This project compares the performance of two different heating and cooling systems.
These two systems are a water based system, which is mainly based on Thermally
Activated Building Systems (TABS), and an air based system, which is based on a simple
heating, ventilation and air conditioning (HVAC) system.
A climate classification for the use of TABS has been created in the current project. The
intention of this classification is to determine in which climate zones a building requires to
implement a heating, a cooling or a dehumidification system. A climate classification
system that considers dehumidification is important when TABS are implemented, since
risk of condensation can be a problem when these systems are used for cooling
requirements.
The new European Climate Classification (ECC) system is based on a combination of the
annual number of heating and cooling degree days and the outdoor dew-point
temperature. Four different thermal categories, which are defined by the number of
heating and cooling degree days, and three dew-point categories, which are defined by the
dew-point temperature, are introduced in the ECC system. In total, the current
classification is based on twelve possible final climate categories and has been evaluated
in 92 European cities.
Some parameters have been introduced in thermal and dew-point categories. These
parameters are investigated in a parametric analysis conducted in this project. This
analysis investigates how changing some parameters in the ECC system affects the
location of the different climate zones in the map of Europe. As shown in this analysis
these parameters have a significant effect on the climate classification of the locations in
Europe. Only two of the five initial base temperature cases were evaluated in the entire
parametric analysis as more suitable classifications for Europe according to existing
climate classifications were obtained with these two cases. These base temperature cases
are HDD18°C/CDD18°C and HDD16°C/CDD19°C.
Thermal comfort and energy consumption are compared between water and air based
systems using the building simulation program IDA ICE. The performance of both systems
is tested in ten European cities classified in seven different climate zones found with the
ECC system. The comparative analysis is carried out in four different offices of the
Balanced Office Building (BOB) in Achen, Germany. The BOB is an energy-efficient and
well-insulated office building in which TABS are implemented for cooling and heating
requirements.
The shading devices implemented at the beginning are modified for offices A, C and/or E,
according to each city case, in order to improve thermal comfort. For all ten locations the
initial shading coefficients have been reduced for office C, since during the first
simulations it was found that indoor temperatures were too high in this office.
