Why is my classroom so muggy?

BARD MANUFACTURING COMPANYVAUGHAN SMITH

Because we’re in Florida!

Energy Recovery and Classrooms• OUTSIDE AIR, VENTILATION AIR, CFM, RH, DEWPOINT, COMFORT

• MEASURING AND REGULATING VENTILATION AIR

• WHY ENERGY RECOVERY, ESPECIALLY IN FLORIDA

• ENERGY RECOVERY: TECHNOLOGIES & PERFORMANCE

• INTEGRATING ENGERY RECOVER WITH HVAC

• ENERGY RECOVERY: EFFICIENCY, LOAD REDUCTION, REBATES

Energy Recovery and Classrooms• LEARNING OBJECTIVES:

• BASICS OF VENTILATIING CLASSROOMS

• ENERGY RECOVERY TECHNOLOGY, TYPES & PERFORMANCE

• HVAC & ERV DESIGN RECOMMENDATIONS

• BEST PRACTICES OPERATING AND MAINTANING ERV

• EFFICIECNY, REBATES

Fresh Air, circa 1969 Macon, GA

ASHRAE Code for classrooms

Classroom numbers• Students: 25

• Classroom square feet: 900 ft²

• Ceiling height: 10 ft.

• 9000 ft³

• 45 ft²/student, 450 ft³/ student

• Fresh air required each student 15 cfm

• 375 cfm for 20 students

• 9,000ft³ /375 ft³ = 24 minutes: Total Room F/A Change every 24 minutes

Heat Gains or Cooling Loads

T

Latent or moisture loads

Ventilation Load of Outside Air

Heat gain of 450 cfm Florida Outside Air (95/77): 9,720S 13,700L

T

All of Florida considered ‘Tropical’

Where the rubber meets the rainforest

Relative Humidity

What is the significance of 95F, 75F, 55F ?

180 cfm

450 cfm

Over 60% Maximum 60% Maximum 30%

Various ERV’s

Energy Recovery Terms• Heat Wheel

• Energy Wheel

• Total Enthalpy Wheel

• Heat Pipe

• Fixed Plate

Energy Recovery Performance

55

95

75

89

81

Free (almost) Cooling• HVAC unit in ventilation only mode

• ERV intake and exhaust blower

• Supply fan on low speed

• Depending on system, low static, low amp draw, ecm supply blower

Energy Recovery Performance

55

95

75

89

81

Unit efficiency: 12.0 EERERV Efficiency: 39.6 RERRecovery Efficiency Ratio

Energy Recovery

• Highly efficient method of pretreating ventilation air• Utilizes energy already spent• Reduces size of HVAC• Reduces peak demand• Power companies recognize benefits• Florida Power & Light (example of FPL payback by Frank Suranyi of AccuAir, Inc.)

What does the Florida Building Code Say for OA?

Florida Power and Light (example)

• Business Heating Ventilation & Air Conditioning ProgramFPL has developed a program to reward customers for using high performance and energy conserving technologies.

• Energy Rebates for Efficiency • Energy Rebates for CO2 Demand Control Ventilation• Energy Rebates for “ENERGY RECOVERY” ERV

Eligibility Requirements– Energy Recovery Ventilation ERV• End User or Customer must• Have an active FPL business account. • Select an ERV that meets all equipment specifications. • Use the equipment to air condition a facility. • Select, verify, and hire a qualified, licensed Contractor to

perform the installation work.

• Governmental entities, including local, state and federal agencies, may, with FPL’s pre-approval, perform installations themselves provided they comply with all other Program Standards requirements.

ERV systems must reflect the following specificationsto meet FPL requirements:

• Equipment must meet or exceed Florida Building Code requirements as specified by FPL.Enthalpy wheel or fixed plate type.

• Listed in AHRI’s current Standard 1060 Certified Directory for Air-to-Air Energy Recovery Ventilation Equipment.

• Actual equipment airflow and AHRI’s listed Nominal Airflow capacity.

• The AHRI Net Total Thermal Effectiveness for the cooling condition must be 50% or greater.

ERV systems must reflect the following specificationsto Meet FPL requirements:

• A copy of air flow design submittal for the ERV must be received by FPL prior to rebate paymentprocessing.

• Operate during FPL’s seasonal summer on–peak periods (3:00 p.m. to 6:00 p.m. weekdays from

June 1 through September 30).

• New (i.e., cannot be refurbished, previously installed or used) unless pre-approved by FPL.

Brand Name: “Bard”ERV must be tested, installed in the HVAC equipment.

Summary: Energy Recovery • IMPROVED COMFORT• IMPROVED PERFORMANCE• IMPROVED EFFICIENCY• REBATES FROM POWER COMPANY

Questions or Comments?

Why is my classroom so muggy?Energy Recovery and ClassroomsEnergy Recovery and ClassroomsFresh Air, circa 1969 Macon, GAASHRAE Code for classroomsClassroom numbersHeat Gains or Cooling LoadsVentilation Load of Outside AirAll of Florida considered ‘Tropical’ Where the rubber meets the rainforestRelative HumidityWhat is the significance of 95F, 75F, 55F ?Slide Number 13Slide Number 14Slide Number 15Various ERV’sEnergy Recovery TermsSlide Number 18Slide Number 19Free (almost) CoolingSlide Number 21 Energy RecoveryWhat does the Florida Building Code Say for OA?Florida Power and Light (example)�Eligibility Requirements– Energy Recovery Ventilation ERVSlide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Summary: Energy Recovery Questions or Comments?