BSE CPD seminar – Toward High Performance Buildings on 23 ... · ‐A CopperSun solar water...

BSE CPD seminar – Toward High Performance Buildings on 23 May 2011 Organized by the Department of Building Services Engineering, a CPD seminar on Toward High Performance Buildings was delivered by Professor Robert Boehm on 23 May 2011 (Monday). The seminar was successfully held with 191 participants attended.

Powerpoint of the CPD Seminar Professor Robert F. Boehm is a Distinguished Professor of Mechanical Engineering and the Director of the Energy Research Center at the University of Nevada Las Vegas (UNLV). His work has been primarily in the area of renewable and conventional energy conversion. He holds a PhD in Mechanical Engineering from the University of California at Berkeley. Dr. Boehm is a Life Fellow of the American Society of Mechanical Engineers (ASME), and he has received several awards, including the John Yellott Award, the highest award of the ASME Solar Energy Division. He has been an invited lecturer at many institutions in the US and abroad, and he has published over 400 papers in renewable energy and design of thermal systems. He is the author or co-author of ten books. He serves as a technical editor for Energy—the International Journal.

Introduction by Prof. W.K. Chow Presentation by Prof. Boehm

Prof. Boehm is an expert in renewable energy and design of thermal systems. In this seminar, he gave a detailed presentation on some work at the Center for Energy Research (CER) UNLV related to energy efficiency aspects of (primarily) single-family residences was described

In addition, projects on zero energy building studies, peak electrical demand reduction in

residences, solar hybrid lighting, and the development of an in-situ fenestration evaluation

facility including building integrated PV were outlined.

Well-received talk with full-house attendance

The talk is useful in understanding the economic viability of various building energy issues.

Souvenir presentation 

BSE News CPD20110523

Toward High Performance Buildings

R. BoehmCenter for Energy Research

University of Nevada Las Vegas (UNLV)Las Vegas, NV

What Will Be Covered

• Some work at the UNLV CER related to energy efficiency aspects of (primarily) single‐family residences will be described.

• This includes – zero energy building studies, – solar hybrid lighting, – development of an in‐situ fenestration evaluation facility including building integrated PV,

– peak electrical demand reduction in residences.

What Is the Center for Energy Research (CER)?

• It is a soft‐money funded research center in the Howard R. Hughes College of Engineering

• No funding from university or state• Primary funding is USDOE, but others are present• Budget runs approximately US$1‐$2M/year• Most work is performed by students• Most projects have industrial or other partners• Most work is with near‐ or in‐market products

Some Recent/Current Projects

Roof of UNLV Engineering B‐Bldg

UNLV Solar Site on Flamingo RoadSite in Eldorado Valley

Major Facilities of the CER

UNLV Campus, Circa 2000

Solar Resource in US

Courtesy of the National Renewable Energy Laboratory

ZERO ENERGY BUILDINGS (ZEB)

• Objective is to have zero net energy usage over a long period of time, typically a year.

• Involves high levels of conservation: natural lighting, highly insulated, good windows, solar water heating, high efficiency appliances including a/c.

• Be able to generate energy by using, say, photovoltaics.  Generation over the year must equal the amount of grid power used.

BACKGROUND OF UNLV ZEH PROJECT• Applied to the National Renewable Energy Laboratory (NREL) for Funding.

• Involved Pinnacle Homes, a local builder (1400 homes since 1992) that has an interest in innovation.

• Task was quite simple as grants go:  develop a zero energy house that looked like a traditional Las Vegas tract house, and monitor its performance.  Hope was to interest builders in ZEHs and similar advances.

• Equipment incorporated was open to our choices.• The builder we worked with also furnished a conventional “base case” house (minimal code, but same footprint as ZEH).  

NORTH FAÇADE OF ZEHNORTH FAÇADE OF ZEH

Served as a model home.

SOUTH ROOF OF ZEHSOUTH ROOF OF ZEH

THE TWO HOUSES’ WALLSTHE TWO HOUSES’ WALLS

Base case on left and ZEH on Right.

The Zero Energy Home is designed to minimize energy consumption and generate electricity through the use of the following features/design elements:

‐A “T‐Mass” insulated concrete exterior wall system developed by the Dow Corporation.

‐A CopperSun solar water heating system looped into the heating system minimizing natural gas consumption for hot water heating.

‐A Noritz “tankless” hot water heater.

‐Approximately 400 square feet of roof‐mounted photovoltaic panels rated at 5.28KW manufactured by GE Energy to generate electricity.  Net metering applicable.

Features, Continued.

‐A 19 EER water‐cooled air conditioning condensing unit manufactured by Freus.

‐Energy efficient vinyl framed windows with low “E”glass.

‐PolarPly reflective roof sheeting.

‐Energy Star rated light fixtures with highly efficient fluorescent bulbs.

‐Energy Star rated GE appliances.

Mass Wall ConstructionConcrete/Styrofoam/Concrete

(3”/2”/3”, R9 SS, ~R36 Transient)

Mass Wall ConstructionConcrete/Styrofoam/Concrete

(3”/2”/3”, R9 SS, ~R36 Transient)

Mass Wall ConstructionMass Wall Construction

ZEH Air Conditioner‐‐FREUS BrandZEH Air Conditioner‐‐FREUS Brand

One Goal of Project We Developed

• To determine the cost effectiveness of many aspects of large scale residential development not being used at the time in Las Vegas.

• Do this by combining three critical aspects– Building energy simulations of as‐built house– Detailed data measurements of as‐built house performance to calibrate the simulations

– Vary the parameters of interest in simulations and determine effects on performance/cost

Data Record

• During a two‐year period both the ZEH and the base‐case houses served as model homes.  They were not inhabited.

• During the following years the houses were inhabited.

• We monitored data for all years.• Used model home period to assess performance of the basic building construction details.

SEASONAL COMPARISONS

HEATING SEASON                                    COOLING SEASON

One End Result: Economic Analyses

Solar Lighting

• Solar lighting approaches bring sunlight into rooms.  Sky lights and windows are commonly used examples.

• Newer approaches involve systems that bring a great deal of light through small apertures.

• Solar hybrid lighting combines bringing in sunlight into lighting fixtures and using controls for conventional lights also there.

At CER Solar Site

SolaTube

(Widely available at home improvement stores)

At CER Solar Site

Sunlight‐Direct Solar Hybrid Lighting System

(Currently Marketed)

Sunlight‐DirectSolar Hybrid 

Lighting

Lighting Quality Comparisons

Solar spectrum compared tosolar hybrid lighting system

Fluorescent lamp spectrum

Solar Lighting, Collaboration between Cheju National University and UNLV

Building Integrated Photovoltaics (BIPV)

• BIPV can denote several things, but primarily means PV is integrally designed into the building, not simply “strapped on”

• One exciting application is where PV is integrally incorporated into facades (either building skin or fenestrations)

• Work on developing glass that is partially transparent and partially PV generating is taking place in China and a few other places

• We have developed a facility to evaluate these

BIPV, Windows for Light and Power

Las Vegas Monthly Flux ComparisonHorizontal vs. South Vertical in Las Vegas

Horizontal and Vertical South Hor+Vert and Hor+2Vert

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Units of kWh/m2/day

Drawings of the FacilityConstructed from a Metal Freight Container

Mounted on a base so it can be rotated to face any direction

Insulation 25 cm Styrofoam, R 40

Façade in Evaluation Mode

Can be Used to Assess:

• Various energy transfer parameters.• Various illumination parameters.• Various comfort parameters.• Energy generation capabilities, if applicable.• All data for a range of temperature differences.

• All data for any directional orientation.

目前無法顯示此圖像。

Another Project (USDOE Funded)• The main objective of the project is to reduce utility peak demand 

through – Energy efficient home construction with roof‐integrated PV system– Direct communication of instantaneous pricing to consumer– Demand Side Management – or demand response–using an 

“Intelligent Agent” approach developed at UNLV– Load shifting with a Battery Energy Storage System (BESS)

Subcontractors

DOE Project Team

Prime Contractor

Electric Utility Daily Load by Season 

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Summer peak is approximately 2x the winter peak.

Objective:  65% Peak Load ReductionsLarge Contract from DOE to UNLV

• Energy conserving design• Photovoltaic panels• Price communication to customer

• Demand side management– Reschedule non‐essential tasks– Time‐of‐use rates – Control of AC unit

• Battery storage at substationor at the residential level

Pulte Homes Villa Trieste Project

Villa Trieste

Feeder Load and Ambient Temp

Feeder Load and Ambient TempTypical Summer Day

Payback vs. Electricity Rates

Villa Trieste• Four home models, 185 homes total

– Floor plans: 1,487 to 1,777 square feet– Building America– LEED for Homes platinum certified– Environments for Living

Pulte standard

Villa Trieste

Code Built vs. Villa Trieste

Some Efficiency Measures Used

Tankless water heaters R‐7 Exterior doors 92 AFUE furnaces

100% CFL lighting Dashboard displays

15 SEER Air Conditioners

Fiberglas vs. Blown‐In Cellulose

Attic Insulation• Vented attic

– R-30 fiberglass/cellulose– Extreme attic temperatures

Unvented attic– R‐22 cellulose– Semi‐conditioned attic space

Source: NREL

Attic Insulation• Drawbacks

– No natural convection– Expanded thermal

boundary– More labor– Large conduction gains– No radiant barrier– Closed-combustion

equipment

Mechanical Ventilation• Infiltration rates: 0.28-0.33 ACH

– ASHRAE standard: 0.35 ACH

• Required ventilation

Additional Cost of Efficiency Upgrades

Source: U.S. DOE – Building America program

Benefit/Cost for Conservation

Building Energy Software• Requirements

– Permit relevant inputs– Hourly calculations based on TMY2/3– DOE-2 simulation tool

• Proposed programs– eQUEST– ENERGY-10– BEopt

– EnergyGauge USA

Measured and Predicted Cooling

Simulated Typical Summer Day

Calculated Annual Energy DemandVilla Trieste Home and a Similar Code‐Built Home

Note: without PV, just the energy efficiency upgrades, load from appliances not included

Special Data Acquisition System

• Since peak reduction is goal, need time‐of‐day monitoring

• All houses are monitored with Smart Meters• Some houses are subjected to special, much more extensive, monitoring

• The special monitoring includes thermostat and interior temperature measurements

Special Data Acquisition System

Simulation vs. Experimental Energy Consumption

Milano

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Schematic of Overall System

Schematic of Overall System

PV Production vs. Size, Orientation

PV Systems at Villa Trieste

Photovoltaics• Current:

– SunPower building-integrated– 1.764 kWp

• May increase in future– 2.280 kWp– 3.192 kWp

Array size Array orientation/azimuth angle

Peak kW No. of Modules East (80˚) South (170˚) West (260˚)

1.764 28 2,769 kWh 3,305 kWh 2,883 kWh

2.280 30 3,580 kWh 4,273 kWh 3,727 kWh

3.192 42 5,011 kWh 5,982 kWh 5,217 kWh

Source: SunPower -17% -12%

Time of Use (TOU) Pricing Options

Measured Use/Generation 

PV Orientation, TOU Rates

Value of PV with TOU Rates

Effect of PV Orientation

Main Electrical InteractionsJune 22, 2009

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Effects of Building OrientationBuilding orientation West East South South North North

PV orientation South South East West East West

Gross electric consumption (kWh/yr) 7,270 7,314 7,113 7,113 7,149 7,149

Net electric consumption (kWh/yr) 3,965 4,009 4,344 4,230 4,380 4,266

Gas consumption (therms/yr) 313 322 312 312 292 292

Annual utility cost $1,009 $1,024 $1,085 $1,038 $1,033 $1,020

Net peak electric consumption (kWh) 2.52 2.68 2.73 2.12 2.25 2.14

HERS Index 44 45 48 47 45 45

• South-facing building orientation– Least electric consumption

• North-facing building orientation– Least gas consumption

• East-facing building orientation– Most consumption

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Impacts of Various Options

Impacts of Various Options

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Electricity Load Variations—Peak Summer Day

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Schematic of Overall System

BESS Aspects

• Distributed community as well as residential BES systems are being evaluated in terms of their performance, lifecycle, controls/communications,  and cost.

• To justify the cost of the BESS, additional applications besides load shifting are being sought. These include– Electric supply capacity – Area  frequency regulation – Voltage Support (ancillary service)– Reserve Capacity (spinning reserve)

(BESS Size:150kW/600 kWh) Peak Period

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5:45 PM 6:00 PM 6:14 PM 6:28 PM 6:43 PM 6:57 PM 7:12 PM 7:26 PM 7:40 PM

upstair_Current_Tempupstair_Cool_Setting

Time

Temperature

Model 1 (#6343)

Thermostat Disturbance by 1 degree F @ 6:47pm

Start DLC at 6pm End DLC at 7pm

DLC Case – 7/22/10‐model 1 upstairs

Some Concluding Comments

• Generally, combining computational techniques with measurements has given us tremendous insights about the economic viability of various building energy issues.

• Solar hybrid lighting can give us a high quality light source.• Related to Peak Reduction Project:

– Working with two companies who are not usually involved with government contracts is a challenge.

– Energy conserving construction can go a long way toward alleviating peak demands, but cannot cover it without high costs.

– PV can furnish peak load energy, but it does not cover the complete peak.

– Batteries are the “wild card.”  They are expensive and their durability is open to question.  However, they offer some great loading shifting possibilities.

Some of the CER Crew  

Thanks for your attention!