Defence of dissertation in the field of building technology, Kaiser Ahmed, M.Sc. (Tech.)

Detailed domestic hot water profiles enable accurate simulation of low and zero energy buildings.
 Zero energy building emulator

The public examination of the doctoral dissertation of Kaiser Ahmed, M.Sc. (Tech.), will be held on 18 December 2018 at 12.00 at the Aalto University School of Engineering. The title of the dissertation is Extensive building usage schedules for energy simulation completed with detailed consumption of domestic hot water.  Field of the dissertation is building technology.

Energy and power needs of domestic hot water (DHW) are highly dynamic and have a significant contribution to heating system sizing and energy use in residential buildings. This research work developed the monthly usage profiles of DHW, which extended to establish the hourly usages profiles for different occupant groups.

We found that the average daily consumption of DHW for Finnish people was 43L/person/day and larger family had higher daily use compared to smaller family. Also, hourly DHW usage profiles showed two peaks in a day and movement of peaks during weekdays compared to the weekend. Besides, smaller occupant groups had higher usage rates during peak hours compared to larger groups.

Developed profiles can explain the DHW use in single-family houses, terraced houses and apartment buildings. Developed mathematical equations for hourly usages of DHW, can be directly implemented in energy simulation tools.

In order to enable reliable energy simulations, other building usage schedules, namely occupancy, lighting, appliances for ten different building categories covered by Energy Performance of Building Directives were developed within close cooperation with REHVA in the preparation of EN16798-1:2018 and ISO 17772-1:2018 standards. The heat emission values from occupant body in winter and summer were also included in the standards. These developed schedules now available in European and international standards are expected to have wide use in energy simulation tools for buildings energy performance analyses and compliance assessment.

One application of these usage profiles was demonstrated for the sizing of ground source heat pump's (GSHP) power need, serving space and DHW heating in a single-family house. Our developed simulation-based correlation equations, reduced the power by 14-44% compared to the conventional sizing methods.

The new contribution of these theses allows to increase the accuracy of energy prediction at a design stage and minimizes the gap between the actual energy uses in buildings compared to the simulated energy uses according to the energy performance certificate.

Opponent: Professor Alireza Afshari, Aalborg University, Denmark

Supervisor: Jari Puttonen, School of Engineering, Aalto University, Finland

Advisor: Adjunct Professor Jarek Kurnitski, School of Engineering

Electronic dissertation:

Doctoral candidate’s contact information: Kaiser Ahmed, [email protected], phone +358 504636777

Place of the defence: Lecture hall R1, Rakentajanaukio 4, 02150 Espoo

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