Arch 8563:Getting Blow the Surfacepub/@ssrd/... · 2015. 6. 2. · Getting Blow Surface: PV...

Research of PV

Application on

UMore Park

Community Design

Arch 8563:Getting Blow

the Surface

Xiaoyu Liu

Getting Blow Surface: PV opportunity on the UMore Park

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Research of PV application on U More Park Community Design

1. Introduction

This report explores the opportunities for the UMore Park community on the aspect of PV

application. There are four parts in this report:

(1) Introduction of UMore Park project, including its primary goal, current master plan,

housing forms for current researching stage, possible form of energy infrastructure in the

future, attitude of developers and future dwellers towards PV ;

(2) PV research, including types of PV products, the issue of grid-tied or grid-off, incentives

and payback of PV, issues of shading effects and solution;

(3) Case study of single solar house and sustainable community design.

(4) Suggestion of community design combining PV application.

2. Basic Information about UMore Park

2.1 Site Location & Goal

The University of Minnesota Outreach, Research and Education (UMore) Park is the

University's 5,000-acre property located 25 miles southeast of the Twin Cities in Dakota


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County. The vision to build a unique, sustainable, University-founded community of 20,000

to 30,000 people, a 25- to 30-year endeavor, was affirmed by the University's Board of

Regents in December 2006.

2.2 Master Planning

Layout of district plan and residential area scenario

The Concept Mater Plan will provide a guide for development of the UMore Park property

over the next 25 to 30 years. It will ensure that the vision of the University for the property is

reflected in the eventual development of the property.

The Concept Master Plan combines elements of several initial planning concepts and features

of two main components:

(1) A master planned community with housing for as many as 30,000 people, neighborhood

commercial, retail centers, civic buildings, and community amenities interspersed with

man-made lakes and open space.

(2) An Eco-Industrial Park in which businesses collaborate with the community to reduce

waste and pollution, share resources, provide opportunities for job creation and help

achieve sustainable development.


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2.3 Basic Housing Prototype

The Performance-Based Research on Housing and Infrastructure Development at UMore

Park final report proposed two generic residential building types for the UMore Park (for the

stage of energy consuming research), which are also the basement of my research of PV

application. The two building types are:

(1) Single family housing: 3900 sft/house, with roof area more than 2000sft/house

(2) Townhouse, consist of 4 units: 1250 sft/unit, with roof area around 800sft/house

The first corresponds to a typical single family dwelling constructed in Minnesota during the

period of about 1995-2005 as defined for the State of Minnesota. The second corresponds to a

typical four-unit multi-family dwelling that conforms to the MN Building code definition of a

“townhouse”.

Single house prototype of the UMore Park Project

town house prototype of the UMore Park Project


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2.4 Possible Energy Planning

District scale energy system could be a good choice for a newly built community as the

UMore Park. According toPerformance-Based Research on Housing and Infrastructure

Development at UMore Park final report, in recent sustainable developments, district scale

systems are becoming more frequently used. The district scale has some of the cost

advantages of the metro scale while avoiding some of the disastrous environmental and

resource depletion consequences that could be brought by metro scale.

The advantages of district scale system are:

The initial cost of development is dramatically reduced.

Better energy efficiency can be created within and between the utility systems.

Sustainable resource loops are more easily closed.

When systems are designed to be interlinked, energy and material utilization efficiency

synergies are possible.

Energy efficiency is increased because the transmission lengths for the services are

shorter and can be designed to be more efficient.

District service can be more adaptable to the local environment.

District service utilities can be profit centers for the development

However, district system also has disadvantages such as: higher maintenance cost and

occupying large dwelling area for setting.


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Layout of distric HVAC system,

(pictures are from the Performance-Based Research on Housing and Infrastructure Development at UMore Park final report)

2.5 Basic Concerns about the Developer and Homeowner’s Attitude towards PV

The developer was very enthusiastic about incorporating the technology and entering

into a partnership to do so. However, the extra cost would have to count on the

homeowners. So the consensus was that the payback of the incremental costs to the

homeowner from energy savings should be no more than 5 years. Marketing innovative

energy technology in an affordable/workforce housing context is challenging as this class

of homeowner is driven primarily by first cost and essentially is indifferent to

environmental or energy motivations for accepting increased costs. The developer felt

that marketing such housing on a rental rather than a purchase basis using the promise of

lower monthly energy costs as an incentive was more promising. Also, there is a general

expectation of single-family homeowners that they own whatever is within the boundary

perimeter. Changing this concept to allow Utility ownership of rooftop solar panels

would be difficult. For this reason, implementing such a strategy in a townhouse or

multi-family building context may be much more readily achievable approach.


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3. PV Opportunities

3.1 Types of PV products

(1) Fixed Solar Panel

Pictures of fixed solar PV

Fixed panel mounts don't move. They remain stationary. Given that, these mounts need to be

positioned correctly to absorb as much light from the sun as possible. Usually, that means the

mounts should be set to point the panels or arrays toward the equator. Fixed mounts are the

simplest system available and therefore cost much less than other mountings. That said, this

type of mount offers the least flexibility. Because users can't easily change its angle, the

amount of sunlight that it can absorb is limited. Additionally, as the earth's orbit changes

throughout the year, the inability to modify the position of the mount (and thus, the panels) to

the varying angle of the sun limits the amount of energy absorption. Fixed PV is relatively

cheaper than other products but has the disadvantages of low efficiency and bad looking,

which will be a big problem for a real estate project like UMore.


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(2) Adjustable Solar Panel

Pictures of adjustable solar PV

Adjustable panel and array mountings provide more flexibility than fixed mounts. As the

seasons change, their position can be altered to compensate for the sun's angle. For example,

during the winter, the sun appears from a lower angle. An adjustable mount can be

repositioned to maximize the panels' exposure and the level of energy absorbed. Then, during

the summer when the sun's angle is higher, the mounting can be repositioned accordingly. By

modifying the inclination of the panel mounts, the solar output of the panels can be increased

by over 25%. However, such PV product relatively raised efficiency, but still has a bad

looking.

(3) Solar Tracker

Pictures of solar trackers

Arguably, the most efficient mountings available are tracking mounts. They follow the sun


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throughout the day to absorb the most energy possible. They're available as a single-axis or

double-axis system. The former will track the trajectory of the sun as it rises and sets during

the day. The latter will do the same but also automatically compensate for the sun's changing

angle throughout the year. The drawback to a tracking mount is the cost. They're expensive.

While they provide up to 30% more solar output than adjustable mountings, they can cost

thousands of dollars. Some people prefer to simply buy additional solar panels and place them

on adjustable mounts rather than invest in trackers. Also, this kind of PV doesn’t solve the

problem of aesthetic issues.

(4) Solar Roof

Pictures of PV roof

In-roof solar PV systems offer a flush finish where aesthetics are important. There is a large

choice of systems that can be used to integrate with most types of roof. In-roof mounting can

be cost effective when needing to re-roof and for new builds as slates, tiles won't be needed

in the spaces covered by the PV. However, additional roof work and materials can make a

system more expensive. Suitable flashings should be used to ensure waterproofing. Adequate

ventilation should be provided as solar PV panels and cables should be kept cool to perform

at their best. Personally, I think roof PV is probably the best choice for the UMore because


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of its acceptable looking (good looking weighs very much for buyers when choosing their

future house) and high efficiency. The biggest problem of roof PV is its relatively higher

cost, but since the UMore is a very large project with 5000 acres, I guess there will be proper

solution on the price of PV because of the large amount of need. Additionally, the average

payback years of grid-tie PV system is around 14 years, although much longer than the

expected 5 years, it is still worthy because: (1) the potential of the rising on electricity fee in

the future; (2) compared with the years people will live in the house, 14 years is not

unacceptable.

3.2 On-grid or Off-grid

Grid-intertied power systems are for folks who are (or will be) connected to utility company

power lines (the "Grid"). They are also called gridtie, grid-tie, gridtied, grid-tied, grid intertied,

grid-intertied. Grid-intertied Solar Power without Batteries is what the Federal

incentives and State rebates are encouraging people to buy. It provides you with electricity

which is less expensive in the long run. It also increases the amount of energy available

through the Grid because electricity in excess of what you use is routed into the Grid. But the

drawback is when the Grid goes down, your house is also without electricity.

Comparison of grid-time system with & without battery


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DC off-grid solar power systems are most often used to power DC appliances in RV’s, boats,

and cabins, as well as farm/ranch appliances like cattle gates and rural telecommunications

systems when utility power is not accessible. DC solar power is less expensive than AC solar

power because an inverter is not required to convert the electricity produced by solar panels

and stored in batteries from DC to AC. But DC solar power does NOT power standard AC

appliances. So if we want to use off-grid solar power, we need to add an inverter allowing this

system to convert DC electrical current coming from the batteries into AC or alternating

current. AC is the standard form of electricity for anything that "plugs in" to utility power and

is the appropriate current for common household appliances. While AC off-grid solar power

systems are more expensive because of the cost of the inverter.

My suggestion for the UMore Park project is that:

(1) Grid-tied PV systems without battery should be the first choice for the UMore, because it

enjoys incentives and less expensive. Also, there is no need to have battery in such system,

which saves a lot of time and money on maintenance. And he drawback of “having no

electricity in blackout” could be solved by other energy backup such as the district

independent electricity generator, as is mentioned in the high-performance housing report.

3.3 Incentives on PV investment

The Emergency Economic Stabilization Act of 2008, which was signed into law on October 1,

2008, contains renewable energy legislation which is great news for solar customers. Not only


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was the 30% commercial solar investment tax credit extended through 2016, but the same tax

credit was also extended to residential installations.

Under this legislation the previous $2,000 cap for residential solar installations was

eliminated. As of January 1, 2009, the purchase of a residential solar electric system makes

you eligible for a tax credit equal to 30% of the cost of your solar system, including

installation.

3.4 Cost and Payback of PV

Solar mapping of the US

(1) State of Minnesota is located in the Zone 5 in the USA solar map, which means that there

is averagely 4.2 hours sunshine in a day. Assuming the average electricity consumption

for a single family is 1200 KWH/Month, and solar power would provide 100% power

needed, the minimum system size for a single family would be around 10,000watts.

(Calculation is based on that the state of Minnesota is located in the zone 5, where the sun

hour per day is 4.2 hours)


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If we choose the 9,400 Solar Sky Sharp Grid-tie System, which the overall cost is $21,050,

and a simple corresponding pay back year is 13 years. (Calculation is based on the fact

that electricity fee is $0.11/WKH. )

Information of Solar Sky Grid-tie System 9,400 watts

(2) Under the same calculation basis, if we alter the 100% dependence of solar power to 60%,

the monthly electricity needed from PV is 720 KWH, we may choose the product of

5,640 Solar Sky Sharp Grid-tie System, of which the overall cost is $13,215, and a simple

corresponding payback year is 13.7.


(3) Under the same calculation basis, if we change the 60% dependence to 30%, the monthly

electricity needed for a family is 360 KWH, we may choose the product of 2,820 Solar

Sky Sharp Grid-tie System, of which the overall cost is $7,365, and a simple

corresponding payback year is 15.5.


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So, from the simple calculation above, we can draw a conclusion that, the more

dependence on PV you have, the less payback years it will be. Also, considering the

possible raise of electricity fees in the future, it is relatively more cost-effective to choose

larger PV systems.

Percentage on PV

Electricity/Month Initial Cost Payback

Years System Size

Roof Area

30% 360kwh/m $7,300 15.5 2820w 300

60% 720kwh/m $13,000 13.7 5640w 600

100% 1200kwh/m $21,000 13 9400w 1000 Summary of PV cost analysis

*Generally, 1kW of solar power system requires about 100 square feet

3.5 Shading Effects

PV modules are very sensitive to shading. Unlike a solar thermal panel which can tolerate

some shading, many brands of PV modules cannot even be shaded by the branch of a leafless

tree.

Shading obstructions can be defined as soft or hard sources. If a tree branch, roof vent,

chimney or other item is shading from a distance, the shadow is diffuse or dispersed. These

soft sources significantly reduce the amount of light reaching the cell(s) of a module. Hard


sources are defined as those that stop light from reaching the cell(s), such as a blanket, tree

branch, bird dropping, or the like, sitting directly on top of the glass. If even one full cell is

hard shaded the voltage of that module will drop to half of its unshaded value in order to

protect itself. If enough cells are hard shaded, the module will not convert any energy and will,

in fact, become a tiny drain of energy on the

output power is to avoid shading whenever possible.

4. Case Study

4.1 Community study: Jackson Meadows, Marine on St. C

Pictures of Jackson Meadow Community

Jackson Meadow is a community in the state of Minnesota, of which the

were simple and powerful:

· Preserve and conserve the land

· Create a sense of neighborhood and community


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the voltage of that module will drop to half of its unshaded value in order to


energy on the entire system. . The best way to avoid a drop in

output power is to avoid shading whenever possible.

Jackson Meadows, Marine on St. Croix, Minnesota

Pictures of Jackson Meadow Community

is a community in the state of Minnesota, of which the guiding principles

Preserve and conserve the land;

Create a sense of neighborhood and community.



the voltage of that module will drop to half of its unshaded value in order to


. The best way to avoid a drop in

guiding principles


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The result is 250 acres of open space placed in conservation easements to be protected from

development in perpetuity, a six-mile trail system and cluster housing for 63 sites that uses

only 30 percent of the available land.

The use of natural system technology and soil-based infiltration methods has allowed

development to occur while preserving open space for the community. Jackson Meadow has

evolved to become a highly-emulated conservation community for other sensible housing

developments across the country. It has raised the bar for conservation, architecture and

natural treatment systems that blend into the natural environment.

Since start-up of the natural treatment systems, NSU’s operating partner, EcoCheck, has

provided the proactive operational services that have enabled to Jackson Meadow to realize

its vision of a sustainable infrastructure. EcoCheck’s business philosophy results in

identifying issues before they become problems, which will be very meaningful for the

UMore Park when considering its general plan. To avoid problems, we need to take all the

requirement of infrastructure and possible future need into consideration. I think the future

community organization way of the UMore Park may learn a lot from Jackson Meadow,

because:

(1) The slightly centralized community could save much open space, which provides other

sustainable potentials that requires large scale of land like constructed wetlands.

(2) The slightly centralized community means we may not need to plant trees besides the

houses, which is good for the PV efficiency, and to compensate this point, we may plant

small scale forest, rain garden, or constructed wetlands in the large rest of land.


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4.2 Single house study

(1) Montague Urban Homestead

The Montague Urban Homestead is a single-story, single-family detached dwelling of 1152

square feet, with three bedrooms and one bath. It also has an attached insulated but unheated

mudroom of 96 square feet.

It has an audited HERS rating of -8 and a Platinum (highest level) LEED rating. The house

is close to German “passive house” standards – a “Power House”, or “Below Zero Energy”

house that is also free of many of the typical toxins used in building.

(2) Science House

Built as part of "The Big Backyard" at the Science Museum of Minnesota, the House serves

as a public environmental experiment facility, classroom, and special event space. The


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building is designed to function as a zero-emission building. By incorporating solar roof

panels and geothermal systems, it provides as much energy as it consumes. More specifically,

with a energy load that is 60 percent below code, and operating a 8.8 kW photovoltaic system,

the building produces more energy than it consumes on an annual basis. The Science House

also uses a solar-electric powered geothermal heat pump consisting of four 250-feet-deep

wells. Combined with passive solar design, all heating and cooling needs are derived from

renewable sources.

5. Conclusion

Scenario of UMore community design (Picture in the bottom is PSed from a layout of the project Third Residential EcoVillage)

Through the study of the UMore Park project and a research of PV products, I suggest:

(1) The community design of UMore Park could consider the way of “slight centralization”,

which is illustrated as the project of Jackson Meadow. The advantage of this kind of

community design is that:


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More open space is reserved for sustainable opportunities like constructed wetlands,

edible landscape, or organic farming, which compensate for the restriction that trees

are not allowed to be planted besides dwelling houses in order to avoid having

shades on PV.

Open space could provide space needed for setting district scale energy

infrastructure.

(2) Consider grid-tied PV system as a roof material in the design of single housing dwelling

and at the same time, consider the possibility of passive housing to minimize the energy

use of each family. Although the payback year of grid-tie PV system calculated above is

around 13 years, there is still possible way of lowering down the price by vast need

amount.

(3) Passive housing could be a very meaningful way for the UMore’s goal of low-impact. If

we could enhance the houses performance and make them close to the standard of passive

housing, we can choose smaller size of PV arrays, which will save a lot of initial cost.


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Appendix:

Principle of Passive Solar Housing Design

The following five elements constitute a complete passive solar home design. Each performs

a separate function, but all five must work together for the design to be successful.

l Aperture (Collector): The large glass (window) area through which sunlight enters the

building. Typically, the aperture(s) should face within 30 degrees of true south and

should not be shaded by other buildings or trees from 9 a.m. to 3 p.m. each day during

the heating season.

l Absorber: The hard, darkened surface of the storage element. This surface—which

could be that of a masonry wall, floor, or partition (phase change material), or that of a

water container—sits in the direct path of sunlight. Sunlight hits the surface and is

absorbed as heat.

l Thermal mass: The materials that retain or store the heat produced by sunlight. The

difference between the absorber and thermal mass, although they often form the same

wall or floor, is that the absorber is an exposed surface whereas thermal mass is the


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material below or behind that surface.

l Distribution: The method by which solar heat circulates from the collection and storage

points to different areas of the house. A strictly passive design will use the three natural

heat transfer modes—conduction, convection, and radiation—exclusively. In some

applications, however, fans, ducts, and blowers may help with the distribution of heat

through the house.

l Control: Roof overhangs can be used to shade the aperture area during summer months.

Other elements that control under- and/or overheating include electronic sensing devices,

such as a differential thermostat that signals a fan to turn on; operable vents and dampers

that allow or restrict heat flow; low-emissivity blinds; andawnings.

l Case study

This house just wined the prize for Massachusetts Zero Energy Challenge for 2009. It is

a very well designed home, showing that a very livable home can be built for a

reasonable price and with zero net energy usage in a difficult climate

The goal of this house is to eliminate dependence on the dirtiest/most harmful energy sources

– coal, nuclear, oil, electricity from biomass – and meet our housing and energy needs with as

little health and environmental impact as possible, in an economically-affordable, low-toxic,

sustainable home.

l The Envelope of this building is super-insulated on all sides, floor and ceiling:


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Double stud walls, each conventionally framed, joined by small plywood trusses to

create a 12” cavity. Filled with dense pack cellulose insulation by Cellus pray at

R=42. The exterior wall is load bearing.

Ceiling/Roof is framed using conventional pre-manufactured trusses with an extra 18”

rise at the eaves. Attic has 30” (after settling) of blown loose-fill cellulose insulation

above the ceiling for R=100.

Conventional concrete footings and 4’ deep frost walls hold a 4” concrete slab with 6" of

extruded polystyrene insulation beneath and around it providing R= 30 for the entire slab

with no thermal breaks.

Envelope was designed to create a continuous insulation blanket with few thermal

breaks.

An improvement to add: rigid foam board all the way down the inside of the 4-foot

footings

l The house also applied careful air sealing on all sides of the house, top and

bottom. Used a “belt and suspenders” approach:

Typar house wrap on ½” cdx sheathing. All Typar seams were taped and all cdx seams

were caulked.

Foundation to sill plate seam was caulked before bolting. All window seams, nail holes

and other penetrations of the exterior sheathing are caulked/sealed.

Dense pack cellulose by itself is an excellent air barrier.

Conventional dry wall system was glued/sealed at all seams.


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All ceiling penetrations were sealed from above with spray-on two-part polyurethane

foam.

Attic access is through the gable end of house, not through the ceiling.

The standing-seam metal roof has conventional soffet vents and a continuous ridge vent.

l Windows are Thermotech, extruded fiberglass frames with triple glazing.

South windows and door: U = 0.21, SHGC = 0.68 (glass values). U= 0.23, SHGC=0.44

(whole window values) ：“SHGC” means Solar Heat Gain Coefficient – higher means

better sun harvesting.

All other windows U = 0.12, SHGC = 0.37 (glass values). U=0.17, SHGC=0.25 (whole

window values)

References:

1/ http://solarpanelspower.net/solar-power/on-grid-off-grid

2/ http://www.solarenergy-solarpower.com/ongrid-solar-energy.html

3/ http://www.wholesalesolar.com/gridtie.html

4/ http://en.wikipedia.org/wiki/Solar_power_by_country#United_States

5/ http://www.ongrid.net/index.php?page=signup

6/http://www.umorepark.umn.edu/prod/groups/ssrd/@pub/@ssrd/@umorepark/documents/co

ntent/ssrd_content_219186.pdf


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7/http://www.umorepark.umn.edu/research/projects/HousingInfrastructureDevelopment/index

.htm

8/ http://www.wholesalesolar.com/products.folder/systems-folder/OffGridPackages.html

9/http://www.wholesalesolar.com/federal-tax-credit.html (30% federal credits)

10/http://www.wholesalesolar.com/StartHere/GRIDINTERTIED/GRIDINTCalculator.html

(calculator)

11/http://www.wholesalesolar.com/StartHere/GRIDINTERTIED/GRIDINTCalculator.html#S

olarmap (solar map)

12/ http://www.wholesalesolar.com/solar-panels.html (suppliers of solar panel)

13/http://www.wholesalesolar.com/gridtie.html (on-grid solar system)

14/http://www.wholesalesolar.com/states/Minnesotasolarpanels.html (Minnesota solar

incentive)

15/ http://www.mrsolar.com/page/MSOS/CTGY/remote

16/ http://www.solarhouse.com/ (solar house case study)

17/http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=1025

0 (passive solar design guidance)

18/ http://www.builditsolar.com/Projects/SolarHomes/plansps.htm (solar house case study)

19/ http://www1.umn.edu/news/news-releases/2010/UR_CONTENT_182607.html (solar

house of UMN)

20/ http://www.coolflatroof.com/ib-solar-roof.php

21/ Performance-Based Research on Housing and Infrastructure Development at UMore Park

final report


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22/ Passive House and High Performance Housing: A Report to the UMORE Park

Manegement Team

23/ Concept Master Plan Book of the UMore Park

Arch 8563:Getting Blow the Surfacepub/@ssrd/... · 2015. 6. 2. · Getting Blow Surface: PV...

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