Multifamily (MF) Combined Heat and Power (CHP) Level 2 Analysis Tool

Piljae Im

Oak Ridge National Laboratory

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Webinar Outline

• Introduction• HUD CHP Level 1 Screening Tool• MF CHP Level 2 Analysis Tool• Quick Starts• MF Building Template• Example Use of the Tool

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Introduction: Background• Promoting the use of combined heat and power (CHP) (cogeneration) in

multifamily housing is an initiative of the HUD Energy Action Plan.

• To help implement it, beginning in 2003 the Department of Housing and Urban Development (HUD) and the Department of Energy/Oak Ridge National Laboratory (DOE/ORNL), executed Interagency Agreements (IAA) to create feasibility screening software (i.e., Level 1 Screening Tool).

• ORNL created, expanded, and validated a Level 1 preliminary screening tool that enables the owners of multifamily housing to consider the feasibility (cost, savings and paybacks) for installing CHP.

• In May 2010 ORNL created for HUD a Level 2 Multifamily CHP Screening Tool (MFCHP) that adapts the BCHP tool used for the Federal Energy Management Program (FEMP) for use on multifamily buildings.

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Before the Level 2 Tool

HUD CHP Level 1 Screening Tool• Level 1 screening tool: Simplified process to

get a “go/no-go” answer as to whether or not a building owner or operator should look more carefully into CHP and perhaps enlist some engineering support in conducting a site inspection and conducting a rigorous economic analysis (i.e., Level 2 analysis).

• This tool is “non-technical” and is directed specifically toward building owners and operators.

• Users of the HUD CHP Screening Tool need to type in data from their monthly power and fuel bills for one consecutive 12 month period as well as some utility rate information.

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Before the Level 2 Tool

HUD CHP Level 1 Screening Tool• The program uses these data to estimate fuel use for space and water

heating and power consumption for air conditioning. The utility costs and rate information are combined with correlations for costs of generator equipment, installation, and maintenance to estimate simple payback periods for a hypothetical CHP system relative to the non-CHP system reflected in the utility data.

• Sites with low estimated simple payback periods are encouraged to look more seriously into CHP for both its energy savings and cost savings opportunities. Sites with high simple payback periods can save the time and effort of examining CHP in detail with assurances that they are not missing a great opportunity.

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Needs for the Level 2 Tool• Once the building owner decided to go for further analysis for CHP

systems after level 1 analysis, a more detailed level 2 analysis will be needed.

• A Level 2 analysis is based on detailed site examination, utility usage and heat consumption, and it can cost $5,000-10,000 in engineering firm charges.

• To provide a Level 2 tool for owners and for analysts that can facilitate the efforts

• The MF CHP Level 2 Analysis Tool provides a building energy simulation with a full hourly level analysis and cost analysis via simple easy-to-use user interfaces.

• This new tool provides a “public” option where anyone can have all the information on how it works (can compare results across practitioners more easily, and public entities like HUD can require more public results be provided on proposed projects). 6

MF CHP Level 2 Analysis Tool• The MF CHP Level 2 Analysis Tool was developed under a

collaborative effort between the U.S. Department of Housing and Urban Development and the Department of Energy/Oak Ridge National Laboratory as a tool to evaluate the combined cooling, heating and power in multifamily housing.

• The MF CHP Level 2 Analysis Tool is a computer program for assessing the economic potential of combined cooling, heating, and power (CHP) systems for multifamily buildings.

• The original program, the BCHP Screening Tool, which is the similar program for commercial buildings (but no MF building type), was developed under Department of Energy funding by a collaborative effort between GARD Analytics of Park Ridge, Illinois and Oak Ridge National Laboratory in Oak Ridge, Tennessee.

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MF CHP Level 2 Analysis Tool• The MF CHP Level 2 Analysis Tool is structured to perform parametric

analyses between a baseline building, typically a conventional building without a CHP system, and up to 25 alternative scenarios with varying selections for building mechanical systems and operating schedules.

• The MF CHP Level 2 Analysis Tool consists of the executable program, databases for HVAC equipment, electric generators, thermal storage systems, prototypical multifamily buildings, and climate data. The program also includes DOE-2.1e to calculate heating, cooling, and electrical loads.

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MF CHP Level 2 Analysis Tool

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Input through the MF CHP Tool

Input through the MF CHP Tool

DRM TemplateDRM Template

DOE-2 BDL File (DOE-2 Input File)DOE-2 BDL File (DOE-2 Input File)

DOE-2 Run for System Sizing

DOE-2 Run for System Sizing

Output for System Sizing

Output for System Sizing

DOE-2 Simulation Run

DOE-2 Simulation Run

DOE-2 Simulation Output

DOE-2 Simulation Output

Output in the MF CHP Tool

Output in the MF CHP Tool

Quick Starts• The tool and User Manual can be downloaded:

http://eber.ed.ornl.gov/MF_CHP/

• Installation procedure: See the user manual

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Quick Starts

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Input

Results

Help

Scenario A:Base Case

Scenario B:Alternative

Quick Starts

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Table tab: Input and

Result

Graph tab: Result

Schematic tab:Result

Building Description:

Result

Add a Scenario

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Insert a column (three options)

Add a Scenario: Copy of Current Column

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Scenario C added

Three Types of Input Method• Direct input

• Drop down menu

• Selection from a separate window

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Drop Down Menu (ex: Story Height)

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Drop Down Menu (ex: Story Height)

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Select from a Separate Window (ex: Location)

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Select from a Separate Window (ex: Location)

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Inputs: Table Tab

– Two categories for the inputs: Mandatory & Additional Inputs

– For a quick run, only the mandatory inputs needs to be entered

– For more detailed controls, the additional inputs needs to be entered.

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Mandatory Inputs

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Overview of the BCHP Screening ToolResult

– Annual Gas and Electricity Consumption & Costs

– Equipment Sizes & Costs– System Life Cycle Costs– Parametric Analysis of Up to 26

Systems– Simple Payback Relative To

Baseline System– Hourly Load Profiles for Selected

Dates

Building Loads: Dec-15

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

12:00 AM 6:00 AM 12:00 PM 6:00 PM 12:00 AM

Time

Lo

ad (

Btu

/ h

)0

200

400

600

800

1000

1200

Ele

ctri

city

Dem

and

(kW

)

Cooling Load

Heating Load

Electrical Load

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Results: Table Tab

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Graph Tab– The graphs, also called charts, can be monthly results or

annual results from the simulation

– The numbers shown on the graph are taken from the grid on the Table tab.

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Graph Tab

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Schematic Tab– Provide a good summary of the energy (elec. and gas)

flow based on the selected case.

– Provide the summary of calculated project cost, operating cost, annual savings and simple payback.

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Schematic Tab

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Building Description

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Overview of the BCHP Screening ToolMF Building Template

– Thermal Model: Does not need to be the same with the actual building shape

– Six zones– Perimeter zone and core zone

for each zone– Two space types: Corner

apartment and Inside apartment

Zone Space Type Building

Fraction (%)

Window/Wall Ratio (%)

North East Corner Apartments

5 21

North Central Inside Apartments

40 23

North West Corner Apartments

5 21

South East Corner Apartments

5 21

South Central Inside Apartments

40 23

South West Corner Apartments

5 2129

Overview of the BCHP Screening Tool

MF Building Defaults– Default values for the “thermal characteristics” of each type of zone

end use Six zones

– Resources:1) ASHRAE Standard 90.1 - 2004, 2) ASHRAE Handbook of Fundamentals, 3) "Estimating Water Heating and Aggregate Electricity Loads in Multifamily Buildings," R. L.

Ritschard, Y. J. Huang, J. M. Fay, ASHRAE Transactions 1990, Volume 96, Pt. 1, pp. 796-8024) “Impact Evaluation of the Energy Retrofits Installed in the Margolis High-Rise Apartment Building,

Chelsea Housing Authority” M.M. Abraham, H.A. McLain. And J.M. MacDonald, Technical report ORNL/CON-413, 1995.

5) and professional judgment.

Use Area/Person (sqft/person)

Lighting (W/sqft)

Plug Load (W/sqft)

Person Heat Gain (Btuh/person)

Sensible Person Heat (Btuh/person)

High Rise Multifamily Housing 424 0.8 1 500 250

Use Heat Set Point (F)

Cool Set Point (F)

Max Humidity (%RH)

Min Humidity (%RH)

Ouside air (CFM/person)

High Rise Multifamily Housing

70 75 100 0 15

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Example: CHP Analysis Study

• Multifamily Building• New Bedford, MA• 7 story• 99 one-bedroom apartments• 82,900 sq.ft. heated floor space• No cooling system• Utility rate

– Average electricity: $0.123/kWh

– Average natural gas: $1.45/Therm31

Monthly Utility Bills (Before CHP System)

Month Elec. N.G.

kWh $ Therm $

January 43,680 $4,805 3,822 $5,557

February 43,520 $4,787 7,976 $11,597

March 39,200 $4,900 5,600 $8,142

April 42,080 $5,260 3,959 $5,756

May 39,680 $4,960 2,904 $4,222

June 43,680 $5,460 1,646 $2,393

July 47,360 $5,920 964 $1,401

August 56,160 $7,020 674 $979

September 54,240 $6,780 771 $1,121

October 46,240 $5,780 1,202 $1,747

November 44,160 $5,520 2,232 $3,245

December 39,360 $4,920 5,314 $7,726

Total 539,360 $66,112 37,064 $53,886

Average Cost   $0.12   $1.45

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Preliminary Screening (Level 1)

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Preliminary Screening (Level 1)

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Preliminary Screening (Level 1)

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Preliminary Screening (Level 1)

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Preliminary Screening (Level 1)

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Example: Level 2 Analysis - Procedure

• Base case: Initial Run (As-built)• Base case: Calibration• Apply generator(s) for the base case building• Change the generator options• Find the optimal scenario

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Example: Level 2 Analysis

• Base case: Initial Run – At least complete the Mandatory Inputs

– Use available data/information

– Use the best guess for unknown data/or

– Leave default values

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Building Size

HVAC (No cooling)

Average Utility Rate

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Building Location

Result Screen (Annual Consumption)1.Total Annual Elec. Use Simulated vs. Utility Bills: 524,379 kWh vs.539,360 kWh (2.8% diff.) 2. Total Annual N.G. Simulated vs. Utility Bills: 59,175 Therms vs. 37,064 Therms (59.7 % diff.)

Annual Elec. Use

Annual N.G. Use

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Month Elec. N.G.

kWh $ Therm $

January 43,680 $4,805 3,822 $5,557

February 43,520 $4,787 7,976 $11,597

March 39,200 $4,900 5,600 $8,142

April 42,080 $5,260 3,959 $5,756

May 39,680 $4,960 2,904 $4,222

June 43,680 $5,460 1,646 $2,393

July 47,360 $5,920 964 $1,401

August 56,160 $7,020 674 $979

September 54,240 $6,780 771 $1,121

October 46,240 $5,780 1,202 $1,747

November 44,160 $5,520 2,232 $3,245

December 39,360 $4,920 5,314 $7,726

Total 539,360 $66,112 37,064 $53,886

Average Cost   $0.12   $1.45

Monthly Elec. Use

Monthly N.G. Use

Utility Bills

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• Discrepancy between the initial simulation and Utility Bills– Default assumption (average MF characteristics) vs.

actual building characteristics

– Unknown input parameters (e.g., windows-to-wall ratio, boiler & chiller size, operation schedule, etc.)

– Equipment performance data

– Actual weather vs. typical weather file

Need Calibration !

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• Base Case: Calibration with Utility Bills/Measure data– Tune the initial simulation to be matched with the utility

bills (i.e., actual use)

– Annual total

– Monthly total

– Useful input parameters for calibration• SHW use (Btu/h-person)

• Infiltration rate (ACH)

• Lighting and Equipment load (W/sq.ft)

• Building insulation value (R-value)

• Type of windows (if unknown)

• Cooling/Heating room set temperatures

• Others 44

• Input Changed

1.Too low heating energy : Change air infiltration rate from 0.5 to 0.752.Too high SWH use: Change service water heating density (Btu/h-person) from 2500 to 500

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Result Screen (Annual Consumption)

1.Total Annual Elec. Use Simulated vs. Utility Bills:526,320 kWh vs.539,360 kWh 2. Total Annual N.G. Simulated vs. Utility Bills:36,137 Therms vs. 37,064 Therms (2.5% diff.)

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Add a Generator– The MF building has a 75 kW reciprocating engine.

– Change the corresponding default values to be the same with the base case scenario

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Add a Generator– The MF building has a 75 kW reciprocating engine.

– Change the corresponding default values to be the same with the base case scenario

– Select a reciprocating engine (5.f. Generator)

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Add a Generator – The MF building has a 75 kW reciprocating engine.

– Change the corresponding default values to be the same with the base case scenario

– Select a reciprocating engine (5.f. Generator)

– Input 75 kW (6.c. Generator Sizing (direct input))

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Add a Generator– The MF building has a 75 kW reciprocating engine.

– Change the corresponding default values to be the same with the base case scenario

– Select a reciprocating engine (5.f. Generator)

– Input 75 kW (6.c. Generator Sizing (direct input))

– Check with III.2. Generator Operation : Thermal demand Option for summer and winter

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Check Result

No Changes in Elec. Use

Reduced Space Heating

Reduced SWH

N.G Use for Generator

Total N.G. Use

Elec. Onsite Generation51

Select Schematic tab

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Select Case B

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Cost AnalysisSystem Configuration

Space and SW Heating

Heat Recovery Summary

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Double Click

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56

Click

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Double Click

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Next Step: Analyze and find the optimal generator

and the schedule for the building

Input parameters can be changed for the analysis– Size of generator

• 30, 45, 70, 100 kW…

– Number of generators

– Type of generator • Reciprocating, Gas turbine, Micro turbine

– Generator operating option• Thermal demand

• Electric demand

• Greater/lesser demand

• Maximum output

– Heat used for space heating/service water heating61

Thanks!

Question/feedback/comment

Piljae Im

Oak Ridge National Laboratory

imp1@ornl.gov

865-241-2312

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