Central Ventilation Research Articles

Study of potential capacity as adsorbent of Moringa oleifera substrates for treatment of radon contaminated air in indoor spaces: Preliminary test

Radon is a radioactive gas known to be a human carcinogenic element that causes lung cancer. The Directive 2013/59/EURATOM establishes action plans for its monitorization and control in water and air specially at workplaces. There are several techniques to reduce the concentration of radon in air mainly based on improving ventilation rates. However, intelligent and energy-efficient buildings are well insulated and have centralized ventilation systems where air is recirculated continuously. This strategy has a negative influence on radon accumulation at indoor spaces. So, ventilation systems should be composed by filters with suitable materials to adsorb radon from indoor air. This work studies the radon adsorption ability of the most used adsorbent (activated carbon) and some not-processed substrates coming from Moringa oleifera, a natural plant with high potential as adsorbent for heavy metals and coagulant in and water treatment. The radon adsorption efficiency of the different solids is analyzed, showing promising results for radionuclide removal from air.

Numerical Investigation of School Stratified Ventilation Systems - A Ventilation Effectiveness Study

Good indoor air quality is an essential prerequisite for a healthy learning environment. Scientific research has shown that there is a direct correlation between air quality and pupils’ ability to learn. For the same supply air volume flow, stratified ventilation systems lead to an improved quality of breathing air than mixing ventilation systems. The ventilation systems that work on the stratified ventilation principle are therefore particularly suitable for the ventilation of classrooms. The air flow characteristics of these systems in classrooms are, however, not thoroughly investigated. In the context of this work, the air flow parameters of various school ventilation systems with stratified ventilation for a typical classroom will be investigated by means of Computational Fluid Dynamics (CFD). For this purpose, centralized ventilation systems with different air outlets as well as decentralized systems are examined and compared regarding their ventilation effectiveness and thermal comfort.

Fitness centers demonstrate CO2 concentration levels above recommended standards

This study aims to compare carbon dioxide (CO 2 ) concentration levels measured in fitness centers with the applicable guidelines from Brazil, France, and Europe. Three fitness centers in Florianopolis, Santa Catarina State, Brazil (fitness centers A, B, and C) participated in this study. The fitness centers have different physical characteristics and ventilation systems. Fitness centers A and B have split ventilation systems, while fitness center C has a central ventilation system. The air quality was assessed by determining the CO 2 concentration level, as measured by a non-dispersive infrared CO 2 concentration sensor. Data was analyzed with descriptive and inferential statistics. All three fitness centers recorded CO 2 concentrations significantly above (p = 0.00) the maximum level of 750 ppm recommended by the European standard. Fitness centers A (= 3752.13 ppm) and C (= 1360.89 ppm) also had CO 2 concentrations significantly above (p = 0.00) the maximum level of 1000 ppm recommended by the Brazilian and French guidelines. CO 2 concentrations in fitness centers were significantly above the maximum permitted levels. Besides suggesting inefficient ventilation in these fitness centers, high CO 2 concentrations can impair indoor air quality and increase risks to the health of practitioners.

A statistical analysis of coalmine fires and explosions in China

Abstract Large-scale coalmine accidents have occurred occasionally with great impact on society. To assess the characteristics of large-scale coalmine accidents, a database involving 782 Chinese accidents from 1950 to 2016 was built and analysed. The historical change of large-scale coalmine accidents was divided into four stages according to the accident number per year. Explosions and fires were the primary causes and deemed to be thermodynamically driven accidents due to their identical thermochemical essence of combustion, interchangeability and producing similar gaseous hazards. By constructing an analysis framework, some useful features were derived from the database. About 55% of the gas explosions occurred in coalmines with low methane-gas emission rates. Coal dust explosions were responsible for about 59% of the fires and explosions with over 100 casualties. The interchangeability of fires and explosions led to 79% of the large-scale coalmine fires and explosions in recent years. As ignition sources, blasting work, self-heating and friction and impact caused 86% of the fires and explosions from 2007 to 2016. About 44% of fires and explosions happened in coalmines with central ventilation systems. About 85% of fires and explosions concentrated on the locations of coalface, heading face and roadway.

THE HISTORIC VENTILATION SYSTEM OF THE HOUSE OF COMMONS, 1840–52: RE-VISITING DAVID BOSWELL REID’S ENVIRONMENTAL LEGACY

Between 1840 and 1846 the Scottish physician David Boswell Reid produced a scheme for a central ventilation system serving the Palace of Westminster. This scheme included a proposal for a sophisticated ventilation and climatic control system in the House of Commons. Although the plans for a central system were abandoned after six years, Reid was able to implement his idea within the confines of the House of Commons. Existing literature on Reid’s involvement in the design of the Palace of Westminster has focused largely on his difficult relationship with the architect Charles Barry, but his actual contribution to the design of the ventilation system has remained largely unexplored. Neither his unfinished early proposal nor his final design for the House of Commons has been studied in any depth before. This paper retraces the evolution of Reid’s original plans, and provides a systematic reconstruction of the ventilation system implemented inside the House of Commons between 1847 and 1854. The historic system is now completely lost, but new archival research, involving the study of several hundred letters, sketches and plans, has yielded detailed insights into its design and how it performed historically. In addition to revealing the ventilation system’s physical arrangements, research has uncovered how scientists and engineers had evaluated its design empirically from a human and technological perspective. As such, this paper provides a new perspective on antiquarian studies and illuminates how architectural technology in the mid-nineteenth century was shaped, evaluated and refined based on environmental performance. Although environmental factors, such as climate or air purity, were more transient dimensions of architecture, in the case of the House of Commons this paper shows that they were key drivers of architectural form.

Method for estimating and analyzing an increase of efficiency of the ventilation system in a livestock house

A method of comparative evaluation of a centralized ventilation system using and not using an ejection unit is developed. The aerodynamics fundamentals are used to substantiate the efficiency of the ventilation with the use of the ejection unit as well as to substantiate its parameters. It is specified that the main parameter of the ejection unit is the ejection coefficient defining the rate of an increase of the air supply due to ejection or the same amount of the ejected air. The structural parameters of the unit, its components, depend on this parameter: nozzle, pressure, mixing chambers, and supply shaft. The analysis of the standard designs of the livestock houses shows that the total resistance of the network of the supply ventilation system makes 600–800 Pa. That is why the ejection coefficient of the units can be assumed to be equal to three. Furthermore, the energy costs are reduced 2.4 times. It is specified that the best conditions for admixing the warm air are created at the smallest angle between the ejecting and ejected air, i.e., with the following motion of the flows.

New calculation method to solve moisture balance in the room with regenerator heat recovery and infiltration

This paper investigates moisture related performance of a regenerator heat exchanger located in a decentralized ventilation unit for residential building application. The decentralized ventilation solutions have recently become a more and more popular alternative to centralized ventilation systems. Due to the small space available and in order to avoid maintenance of these types of units, they are equipped with regenerator heat exchanger in some cases. In the recent past and also presently, Building Regulations (BR) and European directives have increased demands for heat recovery efficiency in air handling units (AHUs). In the case of regenerator heat exchanger, the higher the heat recovery efficiency obtained the higher risk that condensation might occur. This condensation might form small droplets on the surface of the regenerator that might not be possible to drain in the short switching time of the regenerator and consequently might be evaporated in the next cycle back to the building and cause elevated humidity conditions in the indoor spaces. Due to the fact that the traditionally used dilution equation must not be used to solve moisture balance in the room with regenerator heat exchanger and infiltration, this paper presents a new calculation methodology that takes into account infiltration, condensation in the regenerator, and back evaporation to the room. The paper compares humidity levels in the room ventilated with regenerator heat exchanger and ordinary counter-flow exchanger. Theoretical calculations indicate that the ability of a ventilation system with regenerator to remove moisture from the room is very dependent on moisture loads in the room, air change rate, and infiltration rate.

A-40 寒冷地域の集合住宅における温熱環境とエネルギー消費に関する研究 : その3.排気型セントラル換気システムの効果

A-40 寒冷地域の集合住宅における温熱環境とエネルギー消費に関する研究 : その3.排気型セントラル換気システムの効果

B-28 高気密住宅用ダクト式セントラル暖冷房・換気設備に関する研究 : その3 集合住宅におけるセントラル換気設備の性能評価

B-28 高気密住宅用ダクト式セントラル暖冷房・換気設備に関する研究 : その3 集合住宅におけるセントラル換気設備の性能評価

A-55 機械セントラル換気システムの性能検証と改修事例

A-55 機械セントラル換気システムの性能検証と改修事例

Improving the Energy and IAQ Performance of Ventilation Systems in Dutch Dwellings

MONICAIR - MONItoring & Control of Air quality in Individual Rooms - is a pre-competitive field research project of a broad consortium of Dutch ventilation unit manufacturers and research institutes, supported by the Dutch government. The first aim of the project is to investigate and compare the indoor air quality (IAQ) performance and energy characteristics during the heating season of ten different mechanical ventilation solutions in dwellings that meet strict air-tightness standards and comply with current building regulations. The second goal is to further improve the ventilation systems on their IAQ-performance while minimizing their energy consumption.Over a full year 62 residential dwellings were monitored with, in each habitable room, sensors for occupancy, CO2, relative humidity and air temperature. Power consumption of the mechanical ventilation units was also continuously monitored. The ventilation solutions included traditional mechanical exhaust ventilation or MEV systems (systems with mechanical exhaust in the wet rooms), state-of-the-art MEV systems (systems with mechanical exhaust in all rooms), as well as local and central balanced systems with heat recovery (MVHR-systems), with various types of controls. Although all systems under investigation comply with building codes, the data show that huge differences occur in both the IAQ and energy performance. CO2 excess dose (above 1200 ppm) may vary per dwelling from 10 to 850 kppmh per person per heating season, resulting in a situation in which respectively 1 to approximately 85% of the time spent at home, the ventilation is not sufficient in the room that one occupies. Real life primary energy consumption varies from 23 MJ/m2 for centralized ventilation systems with heat recovery to 144 MJ/m2 for traditional MEV-systems.

Energy analysis of a decentralized ventilation system compared with centralized ventilation systems in European climates: Based on review of analyses

In this study, the decentralized ventilation (DV) performance of a small air ventilator to replace natural ventilation for use in urban areas is analyzed and compared to conventional centralized ventilation (CV) systems in European climates. Selected European weather conditions were used to determine acceptable conditions for the operation of fan-assisted ventilation systems and to analyze the decentralized ventilation system's cooling and heating loads. Entire fan and pump loads of DV system are numerically calculated based on published data. Compared with a conventional centralized ventilation system, this system has shorter air transport distances and therefore entails lower pressure losses. In a decentralized system, fan speed and airflow rate are adjusted simply and effectively depending on indoor thermal conditions. A radiant panel with decentralized ventilation system (RPDV) is shown to have the lowest heating, ventilation, and air conditioning (HVAC) energy consumption because it not only minimizes supply and exhaust air pressure losses, but can also be operated as a fan-assisted natural ventilation system during periods when outdoor air can be used without additional thermal loads. Based on numerically calculated and measured data, this study newly adds fan and pump energy analysis of decentralized ventilation system compared to centralized ventilation systems. This study shows the fan and pump energy consumption with analysis of fan-assisted DV system considering outdoor weather condition in European climate.

RESEARCH OF APARTMENT BUILDINGS‘VENTILATION SYSTEMS AND ANALYSIS OF SYSTEM RENEWAL OPTIONS / DAUGIABUČIŲ GYVENAMŲJŲ NAMŲ VĖDINIMO TYRIMAI IR SISTEMŲ ATNAUJINIMO GALIMYBIŲ ANALIZĖ

The paper presents experimental study of apartment buildings' ventilation parameters which was carried out during the heating season. The results show that the existing apartment buildings often don‘t guarantee the hygienic conditions that are directly related to the indoor air ventilation. Also article contains an analysis of possibilities to upgrade the ventilation systems of apartment buildings. Four ventilation systems‘ upgrade options were examined. The economic analysis showed that according to the economic aspect the best solution for mechanical ventilation in the typical apartment houses is a centralized ventilation system which operates in combination with ground heat pump when supply ducts are mounted on the building facade, and extraction takes place at existing natural ventilation system channels. Straipsnyje pateikiami daugiabučių gyvenamųjų namų vėdinimo parametrų eksperimentiniai tyrimai, kurie buvo atlikti šildymo sezono metu. Tyrimų rezultatai rodo, kad esamuose daugiabučiuose namuose dažniausiai nėra užtikrinamos higieninės sąlygos, kurios yra tiesiogiai susijusios su šių namų vėdinimu. Taip pat straipsnyje pateikiama daugiabučio vėdinimo sistemų atnaujinimo galimybių analizė. Ekonomiškai išnagrinėti keturi vėdinimo sistemų atnaujinimo variantai. Atlikus ekonominę analizę, nustatyta, jog ekonominiu aspektu geriausias mechaninio vėdinimo sprendimas tipiniame daugiabučiame name yra centralizuota vėdinimo sistema, veikianti kombinuotai su gruntiniu šilumos siurbliu, kai tiekiamieji ortakiai montuojami ant pastato fasadų, o ištraukimas vyksta esamais natūralios vėdinimo sistemos kanalais.

Central Ventilation System with Heat Recovery as One of the Measures to Upgrade Energy Efficiency of Historic Buildings

Improving thermal shield in buildings and reducing energy consumption have become major problems to be solved for the recent decades. Natural ventilation accounts for nearly half of heat losses in existing buildings. A controlled heat recovery ventilation system makes it possible to reduce irrational heat losses and improve microclimatic comfort. A typical historic residential apartment building constructed before industrial times in Saint-Petersburg is subject of this article. Options of centralized controlled heat recovery ventilation systems for old historic apartment buildings in Saint-Petersburg are suggested in this article.

Energy and exergy analyses of advanced decentralized ventilation system compared with centralized cooling and air ventilation systems in the hot and humid climate

Abstract This research presents energy and exergy analyses of a new decentralized ventilation system to adapt to the hot and humid climate compared to general centralized ventilation systems. A zone model of an office building was applied for a heat pump cooling system in Singapore. The cooling load capacity of the zone model was simulated using the building energy simulation software “TRNSYS” and energy and exergy analyses of the new ventilation system were carried out through numerical calculations based on the measured cooling load capacity. An effective energy solution for buildings was to increase cooling and ventilation efficiency. The energy and exergy analyses evaluated the performance of the various cooling systems. The research revealed that the new decentralized ventilation system adapted to the hot and humid climate had better performance compared to a centralized all-air system and to a chilled ceiling with centralized air handling unit system.

Factors Influencing Indoor Air Quality in an Urban High-Rise Apartment Building

Background: Eighty percent of North Americans reside in cities and many urban dwellers live in high-rise apartments. However, few studies have examined pollutant concentrations in North American high-rise homes. The Ottawa Apartment Study examined factors influencing pollutant concentrations in an urban high-rise apartment building in downtown Ottawa, Ontario. Methods: We recruited apartments on lower, middle, and upper levels of the building. Neighboring units were included to assess vertical and horizontal infiltration. The study measured particulate matter (PM2.5), metals, and volatile organic compounds (VOCs), as well as air exchange. Continuous and integrated measurements were collected at approximately 30 sites including apartments (indoor and balconies), hallways, stairwells and the rooftop. Perfluorocarbon tracers were deployed to provide air exchange rates between indoor micro-environments as well as the outdoor air exchange rate. Building and occupant information were obtained through baseline and daily questionnaires. Results: Metal concentrations were typically higher on balconies and in hallways, while VOC concentrations were higher in apartments. PM2.5 concentrations did not vary significantly between micro-environments. There was some evidence to suggest that ambient concentrations of some metals and VOCs were higher at street level compared with upper level balconies. Outdoor PM2.5 from the balconies and central ventilation system were the major predictors of continuous PM2.5 concentrations in the apartments, with a smaller contribution explained by neighboring units. These results were consistent with the percent contribution based on air exchange measurements. Other factors influencing indoor concentrations (e.g., occupant activities and indoor sources) were similar to those for single family homes. Conclusions: Although many North Americans live in high-rise buildings, little information is available about their residential exposures. This study provides support for identifying strategies to reduce exposure in high-rise buildings.

Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons

Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2–4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (rp > 0.769, p < 0.05), and the slopes (1.2–4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs. During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

Large-Scale Intelligent Building Energy-Saving Measures Based on BA System

With the rapid development of the intelligent building in China, Intelligent building energy consumption has become a social and economic development in a strategic issue that can not be ignored in our society. In this paper, we proposed the energy saving measures in central air conditioning and ventilation system and lighting system of large-scale intelligent building building automation (BA) system from four aspects.

Assessment of Air Quality and Performance of Central Ventilation System

Central HVAC is a critical constructed facility in the built environment, yet polluted air quality has been causing environment, health, and safety problems to end-users worldwide, particularly in multistory commercial buildings with such systems installed. An index system was introduced in Hong Kong to measure the external air quality, but no system has yet been introduced for measuring internal air quality, nor the legislation to control it. The Hong Kong government states that more than 32% of commercial buildings and 37% of shopping arcades have sick building syndrome, which leads to nausea, dizziness, headaches, sore throats, nose irritation, sinus congestion, and other symptoms in the occupiers. In this study, the major causes, design, construction, users’ habitual modes, and mitigating measures will be investigated, with supporting case studies in Hong Kong. A preliminary investigation, air sample analysis, and end-users’ feedback from questionnaires will be gathered and analyzed to establish a long-term solution for air quality problems.

Investigation and Research of Biological Contamination of HVAC in Public Places

According to the normal method for sampling in the appendix of “The Central Air-Conditioning Ventilation System of Public Health Standard” by the ministry of health in 2006 were the HVAC on-site examined and sampled. The examined indicators include: total number of bacteria, fungus and beta Streptococcus in air supplied outlet, Legion Ella pneumophila in cooling water, the quantity of dust and microbe amounts to each square meter pipeline surface area and other sanitation indexes.