technical understanding of the HVAC systems in areas that include but are not limited to:

Renewable energy;
Energy savings;
Heating;
Ventilation;
Air conditioning;
Energy efficiency;
Smart systems;
Cooling;
Energy efficiency;
Thermal storage;
Evaporative cooling;
Desiccant systems;
Adsorption;
Advanced buildings.

Dr. Demis Pandelidis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Renewable energy
Energy savings
Heating
Ventilation
Air conditioning
Energy efficiency
Smart systems
Cooling
Energy efficiency
Thermal storage
Evaporative cooling
Desiccant systems
Adsorption
Advanced buildings
Geothermal energy
New HVAC technologies
Innovation in HVAC

Published Papers (7 papers)

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Research

Jump to: Review

18 pages, 1524 KiB

Open AccessArticle

Analytical Investigation of a Novel System for Combined Dew Point Cooling and Water Recovery

by Aleksandra Cichoń and William Worek

Appl. Sci. 2021, 11(4), 1481; https://0-doi-org.brum.beds.ac.uk/10.3390/app11041481 - 06 Feb 2021

Cited by 4 | Viewed by 2074

Abstract

This paper presents the analytical investigation of a novel system for combined Dew Point Cooling and Water Recovery (DPC-WR system). The operating principle of the presented system is to utilize the dew point cooling phenomenon implemented in two stages in order to obtain both air cooling and water recovery. The system performance is described by different indicators, including the coefficient of performance (COP), gained output ratio (GOR), energy utilization factor (EUF), specific energy consumption (SEC) and specific daily water production (SDWP). The performance indicators are calculated for various climatic zones using a validated analytical model based on the convective heat transfer coefficient. By utilizing the dew point cooling phenomenon, it is possible to minimize the heat and electric energy consumption from external sources, which results in the COP and GOR values being an order of magnitude higher than for other cooling and water recovery technologies. The EUF value of the DPC-WR system ranges from 0.76 to 0.96, with an average of 0.90. The SEC value ranges from 0.5 to 2.0 kWh/m³ and the SDWP value ranges from 100 to 600 L/day/(kg/s). In addition, the DPC-WR system is modular, i.e., it can be multiplied as needed to achieve the required cooling or water recovery capacity. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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11 pages, 5112 KiB

Open AccessArticle

Model-Based Fiber Diameter Determination Approach to Fine Particulate Matter Fraction (PM_2.5) Removal in HVAC Systems

by Marlena Drąg

Appl. Sci. 2021, 11(3), 1014; https://0-doi-org.brum.beds.ac.uk/10.3390/app11031014 - 23 Jan 2021

Cited by 3 | Viewed by 1848

Abstract

Particulate Matter (PM) is a general term to classify air pollutants consisting of airborne particles. The particles vary in composition and size, and the sizes of particles range from 2.5 µm (PM_2.5) to 10 µm (PM₁₀). Anthropogenic activity (e.g., industrial processes or fuel/waste combustion) stands as the main emission source of PM. Due to the fact that indoor PM penetrates from the outside to indoor air, Heating, Ventilation, and Air-Conditioning (HVAC) filtration systems may play a significant role in decreasing air pollution indoors. The section of the respiratory tract affected by particulate matter depends on the particle size. The smaller the fraction, the more deeply it can enter into lungs and bronchi, causing a series of health problems. Conventional electret air filters applied in HVAC systems are not able to efficiently remove PM_2.5 (e.g., huge gaps between thick fibers and unintentional elimination of electrostatic effects). The electrospinning process allows for the production of fibers of diverse diameters, including ultrathin yarns. The following work presents the axial length scale χ

χ

estimation method for the given conditions and experimental results. According to this approach, it is possible to find out what parameters should be used to produce materials at certain fiber diameters and to capture fine particulate matter fractions (PM_2.5). This research refers to poly(acrylonitrile) (PAN) fibers. The most important advantages, limitations, and challenges of the presented methodology are detected and discussed in this work. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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14 pages, 1616 KiB

Open AccessArticle

A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in an Indoor Vertical Farm. Part 2: Rainwater Harvesting

by Anna Jurga, Anna Pacak, Demis Pandelidis and Bartosz Kaźmierczak

Appl. Sci. 2021, 11(1), 310; https://0-doi-org.brum.beds.ac.uk/10.3390/app11010310 - 30 Dec 2020

Cited by 9 | Viewed by 4045

Abstract

The aim of this study was to determine the suitability of a rainwater harvesting system to cover the water demand for indoor hydroponic lettuce cultivation located in Wrocław (Poland). The analysis was performed on the basis of the recorded rainfall in Wrocław in 2000–2019. The analyzed cultivation is located in a hall with an area of 300 m², where the lettuce is grown vertically by the hydroponic method. The calculations of the rainwater harvesting (RWH) system were carried out considering the selection of the tank capacity for the collected water. The operation of the water storage is simulated using a yield after spillage (YAS) algorithm. It was evident that the proposed system might be an auxiliary system that relieves the water supply network or supports other water recovery systems (e.g., the water vapor condensation in a cross-flow heat exchanger operating as an element of the air conditioning system, proposed in Part 1 of this study). The harvesting system for the selected vertical farming indoor hall covers an average of 35.9% of water needs and allows a saving of 146,510 L of water annually for the cultivation. An average water demand coverage increases up to 90.4%, which allows a saving of 340,300 L per year when the RWH system is combined with water recovery from exhaust air from the hall. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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19 pages, 334 KiB

Open AccessArticle

A Direct Optimization Algorithm for Problems with Differential-Algebraic Constraints: Application to Heat and Mass Transfer

by Paweł Drąg

Appl. Sci. 2020, 10(24), 9027; https://0-doi-org.brum.beds.ac.uk/10.3390/app10249027 - 17 Dec 2020

Cited by 5 | Viewed by 1346

Abstract

In this article, an optimization task with nonlinear differential-algebraic equations (DAEs) is considered. As a main result, a new solution procedure is designed. The computational procedure represents the sequential optimization approach. The proposed algorithm is based on a multiple shooting parametrization method. Two main aspects of a generalized parametrization approach are analyzed in detail: a control function and DAE model parametrization. A comparison between the original and modified DAEs is made. The new algorithm is applied to solve an optimization task in heat and mass transfer engineering. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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13 pages, 1929 KiB

Open AccessArticle

A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air

by Anna Pacak, Anna Jurga, Paweł Drąg, Demis Pandelidis and Bartosz Kaźmierczak

Appl. Sci. 2020, 10(24), 8907; https://0-doi-org.brum.beds.ac.uk/10.3390/app10248907 - 14 Dec 2020

Cited by 9 | Viewed by 3533

Abstract

This paper presents the characteristics of the operation of the system for recovery of water from exhaust air in moderate climates in the years 2012–2019. The proposed system for water recovery uses the phenomenon of condensation in a cross-flow heat exchanger operating as an element of the air conditioning system. The parameters of exhaust air behind the heat exchanger have been determined using a mathematical model of the so-called black box. The mathematical model considers the risk of the cross-freezing of the heat exchanger. The calculations carried out for variable parameters of external air during the analyzed period confirm that the system allows to cover the demand for water for lettuce irrigation during the cold and transitional period, which is a major part of the year. It has been noted that the effectiveness of the system is very high (av. 67.12% per year) due to the specific parameters of the internal air in which the lettuce must be grown and the need for continuous air exchange in such facilities. This means that air is a stable source of water recovery, where the recovery rate depends on the parameters of external air. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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11 pages, 820 KiB

Open AccessArticle

Performance Optimization of the Low-Capacity Adsorption Oxygen Generator

by Wojciech Gizicki and Tomasz Banaszkiewicz

Appl. Sci. 2020, 10(21), 7495; https://0-doi-org.brum.beds.ac.uk/10.3390/app10217495 - 25 Oct 2020

Cited by 2 | Viewed by 3615

Abstract

This paper presents an innovative method of optimizing energy consumption by a low-capacity adsorption oxygen generator. As a result of the applied optimization, reduction in the energy consumption of oxygen separation by about 40% with a possible increase in the maximum efficiency by about 80% was achieved. The experiments were carried out on a test stand with the use of a commercially available adsorption oxygen generator using the PSA technology. The experimental analysis clearly shows that the adsorption oxygen generators offered for sale are not optimized in terms of energy consumption or capacity. The reduction of the oxygen separation energy consumption was achieved by appropriate adjustment of the device operating parameters for the given adsorption pressure and maintaining an appropriate pressure difference between the adsorption bed and the product tank. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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Review

Jump to: Research

18 pages, 23003 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Review of Dew Point Evaporative Cooling Technology for Air Conditioning Applications

by Anna Pacak and William Worek

Appl. Sci. 2021, 11(3), 934; https://0-doi-org.brum.beds.ac.uk/10.3390/app11030934 - 20 Jan 2021

Cited by 24 | Viewed by 4820

Abstract

Indirect evaporative cooling has the potential to significantly improve the natural environment. It follows from a significant reduction in electricity consumption in the hot period, and hence lower operating costs for cooling systems. This paper presents the current state of knowledge and research directions on dew point indirect evaporative cooling. It was found that researchers focus on the development of dew point indirect evaporative coolers (DPIEC) by improving its design, geometry, water distribution, and new porous materials implementation. To evaluate the performance of new types of DPIEC, different methods are used by the scientists. Finally, optimized devices are studied in terms of their performance in different systems, like hybrid and desiccant systems, considering different climate conditions. Potential directions of development of evaporative technologies were indicated, such as increasing the coefficient of performance of solid desiccant evaporative cooling systems, developing novel geometry, and efficient water distribution, including development of porous materials. Full article

(This article belongs to the Special Issue Fundamentals and Recent Advances in Heating, Ventilation, and Air-Conditioning Systems (HVAC))

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