scholarly journals The Effect of High Occupancy Density on IAQ, Moisture Conditions and Energy Use in Apartments

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4454 ◽  
Author(s):  
Kristina Mjörnell ◽  
Dennis Johansson ◽  
Hans Bagge
Keyword(s):  
Air Quality ◽  
Energy Demand ◽  
Heat Recovery ◽  
Energy Use ◽  
Ventilation System ◽  
Moisture Damage ◽  
Housing Shortage ◽  
Additional Energy ◽  
Moisture Conditions ◽  
Ventilation Rates

Apartments built in Sweden during the record years 1961–1975 with the aim to remedy the housing shortage and abolish poor standards, were designed for a normal-sized family of 2–4 persons. The mechanical ventilation system, if existing, was primarily designed to ensure an air exchange in the apartment according to Swedish building regulations. During the last few years, the number of overcrowded apartments has increased due to housing shortage in general but also due to migration. Another aspect is that the ventilation in many apartments built during the record years is already insufficient at normal occupant load. The question is how doubling or tripling the number of occupants and thus, the moisture load will affect the risk of bad air quality and moisture damage. To find out, simulations were made to estimate whether it is possible to obtain sufficient air quality and low risk of moisture damage by only increasing the ventilation rates in existing systems or introducing new ventilation systems with and without heat recovery and what the consequence would be in terms of the additional energy demand. Measurements from earlier studies of CO2 and moisture supply in Swedish apartment buildings were used as input data.

scholarly journals Heat Recovery Ventilation for Energy-Efficient Buildings: Design, Operation and Maintenance

2019 ◽  
Vol 9 (1) ◽  
pp. 3713-3715
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Efficient ◽  
Heat Recovery ◽  
Energy Use ◽  
Ventilation System ◽  
Major Effect ◽  
Energy Efficient Buildings ◽  
Operation And Maintenance

Since the 1990s, many efforts have been intensified to fight global warming and energy crisis. Considering that the building sector is responsible for about 40% of the EU energy use and 36% of CO2 emissions, many sustainable concepts have been revived from the past, a number of new innovative technologies have been invented, and new construction standards and policies have been implemented. Sustainable architecture offers tailor-made solutions to minimize the negative environmental impacts of buildings without compromising its users' comfort. According to studies, humans spend about 90% of their live-time indoors; indoor air quality has a major effect on human health. Hence, bringing fresh air into all habitable areas without letting the warm/cool air escape has become a priority. If properly operated and maintained, heat recovery ventilation (VHR) in energy-efficient buildings leads to an increased filtration and removal of micropollutants, and an overall improvement of the indoor air quality, thus generating more comfort and less health-related problems. A systematic case study in Italy is used in this research providing evidences of the effectiveness of mechanical ventilation heat recovery systems. This paper discusses a case with a combination of poor design, operation and maintenance to answer the questions of: what are the concerns about potential failures that are associated with these systems; and are there any cons in the technical aspects of a mechanical heat recovery ventilation system?

Energy Conservation, Ventilation and Acceptable Indoor Air Quality

1978 ◽  
Vol 22 (1) ◽  
pp. 538-538
Author(s):  
James E. Woods
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Use ◽  
Renewable Energy Resources ◽  
Construction Techniques ◽  
Consumption Rates ◽  
New Codes ◽  
Current Concerns ◽  
Ventilation Rates

In response to current concerns about the depletion rates of non-renewable energy resources, new codes and standards have been promulgated which require improved construction techniques and reduced ventilation rates. While implementation of these codes and standards has reduced energy consumption rates, degradation of indoor air quality has also been reported. These complaints indicate that arbitrary reduction of ventilation rates can result in deleterious effects to the occupants. Thus, a compromise solution is required with the objective to provide a safe, healthy, and comfortable indoor environment by using materials and methods that optimize efficiency of energy use.

Determining the impact of air-side cleaning for heat exchangers in ventilation systems

2019 ◽  
Vol 41 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Akram Abdul Hamid ◽  
Dennis Johansson ◽  
Michael Lempart
Keyword(s):  
Pressure Drop ◽  
Energy Loss ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Energy Use ◽  
Ventilation System ◽  
Field Measurements ◽  
The Impact ◽  
Over Time ◽  
Ventilation Systems

Cleaning coils can be an efficient way to reduce the need for reparations and maintain the functionality of a ventilation system. This study builds upon existing knowledge concerning the contamination of heat exchangers. Through field measurements on coils and heat-recovery units, a laboratory experiment on a coil, and a generic calculation example, this study determines the impact of sustained contamination on heat-recovery units with regards to energy use. Field measurements made before and after cleaning of heat exchangers show an average increase in the pressure drop by 12% and decrease in the thermal exchange efficiency by 8.1% due to mass deposited on the surface of the heat exchangers. Results from a laboratory test show a correlation between the mass deposited on a coil and (1) the increase in pressure drop over the coil, as well as (2) a diminishing heat exchange. Accumulating contamination on heat-recovery units in residential and commercial buildings (over time) is then linked to increasing pressure drop and diminishing thermal efficiency. With models based on these links, energy loss over time is calculated based on a generic calculation example in a realistic scenario. Practical application: The results from this study emphasize the need for maintenance of buildings with ventilation systems with coils, but more so those with heat-recovery units. The presented field measurements and laboratory study correlate energy loss with sustained accumulation of contaminants on coils and heat-recovery units. These results should serve as a recommendation to property owners considering maintenance of such units in their buildings.

scholarly journals Simulation and Analysis of Various Ventilation Systems Given in an Example in the Same School of Indoor Air Quality

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2845 ◽  
Author(s):  
Katarzyna Gładyszewska-Fiedoruk ◽  
Vasyl Zhelykh ◽  
Andrii Pushchinskyi
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Carbon Dioxide Concentration ◽  
Additional Energy ◽  
Exhaust Ventilation ◽  
Building Ventilation ◽  
The Cost

The quality of internal air is one of the factors that affect the pace and quality of knowledge acquisition. Therefore, it is important that classrooms have high quality of air. Using computer simulation, the effect of various building ventilation variants on air quality in classrooms was analyzed. Two criteria were analyzed and six variants of ventilation. The analysis was carried out using the CONTAMW program, used for multi-zone analysis of ventilation and air quality in a building. As an indicator of air quality, the concentration of carbon dioxide in school halls was adopted. The analyses show that natural ventilation is not able to provide proper air exchange. Regular airing of classrooms during breaks can reduce the carbon dioxide concentration to 2500 ppm, however, there is a significant reduction in indoor temperature (even below 10 °C). The best control over the internal environment can be obtained by using a supply–exhaust ventilation system with heat recovery. Obtaining a higher stabilization of ventilation is achieved by supplying additional energy to drive fans, however, this is only a small amount of energy compared to the cost of heat for heating the building (maximum 2%).

scholarly journals Research on Best Solution for Improving Indoor Air Quality and Reducing Energy Consumption in a High-Risk Radon Dwelling from Romania

2021 ◽  
Vol 18 (23) ◽  
pp. 12482
Author(s):  
Ion-Costinel Mareș ◽  
Tiberiu Catalina ◽  
Marian-Andrei Istrate ◽  
Alexandra Cucoș ◽  
Tiberius Dicu ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Heat Recovery ◽  
Natural Ventilation ◽  
High Efficiency ◽  
Ventilation System ◽  
Radon Level

The purpose of this article is the assessment of energy efficiency and indoor air quality for a single-family house located in Cluj-Napoca County, Romania. The studied house is meant to be an energy-efficient building with thermal insulation, low U-value windows, and a high efficiency boiler. Increasing the energy efficiency of the house leads to lower indoor air quality, due to lack of natural ventilation. As the experimental campaign regarding indoor air quality revealed, there is a need to find a balance between energy consumption and the quality of the indoor air. To achieve superior indoor air quality, the proposed mitigation systems (decentralized mechanical ventilation with heat recovery combined with a minimally invasive active sub-slab depressurization) have been installed to reduce the high radon level in the dwelling, achieving an energy reduction loss of up to 86%, compared to the traditional natural ventilation of the house. The sub-slab depressurization system was installed in the room with the highest radon level, while the local ventilation system with heat recovery has been installed in the exterior walls of the house. The results have shown significant improvement in the level of radon decreasing the average concentration from 425 to 70 Bq/m 3, respectively the carbon dioxide average of the measurements being around 760 ppm. The thermal comfort improves significantly also, by stabilizing the indoor temperature at 21 °C, without any important fluctuations. The installation of this system has led to higher indoor air quality, with low energy costs and significant energy savings compared to conventional ventilation (by opening windows).

scholarly journals The relationship between airtightness and ventilation in new UK dwellings

2018 ◽  
Vol 40 (3) ◽  
pp. 274-289 ◽  
Author(s):  
Jenny Crawley ◽  
Jez Wingfield ◽  
Cliff Elwell
Keyword(s):  
Air Quality ◽  
Energy Demand ◽  
Energy Savings ◽  
Ventilation System ◽  
Energy Performance ◽  
Regulatory Compliance ◽  
Current Approach ◽  
Ventilation Strategy ◽  
Significant Difference ◽  
The Uk

The UK’s Air Tightness Testing and Measurement Association competent persons scheme collects pressure test data and metadata from the majority of new build dwellings in the UK. This article uses the dataset to investigate the importance of the ventilation strategy in airtightness design and construction. Design and measured airtightness were tested for association with declared ventilation strategy. It was found that ventilation strategy makes a statistically significant difference to airtightness; however, this difference is too small to be practically relevant. Properties with mechanical ventilation and heat recovery (MVHR) were shown to have a mean designed air permeability only 0.46 m3/m2h lower than naturally ventilated dwellings. Seventy-three per cent of homes with MVHR have design airtightness greater than or equal to 5 m3/m2h and 17% of naturally ventilated dwellings have design airtightness less than 5 m3/m2h. We discuss how current design is not maximising the CO2, cost and air quality benefit of each ventilation strategy. A new approach to regulatory compliance is proposed, which explicitly links the designed airtightness and chosen ventilation system. It is suggested that compliance could then be achieved using a set of airtightness ranges linked to appropriate ventilation strategies. This could be expected to result in reduced energy consumption and carbon emissions for new build homes compared to the current approach and would also potentially lead to better outcomes for occupants in terms of indoor air quality. Practical application: Analysis of a large database of the airtightness of new UK dwellings found that ventilation strategy makes very little difference to airtightness design. For dwellings with MVHR, the results suggest that infiltration levels are too high to maximise the energy savings; for naturally ventilated homes, there may be air quality issues. Coupling airtightness design and ventilation strategy can reduce a dwelling’s energy demand and can support achieving the required energy performance rating.

scholarly journals Feasibility of a Passive Ventilation System with a Thermal Damper - Simulations and measurement results of an experimental house in a mild region of Japan -

2019 ◽  
Vol 111 ◽  
pp. 06047
Author(s):  
Motoya Hayashi ◽  
Hoon kim ◽  
Yoshinori Honma ◽  
Junichiro Matsunaga
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Indoor Environments ◽  
Air Supply ◽  
Measurement Results ◽  
Simulation Results ◽  
Ventilation Rates ◽  
Ventilation Systems

In order to retain good indoor air quality through the year in detached houses with passive ventilation systems, the authors investigated a mechanical control air-supply method. Firstly, indoor environments in houses with passive ventilation systems with thermal dampers, were examined using a simulation program (Fresh). Secondly, a passive ventilation system with a thermal damper, an under-floorheating system with a heat pump and were installed in an airtight house at Maebashi in Japan and measurements on its ventilation characteristics and indoor air quality were made. The simulation results showed that if the thermal damper is well tuned, this mechanically controlled air-supply opening keeps ventilation rates adequate through the year especially in airtight houses. The measurement results showed that the ventilation rates were kept above the required level through the year and the TVOC concentration decreases from 3000 to 200 μg/m3 in 5 months after the construction.

scholarly journals Analysis of the Dependence between Energy Demand Indicators in Buildings Based on Variants for Improving Energy Efficiency in a School Building

2017 ◽  
Vol 26 (3) ◽  
pp. 31-41
Author(s):  
Marta Skiba ◽  
Natalia Rzeszowska
Keyword(s):  
Energy Efficiency ◽  
Energy Demand ◽  
Energy Use ◽  
Primary Energy ◽  
School Building ◽  
The European Union ◽  
Public Buildings ◽  
Additional Energy ◽  
The Impact ◽  
The Relationship

Abstract One of the five far-reaching goals of the European Union is climate change and sustainable energy use. The first step in the implementation of this task is to reduce energy demand in buildings to a minimum by 2021, and in the case of public buildings by 2019. This article analyses the possibility of improving energy efficiency in public buildings, the relationship between particular indicators of the demand for usable energy (UE), final energy (FE) and primary energy (PE) in buildings and the impact of these indicators on the assessment of energy efficiency in public buildings, based on 5 variants of extensive thermal renovation of a school building. The analysis of the abovementioned variants confirms that the thermal renovation of merely the outer envelope of the building is insufficient and requires the use of additional energy sources, for example RES. Moreover, each indicator of energy demand in the building plays a key role in assessing the energy efficiency of the building. For this reason it is important to analyze each of them individually, as well as the dependencies between them.

scholarly journals Determination of the most influential and cost-optimal building characteristics on the energy performance of commercial and industrial buildings

2019 ◽  
Vol 111 ◽  
pp. 03030
Author(s):  
Hilde Breesch ◽  
Barbara Wauman ◽  
Marcus Peeters
Keyword(s):  
Energy Demand ◽  
Ventilation System ◽  
Energy Performance ◽  
Building Envelope ◽  
Additional Energy ◽  
Heating And Cooling ◽  
Industrial Buildings ◽  
Thermal Bridges ◽  
Energy Simulations ◽  
The Cost

Unlike other types of buildings, commercial and industrial buildings have been so far “forgotten”. In addition, EPBD requirements are increasingly challenging for this type of buildings. This paper aims to identify the most building determinants of the energy performance of commercial and industrial buildings, focussing on the building envelope. Building energy simulations (BES) in TRNSYS are used to simulate the energy demand for heating and cooling in five building variants. The Pareto optimality approach that considers the economic and energetic objectives equally, is used to determine the cost-optimal solutions. The sensitivity analysis and cost-optimal study clearly reveal that airtightness seems to be the most important factor. Although heat recovery on a balanced mechanical ventilation system has a major impact on the energy demand for heating, this measure is not cost-optimal. The large impact of the U-value of the roof on the energy demand for heating is also reflected in the cost-optimal study. The insulation of the floor do not appear to be cost-optimal. Moreover, attention to construction detailing is important. The additional energy losses that can occur due to thermal bridges quickly reach significant values although solving the thermal bridges seems not to be cost-optimal.

The impact of design ventilation rates on the indoor air quality in residential buildings: An Italian case study

2016 ◽  
Vol 26 (10) ◽  
pp. 1397-1419 ◽  
Author(s):  
Roberta Moschetti ◽  
Salvatore Carlucci
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation System ◽  
Residential Building ◽  
Limit Values ◽  
Italian Case ◽  
Ventilation Rates ◽  
The Impact

The paper investigates the effects on building indoor air quality (IAQ) resulting from the choice of different design ventilation rates. A reference residential building was analysed by means of the multizone modelling software CONTAM, by monitoring the concentration of two pollutants: occupant-generated carbon dioxide (CO2) and total volatile organic compounds (TVOC) from indoor sources. A demand-controlled ventilation strategy based on building occupancy was implemented and users' presence schedules were defined. Specifically, the evolution of indoor pollutant concentrations was investigated when the design ventilation rates, recommended by two IAQ-related standards (the Italian UNI 10339 and the European EN 15251), were implemented through a mechanical ventilation system. Different results regarding the IAQ level were achieved accordingly to the dissimilar ventilation rates. After a statistical analysis on the distributions of CO2 and TVOC concentrations, EN 15251 outcomes showed overall better results of the analysed statistical metrics, i.e. prevalence, sensitivity and accuracy. Indeed, the EN 15251 design airflows led to indoor conditions that were more often classified either in the correct air quality class or in a higher class. Finally, a better alignment between the national and European IAQ standards is recommended, especially in terms of airflows, air quality classes and pollutant limit values.

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