Main building Vilnius Gediminas Technical University (VGTU), Vilnius, Lithuania |
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Typology
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University education and research centre
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Total floor area
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8484,20 m2
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Responsible project partners
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Renovacijos projektai Ltd. |
Summary
This demonstration project proves that by applying the methodology of multi-variant design and multiple criteria analysis of a
building refurbishment more efficient building refurbishment can be realized.
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The project, the challenges
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The challenge in this project was to show how energy efficient solutions can be achieved
in applying the methodology of multi-variant design and multiple criteria analysis of a building refurbishment by forming thousands
of alternative versions. This methodology allowed to determine the strongest and weakest points of each the main building's of
Vilnius Gediminas Technical University (VGTU) refurbishment project and its constituent parts.
"Every morning I look at the Main building of VGTU on my way to work and a feeling of admiration sweeps me: it has become so beautiful
after refurbishment. It's sad that we could not refurbish other buildings of VGTU yet". Prof. Dr. habil. Romualdas Ginevicius,
Rector of Vilnius Gediminas Technical University. |
Context |
The site of the VGTU main building is in a suburb, nearby Vilnius university (VU), residential buildings and a forest. Lithuanian climate is maritime/continental. The highest temperature in July is +30.1°C, the lowest in January is -22.7°C. The Lithuanian climate is temperate.
From May to September daytime highs vary from about 14°C to 22°C, but between November and March it rarely gets above 4°C. July and August, the warmest months, are also wet, with days of persistent showers. May, June and September are more comfortable, while late June can be thundery. Slush underfoot is something you have to cope with in autumn, when snow falls and melts.
In spring, when the winter snow thaws. Average annual precipitation is 717 mm on the coast and 490 mm in the East. Vilnius is located is the east of the country, 140-150 m above sea level. It has a mean annual temperature - 6.4°C, the mean winter temperature -4 °C.
The rectangular building is a public one, the first one to see while approaching the university. The main details are:
- Length and width: 74.30 x 17.22 m.
- Floor area: 8,484.20 m2.
- Number of storeys: 7.
- Number of occupants: 1,084.
- Number of rooms: 219.
- Several departments and lecture halls, with seating for 50 to 100 students.
- Average area per user: 7.83 m2.
- Building date: 1971.
The substructure of the building was made from frame pillar with columns of the UK type. The walls of the building have a ferroconcrete frame and three-layer ferroconcrete panels (60/90/90 cm). The thermal transmittance of walls is Uw = 1.07 W/m2K. During thirty years of exploitation, both sun and rainfall have had their impact on external sectors.
On some places connection junctures of three-layer panels were already partly crumbled. Such sealing junctures were easily blowable and pervious to moisture. Juncture in damaged places of the external sectors was sealed with sealing material and filled up with a sealant.
There were drawings available for the project. Below the two photos show the state of the building before retrofit.
The biggest part of the external sectors in the main facades was occupied by glass area. All window glass was placed in wooden or
aluminium profile frameworks. The windows were very old: closing windows and lack of tightness were the biggest inconveniences. Current
construction of the windows did not correspond to the modern window requirements and did not ensure proper inside comfort conditions. The
thermal transmittance of existing windows was Uwi = 2.5 W/m2K. Lateral entrance doors in the building were old, unsealed and very insecure
as well. The thermal transmittance of doors was Ud = 2.3 W/m2K.
All roofs of the building were flat, and the covering was made from the roll. In October 2002, the roof was repaired. After unwrinkling all blowholes and other roughness of the old covering, new hydro-isolating roofing was fit up. While renovating the roof, due to a shortage of financing, current old parapet tins were changed only in these places where they were very rusty. The thermal transmittance of roof was Ur = 0.8 W/m2K.
Structural unit
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U-value (W/m2K) |
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before retrofit |
after retrofit |
Windows
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2,5
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1,16
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Walls
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1,07
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0,2 |
Roof
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0,8
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0,2
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Doors
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2,3
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1,5 |
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Solutions
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Building construction
Keeping in mind that the building is now in use more than thirty years, the following measures have been suggested:
- Renovation of facades.
- Replacement of windows.
- Renovation of the roof.
- Replacement of entrance doors.
- A slight optimalisation of the renovated thermal unit and complement of the automatic part.
- Renovation of the heating system.
The retrofit concept than looks as follows:
Heating
It was suggested to carry out renovation of current morally and physically out-of-date heating system. It would include three stages:
- 1. A new, fully automated heating system, with automated compensation valves designed for the stands of the heating systems, new
closing reinforcement, the installation of thermostatic valves for heating equipment, change of trunk pipelines and co-ordination of
this part of the project.
- 2. Implementation of this heating system renovation.
- 3. Coordination and operation of the renovated heating system. This regards the heat effect.
During the partial renovation of the thermal unit, an electromagnetic indicator for heat and water quantity will be installed. With the
help of the indicator the heat quantity, the quantity of flowing water, instantaneous debit, initial and recursive temperature, initial
and final pressure is determined. Data of indicator may be transmitted by internet and the indicator managed by computer programs.
Ventilation
Renovation of mechanical air supply/removal systems includes:
- 1. Replacement of the current ventilation system with at new one, fully automated. Ventilation should be mechanical, with 50-70
percent recuperation. In addition, new pipelines of air supply/removal and equipment will be installed.
- 2. Implementation of this air supply/removal systems renovation.
- 3. Installation and co-ordination of the new systems. This includes installation and co-ordination of the systems.
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Energy data and additional results |
Estimated savings
Energy costs used for the payback calculation:
- Thermal : 36.14 €/MWh.
- Electric: 85.15 €/MWh.
Energy saving measures, heating
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(kWh/m2a)
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Total
(kWh/a)
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high-efficient windows
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26
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220,589
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insulation of roofs and facades
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27.9
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236,672 |
heating system
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36
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305,663
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ventilation system
(heating recovery system)
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42.2
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297,000 |
total heating energy savings
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132.1
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1,059,924
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| Energy saving measure/ investment/ savings/payback |
Total costs
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Saving
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Pay-
back periods
(a)
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(€)
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(&euro/a)
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Total
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462,000
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40,840
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11.31 |
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Measurements and evaluations
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The monitoring of the VGTU main building started in March 2006. The conclusions of an energy audit
(performed in 2002) showed that 14-16 °C was the average temperature in premises during a heating season. The indoor air temperature increased
by 2-4 degrees after replacement of windows, insulation of roof and renovation of the thermal unit.
Now the indoor air temperature meets the requirements. However, the analysis of volume flow, air velocity and relative humidity shows that
current values are lower than those of specifications. Insufficient speed of the indoor volume flow determines lack of oxygen. As a result,
indoor hygiene conditions are bad, people feel worse and their productivity decreases.
It was possible to compare the data on energy consumption before the renovation and during the renovation. In summer of 2004, the windows of the main building were replaced. In autumn of 2005, the roof and walls of the semi-basement were insulated.
In 2003, the heating energy consumption was 920,000 kWh, and in 2005 already 532,000 kWh, i.e. it decreased by 42%. In 2006, the heating energy consumption made up 547,000 kWh. Compared to 2003, the heating energy consumption decreased by 41%. In 2005, electricity consumption decreased by about 16% compared to 2003, and compared to 2004 by 26%.
The level of pollution was measured in the environment of VGTU in 2006-2007: noise pollution (dB), CO pollution (ppm), particular mates
pollution (particle pollution) (mg/m3).
A forecast of pollution (noise pollution, dB; CO pollution, ppm) in the environment of VGTU for theyear 2010 is provided.
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First hand experiences
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During the VGTU renovation aiming at energy savings measures, modifications occurred. Because of financial shortages the third renovation component, i.e. ventilation and in consequence the ventilation system, was not foreseen to be refurbished.
However, in the process of renovation the three main components - building envelope, heating and ventilation - must be kept in balance. As € 42,605.61 was saved by replacement of the windows, it was therefore decided to use that money for the renovation of the ventilation system.
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COORDINATION CONTACT |
If you have any questions about our project, please contact:
Hans Erhorn
Fraunhofer Institute of Buildings Physics
Phone: +49-711-970 3380
E-mail: Hans Erhorn |
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