Ministry of Finance, GreeceGSIS Ministry of Finance, Greece

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About the building

The General Secretariat for Information Systems (GSIS) building in Athens is a public, administration agency belonging to the Greek Ministry of Economy and Finance. It is an unusual office building, as it was built as a factory in the 1960s and converted to offices in the 1990s.

Objectives
Integration of low energy and sustainable design and technology into the overall architectural design, optimising efficiency of applied measures and reporting on their implication

Refurbishment Strategy

Solar Gain Control

External perforated metal horizontal and vertical shading devices were fitted to the south and west facades to reduce solar gain which previously caused overheating.

Lighting

All lighting was replaced with energy efficient T5 luminaires, with electronic dimming capabilities. The lighting automatically dims in response to natural daylight levels to minimise the use of artificial lighting.

 

Heating and Cooling

Prior to refurbishment, fan coil units met the thermal and cooling requirements of the office areas.  These were grouped in zones and provided heating with pumped, boiler heated water. Similarly, water was passed through central chillers when necessary to provide cooling. The units were equipped with local controls (thermostat and speed controls) and operated independently of any other environmental parameters. Consequently, it was common practise to have the fan coil units operating at full capacity whilst the windows were open. Also, the water pumps operated at full capacity regardless of the heating or cooling demands of the building.

During the refurbishment, wall mounted thermostats were introduced to control the operation of each fan coil unit. All thermostats were wireless and communicated with a centralised BEMS. The thermostats were configured to operate only when the offices were occupied and in night setback mode, when the office was cooled. The valves of the fan coil units were replaced with motorised valves, which could be controlled through the BEMS. Magnetic contacts were installed at the windows, which could switch off the fan coil units when the window was opened.

To make the operation of the pumps more efficient, calorimeters (combined with flow meters) were installed in all primary circuits to measure the thermal loads of each zone. Inverters were also installed to control the output of the pumps. The calorimeters are monitored constantly and the speed of the pump is automatically adjusted to respond to demand for heated or cooled water.

Ceiling fans were introduced to make use of the evaporation cooling effect. These are connected to the centralised system and switch on or off depending on whether a person has been detected by the occupancy sensor, or if the temperature exceeds a preset level.

 

 

For this part of the innovation procedure, temperature and CO2 sensors were installed. Also, the central wire and wireless network for each floor was installed. In the next few days the installation of inverters and calorimeters will be done.

Ventilation

Before the refurbishment, air handling units pre-conditioned the air from outside. These were distributed in zones, each of which served a number of office areas. The building is the workplace for 1400 permanent employees spread over 30,000 m2. Offices were densely occupied and CO2 concentrations were sometimes extremely high.

A Demand Control Ventilation system was installed. Motorised Volume Dampers were installed to the air handling unit zones. Air quality and CO2 concentration is monitored and the dampers are opened when the CO2 concentration increases above a preset level. When the CO2 concentration is below this level, the dampers are set to provide at least 30% fresh air to the offices. At these times, the unused fresh air is directed to other zones, ensuring that the air circuit is kept balanced. An additional damper has been installed between the fresh air supply and return air to compensate when there is an overall excess of fresh supply air and redirect it to the return air stream. This redirected air is already preconditioned and therefore reduces the amount of energy that the air handling unit consumes to precondition the fresh air. All measurements from the Motorised Volume Dampers and CO2 and air quality sensors are visible to the SCADA system.

 

Renewable Technologies

A photovoltaic array was installed, consisting of 19 semi-transparent cells.

GSIS Final Photos 033

GSIS solar PV installation

Energy Management, Control & Monitoring
HVAC management with thermostatic control, remote valves, zoning techniques, distribution control (BMS) - use of optimisation techniques, application though the use of neural network and fuzzy logic control, telemonitoring of BMS by use of innovative ICTs like the Smart e-Box (Ericsson) or EuroBus EIB (Siemens), telemonitoring and continuous optimisation of control strategies to minimise energy consumption and to optimise indoor environmental quality and comfort.

Economiser control
selective use of fresh air whenever this is cooler than the recirculated indoor air as well as redistribution of of cooler air from nearby indoor spaces with different indoor comfort requirements. And heat recovery on ventilation, by installing a heat exchanger unit in the exhaust air stream, energy recovery will be achieved during the whole year by preheating or pre-cooling the incoming ventilation air contributing considerably to the heating and cooling savings

  • Using radio controls, no cable installation is necessary which means that disturbance of the users will be avoided. All the readings will transferred to the BMS. Terminal via M-Bus protocols. The BMS. Will take into account the consumed energy and the water volume and will control the inverter pumps which will replace the existing ones and it will control the activation sequence of the chillers as well.
  • The BMS will gather all consumptions and monitor / allocate the energy costs. With the above described system, we have two types of controls. One in each zone, which gives freedom to the user setting of course certain limits and one in the production which works according to the weather conditions, and according to the end users demands.

Sustainability and Materials
Adoption of sustainability principles - application of Life Cycle analysis techniques during the whole building renovation on all aspects relating to, energy, materials, systems, etc. selection / adoption of strategies on systems / materials, according to the European directives on energy efficient building and building materials during the whole design phase.

Commissioning

Several technical problems were encountered but these were relatively minor and were generally caused by the fact that the building remained operational throughout the refurbishment, and new systems had to be installed into a building with existing infrastructure. For example, in order to replace the motorised valves on the fan coil units, the system needed to be drained, which was not possible whilst the building was in use. A special process had to be devised where the water in the central water pipes was cooled to freezing, in order to stop water leaking from the fan coil units.

It was decided to install a completely new BEMS as part of REVIVAL, which would operate independently from the existing BEMS. The new BMS is successful and is essential for troubleshooting in such a large building. The solar PV installation also delivers the expected savings.

Monitoring
Monitoring activities are necessary in order to evaluate in practice the specific and the global energy and environmental quality of the building. Thus, monitoring protocols and strategies will be defined and designed in order to get the necessary information which will then be compared with the theoretical results obtained during the evaluation - simulation phase.

In the frame of the present task, a very detailed monitoring strategy will be defined and the specific performance of each of the major subsystems defined will be monitored using the appropriate protocols and instrumentation. The protocols and monitoring techniques that are going to be used have been established either by international bodies and organizations or have been developed in the frame of previous research projects. In addition, a survey will be planned and performed among the employees of the building in order to evaluate the level of thermal comfort and indoor environment quality achieved.

The monitoring system will be included into the BEMS. For this purpose additional heating volume meters and electricity meters will be installed and a special performance specification for the BEMS will be written.

The monitoring phase will have the duration of a whole year and the obtained data are going to be analysed and evaluated in order to identify the efficiency of the implementation of the proposed energy saving strategies and technologies in the building.

The Completed Building

The GSIS design team were able to integration “low energy and sustainable design” into the refurbishment process, as targeted in the original contract. The GSIS is a public, administrative building and has experienced severe, bureaucratic delays and communication issues during the refurbishment. The fact that the building was still in use during refurbishment mean that for safety reasons, some work had to be carried out on weekends, causing delays. The concepts of sustainable building refurbishment are not widely recognised in Greece and the design team felt it was an achievement simply to complete the project. The building is in need of other areas of refurbishment and the design team expressed regret that they were unable to refurbish some of the areas that were outside the scope of REVIVAL.

The demand control ventilation strategy, where CO2 sensors are used to control the supply of outdoor fresh air based on the actual occupancy of the room, is an effective way of saving energy. However, occupant satisfaction at the GSIS building after refurbishment was not as high as expected, with users commenting on the indoor temperature and air quality in particular. The ventilation system may have been more successful if it provided a gradual increase in fresh air supply as the CO2 concentration increased, rather than responding to fixed CO2 limits. This feature was not possible at the GSIS building due to limitations of the existing infrastructure.

Dissemination.
Preparation of deliverables and distribution to designers, engineers, clients and authorities in the field while using the opportunity to disseminate to the actual visitors of the buildings as education of the general public.

Papers & presentations:

·         Monitoring of the indoor air quality of the GSIS building within the frames of the EU project REVIVAL, Group of Building Environmental Studies, 2007

·         Results of the BEMS monitoring on the energy consumption and indoor air quality of the GSIS, Group of Building Environmental Studies, 2008

·         Article published in the national magazine ‘Energy Point’, May 2008

·         Final results of the G.S.I.S. renovation, submitted to the 7th International Conference on Sustainable Energy Technologies, August 2008.

·         Energy and environmental design of the GSIS building, Energy at Urban Areas, Athens, 29 Nov. 2006