A semi-centralized, valveless and demand controlled ventilation system in comparison to other concepts in field tests

Merzkirch, Alexander; Maas, Stefan; Scholzen, Frank; Waldmann, Danièle

doi:10.1016/j.buildenv.2015.06.007

Cited by 20 publications

(7 citation statements)

References 10 publications

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“…The main cause for the large difference between standardised and measured HRE, is likely to be due to unbalanced flows. In a study of both centralised and decentralised systems Merzkirch et al found that systems that are unbalanced can lead to decreased heat exchange efficiency [20]. Flows in the Rural location would appear to be more balanced.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the theoretical and in-use performance of Exhaust Air Heat Pumps

O’Sullivan

Colclough

Morehead³

et al. 2021

E3S Web Conf.

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Integrated units that combine Exhaust Air Heat Pumps (EAHPs) with Heat Recovery Ventilation (HRV) and, in some instances, Domestic Hot Water Storage (DHW), are becoming increasingly popular in the domestic market across Europe with over 24,000 EAHPs purchased in the EU in 2017 alone. Early research into using EAHPs demonstrated energy savings being conservatively between 20% and 50% when compared to conventional systems. Recent research has suggested that, in reality, EAHPs in-use energy performance can be worse than that estimated by various standardised theoretical assessment methods (COP/SPF in the range of 0.4 to 6.0). More worryingly, published data on this in-use operation is effectively non-existent for NZEB type dwellings and few studies have stress tested the robustness of the EN standards in accounting for the effects of in-use operation. The study presented in this paper investigated whether the standard methods used to predict in-use energy performance are sufficiently robust and adequately capture operational performance for EAHP systems. The energy performance of two identical EAHP systems in Ireland (one rural/ one urban) were monitored for close to 12 months. During the live in-use monitoring period, the EAHPs had ‘heat-pump/heat recovery only’ operating mode ratios of 16%/84% and 22%/77% for rural and urban systems respectively. The average HRE in-use efficiency was 92% and 64% for the rural and urban systems respectively. While the manufacturers stated Seasonal performance factors (SPF) ranging from 2.2 (for DHW) to 5.8 (for Space Heating), the average in-use SPF was found to vary between 1.7 and 3.8 depending on the boundary reported and the location. More research is urgently required in order to bring much needed clarity for designers and energy assessors regarding which boundaries can be universally applied to EAHP systems. Given the range of SPF which could apply to the HP’s examined, the paper highlights the importance of ensuring that realistic indicators of in use performance are provided, aiding appropriate decision-making by policymakers, industry and end-users.

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Section: Resultsmentioning

confidence: 99%

Evaluation of the theoretical and in-use performance of Exhaust Air Heat Pumps

O’Sullivan

Colclough

Morehead³

et al. 2021

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…However, existing buildings may pose problems during their modernisations or if the building uses change. A partial solution for lack of space involves use of a decentralised system consisting of the local ventilation unit dedicated to a limited number of rooms [32,[34][35][36][37].…”

Section: Air Quality Standardsmentioning

confidence: 99%

The Well-Being of Children in Nurseries Does Not Have to Be Expensive: The Real Costs of Maintaining Low Carbon Dioxide Concentrations in Nurseries

Ratajczak

Basińska

2021

Energies

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There are different standards and regulations outlining the requirements regarding building air quality as well as in nurseries. These requirements specify air stream supplies and carbon dioxide concentration levels, both of which ensure proper indoor air quality. Mechanical ventilation should be used to maintain acceptable carbon dioxide levels. This article analyses the use of ventilation equipped with decentralized units, which helps secure the well-being of children. This paper proposes and evaluates economically affordable ventilation units. An algorithm for selecting the size of the devices is described by the supplied air stream depending on the number of children present at the nursery. A method of transferring the investment costs related to the assembly of the given units to the parents is proposed. Air quality in terms of CO2 concentrations was based on the following levels: 750 ppm, 1000 ppm, 1500 ppm. This assessment also includes the investment costs resulting from device usage and the costs of electricity consumed by the fans. These results showed the additional costs that assure the air quality improvement do not have to be high (45 PLN/month, ~10 EUR/month) per child attending the nursery. A 3% tuition increase returns the investment costs on mechanical ventilation within four years.

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“…Centralized demand-based systems with the combined control strategy of CO 2 , TVOC and humidity are often proposed and simulated in studies. Their energy efficiency and overall performance are good, but we still have limited measured case studies where the benefits of demand-based systems are demonstrated [26].…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of the Demand-Based Ventilation in a Nordic Apartment Building

2020

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In general, new Finnish apartment buildings are equipped with mechanical balanced demand-based ventilation. The airflow rate in the kitchen hood is boosted on demand to improve pollutant extraction during cooking. However, in practice, it has been found that the system does not work as desired. The focus of the paper was to present the simulation results from a case building equipped with a ventilation system that is commonly used in Finland. In the analysis, the airflow rates are calculated for the room, apartment, and air handling unit (AHU) levels for various ventilation mode scenarios. A significant imbalance of over 10% between the supply and exhaust airflows at the room and apartment levels was observed in the boosting mode. This imbalance creates a pressure difference over the building envelope, particularly in small studio apartments. The calculated pressure difference for future buildings with high airtightness were at the warning level of 40 Pa below atmospheric level. The kitchen hood exhaust system showed a 28% lower airflow rate in certain scenarios. A new solution to guarantee the designed airflow rates was proposed and assessed. The new solution consists of replacing the apartment level flow control damper and a new balancing method for the kitchen hood exhaust branch. The proposed design was able to stay within 10% of the designed airflow rates in all operation modes.

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A semi-centralized, valveless and demand controlled ventilation system in comparison to other concepts in field tests

Cited by 20 publications

References 10 publications

Evaluation of the theoretical and in-use performance of Exhaust Air Heat Pumps

Evaluation of the theoretical and in-use performance of Exhaust Air Heat Pumps

The Well-Being of Children in Nurseries Does Not Have to Be Expensive: The Real Costs of Maintaining Low Carbon Dioxide Concentrations in Nurseries

Performance Analysis of the Demand-Based Ventilation in a Nordic Apartment Building

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