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Retrofitting Existing University Campus Buildings to Improve Sustainability and Energy performance

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Abstract

In order to ensure a sustainable future, universities should start to use and spread the knowledge potential, technology and tools in research and education to serve as role models. The University of Applied Sciences Stuttgart (UAS) aims to become a CO2 neutral university and implement key principles of sustainable development through a trans-disciplinary approach. As part of the technical solutions studied in this large project this paper investigates efficient ventilation and lighting solutions for the retrofitting of campus buildings, with a particular emphasis on a lecture hall. Evaluations of the pre-retrofitting lighting and ventilation performance are based on recent measurements. A desiccant and evaporative cooling system (DEC) for ventilation and air conditioning is compared with a reference electrical compression cooling system. Following a detailed performance analysis, the best applicable options are identified.
PLEA 2016 Los Angeles - 32th International Conference on Passive and Low Energy Architecture.
Cities, Buildings, People: Towards Regenerative Environments
post- print version of ISBN: 978-0-692-74961-6
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DILAY KESTEN ERHART, MAXIMILIAN HAAG, ANDREAS SCHMITT,
DANIEL GUERLICH, MARINA BONOMOLO, URSULA EICKER
Title:
Retrofitting Existing University Campus Buildings to Improve Sustainability and Energy performance
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PLEA 2016 Conference, 32nd International Conference on Passive and Low Energy Architecture: Cities, Buildings, People:
Towards Regenerative Environments, Publication Date: Jul 2016, ISBN: 978-0-692-74961-6
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PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
Retrofitting Existing University Campus Buildings to
Improve Sustainability and Energy performance
A case study at Stuttgart University of Applied Sciences
DILAY KESTEN ERHART1, MAXIMILIAN HAAG1, ANDREAS SCHMITT1, DANIEL
GUERLICH1, MARINA BONOMOLO2, URSULA EICKER1
1Institution Centre of Applied Research on Sustainable Energy Technology, University Stuttgart University of Applied
Sciences, Stuttgart, Germany
2DEIM - Department of Energy, Information Engineering and Mathematical Models, Università di Palermo, Palermo,
Italy
ABSTRACT: In order to ensure a sustainable future, universities should start to use and spread the knowledge potential,
technology and tools in research and education to serve as role models. The University of Applied Sciences Stuttgart
(UAS) aims to become a CO2 neutral university and implement key principles of sustainable development through a
trans-disciplinary approach. As part of the technical solutions studied in this large project this paper investigates
efficient ventilation and lighting solutions for the retrofitting of campus buildings, with a particular emphasis on a
lecture hall. Evaluations of the pre-retrofitting lighting and ventilation performance are based on recent measurements.
A desiccant and evaporative cooling system (DEC) for ventilation and air conditioning is compared with a reference
electrical compression cooling system. Following a detailed performance analysis, the best applicable options are
identified.
Keywords: energy efficiency, monitoring, building simulation, desiccant cooling, comfort, lighting
INTRODUCTION
In order to ensure a sustainable future, universities should
start to use and spread the knowledge potential,
technology and tools in research and education to serve
as role models. An initiative, financed by the Innovation
and Quality Fund of Baden-Württemberg (Germany),
supports the development of universities as living
laboratories to demonstrate and implement sustainability
(Ministry of Higher Education, Research and the Arts,
2014). The UAS with its EnSign Project aims to become
a CO2 neutral university and to implement key principles
of sustainable development through a trans-disciplinary
approach. The process requires a range of integrative
measures at different levels: improvement of the urban
situation, improvement of the basic building structure and
HVAC including the operation concept as well as internal
processes, integration of renewable energies on campus,
development of innovative finance models for the
rehabilitation of public buildings, development of an
appropriate mobility concept together with an
infrastructure and urban development strategy with
regard to an energy concept including neighboring areas.
This study, accomplished by several faculties of the
UAS, focuses on energy demand reduction and the
increased use of renewables in the UAS buildings.
Through interdisciplinary work of the EnSign Team,
different monitoring systems were installed to find out the
potential of reducing energy consumption and
greenhouse gases, and further campus sustainability
efforts. A number of energy efficient ideas have been put
into action to reduce universities total energy demand and
increase the usage of the renewables (Dalibard, 2015).
The implementation of solar, environmental and
geothermal resources on the Campus will start in summer
2016. The progress is documented continuously and
optimization potentials will be pointed out in consecutive
stages of the project.
One of the two main objectives of this work is to show
the potential of energy savings in existing campus
buildings via DEC cooling. The other is to quantify the
increase of energy efficiency and the resulting ecological
impact (primary energy and carbon dioxide savings) by
different approaches concerning load reduction (raise of
user-awareness, automated control of lightning and
shading). With temperatures of up to 40°C in summer the
investigated lecture rooms’ thermal comfort is
insufficient. Therefore the DEC system with CPC and air
collectors will be integrated to the existing mechanical
ventilation in autumn 2016.
This paper investigates the efficient air-conditioning
and lighting solutions for the retrofitting of campus
buildings, with a particular emphasis on three lecture
halls in Building 3. Recent studies have estimated that
European schools contribute 15% of the public sector
carbon footprint (Kesten Erhart & Tereci, 2015). Lighting
is one of the largest electricity users in educational
buildings and responsible 19% of the total lighting
consumptions in commercial buildings (IEA -
International Energy Agency, 2010). Evaluations of the
pre-retrofitting lighting and ventilation performance of
one lecture room are based on recent measurements and
PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
observations. After a detailed performance analysis, best
applicable options are identified. The scenarios are
simulated and their impact in terms of identifying the
most efficient are discussed.
METHODOLOGY
The monitored test room is a lecture hall in Building
3 of the UAS, geographically located at 48°68'N latitude
and 9°22'E longitude. The room above and below are also
taken into account because these three rooms are supplied
from the same AHU. The location of building 3 and the
site plan of the campus are shown in Figure 1. The
duration of sunshine varies between 1300 and 2000
hours, while global radiation varies between 780 and
1240 kWh/m2. During winter, Stuttgart`s daylight can
range from 8 and a half to 9 hours. In summer the average
daylight period is almost 16 hours. The annual mean
temperature for Stuttgart is 10.9°C.
Figure 1: Site plan of the University of Applied Sciences,
Stuttgart.
The main facade of the lecture room is oriented
towards East-northeast. The test room’s floor area is
212.7 m² with about 11.5 m x 19.1 m (width x depth) with
different heights (shown left in Fehler! Verweisquelle
konnte nicht gefunden werden.). Heights are 2.62 / 3.77
/ 4.59 m for R324 / R224 / R124.
Figure 2: left: 3D-Modell of the selected lecture halls; right:
Second floor plan of Building 3 and the selected lecture hall
224
Figure 2 shows the floor plan of building 3 and the
selected lecture hall (R224). The Window-to-wall-ratio
of the lecture hall facade is 40%. The room surface
reflectance values are: Rceiling = 80%, Rwalls =80%, Rfloor =
30%, Rfurniture = 50%. The windows consist of two layers
of clear glass resulting in a visible transmittance (Vt) of
72%.
A detailed monitoring system is installed based on
National Instruments CompactRIO (cRIO) (NI
CompactRIO, 2016) and programmed in LabVIEW
(National Instruments Corporation, 2016). For the
comfort evaluation different room parameters were
identified and monitored via following sensors:
thermocouples (temperature), lux-meter (lighting),
current clamps (lighting electricity), occupancy detector
(presence) and air quality sensor (CO2-concentration).
Luminance and illuminance distribution and electric
lighting use:
In order to investigate the effect of daylight
availability on visual comfort and estimate potential
savings on lighting electricity in educational spaces,
measurements and monitoring were carried out.
As daylight factor (DF) threshold measurement is not
sufficient to assess the daylight performance, climate
based daylight modelling was used to analyze the lecture
rooms. To conduct climate based daylight modelling,
standardized meteorological files were used for specific
geographical locations. Three computer simulation tools
were used to model the daylight performance for the
present study. Three dimensional geometries, including
the rooms’ surroundings were built in Ecotect Analysis
2011. The numeric simulation results were also
visualized via the same tool. Radiance 3P7 for MS
Windows® was used for current moment daylighting
analysis. Climate based annual lighting analysis were
performed via Daysim 3.1 for MS Windows® (Reinhart,
2013). Additionally, an energy analysis of the existing
lighting system and suitable renovation suggestions
including a cost comparison was generated by DIALux.
12 different representative scenarios were chosen (4
times during 4 representative days during a year). For
each scenario, the suitable percentages of luminous flux
and power to achieve the minimum illuminance level of
500 lux, considering the daylight contribution and the
artificial lighting one, were calculated.
Thermal simulation:
For the design and control strategy of the DEC unit
the three rooms’ thermal behavior is dynamically
simulated with TRNSYS 17.2. (Klein, 2010)
The buildings external façade consists of solid
construction elements in concrete (U-value =
0.551W/m²K) and a transom/mullion façade (Schüco
FW50+S, U-value = 1.8 W/m²K) with double-pane
insulated glazing (U-value = 1.4 W/m²K, g-value =
0.622). The external roof has an U-value of 0.392
W/m²K, all floors are with suspended ceilings with U-
values of 0.655 W/m²K. The internal walls are made of
architectural concrete (U-value = 3.039 W/m²K).
PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
Currently there is no external shading system installed
and therefore not mentioned in this study.
For each zone detailed schedules (see Figure 3) were
defined according to the real occupancy time with a
maximum of occupant persons and a scaled down
occupancy during less visited lectures.
Figure 3: Schedule Occupation of the investigated rooms
Internal loads are calculated with a sensible and a
latent heat load of 65 W and 55 W per person (ISO 7730).
A water vapor emission of 60.8 g/h/person was assumed
to occur during occupation with activity level II (VDI
2078, 2015). The equipment’s thermal impact is
calculated according to Table 1 depending on the
schedules in every room. Artificial lighting of 5 W/m² is
considered per occupant person according to the
schedules. An infiltration rate of 0.3 h-1 is assumed.
Semester break with no occupancies are six weeks each
beginning from February 1st and August 1st. The set-point
temperatures of the holidays are set back to 18°C for the
heating and 32°C for cooling period. During the holidays
set-point temperatures are 20°C for heating and 24.5°C
for cooling. For cooling, dehumidification is taken into
account with maximum 65% internal relative humidity.
The heating and cooling loads are ideally calculated with
TRNSYS 17.2.
Table 1: Internal loads, lecture room equipment
max.people
equipment
R124
25
1 PC (140W)
R224
35
1 PC + 1 Beamer (240W)
R324
15
1 PC + 1 Notebook (230W)
For the simulation an hourly weather data file of
Stuttgart was generated with Meteonorm® (Meteonorm,
2012). The hourly ambient temperatures as well as the
cooling and heating loads are shown in Figure 4. The
cooling period starts in April and ends in September. In
winter (Oct. March) no cooling is necessary since
simple natural ventilation through windows is sufficient
to cool peak loads.
The heating demand is covered by district heating of
the local energy supplier. The heating supply is not
further discussed in this paper.
Figure 4: Hourly ambient temperature, heating and cooling
loads
The heating, cooling and electricity demand for
cooling is calculated, the maximum heating and cooling
loads as well as the necessary electrical power
consumption of the CCM of each investigated lecture
room is shown in Table 2.
Table 2: Heating and cooling energy demand, maximum
heating and cooling loads, electricity demand for cooling
𝐐
̇𝐜𝐨𝐨𝐥,𝐦𝐚𝐱
Qcool
Wel,cool
Qheat
[kW]
[kWh/a]
[kWh/a]
[kWh/a]
R124
5.2
802
286
7310
R224
3.9
407
145
5370
R324
11.3
4690
1680
10400
Reference cooling systems:
A reference system is defined to compare the DEC
with a conventional cooling system consisting of a CCM,
a dry cooling tower and a cold water storage tank. The
CCM systems average SEER is 2.8 with an energy
demand of approximately 10% for pumps, 20% for re-
cooling and 70% for the CCM (Eicker, et al., 2015).
DEC calculation:
A technical scheme of the DEC system is presented
in Figure 5. Its control is assumed to work in a control
cascade which starts components step by step depending
on the needed cooling load (Henning, et al., 2013).
Figure 5: Scheme of the DEC system
The available operation modes are free cooling (1),
indirect evaporative cooling (2), combined evaporative
cooling (3) and DEC operation (4). The electrical
consumption of the system results from a simplified static
calculation. The cooling load and external conditions
from the building simulation serve as input for every time
step. In every interval the performance of the operation
PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
modes is calculated using the software MATLAB®. The
mode with the lowest auxiliary energy demand covering
the cooling load is set by control. In this way the
operating state of the DEC in every time step is identified
(Henning, et al., 2013).
Figure 6: Outdoor air conditions during times with cooling
demand. The red frame indicates the used comfort zone based
on DIN EN 15251.
Knowing the auxiliary power consumption of the
different modes the total auxiliary energy demand is
calculated. The pumps of the humidifiers or the drive of
the DW (desiccant wheel) and rotary HEX (heat
exchanger) have a direct electricity demand. The
additional pressure drop from the DEC components are
taken into account concerning the fan power Pel,fan. The
values of the single components and the pressure drop for
a maximum volume flow rate of 3000 m³/h can be found
in Table 3. The simplified assumptions for the DEC
operation lead to a higher auxiliary electrical demand. For
example there is no air bypass of the desiccant wheel
when not in use. With a lower volume flow of the AHU
the pressure loss would consequently decrease. The
regeneration energy needed is assumed to be covered by
solar energy and always sufficient to deliver regeneration
air with a supply temperature of 70°C. This is in favor for
the DEC system energy performance. Further
assumptions are a constant volume flow V
̇ of 3000 m³/h, a
fan efficiency ηfan=0.85 and Pel,fan = V
̇×pfan (with p
= pressure difference and V
̇ = volume flow rate).
In this case the cooling energy demand (Qcool) to cover
the load refers to the difference between exhaust and
supply air. It is not the cooling transferred into the fresh
air stream.
Table 3: DEC components
Pressure Drop
Pel,aux
mode
[Pa]
[W]
[-]
DW
150
50
4
Hdf RA
90
90
2,3,4
Hdf SA
10
65
3,4
Air Collector
600
/
4
Rotary HEX
90
80
2,3,4
Ecological and PE performance:
The Primary Energy Factor (PEF) is the ratio of
primary energy to end energy and has been calculated
with a PEF for grid electricity of 1.8, corresponding to the
current German legislation ( Federal Ministry of Justice
and Consumer Protection, 2013). The GHG emission for
the cooling system is calculated with a GHG-equivalent
of 0.606 kgCO2/kWh (German electricity mix) ( Federal
Ministry of Justice and Consumer Protection, 2013). To
compare both cooling systems the performance indicator
SEER during cooling period t0 - t1 is used. The SEER is
the ratio of the cooling energy output to the electrical
energy input. The necessary auxiliary energy input
includes the electricity demand for pumps, fans and
motors (GEMIS model and database, 2015), (Henning, et
al., 2013).
𝑆𝐸𝐸𝑅 = 𝑄𝑐𝑜𝑜𝑙𝑖𝑛𝑔
𝑄𝑝𝑢𝑚𝑝𝑠 + 𝑄∆,𝑓𝑎𝑛𝑠 + 𝑄𝑑𝑟𝑖𝑣𝑒𝑠
RESULTS
Monitoring results:
Through monitoring evaluation of the existing AHU,
crucial control mistakes could be revealed. Both 4.5 kWel
fans are not following the programmed time schedule.
They are running 24/7, wasting 50% of their total energy
demand during unoccupied times.
Also preliminary data related to the lighting electricity
consumption from the test room indicate saving potential.
Combined with CO2 concentration measurements it can
be deduced that lights remain switched on during
unoccupied hours. An increase in user awareness or light
automation can increase energy savings.
Lighting:
Climate-based daylighting was used to evaluate the
performance of the lecture hall interior. Illuminance
distributions under every sky condition were considered
during occupancy.
Daylight savings time lasts from April 1st to October
31st. The total annual hours of occupancy at the work
place are 2000. The electric lighting system has an
installed lighting power density of 11 W/m2 and is
manually controlled with an on/off switch. Electric
lighting is activated 1798 hours per year. The occupants
perform tasks that require a minimum illuminance level
of 500 lux. The lecture hall has no dynamic shading
system installed.
Daylight autonomy (DA) is the percentage of the time-
in-use that a certain user-defined lux threshold is reached
through the use of just daylight. The daylight autonomies
for all core work plane sensors lie between 41% and 82%.
Daylight illuminances in the range of 100 and 2000 lux
are considered either desirable or at least tolerable.
Furthermore, the useful daylight illuminance between
100 and 2000 lux is generally not causing a visual
discomfort. The Useful Daylight Indices (UDI) for the
PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
evaluated zone are: UDI < 100 lux = 22%, UDI = 100-
2000 lux = 21%, UDI > 2000 lux = 57%.
Figure 7: The daylight autonomy distribution in the lecture hall
assuming existing occupancy schedule and a 500lux target
illuminance
The predicted annual electric lighting energy use in the
investigated lighting zone is 19.6 kWh/m2. Assuming a
lighting zone size of 210.9 m2 corresponds to a total
annual lighting energy use of 4153.3 kWh.
Continuous daylight autonomy (DAcon) gives partial
credit for daylight levels below a defined threshold. For
instance: if the threshold is 500 lux and the calculated
value for a certain time step is 300 lux, DA would give it
zero credit whereas DAcon would return 300/500 = 0.6
credit. This was originally proposed by Reinhart, et al.
(Reinhart, et al., 2006). DAcon is given as a percentage
value although lux data for a point in the room can also
be seen to provide information on how much electrical
lighting is needed. As the difference between the
illuminance level of 500 lux and the illuminance value
calculating from the DAcon, the percentage of power and
of luminous flux were calculated. The results show that
the needed annual electrical consumption for lighting to
achieve the illuminance level of 500 lux is 1010 kWh and
the annual electric lighting energy use is 4.8 kWh/m2. The
calculations were done based on the lighting density
power. The luminaire locations, types and the physical
properties of the lamps were not taken into account.
Considering the same number of occupancy hours, the
electrical consumption savings achievable by installing a
lighting control system were calculated through the
lighting simulations by DIALux. The calculated energy
consumption achievable with an on-off lighting system is
3690 kWh and 17.5 kWh/m2a. While, the calculated
energy consumption achievable with a lighting control
system (lighting sensor and dimming lamps) is 2220 kWh
and the total annual lighting energy use is 10.6 kWh/m2a.
The DIALux method predicts higher but supposedly
more “realistic” lighting energy savings than the DAcon
method because it considers the construction, application
and photometric characteristics of the lighting system.
The calculated primary energy savings of the electric
lighting system is around 2640 kWhPE/a. It can be
concluded that approximately 40% of the energy
consumption can be reduced by proposed lighting system
which involved precision selection of lamps and
luminaires, without sacrificing required illuminance
levels in the interiors.
Figure 8. Load duration curve of the cooling supply via DEC
during the cooling period. The different operation modes are
coloured
Cooling:
Covering the cooling load of 5900 kWh/a via DEC
results in a SEER of 6.9. The free cooling mode runs 16%
of the operating hours of 1530 h while indirect /combined
evaporative cooling/ DEC operation lasts 58/15/11%. In
30 hours or 2% the cooling demand could not be fully
covered. The DEC system’s SEER of 6.9. According to
Henning et al. the SEER of best realized solar cooling
installations reaches up to 8. (Henning, et al., 2013).
Energy savings / ecological performance:
The calculated electricity demand of the conventional
cooling system is about 2110 kWh/a. The electricity
demand for DEC cooling is 850 kWh/a and 2.5 times less
compared to a conventional cooling system. The primary
energy consumption of the DEC is approximately 1530
kWhPE/a and for the reference system 3800 kWhPE/a. In
comparison to the reference system the relative primary
energy saving of DEC is about 60% (2260 kWhPE/a).
The annual GHG emissions are in a range from 0.52 t/a
(DEC) and 1.28 t/a (reference system). In average the
GHG-emissions for the reference system are 2.5 times
higher than for the DEC-system. The DEC has a GHG
saving potential of 60% compared to the reference
system.
CONCLUSION
In this work, the cooling demand of lecture rooms was
analyzed and load reductions by efficient lighting and
renewable supply with desiccant solar cooling were
PLEA2016 Los Angeles - Cities, Buildings, People: Towards Regenerative Environments, 11-13 July, 2016
post- print version of ISBN: 978-0-692-74961-6
investigated. Both topics included an analysis of the
status quo situation in the University.
Visual comfort and energy savings are in the focus of
advanced control lighting systems. The results show that
it is possible to achieve about 36% of lighting energy
savings with a lighting control system.
Monitoring of the technical infrastructure must be an
element of every sustainable concept. Erroneous control
of a complex designed HVAC system can result in a high
waste of energy. Only the combined evaluation of
comfort and energy aspects deserves the term
“sustainable". As presented in the present study a trivial
hidden mistake in operation of the AHU leads to a waste
of additional 100% electricity. Using desiccant
evaporative cooling for building air-conditioning is a
viable scenario. It saves 60% of electricity and GHG in
the case of the investigated lecture rooms compared to a
CCM reference system for cooling. Dehumidification is
only during 11% of the operating hours in considered
moderate climate.
To achieve the goal for universities to realize a role
model position their technical competence should be
applied to their own building stock. From this perspective
the technical infrastructure and its operation should be
scientifically evaluated. Retrofitting measurements
combined with monitoring are essential to obtain and to
sustain a high energy efficiency and comfort level. User
awareness or automated systems (with possibility of
interaction) help saving energy.
NOMENCLATURE
Hdf
Humidifier
SA
Supply air
RA
Return air
HEX
Heat exchanger
CCM
Compression cooling machine
SEER
Seasonal energy efficiency ratio
DEC
Desiccant and evaporative cooling system
AHU
Air handling unit
Reg
Regeneration
PEF
Primary energy factor
DA
Daylight autonomy
DAcon
Continuous daylight autonomy
PV-T
Photovoltaic-thermal collector
PCM
Phase change materials
HVAC
Heating, ventilation, air-conditioning
ACKNOWLEDGEMENTS
The EnSign project is funded by the Ministerium für
Wissenschaft, Forschung und Kunst (MWK) Baden-
Württemberg, Wissenschaft für Nachhaltigkeit (Ministry of
Science, Research and the Arts of Baden-Württemberg, Science
for Sustainability).
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... The government aims till 2050 80% increase in energy efficiency compared to the 2008 level [1]. Universities, as role models, should use their cumulative know-how to obtain and to sustain a high energy efficiency and comfort level [2]. Within the research framework called "EnEff: Campus" (energy-efficient campus), many universities have been running research and development projects to reach this goal [3]. ...
... A shown in Figure 5, a standard retrofitting additionally with PV panels on the existing roof (1) could reduce the primary energy consumption for heat about 300T kWh/a. In comparison, a CE with integrated PV panels (2) could have this reduction 33% up to 400T kWh/a. as the energy substitution is related to the available surface area, the options (3) and (4) would not change the amount of the substation but as mentioned before the heating energy saving. ...
... as the energy substitution is related to the available surface area, the options (3) and (4) would not change the amount of the substation but as mentioned before the heating energy saving. (2,3,4) with integrated PV panels (blue: final energy, orange: primary energy) ...
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... The government aims till 2050 80% increase in energy efficiency compared to the 2008 level [1]. Universities, as role models, should use their cumulative knowhow to obtain and to sustain a high energy efficiency and comfort level [2]. Within the research framework called "EnEff: Campus" (energy-efficient campus), many universities have been running research and development projects to reach this goal [3]. ...
... as the energy substitution is related to the available surface area, the options (3) and (4) would not change the amount of the substation but as mentioned before the heating energy saving. (2,3,4) with integrated PV panels (blue: final energy, orange: primary energy) ...
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Full-text available
This article draws an innovative architectural solution for enhanced energy efficiency by retrofitting ensembles of listed buildings. A combination of various simulation tools and a self-developed feasibility tool has been used at the preliminary design stage to develop a measure at an urban scale within the campus of TU Berlin. First, a potential analysis for 48 buildings within the campus has been run using multi-zone simulations with Modelica. Afterward, with the feasibility analysis tool based on Python, called HCBC-Tool, all possible measures have been ranked at the pre-stage of this project. As a conclusion, by buildings where standard measures are not feasible, alternative solutions have been developed using DesignBuilder, where not only energy-related issues both also architectural ones were considered. Additionally, energy substitution measures have been simulated with SunnyDesign to complete the concept. Here, a “climate envelope (CE)”, which is an additional transparent envelope covering the buildings partially, has been developed for a building ensemble built between 1883-1975. Enhancing the energy efficiency of all five buildings within the ensemble with standard measures up to the new building level according to the German energy efficiency regulations would reduce their energy consumption app. 32%. Nevertheless, this regulation is not mandatory by listed buildings. Besides, 12,152 m2 external envelope surface should be retrofitted. By comparison, a CE could lead to enhanced energy efficiency and it alone could reduce the energy demand of the building ensemble up to 33% and combining it with standard measures could increase the savings up to 60%.
... As they are not dependent on climatic conditions but rather on the efficiency of the systems itself, they are unanimously reported as having positive effects in reducing the energy consumption of buildings. The adoption of efficient equipment such as LED lighting (Fonseca et al., 2018;Hu, 2018;Udas et al., 2018), heating, ventilation and air-conditioning (HVAC) (Erhart et al., 2016;Escobedo et al., 2014;Nagpal and Reinhart, 2018), or control sensors for those systems (Granderson et al., 2011;Omar et al., 2018;Petratos and Damaskou, 2015), results in significant energy savings in all campus dimensions and locations. ...
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... DA con , [19] as proposed by Roger's [18] associates partial credit for daylight levels below a user-defined threshold in a linear fashion. These data can be useful to estimate achievable energy savings for the artificial lighting system [20]. It can be observed that the contribution of daylight is highest in the cases where the application of the skylights is considered and it is proportional to the numbers of devices (or ratio of roof-light opening area and room ones). ...
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... An accurate predictive analysis of different possibilities of intervention and strategies is necessary to achieve good energy and comfort performances. Kesten Erhart et al. [3] presented a study developed within an initiative, financed by the Innovation and Quality Fund of Baden-Württemberg (Germany), that supports the development of universities as living laboratories to demonstrate and implement sustainability (Ministry of Higher Education, Research and the Arts, 2014). In particular, they investigated efficient ventilation and lighting solutions for the retrofitting of campus buildings, with a particular emphasis on a lecture hall. ...
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Integration of different solar cooling technologies in the cooling supply of a data center
  • A Dalibard
Dalibard, A., 2015. Integration of different solar cooling technologies in the cooling supply of a data center. Rome, Italy, Solar Air-Conditioning Conference.
Systemdesignsoftware LabVIEW
National Instruments Corporation, 2016. Systemdesignsoftware LabVIEW. [Online] Available at: http://www.ni.com/labview/d/ [Accessed 02 02 2016].