A NOVEL VENTILATION AND HEATING SYSTEM FOR RESIDENTIAL BUILDINGS

Transcription

1 DANVAK Dagen 2018 April 11, 2018 A NOVEL VENTILATION AND HEATING SYSTEM FOR RESIDENTIAL BUILDINGS Joanna Polak, Ph.D. candidate Danish Building Research Institute, Aalborg University, Copenhagen, Denmark

2 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 2

3 Residential ventilation 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 Passive Stack Ventilation Mechanical Extract Balanced Mechanical Ventilation with Heat Recovery Ref. Technical Note AIVC 57: Residential ventilation, 2002 Ref. Danish Building Regulations,

4 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 postheating 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 The Passivhaus Standard. Ref. Feist et al Energy and Buildings, 37,

5 Combined ventilation and heating systems Limitations related to provision of the desired thermal comfort on room level within a dwelling 5

6 Combined ventilation and heating systems Limitations related to provision of the desired thermal comfort on room level within a dwelling t ref t air The same supply air temperature t air in all rooms Regulation in individual room is not possible 6

7 Combined ventilation and heating systems Limitations related to provision of the desired thermal comfort on room level within a dwelling t ref t air 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 7

8 Ph.D. project Title: A new ventilation system for sustainable residential buildings Supervisor: Co-supervisors: Alireza Afshari, professor with specific responsibilities, SBi, AAU 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 8

9 Regulation on room level 9

10 Regulation on room level manifold Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings, accepted for Indoor Air Conference,

11 Supply ductwork Ref. 11

12 Laboratory experiment Full-scale prototype of the system Experimental setup, Lindab A/S, Farum 12

13 Air temperature, C 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 Damper position, t1 t2 t3 Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings, accepted for Indoor Air Conference,

14 Power delivered in water, kw Effectiveness, - 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: ε = ሶ Q ሶ Q max Q ሶ = qሶ m,air Qሶ max = qሶ m,water h outlet,air h inlet,air h inlet,water h outlet,water 3,00 2,75 2,50 2,25 2,00 1,75 1,50 1,25 1,00 0,75 0,50 0,25 0,00 y = 0,0649ln(x) + 0,6689 R² = 0,6739 y = 0,0269x + 0,194 R² = 0,9982 1,00 0,95 0,90 0,85 0,80 0,75 0,70 0,65 0,60 0,55 0, Airflow rate, l/s maximum power delivered in water effectiveness of heat exchange Ref. Polak et al., Development of a novel temperature-based demand controlled ventilation system for residential buildings, accepted for Indoor Air Conference,

15 Thermal comfort in a room Air flow rate: 14 l/s Supply air temperature: 37 C 15

16 Further steps Energy performance Installation in a building Simulations: Modelica model of the system 16

17 Thank you Joanna Polak Danish Building Research Institute Aalborg University 17