Houston Independent School District: Farias Early Childhood Center Retrocommissioning

Background

Farias Early Childhood Center (FECC) is one of the 238 schools that are part of the Houston Independent School District (HISD). In 2015, the district developed an Energy Master Plan to implement retrocommissioning across 20 targeted campuses. FECC was identified as having the highest energy use index amongst school buildings based on energy consumption, square footage and occupancy.

FECC is a dual-language facility serving over 430 children in pre-kindergarten. The building was constructed in 2005 using several energy efficient design elements including corridor skylights, energy efficient windows, and VAV HVAC systems. However, in recent years, this facility realized atypical electrical loads attributed to a fault in the direct digital control (DDC) programming and skill deficiencies of the maintenance staff. The DDC programming allowed for the building to operate on a 24/7 schedule.

Solutions

Energy efficiency measures included adjustments to set points and building system controls, repair to damaged sensors, de-lamping and cleaning of equipment. Implementation began in October of 2015 and is expected to result in an annual energy savings of 58% and $88,000 at the project’s conclusion.

Below is a list of energy efficiency measures implemented at FECC including the cost per measure and savings achieved:

Savings Measure	Project Cost	Cost Savings Achieved	Notes
Reduce air handling unit (AHU) run time	$3,040	$32,000	Repaired conflicts causing systems to run continuously Adjusted night setback points to eliminate night-time operation
Space temperature set point control	$0	$12,000	Adjusted space temperature heating (HSP) and cooling set points (CSP) so that CSP – HSP > 4 degrees Fahrenheit (F) Repaired damaged space temperature sensors
Variable air volume (VAV) box minimum air flow set point	$0	$8,000	Reduce minimum airflow set point from 40% of max to 10% of max to reduce reheat in unoccupied classrooms
VAV AHU air flow control	$500	$8,000	Repaired two AHU variable fan drive’s (VFD) running at full speed Repaired one static pressure sensor controlling the VFD speed for one AHU
Chilled water coil discharge air temperature control	$0	$2,400	Established chilled water coil discharge air temperature set points at design value Repaired one damaged CHW valve
Preheat coil discharge air temperature control	$0	$2,400	Reduced preheat discharge air temperature set points from 55 to 40 degrees F (previously at or above chilled water coil discharge air temperature set points)
Reduce central plant equipment run time	$4,505	$2,400	Repaired start/stop relay controlling the chiller operation Replaced failed chilled water pump starter with new VFD
Open throttled isolation valves	$0	$2,400	Opened new chilled water pump VFD chiller isolation valves to 100% Reduced VFD speed to provide design chiller flow with final max speed set to 50Hz.
Reduce domestic hot water set point	$0	$2,400	Reduced electric water heater set point from 130 degrees F to 120 degrees F in the building automation system (BAS)
De-lamp corridor lighting fixtures	$871	$2,400	Reduced over-lit corridors by removing one lamp per light fixture
Central Plant Maintenance	EST. $500	$2,400	Verified chiller flow switch Cleaned condenser coils Replaced chilled water supply and return sensors
Perform air-side equipment maintenance	EST. $500	$3,200	Verified valve and fan operations Replaced bad temperature sensors and fuses Modified set points to eliminate unnecessary reheat

Other Benefits

In addition to the energy savings above, the measures are expected to increase overall building comfort, therefore improving the learning environment for the kids and the teachers by eliminating over-cooling of classrooms. The reduced equipment run times will also improve system reliability and increase equipment life, as well as reduce maintenance cost over the life of the building.

The district benchmarks Farias using the EPA’s ENERGY STAR® Portfolio Manager tool and expects these savings to result in an improved ENERGY STAR Portfolio Manager score with the potential for certification in the future. In addition, HISD plans to reinvest cost savings achieved district-wide to fund additional efficiency measures and academic support needs.

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(Source EUI)

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IN BUILDING ENERGY USE

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Farias Early Childhood Center

Houston Independent School District: Farias Early Childhood Center Retrocommissioning

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Farias Early Childhood Center