Green-Roof Integrated Photovoltaic Canopy (GRIPV-c) is a study being conducted by Marc Perez, Christina Ho, and Nathaniel Wight with the support of Columbia University and Alfred E. Smith CTE High School students (Ashley Grant, Brandon Harvey, Michael Smith, William Alicea, Jared Hatcher, Marco Dwyer, Warrick Balfour). GRIP-c aims to evaluate data collected from four model houses, one housing a control roof, another with a green roof, a standard fixed photovoltaic system, and a GRIPV-c system. The study is ongoing and is looking at temperature, relative humidity, and solar insolation data to qualitatively and quantitatively assess the positive impact of a combined green roof and photovoltaic canopy system on the health of the green roof vegetation, the PV canopy system efficiencies, and the efficiency of roof mounted HVAC air handling units.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Energy simulation & analysis of two residential buildingschirag aggarwal
-> Analysed and compared the energy consumption of a residential building modelled using common building materials and specifications used in Delhi for decades to that of modelled by altering the building envelope and the AC system specifications.
-> Used eQUEST software.
The building integrated photovoltaic (BIPV) system have recently drawn interest and have demonstrated high potential to assist building owners supply both thermal and electrical loads. In this paper, the BIPV technology has been reviewed, in terms of its performance, efficiency and power generation capacity. Specifically, the applications of the BIPV in tropical climate regions have been discussed, together with its prospects and challenges. For these schemes to be implemented in a tropical climatic region, the following issues must be considered: 1) Certain studies must be done relating to electrical load demand, predicted PV output, location of the buildings and its integration and constraints associated with roof design; 2) For the highest energy production from solar PV, the solar collectors need to be with the right tilt depending on the location; 3) Design criteria such as safety, efficiency, durability, flexibility and constructive issues need to be considered; 4) The government of such countries must train electricians and carpenters on PV installations; 5) The BIPV roofing must perform same function as normal roofing materials, such as noise protection, water tightness, insulation and climate protection, and 6) As practiced around the world, these countries must establish design standards for the BIPV.
Strategic Renewable Energy Planning on Campus
Part of a workshop presented by Mieko A Ozeki, University of Vermont
This workshop will share lessons learned from two public institutions, University of Connecticut and the University of Vermont, that carried out comprehensive renewable energy feasibility studies and renewable energy plans on their respective campuses. Participants will break up into small groups to brainstorm ideas to implement a renewable energy and microgrid plan, and mindmap how these ideas can be tied to research, co-curricular education activities, green job opportunities, operations, and climate action planning on their respective campuses.
Performance Analysis of BIPV Prototype System Installed in Greece and Main Af...CrimsonpublishersPRSP
Performance Analysis of BIPV Prototype System Installed in Greece and Main Affecting Parameters by A Peppas*, K Kollias, M Taxiarchou, D Mantelis, Ch Politi and I Paspaliaris in Peer Review Journal of Solar & Photoenergy Systems
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Energy simulation & analysis of two residential buildingschirag aggarwal
-> Analysed and compared the energy consumption of a residential building modelled using common building materials and specifications used in Delhi for decades to that of modelled by altering the building envelope and the AC system specifications.
-> Used eQUEST software.
The building integrated photovoltaic (BIPV) system have recently drawn interest and have demonstrated high potential to assist building owners supply both thermal and electrical loads. In this paper, the BIPV technology has been reviewed, in terms of its performance, efficiency and power generation capacity. Specifically, the applications of the BIPV in tropical climate regions have been discussed, together with its prospects and challenges. For these schemes to be implemented in a tropical climatic region, the following issues must be considered: 1) Certain studies must be done relating to electrical load demand, predicted PV output, location of the buildings and its integration and constraints associated with roof design; 2) For the highest energy production from solar PV, the solar collectors need to be with the right tilt depending on the location; 3) Design criteria such as safety, efficiency, durability, flexibility and constructive issues need to be considered; 4) The government of such countries must train electricians and carpenters on PV installations; 5) The BIPV roofing must perform same function as normal roofing materials, such as noise protection, water tightness, insulation and climate protection, and 6) As practiced around the world, these countries must establish design standards for the BIPV.
Strategic Renewable Energy Planning on Campus
Part of a workshop presented by Mieko A Ozeki, University of Vermont
This workshop will share lessons learned from two public institutions, University of Connecticut and the University of Vermont, that carried out comprehensive renewable energy feasibility studies and renewable energy plans on their respective campuses. Participants will break up into small groups to brainstorm ideas to implement a renewable energy and microgrid plan, and mindmap how these ideas can be tied to research, co-curricular education activities, green job opportunities, operations, and climate action planning on their respective campuses.
Performance Analysis of BIPV Prototype System Installed in Greece and Main Af...CrimsonpublishersPRSP
Performance Analysis of BIPV Prototype System Installed in Greece and Main Affecting Parameters by A Peppas*, K Kollias, M Taxiarchou, D Mantelis, Ch Politi and I Paspaliaris in Peer Review Journal of Solar & Photoenergy Systems
De bouw van LENTmark1 - uitkijktoren in de Waalsprong - nadert zijn voltooiing. Het bouwwerk is het resultaat van een samenwerking tussen het bedrijfsleven, het onderwijs en het UWV in de regio
Nijmegen. LENTmark1 is eigendom van het NVOB Cultuurfonds. De toren is volledig demontabel. Er wordt geen gebruikgemaakt van kit of pur en bijna alle materialen zijn hergebruikt: balken voor de constructie en de trappen, schrootjes voor de gevel, plaatmateriaal voor het dakbeschot en klinkers voor het toekomstige terras. Het is daarmee een voorbeeld van het hergebruik van bouw‘afval’ en heeft een van de eerste groene daken in de Waalsprong. (bron: publicatie vakblad Dak en Gevel Groen december 2011)
Buiten word je beter! Iedereen weet instinctief dat natuur gezond is. Toch heeft de natuur nog geen vanzelfsprekende plek in de gezondheidszorg. In de praktijk ontdekken steeds meer zorginstellingen de baten van groen voor hun cliënten. Hoe pakken zij dit aan en wat zijn hun ervaringen? In deze publicatie beschrijven we zes inspirerende voorbeelden waarin de gezondheidszorg gebruik maakt van natuur. Aan het woord komen medewerkers van zorginstellingen en natuurorganisaties, en natuurlijk de cliënten zelf. Boeiende verhalen voor iedereen die zelf aan de slag wil met het onderwerp natuur & gezondheid.
Kennis voor Klimaat Oogst
Het onderzoeksprogramma Kennis voor Klimaat is eind 2014 geeindigd. Een dwarsdoorsnede van alle kennis en ervaringen die in de afgelopen zijn opgedaan, is in negen fraai vormgegeven boeken weergegeven. Acht boeken over onderzoek naar acht verschillende thema’s en één overkoepelend boek.
Forward to Basics by Willem Jan Snel - MecanooGeert Elemans
Forward to Basics: cycling and cargobikes can fundamentally change the face of a city and can contribute to making it a better place for people. #ICBF2015 International Cargo Bike Festival #Nijmegen
The Dutch and their bikes is the new photobook of Shirley Agudo about cycling in the Netherlands. In her new photo book US photographer and author Shirley Agudo gives us a glimpse of Holland's unique cycling culture.
Akkerranden in Groesbeek voor landbouw, natuur en landschap. Wethouder Theo Giesbers over bloemrijke akkerranden:"Je dient hiermee zoveel doelen: de flora en de fauna en tegelijkertijd het geluksgevoel van onze inwoners en toeristen."
Natuurlijk verder - Rijksnatuurvisie 2014Geert Elemans
Kern van de natuurvisie is een omslag in denken: van natuur beschermen tégen
de samenleving naar natuur versterken mét de samenleving. Door scheiding en
isolatie van natuur te vervangen door vervlechting en wederzijdse versterking wil
het kabinet een effectieve invulling geven aan de natuurdoelen die Nederland
internationaal heeft afgesproken. De visie bevat geen extra beleid of nieuwe
regelgeving. Spanningen die kunnen optreden tussen economische activiteiten en
natuurregelgeving worden benoemd en van mogelijke oplossingen voorzien.
Centrale stelling in de natuurvisie is: natuur en economie profiteren van elkaar.
Uiterwaarden Park Arnhem - artist impression 2014Geert Elemans
Invulling nieuwe Uiterwaarden Park Arnhem: 1. Stel de belevingswaarde van het uiterwaardenlandschap centraal 2. Voeg activiteiten en progamma van betekenis met icoonwaarde toe 3. Breng cultuurhistorie in beeld en maak deze toegankelijk.
Vasim haalbaarheidsonderzoek 2013 Gemeente Nijmegen / BOEIGeert Elemans
1.1 Achtergrond en vraagstelling
Het plan voor een nieuw waalfront en stadsbrug ten westen van de stad heeft de
gemeente Nijmegen doen besluiten om in 2002 het Vasim gebouw te verwerven. Op een
gedeelte van deze locatie verrijst de nieuwe stadsbrug. Daarnaast vormt dit gebied de
overgang van zware industrie naar het toekomstig woon-werkgebied van een nieuw
waalfront. Sinds de verwerving is de gemeente Nijmegen op zoek naar een permanente
invulling voor het Vasim gebouw. Doelstelling is om het complex te herbestemmen na
restauratie. Sinds 2002 is het pand tijdelijk verhuurd en vanaf 2010 tot heden in gebruik
gegeven aan Stichting Cultuurspinnerij De Vasim, die hier een broedplaats voor de
creatieve sector heeft gecreëerd.
In verband met de geplande aanleg van een nieuwe Waalbrug is in opdracht van de
gemeente Nijmegen door het Bureau voor Bouwhistorie en Architectuurgeschiedenis
(BBA) uit Utrecht een bouwhistorische verkenning uitgevoerd naar de voormalige N.V.
Kunstzijdespinnerij NYMA, Winselingseweg 12-16 en 41 te Nijmegen.
Dit heeft geresulteerd in een rapport met als doel inzicht te krijgen in het ontstaan
en historische ontwikkeling van deze fabriek. Voor dit doel bleek een korte inleidende
beschouwing van belang over het productieproces van de fabriek.
De verslaglegging in dit rapport berust op een analyse van het gebouw zelf. Daarnaast
is een beperkt literatuur- en archiefonderzoek uitgevoerd. Vanwege de aard van de
opdracht is het onderzoek ter plaatse beperkt gebleven tot visuele waarnemingen.
De fabriek noch de continuespinnerij heeft op dit moment een beschermde monumentale
status.
Het bouwhistorisch veldwerk is verricht door dr. ing. R. Stenvert en mw. drs. S.G.
van Ginkel-Meester. Het literatuur- en archiefonderzoek is uitgevoerd door R. Stenvert
die ook deze rapportage schreef.
Onze dank gaat uit naar de heren H. Zoutenbier en S. van Stekelenburg van CP Kelco
B.V., voorheen Noviant, die ons in het gebouw hebben rondgeleid en mw. drs. H.
Peterse van de afdeling Architectuur & Monumenten van de gemeente Nijmegen.
Research Vasim Heritage - Boudewijn Wijnacker Radboud University Nijmegen 2011Geert Elemans
Revitalizing a once forgotten past? How the Arnhem Nijmegen City Region can use its industrial DNA to contribute to spatial, economic and tourist development.
This report is written as a Master Thesis for the Master specialization ‘Urban and Cultural Geography’ from the master Human Geography at the Radboud University Nijmegen, Faculty of Management. Furthermore this research is written on behalf of the Arnhem Nijmegen City Region and the Regional Tourist Board (RBT-KAN).
VASIM-factory in the city of Nijmegen: Planned to be a creative centre since 2006. The
former factory was considered to be as important industrial heritage that was destined to
give birth to creative entrepreneurship. According to the first reports, painters, constructors, dancers, thinkers, creators, entrepreneurs and skaters should be given the space to develop themselves. Issues as arts, graphical design, cultural institutions and festivals are mentioned destinations for this redevelopment. The VASIM-factory case shows that redevelopment can be successful in attracting creative industry, funded by an innovative funding system to support economic competitiveness.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
1. THE GREEN-ROOF INTEGRATED PHOTOVOLTAIC CANOPY (GRIPV-C)
Exploring Aesthetic and Environmental Synergies
EAEE E4006 Field Methods for Environmental Engineering
Columbia University, Spring 2011
Marc Perez
Christina Ho
Nathaniel Wight
ABSTRACT
In the urban environment, space is a premium. From micro-studios to multi-functional furniture,
optimizing usage of available space is a critical part of the city lifestyle. Finding purpose for
underutilized space is becoming increasingly important; further, as square foot of usable space
increases, so does value. In terms of real estate, no space can go unused and rooftops are fair game
particularly in the realm of energy efficiency. A variety of methods exist for use of roof top area for
energy offset purposes, but most have been studied independently of each other. Few examples of
research exist that study the synergistic effects of combining these elements.
Green-Roof Integrated Photovoltaic Canopy (GRIPV-c): Exploring Aesthetic and Environmental Synergies
aims to evaluate data collected from four model houses, one housing a control roof, another with a
green roof, a standard fixed photovoltaic system, and a GRIPV-c system. The study aims to use
temperature, relative humidity, and solar insolation data to qualitatively and quantitatively assess
the positive impact of a combined green roof and photovoltaic canopy system on the health of the
green roof vegetation, the PV canopy system efficiencies, and the efficiency of roof mounted HVAC
air handling units.
It is anticipated that for the GRIPV-c there is equivalent vegetation growth, and approximately 0.5%
improvement in PV performance due to improved cooling of 10 °F. Improvements in roof mounted
HVAC is roof area to building volume ratio dependant, but is anticipated to result in 35%
improvement on thermal performance for a building with a ratio similar to the enclosure.
BACKGROUND
Few studies have examined the synergies between green roofs and Photovoltaic (PV) arrays and
there remains a great need for further testing. Several notable examples provide a foundation and
justify the need for continued research.
For example, Brownson, Iulo and
Witmer of Penn State presented results
at ASES 2010 outlining the gains in
performance (both of the green roof
substrate and of a PV system atop it)
based on analysis of Penn State’s 2009
“Natural Fusion” home they designed
for the 2009 Solar Decathlon. The
Natural Fusion home employed deep
sedum trays on the roof with low-lying Solyndra/ Green-roof canopy atop the Natural Fusion home
mixed vegetation and a canopy several
inches above holding Solyndra^Tm CIGS (Cadmium-Indium-Gallium di-Selenide) PV cylinders.
The solyndra system is unique because each cylinder is coated completely on every surface with the
2. CIGS semiconductor material. The idea behind the cylinders that performance can be improved vis-
a-vis a traditional fixed-tilt PV array by always having some portion of the cylinder normal to the
sun’s position--and to use reflected radiation from the underlying roof surface that passes through the
spaces between the cylinders. Although the Natural Fusion GRIPV system described in the papers
by Brownson et. al provides a summary description of this interesting application of a novel PV
technology, a 2002 paper by Kohler et. al, presented at Rio ‘02, examines and identifies the key
synergies unique to GRIPV systems in much more thorough detail.
Furthermore, Kohler et. al examine somewhat un-
conventional GRIPV designs in that their green roof
incorporates plants growing up to a height of 40 cm
and required periodic (annual trimming) to maintain
height. The picture at left displays one of these
GRIPV-tested systems which features 1-axis tracking
and multi-crystalline PV modules.
The positive interactions measured and identified in
the study were:
1) Green roofs reduce operation temperature of the PV
system, thus increasing efficiency and energy yield
2) The PV array offers shading for the green roof, thus
improving growth of plants and increasing species
variety.
We also seek to measure this reduction in back-of-
module temperature, given the temperature drop in the local micro-climate from the green roof’s
evapotranspiration in our study and thereby simulate performance gains vis-a-vis a more traditional
PV system.
Both the GRIPV systems referenced above share the common shortcoming of not allowing for
synergistic use of space on the roof. On
buildings were point-loading considerations
are not an issue and green roofs provide the
potential for a recreational park-setting for
the occupants, the PV array would be better
situated at an elevation above head-height.
Our experimental study hopes to explore
and quantify the benefits outlined by Kohler
et. al under a new design paradigm: the
GRIPV-canopy. In addition to these
benefits, we will be simulating the reduced
burden on HVAC loads given reduction in
surface temperatures and addition of
The GRIPV system with intensive green roof and moncrystalline PV
in Kohler et al, 2002 photovoltaic generating capacity.
2
3. STUDY SITE
Bronx Design & Construction Academy1 is located in The South Bronx, one of the poorest
congressional districts in the United States. BDCA’s certified Career and Technical Educational
(CTE) programs allows economically disadvantaged students to get
unparalleled hand-on instruction in the trades, thereby provide a way
out of the poverty cycle. A majority of BDCA graduates will find jobs
upon graduation. BDCA high school offers endorsed diplomas in the
Building Trades including plumbing, carpentry, electrical practice and
installation, architectural drafting, and Heating, Ventilating, and Air
Conditioning. These diplomas enable graduates to obtain Master
Licenses from the NYC Department of Buildings. Once licensed,
graduates can open their own contracting firms.
Additionally, BDCA (formally Alfred E. Smith CTE HS) partners with
Edward J. Molloy for Initiative for Construction Skills that provides students the unique opportunity
to enter NYC Unions upon graduation. Since 2001 Alfred E. Smith has repeatedly helped place
over 20 percent of each graduating class in high-level union jobs,
including MTA, Metro North, Long Island Railroad, Smalls
Electrical Construction Inc., and New York City School
Construction Authority to name a few. Many others find
professional jobs in Plumbing, Electrical, Carpentry, Auto
Mechanics, HVAC as well as Pre Engineering. AES is associated
with New York Electrical Contracting Association, New York
Building Congress, New York Building and Construction Trades
Council of Greater New York, Building Trades Employers
Association, Architectural Construction and Engineering (ACE)
Mentoring program
Alfred E. Smith CTE HS also offers the training to put technical education to the test in regional and
National competitions. Year after year Smith
students practice what they've learned,
compete, and consistently take home trophies
from Skills USA and the National Automotive
Technology Competition.
BDCA provides CTE opportunities for special
needs students. Specifically, 20 percent of the
AES’ student body has an Individualized
Education Program (IEP). Smith is one of the
last standing schools in this city that provides
self-contained classes and integrated Career &
Technical Education shop classes for a large IEP population. Many of these IEP students have
excelled in their respective trades and have gone on to secure employment. In addition, Alfred E.
Smith CTE HS provides free adult classes at night for the community; Smith is not only an
educational facility for adolescents, but also for the community.
1
http://bxdca.com/director-letter/
3
4. For partial fulfillment of our grade in the course E4006 Field Methods for Environmental Engineers,
we collaborated with students on the Smith
campus to construct model homes. We are
currently monitoring the different rooftop
systems in an effort to demonstrate that solar
photovoltaic and green roof technology are not
mutually exclusive. With the help of BDCA
students we designed and built four model
homes, each with a different rooftop coverage
types: Control with gravel bed, Greenroof only,
Mock solar PV coverage only, Green roof with
mock solar PV coverage.
METHODOLOGY
1. Experimental Set Up
To assure that the data collected is consistent and comparable, specially designed monitoring
enclosures were constructed and co-located adjacent to each other. Four enclosures were designed to
collect the data used to calculate the performance and efficiency improvements of the GRIPV-c
system. Additionally, a stand to hold a pyranometer and ambient temperature and relative humidity
monitor was constructed and located with the monitoring enclosures.
The enclosures are designed to withstand the loading of the maximum roofing weights and to be
highly sealed to prevent air/energy leakage. They are approximately 2’ x 2’ x 4’ long and are
constructed from 2” x2” cedar dowels, 1” rigid insulation, and sealed with silicon sealant. They are
painted with a flat black paint so that the enclosures act as a black body to absorb maximum
radiation energy.
4
5. Enclosure 1 is the control with a standard gravel bed roof. Monitoring parameters for this enclosure
include internal temperature, and near surface roof temperature.
Enclosure 2 is the standard green roof installation. Monitoring parameters for this enclosure include
internal temperature, and near surface green roof temperature. Varietal sedum trays were used for
the green roof materials. The tray depths are approximately 4”.
Enclosure 3 is the standard solar roof installation. Monitoring parameters for this enclosure include
internal temperature, near surface roof temperature and rear solar panel temperature.
Enclosure 4 is the GRIPV-c system. Monitoring parameters for this enclosure include internal
temperature, near surface roof temperature and rear solar canopy temperature.
The below pictures show Smith students framing the model homes and calibrating and labeling the
sensors.
5
6. 2. Modeling Photovoltaic System Performance from Empirical Data
Silicon-based Photovoltaics are adversely affected (in terms of solar/electric conversion efficiency)
by elevated temperatures and to a lesser extent by decreased solar radiation. In this section, we
develop a modeling tool to interpret Irradiance and back-of-module temperature data from our
experimental setup and calculate expected energy generation and therefore, expected cost savings.
We have chosen to model the JAMS(L) 72-180 solar module as the physical basis for our modeling
because the manufacturer, JA Solar was as of Q1 2011 the dominant player in solar module sales
worldwide. It was thought that by using specifications from the best selling solar module as such,
our results would best allow themselves to be generalized.
2.1 Deriving Current/Voltage Characteristics from the Shockley Diode Equation:
To model the dependencies, we needed to estimate the current/voltage (I/V) characteristic curve for
this module using the Shockley diode equation. We model these I/V curves as a function of many
parameters (which will be detailed below) as such:
⎛ qV ⎞
IL − I0 ⎜e nkT −1⎟
⎝ ⎠
Imod =
⎛ qV ⎞ R I
1+ I0 ⎜e nkT −1⎟ s L
⎝ ⎠ nKT
In the equation above, Imod is the module current given the module voltage (V) and temperature (T).
(It is a modified version of the Shockley-Diode equation, solved for the module current instead of for
€
voltage as it is typically given.)
The light-induced current, IL , is calculated as such:
6
€
7. IL = ISC ⋅ E + K 0 (T t − TSTC )
Above, the ISC is the short-circuit current (a characteristic taken from the module’s specification
sheet,) E is the instantaneous radiation in terms of suns (at time ‘t’), Tt is the module temperature at
€
time ‘t’, TSTC is the “Standard Test Conditions” (STC) temperature at which modules are tested at
and Ko is a parameter that changes the temperature to reference the Normal Operating Cell
€
Temperature (NOCT) instead of STC. Ko is calculated as such:
ISC NOCT
− ISC STC
K0 =
(TNOCT − TSTC )
Above, ISC NOCT is the short-circuit current evaluated at the NOCT and ISC STC is the short-circuit
current evaluated at the STC. € Both of these values are given on module specification sheets.
I0 is known as the ‘dark saturation current’ and this is calculated as such:
€ 3 −qV ⎛ € ⎞
⎛ T ⎞ n nK g ⎜ T1 − T 1 ⎟
⎜ ⎟
I0 = I0 STC ⎜ t ⎟ ⋅ e ⎝ t STC ⎠
⎝ TSTC ⎠
In the equation above, Tt is the temperature at time ‘t’, TSTC is the STC temperature, ‘n’ is the diode
factor (which we assume to be 2), q is the intrinsic charge of an electron, Vg is the band-gap voltage
€
of mono-crystalline Silicon, k is Boltzmann’s constant, and I0 STC is the dark saturation current
evaluated at STC which we evaluate as such:
ISC
I0 STC = €qVOC
⎛ ⎞
⎜ e nkTSTC −1⎟
⎜ ⎟
⎝ ⎠
Note that the above is a fixed constant a function of module-specific parameters from the
specification sheet: VOC (open circuit voltage) and ISC (short circuit current.)
€
Finally, the shunt resistance, Rs is calculated as such:
∂V 1
RS = −
∂IVOC X V
∂V
We assume to be a fixed constant (-9 x 10-3) that is a function of the number of cells on the
∂IVOC
€
module (in the case of the JAMS(L), the number of cells is 72) and the VOC of the cell. XV is the
impedance at STC:
€ q⋅ I0 STC
qVOC
nkTSTC
XV = ⋅e
nkTSTC
From these equations, we can simulate the I-V curves for any combination of T, E by modulating
the appropriate parameters.
€
7
8. 2.2 Testing the Model: Synthesized Performance Curves:
Above is a plot showing the characteristic I/V curves for our chosen solar module, modeled as
previously outlined for various cell temperatures. Note how the warmer the cell temperature
becomes, the lower the open-circuit voltage (V0C). The drop in VOC is what has the detrimental effect
on conversion efficiency.
Modern inverters (DC/AC conversion) have built-in algorithms to calculate the voltage to set the
string of solar modules at in order to maximize the area under the I/V curve. This position is known
as the maximum power-point (MPP.)
As can be seen in the plot below, where we’ve calculated Power output as a function of module
voltage for the same set of temperatures, we can identify the MPP as the location where each curve
peaks.
As can also be deduced from the above plot, the maximum power output of the module decreases
with increasing temperature.
8
9. 2.3 Simplifying the Model for quickly calculating performance from Time-Series Data:
From this complex model, we can also modulate incident radiation at each temperature to determine
relationships between the two. In the following (surface) plot, we show how the module conversion
efficiency (from sunlight to DC electricity) as a function of both incident radiation and temperature.
Note that the only reason efficiency changes as a function of irradiance is because the maximum
power point will have to slightly shift—this is an artifact of the I/V curve shape. This yields a much-
simplified model for calculating efficiency for simple integration into our modeling of power
production:
η = ( mb E + bb ) + TB .O.M ( ms E + bs )
The factors mi and bi are derived from linear regression of the modeled I/V curves and E is in terms
of Suns (i.e. 1000 W/m2 = 1 sun)
€
Finally, our AC-side Power output is calculated as such:
PAC = E W ( m )⋅ ∂ ⋅ η
2 r T, E
where ∂r is the de-rate factor (we’ve assumed this to be ~78% as a result of losses from conversion
from DC/AC in the inverter, wiring, voltage mis-match, deviation from the name-plate power
output in the specification sheet, etc.) E is the radiation in W/m2. From this simplified formula, we
€
have a model to calculate power production (per m2 at any T and E) for our module.
€
3. Modeling Expected HVAC Loading from Empirical Data
9
10. In order to estimate the impact each individual roof design has on HVAC loads—in lieu of an actual
AC unit in operation—is to simulate the performance of one based on physical measurements and
empirical relationships. In this section, we discuss how we modeled these performances from
derived R-values of the different roof substrates based on exterior surface, interior and exterior
ambient temperature readings.
3.1 Modeling R-values from data:
From a recent report from the DOE2 Energy Efficiency and Renewable Energy division, we
extracted an empirical relationship between the temperature of an internal wall (TW,INT ), the
temperature of an external-facing wall (TW,EXT ) and the ambient external temperature (TEXT,A.)
Internal wall temperature we take as mean air temperature from our thermistor hanging in the center
of each box, but external wall temperature, we will need to calculate periodically using an IR
thermometer or equivalent as this is not a quantity we are directly measuring in real-time. External
temperature we are also measuring directly.
From this DOE report, which is reproduced by the North Dakota Department of Commerce in a
handy table3, we used multiple ordinary least squares regression to build empirical relationships for
any combination of TW,EXT TW,INT and TEXT,A. In fact the only quantity we care about at this point is
the difference between the temperatures of the internal facing wall and the external facing wall:
ΔT = TW ,EXT − TW ,INT
After examining the data roughly, a power-model of the form:
€ B ΔT
R T = AΔT ( ΔT )
Is determined to best fit R values (we fit the imperial R values in BTU to the ΔT readings. Using
o.l.s. regression, we fit the parameters AΔT and BΔT from empirical data with an R2 of over 99% for
€
each discrete exterior temperature given, (hence R T ). Following this, we examined the change in
both AΔT and BΔT with external temperature. The result being that€ ΔT can be approximated by
A
linear regression quite well and that BΔT shows no trend so we took the mean across all discrete
€ €
temperatures: €
€ € €
AΔT = mm (TEXT ,A ) + bm
€
BΔT = BΔT
In excel, extracting the 0th and 1st order moments from a regression is simple using a combination of
index() and linest() functions. € the end, we end up with a combined formula for the R value of:
In
€
[ ]
R = mm (TEXT ,A ) + bm ⋅ [ ΔT ]
B ΔT
2
€
U.S. Department of Energy. EERE. (2006, 0530). Insulation. Retrieved March 10, 2008,from Energy Savers, Tips on saving energy
and money at home: www1.eere.energy.gov/ consumer/tips/insulation.html
3
Pedersen, C., Hellevang, K.. NDSU. (2010, March.) Determining Insulation and Infiltration Levels Using an Infrared Thermometer:
10
11. ft 2 °F⋅ hr
The above form was derived such that R is in units of --it is not as easy to visualize in
BTU
metric units with the Temperatures in terms of °C. Below are the values:
€
Using these empirical relationships, we are now able to determine an R value for any combination of
the three key temperature readings (TW,EXT TW,INT and TEXT,A.) However, as there might be some
error in the measurements we take on the exterior wall surface, we will calculate an R value at each
time all pieces of data are available and take a moving cumulative average.
In the plot above, we see the results of modeling this empirical data from DOE. As ΔT increases,
the R-value experiences exponential decay, while the higher the ambient external temperature, the
expected R-value sees a linear decrease. Because the data from which these relationships were
derived only represents external temperatures from -40°C to 10°C, that is the only range of
€
temperatures at which we will calculate R.
3.2 Modeling Heat Transfer out of the Boxes:
Using these derived R values—which we will calculate for each interior surface of the boxes, we can
•
calculate the heat flux ( Q ) at any given time. Using an ASHRAE standard for thermal comfort (we
choose ~23°C for our model), we keep the internal temperature fixed at this level and measuring the
temperature difference between this value and the ambient external temperature. This gives us a
new ΔTop (op for operational), and along with the R-values, we calculate the flux as such:
€
11
€
12. • ΔTop
Q=
R
Fluxes are calculated for each surface within the boxes corresponding to their respective R-values
and a relative weight is given to each depending on the fraction (fi) of the interior surface area
covered by each: €
• i •
QTOT = ∑ Qi f i
1
Our model is flexible enough to take any house dimensions and calculate these weighting factors and
the corresponding fluxes for each surface (and net flux). These flux values are ostensibly in W 2 ,
€ m
and the final step is to convert these values—which are required HVAC loads—to the required
electrical load by dividing by the SEER rating (Btu/Wh) given as a badge of efficiency to HVAC
units. These can range widely—from near zero to over 26 for the best, most modern units—so we
have left it as a user parameter. Our total energy flux for a given time period (t = 0€ t = t ) is just
to
the integral of the instantaneous heat fluxes… in our discrete case it will be a sum of these fluxes
multiplied by the length of the recording interval:
t •
E tot,electrical = ∫Q
0 TOT dt
€
RESULTS & DISCUSSION
12
13. As limited data is available at the time of this report, simulated time series data has been used to
produce anticipated results for the following areas of concern.
1. Comparison of Simulated HVAC Loads
This plot shows expected results using our model to interpret the predicted time series data. This
model used data simulated from a Typical Meteorological Year from the National Solar Radiation
Database in New York State for solar radiation. Using the methods discussed previously for thermal
energy transfer, our model outputs estimated energy
loads for each house (on a /m3 basis) based on the
internal temperatures, solar radiation and estimated R-
value.
ASHRAE Standard 55 - Thermal Environmental
Conditions for Human Occupancy is used to define
indoor conditions. The envelopes, or shaded regions,
define a range of comfortable temperatures and
humidity levels for two reasonable insulation levels for
the occupants (0.5-1.0 CLO).
This allowed for calculation of the required energy to
bring the internal temperature into to the ASHRAE standard envelope.
The results below reflect the net energy load for a 1-story house (360 m3) with 120 m2 of roof space
from each of our individual houses. This house model was chosen as it most closely resembles the
relative dimensions of the monitoring enclosures.
The dramatic reduction in net energy for the PV based systems accounts for the offset in net energy
required due to the supply of energy from the PV system itself. As this graphic shows, there is a real
reduction in energy requirements for HVAC loads anticipated due to the insulating value of the
green roof itself. Coupled with the significant offset of net energy required for the system due to the
PV power generation, a combined system is anticipated to have excellent gains over a traditional
gravel roof.
One shortcoming of
Key: GRAV gravel roof only, GR_1 Green roof only, GRAV-pv gravel roof with PV, GRIPV-c this model is that it
geen roof with pv canopy can only describes
13
14. savings for buildings with roof area to building volume ratios similar to the enclosure.
2. Comparison of Net Energy Costs
Based on the annual energy saving described in the pervious section, we have calculated the
estimated cost savings for each module type for a house with dimensions mentioned in the previous
section. Here, we have assumed the cost of electricity to be $0.12/kWh (NYPA’s average rate
throughout 2010), and net metering to occur at the same rate for the PV. PV system size is 11 kW
and considered to be flat for the purposes of testing the model. These costs are relative operating
costs; they do not take into account amortized capital outlays for the Green Roof or for the PV.
These will be an addition to the models over the course of the summer.
FUTURE STEPS
To improve data collection results, a number of changes to the experimental set up and data analysis
methods will be considered. These include:
• Calibrate probes periodically to ensure monitoring values are representative
• Relocation of the experimental monitoring enclosures to a location with a higher percentage
of daily solar insolation exposure
• Potential expansion of the data collection set up to other high schools/locations in the area
for additional data sets
• Evaluation of capital costs of installations
• Develop method to compare impact on HVAC system loads with varying roof area to
building volume ratios.
• Secure funding and construct GRIPV-c monitoring enclosure with real solar PV panels to
demonstrate the calculated performance levels
14
15. In the future we also plan to conduct a qualitative and quantitative assessment of Green Roof’s
health. Using an NDVI (Normalized Difference Vegetation Index) camera, we will use image
analysis to conduct various types of measurements, color quantification and classifications. A
Normalized Difference Vegetation Index camera will allow us to measure the diseased area on our
green roof sedum leaves, and quantify plant health and vigor.
Additionally, students at Bronx Design & Construction Academy & Alfred E. Smith Career &
Technical Education high school have already began planning to set up a blog site and Facebook
page in an effort to communicate and document their work and continued involvement in this
project.
Furthermore, teachers and students at Alfred E. Smith Career & Technical Education high school
will engage in activities that will strengthen their understanding of science, enhance school
curriculum, as well as provide content that meets below National Science Standards4.
Standard 1: Analysis, Inquiry, and Design
Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to
pose questions, seek answers, and develop solutions.
Standard 4: Science
Students will understand and apply scientific concepts, principles, and theories pertaining to the
physical setting and living environment and recognize the historical development of ideas in science.
Standard 5: Technology
Students will apply technological knowledge and skills to design, construct, use, and evaluate
products and systems to satisfy human and environmental needs.
Standard 6: Interconnectedness: Common Themes
Students will understand the relationships and common themes that connect mathematics, science,
and technology and apply the themes to these and other areas of learning.
Finally, future work on this project will provide students and staff at Bronx Design & Construction
Academy & Alfred E. Smith Career & Technical Education high school
1. Integrate Career and Technical Education and content-based curricula,
2. Project-based learning opportunities,
3. Students the opportunity to identify, evaluate and reflect on environmental issues in the
community and in our world,
4. Strengthen the ability of students to make predictions and decisions based on measurement,
observations, and calculations, and
5. Heightened awareness of environmental awareness and stewardships
ACKNOWLEDGMENTS
4
http://www.nap.edu/
15
16. Many thanks to Wade McGillis, Nadine Els, and Diana Hsueh for their continued advisement and
financial support, without which this project would not have happened. Additionally, thanks to all
the students who participated from the Bronx Design & Construction Academy & Alfred E. Smith
Career & Technical Education high school, specifically: Ashley Grant, Brandon Harvey, Michael
Smith, William Alicea, Jared Hatcher, Marco Dwyer, Warrick Balfour.
REFERENCES
Brownson, J.R.S. and L.D. Iulo. Upsetting the Balance Beam: System Integrative Photovoltaics as
Purposeful Manipulation of Energy Demand and Microclimate in the Built Environment. in proc. ASES
National Solar Conference. 2010. Phoenix, AZ: American Solar Energy Society.
Kohler, M., et al., Photovoltaic Panels on Greened Roofs: Positive Interaction Between two Elements of
Sustainable Architecture, in RIO '02 - World Climate & Energy Event. January 6-11, 2002: Rio de
Janiero. p. 151-158.
Sui, J. and J. Munemoto, Shape Study on a Green Roof Integrated Photovoltaic System for Bi-objective
Optimization of Investment Value and CO2 Emission. Journal of Asian Architecture and Building
Engineering, 2007. 6 (2): p. 307-314.
Witmer, L.T. and J.R.S. Brownson. System Integrative Design in the 2009 Penn State Solar Decathlon Net-
Zero Energy Home. in Proc. ASES National Solar Conference. 2010. Phoenix, AZ: American Solar
Energy Society.
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