Advanced Residential Integrated Energy Solutions

Building America Stakeholder MeetingAustin, Texas February 29 to March 2, 2012

Hugh Henderson, CDH Energy Corp. Jordan Dentz, The Levy Partnership, Inc.

Hydronic Controls Retrofits for Low-Rise Multi-Family Buildings

Research Objective

• Determine the impact of control strategies that use apartment temperatures for central boiler control on energy consumption, comfort and cost.

• Compare energy performance, comfort and cost to individual radiator valve controls in each apartment.

Background

• Most multi-family boiler systems have:– No zone/apartment level control, or– Non-electric thermostats on radiator valves

• Central boiler system resets hot water based on outdoor temperature

• Problem: – apartments are often too hot or too cold. – Occupants often open windows to “control”

temperature

Concept

• New wireless temperature sensors offer the potential to cost-effectively retrofit poorly-controlled heating systems to reduce energy use

• More intelligent boiler plant “reset” control strategies may be more cost effective than full scale retrofits that put zone controls in each apartment.

Test Site - Project Participants

• The ARIES Collaborative, a Department of Energy Building America research team– The Levy Partnership, Inc.– CDH Energy Corp.

• Homeowners' Rehab Inc., a non-profit housing developer in Cambridge, MA.

• Massachusetts Low Income Multi-Family Retrofit Program (LEAN), a utility program proving funding for the retrofit

• EnerSpective, Inc., assessing the project for the utility program

Test Site

• 42-unit complex of three, three-story masonry buildings in Cambridge, MA

• Each building has two or three 87% eff space heating boilers (+one boiler for DHW)

Technical Approach

• PHASE I: Replace boiler controls with wireless system that supplies heat based on both apartment and outdoor temperatures. Rigorously quantify the effectiveness of this strategy.

• PHASE II: Install radiator zone valves to provide local control.

PHASE I: Indoor Temperature Based Boiler Control

• Wireless temperature sensors in apartments - data used to adjust building supply water temperature

• Web-enabled. Off-site server stores data and makes it available on a website

• Adaptive and intelligent reset and night setback approaches

• Where required, maintain boiler return water temperatures above 140°F with new 3-way mixing valve

• Goals: – Reduce spacing heating energy by 15% to 20%– Maintain space temperatures closer to the required set points

(reduce overheating)

System Configuration

Boiler 1

3rd Floor Non-Elect

Tstat

2nd Floor Non-Elect

Tstat

3rd Floor Non-Elect

Tstat

2nd Floor Non-Elect

Tstat

1st Floor Non-Elect

Tstat

1st Floor Non-Elect

Tstat

Boiler 2

Boiler 3

Circuit Setter

Circuit Setter

Circuit Setter

Circuit Setter

2 Pumps (One at a time)

Front of Building

Rear of Building

Add 3-way Mixing

Valve Here

AB

B A

Apt Complex Layout

Current Zone Controls

• Each apartment has 1-2 non-electric, remote “thermostats” to regulate baseboard water flow

• Valve calibration is unknown• Many have failed in open position

(resulting in overheating)• Residents typically disregard

municipally mandated set points (68°F day, 64°F night)

Boiler Controls

• Both Buildings have Outdoor Reset control

• Supply T about 30°F higher in Bldg 3 on April 7, 2011

100

110

120

130

140

150

160

170

180

190

0 20 40 60 80

Outdoor Temperature (F)

HW S

uppl

y Te

mpe

ratu

re (F

) Bldg 3 Weil MclainBldg 4 Tekmar

Observed on April 7

Adjusted Test Plan

• BUILDING 3: Wireless, Web-enabled system (Intech 21)– Full functionality– Web-based data collection

• BUILDING 4: Updated Baseline system (Tekmar)– Standard controls, boiler protection valve– Data collection capabilities

Baseline Performance

DHW Baseline Use

Load line of monthly gas use vs. temperature 2009-2012

Data Collection (Intech 21)

• Web-enabled control will be used to collect data at 15-minute intervals:– Apartment temperatures– Outdoor temperature– Hot water supply temperature– Hot water return temperature– Hot water return temp (entering boilers)– Cumulative boiler run time (each boiler) – Mixing valve position– Cumulative runtime of hot water pump

• Also…– Comfort will be gauged by heat complaint reports, surveys and

observations of open windows– Monthly gas consumption from fuel bills

Test in Various Modes

• Control Modes:1. Existing conditions (baseline outdoor reset)2. Indoor temperature-based control 3. Control with nigh-time setback

• Spend several weeks in each mode• Directly compare energy performance and

comfort impacts after normalizing for weather

Analysis Approach

• Daily load line analysis relating total boiler runtime to outdoor temperature for each day

• Compare resulting linear trends for different performance periods / control modes to discern impacts– Multi-linear regression analysis with dummy variables

to determine if the differences are statistically significant

– Relate monthly runtimes to billed gas use to discern impact on fuel use

First Results (Tekmar)

• Collected (1-min) Data on (Baseline) Tekmar Performance in Building 4 and Building 55– Tried to incorporate mixing valve control in

Bldg 4• Understanding details of baseline controls• Assessing impact of night setback

Tekmar, Bldg 4/6 - 02/02/12 (TAO mn/mx = 34.1/ 45.0)

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:1 2 3

100

120

140

160

180

Tem

p (F

)

BLR Supply BLR Return BLR Target SYS Supply SYS Return

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:1 2 3

1 Blr

2 Blrs

3 BlrsBoiler Controller (Tekmar 274) is set to lead on Feb 2

BLDG 4Disabling Mixing Valve Control

Tekmar, Bldg 55 - 02/02/12 (TAO mn/mx = 36.9/ 47.0)

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:1 2 3

80

100

120

140

160

180

Tem

p (F

)

BLR Supply BLR Return Target

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:1 2 3

1 Blr

2 Blrs

Start of Night-time Setback on Feb 2

BLDG 55Start of Night Setback

Tekmar, Bldg 55 - 02/08/12 (TAO mn/mx = 30.1/ 39.6)

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:7 8 9

80

100

120

140

160

180

Tem

p (F

)

BLR Supply BLR Return Target

22: 0: 2: 4: 6: 8: 10: 12: 14: 16: 18: 20: 22: 0:7 8 9

1 Blr

2 Blrs

Night-time Setback made less Aggressive on Feb 8

Bldg 55

20 40 60 80Outdoor Temperature (F)

100

120

140

160

Boi

ler S

uppl

y Ta

rget

(F)

Outdoor Air Reset Schedules (with various levels of Setback)

BLDG 55Night Setback

BLDG 55 (100% = 1 Blr all day)

0 20 40 60 80Avg Outdoor Temperature (F)

0

20

40

60

80

100

Boi

ler L

oadi

ng (%

)

Aggresive Setback (Feb 3-7)

Moderate Setback (after Feb 8)

Impact of Setback on Boiler Runtime

BLDG 55Night Setback

First Results (Intech 21)

• Collected (15-min) Data on Building 3 since October 2011– Measuring indoor temperatures– Controller functions not fully enabled

• Test plan– Mixing valve control enabled (Feb 8)– Just started outdoor air reset (Feb 22)– Enable indoor air control features in March

Summary

• Testing program has just started– Gathering data to quantify control changes

• Looking at various control issues in multiple buildings– Understanding baseline operation… and

mixing valve control– Impact with and without night setback– Various forms of reset control

Advanced Residential Integrated Energy Solutions

Building America Stakeholder MeetingAustin, Texas February 29 to March 2, 2012

Hugh Henderson, CDH Energy Corp.hugh@cdhenergy.com

Jordan Dentz, The Levy Partnership, Inc.jdentz@levypartnership.com

Hydronic Controls Retrofits for Low-Rise Multi-Family Buildings

BLDG 55 (100% = 1 Blr all day)

0 20 40 60 80Avg Outdoor Temperature (F)

0

20

40

60

80

100

Boi

ler L

oadi

ng (%

)

JanuaryFebruaryOctoberNovemberDecember

01/05/12

01/06/12

01/17/12

01/18/12

01/19/12

01/20/12

02/13/12

Some days show unexpected behavior

BLDG 4 (100% = 1 Blr all day)

0 20 40 60 80Avg Outdoor Temperature (F)

0

200

400

Boi

ler L

oadi

ng (%

)

Reset (after Feb 2)

Boiler runtime data not meaningful before Feb 2