a novel ventilation and heating system … · passive stack ventilation mechanical extract balanced...

Joanna Polak, Ph.D. candidate

Danish Building Research Institute, Aalborg University, Copenhagen,

Denmark

A NOVEL VENTILATION AND HEATING

SYSTEM FOR RESIDENTIAL BUILDINGS

DANVAK Dagen 2018 April 11, 2018

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Indoor climate in residential buildings and

importance of ventilation

Indoor air pollutants in residential

buildings can lead to discomfort or may

cause health implications

Pollutants are produced externally or

within the building

Ventilation is a key factor in maintaining

a satisfactory indoor climate for the

occupants

Common sources of indoor air pollution

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Residential ventilation

Ref. Technical Note AIVC 57: Residential ventilation, 2002

Ref. Danish Building Regulations, 2018

Passive Stack Ventilation Mechanical Extract Balanced Mechanical Ventilation

with Heat Recovery

Transition from traditional ventilation concepts towards mechanical ventilation with

heat recovery

Due to strict energy regulations mechanical ventilation is common a requirement

in residential buildings

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Combined ventilation and heating systems

Incorporation of heating into ventilation system

Simplified space-heating distribution system, reduction of HVAC system installation

and maintenance costs

Suitable for passive houses, where thermal comfort can be achieved solely by post-

heating of the supply air

Possibility to supply heat via supply air at ventilation rates based on IAQ

requirements with a maximum supply air temperature of about 50°C

Ref. Passive House Institute. 2014. The Passivhaus Standard.

Ref. Feist et al. 2005. Energy and Buildings, 37, 1186-1203.

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Combined ventilation and heating systems

Limitations related to provision of the desired thermal comfort on room level within a

dwelling

t air

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Combined ventilation and heating systems

Limitations related to provision of the desired thermal comfort on room level within a

dwelling

t ref

The same supply air temperature t air in all rooms

Regulation in individual room is not possible

t air

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Combined ventilation and heating systems

Limitations related to provision of the desired thermal comfort on room level within a

dwelling

t ref

The same supply air temperature t air in all rooms

Regulation in individual room is not possible

According to Danish regulations it should be possible adjusted the air temperature on

room level

Ph.D. project

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Title: A new ventilation system for sustainable residential buildings

Supervisor: Alireza Afshari, professor with specific responsibilities, SBi, AAU

Co-supervisors: Niels Christian Bergsøe, senior researcher, SBi, AAU

Göran Hultmark, development manager, R&D, Lindab A/S; adjunct professor,

SBi, AAU

Objectives: The goal of the project is to design, develop and evaluate the performance of a

novel, temperature-based demand controlled ventilation system. The novelty of

the system is its capability to adjust the supply air flow rate and air

temperature on a room level.

Methodology: Calculations/ Simulations

Experiment in a laboratory

Full-scale test in a real building

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Regulation on room level

Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings,

accepted for Indoor Air Conference, 2018

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Regulation on room level

manifold

Ref. www.lindab.com 11

Supply ductwork

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Laboratory experiment

Experimental setup, Lindab A/S, Farum

Full-scale prototype of the system

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15

20

25

30

35

40

45

50

55

0 15 30 45 60 75 90

Air t

em

pera

ture

, °C

Damper position, °

t1 t2 t3

Control of the air temperature

The temperature of the supply air can be controlled individually in each of the supply

ducts in a range of 25 °C and 52 °C, for the input parameters used in the experiment

Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings,

accepted for Indoor Air Conference, 2018

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y = 0,0269x + 0,194R² = 0,9982

y = 0,0649ln(x) + 0,6689R² = 0,6739

0,50

0,55

0,60

0,65

0,70

0,75

0,80

0,85

0,90

0,95

1,00

0,00

0,25

0,50

0,75

1,00

1,25

1,50

1,75

2,00

2,25

2,50

2,75

3,00

0 10 20 30 40 50 60 70 80

Eff

ectiveness,

-

Pow

er

deliv

ere

d in w

ate

r, k

W

Airflow rate, l/s

maximum power delivered in water effectiveness of heat exchange

𝜀 =ሶ𝑄

ሶ𝑄𝑚𝑎𝑥

ሶ𝑄 = ሶ𝑞𝑚,𝑎𝑖𝑟 ∙ ℎ𝑜𝑢𝑡𝑙𝑒𝑡,𝑎𝑖𝑟 − ℎ𝑖𝑛𝑙𝑒𝑡,𝑎𝑖𝑟

ሶ𝑄𝑚𝑎𝑥 = ሶ𝑞𝑚,𝑤𝑎𝑡𝑒𝑟 ∙ ℎ𝑖𝑛𝑙𝑒𝑡,𝑤𝑎𝑡𝑒𝑟 − ℎ𝑜𝑢𝑡𝑙𝑒𝑡,𝑤𝑎𝑡𝑒𝑟

Effectiveness of heat exchange

The effectiveness of heat exchange was defined as a ratio of the actual heat

transfer rate to the maximum possible heat transfer rate and calculated as:

Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings,

accepted for Indoor Air Conference, 2018

Air flow rate: 14 l/s

Supply air temperature: 37 °C

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Thermal comfort in a room

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Further steps

Energy performance Installation in a building

Simulations: Modelica model of the system

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Joanna Polak

jop@sbi.aau.dk

Danish Building Research Institute

Aalborg University

Thank you