Seminar 4 Energy Performance of Active Chilled Beam Installations

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Paul Christy Superintendent Clark County Public Schools paul.christy@clark.kyschools.

1 Paul Christy Superintendent Clark County Public Schools Seminar 4 Energy Performance of Active Chilled Beam Installations Successful Application of Chilled Beams in a High School Building Font Size 32

2 Learning Objectives 1. Distinguish between over designing and opportunities to properly load match a chilled beam system. 2. Describe the benefits of a decoupled outside air approach on a chilled beam system using 100% outside air for primary air. 3. Identify design savings methods to help balance first cost and maximize energy savings to result in the best return on investment. 4. Apply chilled beams in a university or K12 classroom to result in a high performance building design. ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA members. Certificates of Completion for non-aia members are available on request. This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Page 2

3 George Rogers Clark High School Winchester, Kentucky 18 th largest high school in Kentucky Grades 9 through 12 Page 3

George Rogers Clark High School Completed August 2013 1,900 student capacity 245,000 SF Approx.

4 George Rogers Clark High School Completed August ,900 student capacity 245,000 SF Approx. 100 classrooms, offices, media center, cafeteria, gymnasium, 2015 Center of Excellence Award Winner auditorium George Rogers Clark High School was built as a replacement high school Page 4

5 HVAC System Multiple Geothermal Water to Water units Dedicated Outside Air System with integrated WSHP Active Chilled Beams Geothermal heat pumps (for high ceiling areas) Dew point and temperature controls system Page 5

6 Still Geothermal with a twist Original design 350 heat pumps Heat pumps still used for cafeteria, gymnasium and auditorium New design 542 active beams Single Water to water heat pumps serves classrooms Page 6

Dedicated Outside Air System Original design was Energy wheel air cooled roof top units New design dual wheel dehumidification systems Ventilation air conditioned to approximately 43

7 Dedicated Outside Air System Original design was Energy wheel air cooled roof top units New design dual wheel dehumidification systems Ventilation air conditioned to approximately 43 F (6.1 C) dew point Handles all outdoor load and indoor humidity using only ventilation air Recirculation mode for minimum ventilation during unoccupied times (nights/weekends) Page 7

8 Indoor comfort Education required Most schools in the district operate at 70 F (21.1 C), with occasional too warm complaints George Rogers Clark have minimal complaints even with average temp of 75 F (23.9 C) due to 80% 70% 60% 50% 40% 30% Relative Humidity ASHRAE Standard 55 Comfort Zone 68 o F WB Comfort Zone Suggested by Berglund (1) Humidity Ratio - Grains of Moisture Per Pound of Dry Air dryer building operation Dry Bulb Temperature ( o F) Page 8

9 Simple System Ductwork Ventilation duct to the beams Exhaust from classrooms (10% less for pressurization) 12 duct 6 duct Page 9

10 Active Chilled Beams Four beams typical per classroom 450 cfm (212 l/s) ventilation 15 cfm/person (7 l/s) Constant volume operation Page 10

11 Preliminary Energy Modeling Electric rate of $0.07/kwh. Page 11

12 Actual Operational Results The old high school was 30% smaller and has 35% more expensive utilities National average high school runs 96 kbtu per ft 2 (8.9 kbtu per m 2 ) George Rogers Clark is running at 31 kbtu per ft 2 (2.9 kbtu per m 2 ) 2/3 reduction on energy confirms preliminary energy analysis accuracy High efficiency lighting and well built envelope contribute to the overall success of the building, but the HVAC is a large part of the utilities. Page 12

13 How much was first cost? The mechanical system installed for $19.50 per ft 2 ($1.81 per m 2 ) Cost was equal to the estimates given for the original geothermal heat pump design Page 13

14 Cost Savings Construction Less geothermal wells required Less number of geothermal units Less ductwork (water in lieu of air) 1 water to water unit vs 10 heatpumps) Less pipe than traditional geothermal Page 14

15 Return On Investment - Dollars No first cost premium Annual utility dollars saved versus the replaced and smaller high school is approximately $65,000 Page 15

16 Return On Investment - Sense Fewer teacher complaints Quieter classroom More comfortable room conditions Constant Ventilation to the classrooms Less absenteeism Less maintenance No Filters (vacuum coil once / 5 years) No Drain Pans Page 16

17 Parting thoughts Condensing beams (raining in classroom) is not a concern if you design for humidity control first Educate the occupants that the building will feel different than other buildings, they will adapt Worry about air comfort, don t try and do a room with one or two beams as it will not have good room coverage. Enjoy the results Page 17

18 Questions? Paul Christy Page 18

Reducing Hospital Energy Use and Maintaining Savings. Glen Anderson, PE

Reducing Hospital Energy Use and Maintaining Savings Glen Anderson, PE AIA Quality Assurance The Building Commissioning Association is a Registered Provider with The American Institute of Architects Continuing