Project group membersand presentation time

Thursday• Chris Holcomb• Cristian Wolleter• Michelle Noriega• Mei Baumann, Zahid Alibhai, Ellie Azolaty• Randy Maddox and Garrett Jones• Mariel Kerbacher

Friday• Jeremy Theodore• Steve Bourne• Jordan Clark and Adam Keeling • Meg Gunther and Nick David• Joshua Rhodes and Marwa Farhat • Yogita Manan and Kostas Mouratideis• Sarah Johnson, Jocelyn Citty, Benjamin Ash• Lauren Davis and Marcus Allen• Jae Koh and Kenneth Graeves

Presentation length: 8 minutes presentation + 2 minutes for questions

Lecture Objectives:

• Discuss accuracy of energy modeling

• Talk about available modeling tools

• Review the course outcome

What are the reasons for energy simulations?

• System Development

• Building design improvement

• Economic benefits

• Budget planning

How to evaluate the whole building simulation tools

Two options:

1) Comparison with the experimental data - monitoring

- very expensive- feasible only for smaller buildings

2) Comparison with other energy simulation programs- for the same input data

- system of numerical experiments - BESTEST

Comparison with measured data

Cranfield test rooms (from Lomas et al 1994a)

BESTEST Building Energy Simulation TEST

• System of tests (~ 40 cases) - Each test emphasizes certain phenomena like

external (internal) convection, radiation, ground contact

- Simple geometry- Mountain climate

6 m

2.7 m

3 m

8 m

0.2 m

0.2 m

1 m

2 m

S

N

E

W

COMPARE THE RESULTS

Example of best test comparison

BESTEST test cases

0

2000

4000

6000

8000

10000

12000

195 200 220 230 240 270

Annual heating load [kWH]

new ES prog

ESP

BLAST

DOE2

SRES/SUN

SRES-BRE

S3PAS

TRYNSYS

TASE

What are the reasons for energy simulations?

• System Development

• Building design improvement

• Economic benefits

• Budget planning

Life Cycle Cost Analysis

• Engineering economics

Example

• Using eQUEST analyze the benefits (energy saving and pay back period)

of installing

- low-e double glazed window

- variable frequency drive

in a school building in NYC

What are the reasons for energy simulations?

• System Development

• Building design improvement

• Economic benefits

• Budget planning

For budget planning

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 900

50

100

150

200

250

300

350

400

450

500

Q [t

on]

t [F]

Load vs. dry bulb temperature Measured for a building in Syracuse, NY

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 900

50

100

150

200

250

300

350

400

450

500

Q=-11.33+1.2126*t

Q=-673.66+12.889*t

Q [t

on]

t [F]

8760

1i ii

ii

57 tif t889.1266.673

57 tif t126.133.11(Q

Model

Empirical model

8760

1i ii

ii

57 tif t889.1266.673

57 tif t126.133.11(Q

For average year use TMY2

=835890ton hour = 10.031 106 Btu

Advance Energy Modeling with coupled

energy and airflow Example: Night Cooling/Hybrid Ventilation

The IONICA Office Building, Cambridge, UK

Night Cooling/Hybrid Ventilation:

Requires combined Energy and airflow modeling

Night Cooling/Hybrid Ventilation:The IONICA Office Building, Cambridge, UK

Available software

http://www.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm

Which software to use:

- Depends on project requirements

- If you have a choice: the one which passed BETEST

Be ready to conduct additional analysis based on your modeling skills

Structure of ES programs

SolverInterface for input data

Graphical User Interface (GUI)

Interface for result presentation

Preprocessor Engine

Preprocessor

ASCIfile

ASCIfile

Modeling steps

• Define the domain

• Analyze the most important phenomena and define the most important elements

• Discretize the elements and define the connection

• Write energy and mass balance equations

• Solve the equations

• Present the result

ES program

Preprocessor

Solver

Postprocessor

EnergyPlus

Component-based simulation programs - Trnsys

ESPrUniversity of Strathclyde - Glasgow, Scotland, UK

• Detailed models

– Research program

1. Identify basic building elements which affect building energy consumption and analyze the performance of these elements using energy conservation models.

2. Analyze physics behind various numerical tools used for solving different heat transfer problems in building elements.

3. Use basic numerical methods for solving systems of linear and nonlinear equations.

4. Conduct building energy analysis using comprehensive computer simulation tools.

5. Evaluate performance of building envelope and environmental systems considering energy consumption.

6. Perform parametric analysis to evaluate the effects of design choices and operational strategies of building systems on building energy use.

7. Use building simulations in life-cycle cost analyses for selection of energy-efficient building components.

Course Objectives