1. Georgios Vagiannis
Project Manager Engineering
Engineering and Special Projects
Business Group Indoor Climate
Tangstedter Landstr. 111
22415 Hamburg Germany
T +49 (0)40 30 986-465
F +49 (0)40 30 986-49465
georgios.vagiannis@uponor.com
The concept of combined geothermal energy and
Thermal Active Building Systems (TABS): GEOTABS
Date: 15.03.2013
Location: Hamburg
Distribution: Ioannis Filippidis, Energia innovation Ltd
Salman Zafar, ecoMENA
Dear Sirs,
Uponor is a leading international provider of plumbing and indoor climate systems for the
residential and commercial building markets. Our solutions play an important role in
people's lives globally by providing products that create a comfortable environment for
living, work and leisure.
The concept of combined geothermal energy and Thermal Active Building Systems
(TABS), known as GEOTABS, has been developed the last years and has known great
success. The energy saving potential is substantial, starting from 20% and going up to
70%. For a system like this though to reach its maximum potential of energy savings,
professional design, control and installation, combined with a product of highest quality,
must be combined from feasibility stage to final building-in-operation stage. The latter
means that experienced and professional partners are considered crucial for system
optimization.
There are numerous researches, studies and references in the last years that show the
energy savings that the GEOTABS system can provide when it comes to heating and
cooling of buildings. Apart from some other studies that have been sent to you, we would
like to provide you with some general results of a related study from Uponor “Full cost
comparison of TABS vs. other HVAC”, conducted in cooperation with Equa Simulation
Finland Oy and Mott MacDonald Limited, UK.
This study compared a Life Cycle Cost (LCC) analysis of an office building with a TAB
system to dominant traditional systems in five European countries; Germany, UK,
France, Russia and Spain. Two locations where selected from each country and the local
dominant traditional systems where compared to TABS and also GEOTABS (TABS with HP
as seen below). Spain which its two selected locations, Madrid and Barcelona, are
considered to be closer climatically to the Middle East and the locally dominant systems
in Spain, all air system and fan coils, very close to the systems installed in the most
cases in the Middle Eastern region also. It should also be noted that the mechanical
minimum fresh air ventilation system was introduced to create the same indoor air
quality (IAQ) condition for all compared cases.
The Building Energy Simulation (BES) data used to collate the report was provided by
Equa Simulation Finland Oy. Cost analyses were performed by Mott MacDonald Limited.
Using outputs from thermal modelling by Equa carried out on each case, Mott MacDonald
created design concepts and quantity survey for each mechanical services method. Costs
were obtained from a variety of sources, including manufacturers, construction
economists, and Mott MacDonald’s own expertise.
The building consisted of four floors with a total area of 1000 m2
, length of 29 m, width
of 11 m, storey height of 2.8 m and total height of 12 m (Fig.1).

2. Georgios Vagiannis
Project Manager Engineering
Engineering and Special Projects
Business Group Indoor Climate
Tangstedter Landstr. 111
22415 Hamburg Germany
T +49 (0)40 30 986-465
F +49 (0)40 30 986-49465
georgios.vagiannis@uponor.com
Fig. 1: The office building into investigation.
The LCC calculation is undertaken in accordance with the method corresponding to the
term of global cost in EU Regulation No 244/2012, in terms of whole life cost for a 15
year calculation period. Local and central plant (HVAC system items) were sized based on
cooling/heating loads and ventilation rates from BES modeling, in the same method in
the course of completing a mechanical scheme design. Whole life costs for building and
building elements were calculated by summing up the different types of costs (initial
investment, energy, running, disposal) and applying on these the discount rate as to
refer them back to the starting year, plus the residual value as can be seen in Fig. 2
below.
Fig. 2: Whole life costs calculation.
So the LCC comprises the initial investment costs (material and labor cost, project
management and design cost as a percentage of material cost), running costs
(maintenance, capital for renovation/replacement at the end of equipment lifetime) and
energy costs (utilities and fuel prices, annual energy use).

3. Georgios Vagiannis
Project Manager Engineering
Engineering and Special Projects
Business Group Indoor Climate
Tangstedter Landstr. 111
22415 Hamburg Germany
T +49 (0)40 30 986-465
F +49 (0)40 30 986-49465
georgios.vagiannis@uponor.com
Some final and general results for the location of Madrid are provided below. Annual used
primary energy shows a total sum that has been used by the building. Primary energy
refers to the energy carriers at the beginning of the energy conversion chains (natural
resources) prior to undergoing any human-made conversions or transformations. Primary
energy factors: for electricity 2.21 and for natural gas 1.07.
Fig. 3: Annual delivered primary energy [kWh].
Annual energy cost including cost of installing a new connection and annual standing
charge calculated for 15 years of life cycle. Cost of installing a new connection for natural
gas is not included in the case of TABS with HP.
Fig. 4: Average annual energy costs comparison average per year, 15 years calculation period.
To conclude on the LCC comparison between the proposed systems, the whole life cost
per year is provided, for a calculation for 15 years period and with medium price
escalation of 3% for gas and electricity.
0
20000
40000
60000
80000
100000
120000
140000
160000
All air fancoil TAB TAB w HP
Heating
HVAC aux
Cooling
0
2000
4000
6000
8000
10000
12000
TAB TAB w HP Fan coil All air
HVAC aux. cost/year
Heating cost/year
Cooling cost/year

4. Georgios Vagiannis
Project Manager Engineering
Engineering and Special Projects
Business Group Indoor Climate
Tangstedter Landstr. 111
22415 Hamburg Germany
T +49 (0)40 30 986-465
F +49 (0)40 30 986-49465
georgios.vagiannis@uponor.com
Fig. 5: Global cost, average per year, 15 years calculation period.
Concluding in the results for the location that was provided above, Madrid, and also from
the results from all the other locations, the TAB system (TABS) had the lowest LCC global
cost from the studied systems. This low LCC global cost was also accompanied by the
best thermal comfort results among all the studied systems, thermal comfort advantages
that only a radiant cooling system can provide. The TABS with heat pump had the second
average lowest LCC global cost with lowest primary energy consumption, accompanied
by the same optimized thermal comfort conditions. The TABS without heat pump had the
second best average primary energy consumption.
It is important also to mention that the LCC global cost average rankings for both TABS
variations (with or without heat pump) were the same with all variations of electricity and
gas price escalation rate and for both calculation periods (10 and 15 years).
The advantageous use of TAB ceiling cooling with high supply water temperatures (17°C
- 22°C) enabled the high COP in cooling and constituted more efficient free cooling from
ground with the installation of the heat pump. The utilization of an intelligent control
system was the key to minimize the energy demand for cooling and thus the related
costs.
The investment costs of both TABS versions were the lowest of the investigated systems
and also the cost optimal one. The latter was enabled also through the lowest
maintenance costs among the systems, simply due to the compared lower amount of
components which needed service and maintenance. It is essential to point out that the
TABS with the installed pipework in the ceiling provides relative safety from mechanical
and chemical stress and has an estimated lifetime of 50 years. Moreover, the residual
value of TABS investments after 10 or 15 years calculation period is in both TABS cases
bigger than with the other systems, where most of their components have a shorter
lifetime (10-30 years) than the TABS ones.
The advantages that TABS is equipped with derive from the function of the TABS itself.
All the other investigated systems have lower supply temperature level with typical
dimension supply temperature of 7°C. Besides, cooling of the office spaces takes place
mainly by convection. The latter means that without cooled radiating surfaces the same
indoor operative temperature requires more cooling than with the TABS ceiling system.
At the same time the lower cooling water temperature decreased the COP for cooling in
lower levels than with the TABS. Furthermore, the convective cooling with high air
0
10000
20000
30000
40000
50000
60000
TAB TAB w HP Fan coil All air
HVAC aux. cost/year
Heating cost/year
Cooling cost/year
Maintenance cost/year
Renovation cost/year
Investment cost/year

5. Georgios Vagiannis
Project Manager Engineering
Engineering and Special Projects
Business Group Indoor Climate
Tangstedter Landstr. 111
22415 Hamburg Germany
T +49 (0)40 30 986-465
F +49 (0)40 30 986-49465
georgios.vagiannis@uponor.com
quantities increases the risk of draught and thus comfort dissatisfaction. Finally, the all
air system and the fan coil system used higher air volumes and lower supply
temperatures than TAB system, resulting in that way in higher fan energy and so even
higher risk for draught and comfort dissatisfaction.
All the above conclude to the fact that a TAB system can constitute an economical
optimal solution, when calculated for an economically reasonable time, where all relevant
costs are included. A ground source heat pump can deliver also lower running costs,
accompanied though with increased investment costs, which by all means constitute
lower LCC global costs of the other investigated systems. Moreover, the substantial
economical LCC advantages of the TABS are accompanied by optimized indoor thermal
comfort results of a radiant cooling system. In conclusion, a TAB system has proven
adaptable and cost effective for the Spanish conditions, providing both cost reductions
and improved indoor environment. Finally, the system is future proof as it works with any
kind of energy source and facilitates the integration of renewable and free cooling
sources.
Hamburg, 15.03.2013
Georgios Vagiannis