Assessment of the air streams mixing in wall-type heat recovery units for ventilation of existing and refurbishing buildings toward low energy buildings

Ratajczak, Katarzyna; Amanowicz, Łukasz; Szczechowiak, Edward

doi:10.1016/j.enbuild.2020.110427

Cited by 32 publications

(23 citation statements)

References 41 publications

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“…Various problems associated with the operation of mechanical ventilation systems have been reported, including an insufficient supply of fresh air, inadequate temperature, humidity and velocity settings or failure to regularly clean and maintain the equipment [50]. Mechanical ventilation requires electrical power, and although systems with heat recovery can decrease useful and final energy, the consumption of primary energy may actually increase [51].…”

Section: Mechanical Ventilationmentioning

confidence: 99%

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Skotnicka-Siepsiak

2020

Energies

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Energy-saving ventilation systems are designed to improve the energy efficiency of buildings. Low energy efficiency in buildings poses a considerable problem that needs to be addressed. Mechanical ventilation with heat recovery has gained increased popularity in recent years. Mechanical ventilation has numerous advantages, including easy adjustment and control, high indoor air quality and elimination of indoor pollutants. Mixing ventilation is the most popular type of mechanical ventilation, in particular in residential buildings. Unsteady ventilation is a type of mixing ventilation that involves stronger mixing effects and smaller vertical temperature gradients to improve indoor air quality (IAQ) and minimize energy consumption. This study examines the possibility of controlling and modifying Coanda effect hysteresis (CEH) to generate unsteady flow and simulate the conditions of unsteady mixing ventilation. The experiment was performed on a self-designed test bench at the University of Warmia and Mazury in Olsztyn. It demonstrated that an auxiliary nozzle can be applied at the diffuser outlet to control CEH and the angles at which the air jet becomes attached to and separated from the flat plate positioned directly behind the nozzle. The study proposes an innovative mixing ventilation system that relies on CEH. The potential of the discussed concept has not been recognized or deployed in practice to date. This is the first study to confirm that an auxiliary nozzle by the diffuser outlet can be operated in both injection and suction mode to control CEH. In the future, the results can be used to design a new type of nozzles for unsteady ventilation systems that are based on CEH control.

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Section: Mechanical Ventilationmentioning

confidence: 99%

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Skotnicka-Siepsiak

2020

Energies

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Section: Façade Decentralised Ventilationmentioning

confidence: 95%

“…The researchers used carbon dioxide as an indicator of air quality when analysing façade ventilation units for single premises. In the case of devices with a reversible fan, at various air flow velocities, a sufficient reduction of CO2 concentration was observed (Figure 8) to ensure an appropriate IAQ [138]. The analysis of the air exchanges achieved by the unit with a dampers system [135] showed that, for both the 2-min supply/exhaust time and the 10-min time, the air exchange was sufficient for an office premise.…”

Section: Façade Decentralised Ventilationmentioning

confidence: 95%

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Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Zender–Świercz

2021

Atmosphere

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Poor indoor air quality affects the health of the occupants of a given structure or building. It reduces the effectiveness of learning and work efficiency. Among many pollutants, PM 2.5 and 10 dusts are extremely important. They can be eliminated using mechanical ventilation equipped with filters. Façade ventilation devices are used as a way to improve indoor air quality (IAQ) in existing buildings. For their analysis, researchers used carbon dioxide as a tracer gas. They have shown that façade ventilation devices are an effective way to improve IAQ, but require further analysis due to the sensitivity of façade ventilation devices to the effects of wind and outdoor temperature. In addition, legal regulations in some countries require verification in order to enable the use of this type of solution as a way to improve IAQ in an era characterised by the effort to transform buildings into passive houses (standard for energy efficiency in a building).

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“…A number of similar studies performed in laboratory conditions [47][48][49] focused on different technical aspects of air handling units and heat recovery issues under selected environmental conditions. It was clear that they could not fully match real exploitation circumstances.…”

Section: Introductionmentioning

confidence: 99%

Annual Energy Performance of an Air Handling Unit with a Cross-Flow Heat Exchanger

Michalak¹

2021

Energies

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Heat recovery from ventilation air is proven technology resulting in significant energy savings in modern buildings. The article presents an energy analysis of an air handling unit with a cross-flow heat exchanger in an office building in Poland. Measurements were taken during one year of operation, from 1 August 15 to 31 July 16, covering both heating and cooling periods. Calculated annual temperature efficiency of heat and cold recovery amounted to 65.2% and 64.6%, respectively, compared to the value of 59.5% quoted by the manufacturer. Monthly efficiency of heat recovery was from 37.6% in August to 68.7% in November, with 63.9% on average compared to 59.5% declared by the manufacturer. Cold recovery was from 63.3% in April to 72.8% in September, with 68.1% annually. Calculated recovered heat and cold amounted 25.6 MWh and 0.26 MWh, respectively. Net energy savings varied from −0.46 kWh/m2 in August, when consumption by fans exceeded savings, to 5.60 kWh/m2 in January.

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Assessment of the air streams mixing in wall-type heat recovery units for ventilation of existing and refurbishing buildings toward low energy buildings

Cited by 32 publications

References 41 publications

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Annual Energy Performance of an Air Handling Unit with a Cross-Flow Heat Exchanger

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