scholarly journals Performance assessment of demand controlled ventilation controls concerning indoor VOC exposure based on a dynamic VOC emission model

2019 ◽  
Vol 111 ◽  
pp. 01051
Author(s):  
Klaas De Jonge ◽  
Arnold Janssens ◽  
Jelle Laverge
Keyword(s):  
Performance Assessment ◽  
Building Materials ◽  
Ventilation System ◽  
System Level ◽  
System Control ◽  
Emission Model ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation ◽  
The Impact ◽  
Ventilation Systems

The performance assessment of ventilation systems often focusses only on CO2 and humidity levels. The indoor Volatile Organic Compounds (VOC) emissions of building materials or other products is thereby overlooked. The new generation of ventilation systems, Demand Controlled Ventilation (DCV), are systems that do not supply the nominal airflow continuously but are controlled by CO2 or humidity sensors in order to save energy. This poses potential problems for exposure to VOCs. In this study, a dynamic VOC model, which takes into account changing temperature and humidity that was derived from literature, is implemented in a CONTAM model of the Belgian reference apartment. The impact of a DCV system on the indoor VOC levels is investigated. Results show that the use of a dynamic model is necessary compared to the previously used approximation of a constant emission. Furthermore, on a system level, the influence of the ventilation system control on the indoor VOC levels shows. The overall VOC concentration in the different rooms will be higher because of lowered ventilation rates. Especially in rooms that are often unoccupied during the day, the accumulation of VOCs shows. In the development of DCV system controls, the aspect of VOC exposure should not be overlooked to be able to benefit from both the energy savings and improved Indoor Air Quality (IAQ).

scholarly journals Humidity-Sensitive Demand-Controlled Ventilation Applied to Multi-Unit Residential Building – Performance and Energy Consumption in Dfb Continental Climate

2020 ◽  
Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Ventilation System ◽  
Residential Building ◽  
Primary Energy ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation ◽  
Continental Climate

A humidity-sensitive demand-controlled ventilation system is known for many years. It has been developed and commonly applied in regions with an oceanic climate. Some attempts were made to introduce this solution in Poland in a much severe continental climate. The article evaluates this system's performance and energy consumption applied in an 8-floor multi-unit residential building, virtual reference building described by the National Energy Conservation Agency NAPE, Poland. The simulations using the computer program CONTAM were performed for the whole hating season for Warsaw's climate. Besides passive stack ventilation that worked as a reference, two versions of humidity-sensitive demand-controlled ventilation were checked. The difference between them lies in applying the additional roof fans that convert the system to hybrid. The study confirmed that the application of demand-controlled ventilation in multi-unit residential buildings in a continental climate with warm summer (Dfb) leads to significant energy savings. However, the efforts to ensure acceptable indoor air quality require hybrid ventilation, which reduces the energy benefits. It is especially visible when primary energy use is analyzed.

scholarly journals Impact of Typical Faults Occurring in Demand-controlled Ventilation on Energy and Indoor Environment in a Nordic Climate

2020 ◽  
Vol 172 ◽  
pp. 09006
Author(s):  
Kamilla Heimar Andersen ◽  
Sverre B. Holøs ◽  
Aileen Yang ◽  
Kari Thunshelle ◽  
Øystein Fjellheim ◽  
...  
Keyword(s):  
Indoor Environment ◽  
Energy Use ◽  
Qualitative Interviews ◽  
Building Performance ◽  
Local Approach ◽  
Performance Simulation ◽  
Building Performance Simulation ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation ◽  
The Impact

This study evaluates typical faults occurring in demand-controlled ventilation (DCV) system and the impact on three output results: energy use, thermal comfort, and indoor air quality. The methodologies used in this study were qualitative interviews of selected Norwegian Heating Ventilation Air Condition (HVAC) system experts and numerical modeling using the building performance simulation tool IDA ICE. The faults deduced from the qualitative interviews were modeled as the fault's different consequences to account for a large variety of faults. With a Norwegian school classroom as a case study, a local approach applying a one-at-a-time (OAT) simulation was used to perform an analysis of the extreme fault conditions that can occur. The results from the fault modeling demonstrated that greater attention is needed to avoid faults in the HVAC systems due to its impact on the indoor environment quality and energy efficiency of buildings.

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.

An energy-saving oriented air balancing strategy for multi-zone demand-controlled ventilation system

Energy ◽  
2019 ◽  
Vol 172 ◽  
pp. 1053-1065 ◽  
Author(s):  
Gang Jing ◽  
Wenjian Cai ◽  
Xin Zhang ◽  
Can Cui ◽  
Xiaohong Yin ◽  
...  
Keyword(s):  
Energy Saving ◽  
Ventilation System ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation

scholarly journals Humidity-Sensitive, Demand-Controlled Ventilation Applied to Multiunit Residential Building—Performance and Energy Consumption in Dfb Continental Climate

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6669
Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Primary Energy ◽  
Controlled Ventilation ◽  
Carbon Dioxide Concentrations ◽  
Demand Controlled Ventilation ◽  
Continental Climate ◽  
Ventilation Systems

Humidity-sensitive, demand-controlled ventilation systems have been in use for many years in regions with oceanic climates. Some attempts have been made to apply this technology in Poland, which has a continental climate. This article evaluates the performance and energy consumption of such a system when applied in an eight-floor, multiunit, residential building, i.e., the virtual reference building described by the National Energy Conservation Agency (NAPE), Poland. Simulations using the computer program CONTAM were performed for the whole heating season based upon the climate in Warsaw. Besides passive stack ventilation, that served as a reference, two ventilation systems were studied: one standard and one “hybrid” system with additional roof fans. This study confirmed that the application of humidity-sensitive, demand-controlled ventilation in multiunit residential buildings in a continental climate (Dfb) led to significant energy savings (up to 11.64 kWh/m2 of primary energy). However, the operation of the system on higher floors was found to be ineffective. Ensuring consistent operation of the system on all floors required supplementary fans. The introduction of a hybrid mode reduced carbon dioxide concentrations by approximately 32% in the units located in the upper part of the building. The energetic effect in such cases depends strongly on the electricity source. In the case of the national energy grid, savings of primary energy would be relatively low, i.e., 1.07 kWh/m2, but in the case of locally produced renewable energy, the energy savings would be equal to 5.18 kWh/m2.

Research on Demand Controlled Ventilation Strategy for Laboratory Ventilation System

2013 ◽  
Vol 805-806 ◽  
pp. 1558-1561
Author(s):  
Zhen Hua Bao
Keyword(s):  
Indoor Air ◽  
Energy Use ◽  
Ventilation System ◽  
Substantial Reduction ◽  
Ventilation Rate ◽  
Outdoor Air ◽  
Air Exchange Rate ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation ◽  
Rate Requirement

Reducing the amount of outdoor air entering a space has distinct advantages for ventilation system. However, it often brings the consequence of depressing indoor air quality (IAQ). For laboratories, on average, the laboratory IAQ conditions of low TVOCs and low particulates permitted the substantial reduction of minimum air change rates. With many modern laboratories operating with fewer fume hoods and more energy-efficient equipment and lighting, the labs minimum air exchange rate requirement is often the dominant energy use driver. Current codes or specifications for laboratories ventilation system are the most straight forward approaches. They do not optimize a laboratory's ventilation rate, or verify whether the intended levels of safety and comfort have been achieved by the labs design. Demand controlled ventilation (DCV) can also avoid over-ventilation by providing outdoor air rates based on actual occupancy rather than on design occupancy or full occupancy.

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