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SEMP/Energy Reliability HVAC Systems Overview. Primary purpose of HVAC for commercial/educational facilities- Human thermal comfort Indoor Air Quality Terms/Definitions/Key Concepts HVAC System Types Building/Energy Management Strategies Energy Reliability Effect on HVAC.
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Slide 1

SEMP/Energy Reliability HVAC Systems Overview Primary reason for HVAC for business/instructive offices Human warm solace Indoor Air Quality Terms/Definitions/Key Concepts HVAC System Types Building/Energy Management Strategies Energy Reliability Effect on HVAC

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Human Thermal Comfort Critical parameters : Temperature- "hot versus chilly" Relative stickiness "muggy versus dry" Air conveyance "drafty versus stale" ASHRAE Standards A merican S ociety of H eating, R efrigerating and An ir molding E ngineers ( www.ASHRAE.org) Other concerns: Clothing level/Metabolic rate

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Indoor Air Quality UBC/UMC/Title 24 Ventilation rates: "old" construction law (before 1991) 5 CFM OSA per individual/15 CFM recirc per individual objective was to spare vitality amid oil emergency "current" construction regulation 15 CFM per individual or 0.15 CFM/sq. ft. ASHRAE suggestion 20 CFM per individual for classroom/office space

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Indoor Air Quality "Wiped out Building Syndrome" : Inadequate ventilation because of old code Poor support of HVAC gear standing water @ condensate dish Bacteria development @ cooling towers (Legionella) "Snugness" of today\'s structures; non-operable windows Outgassing of building materials paint, furniture, covering. and so on

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Indoor Air Quality IAQ Solutions : "prepare out" preceding inhabitance ?? (not prescribed by ASHRAE) "ventilation cleanse"- ASHRAE contract autonomous Air Quality Consultants testing of indoor air research facility examination of parts composed report of discoveries

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Definition of Terms/Concepts Heat stream/warm exchange: Temperature- "intensity" of warmth dry knob temp versus wet globule temp Btu- B ritish t hermal u nit "amount" of warmth Btu/hour- rate of warmth vitality trade Watts 1 watt = 3.414 Btu/hour Ton 1 ton = 12,000 Btu/hour HP 1 HP = 2,545 Btu/hour 1 HP = 745 watts

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Definition of Terms/Concepts Basic Heat/Energy Transfer counts : Btu/hr = (1.08)(CFM)( dry knob temp change) ** for "dry or sensible" warmth/cool process ** Btu/hr = (0.69)(CFM)( dampness change ) ** for "wet or dormant" cooling process ** Btu/hr = (4.5)(CFM)( enthalpy change ) ** for "aggregate" cooling process

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Basic Heat/Energy Transfer estimations proceeded with: Btu/hr = (500)(GPM)( water temp change ) ** for hydronic warm/cool process

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Definition of Terms/Concepts Fluid Mechanics - (air/water stream) Volume of airflow: ( CFM , cubic ft./min. ) Speed of airflow: ( FPM , feet per min. ) Pressure of wind stream: ("w.g. , " H 2 O , inches of water gage ) Volume of waterflow: ( GPM , lady./min. ) Speed of waterflow: ( FPS , feet every second ) Pressure of waterflow: ( ft. hd .; ft. of head, ft.of water )

Slide 10

Definition of Terms/Concepts Basic air/water stream counts : CFM = (FPM) X (Area in Square Feet) For bundle units/comfort cooling 1 ton = 400 CFM 3 GPM/ton if water temp distinction is 8 F 2.4 GPM/ton if water temp diff. is 10 F 2.0 GPM/ton if water temp diff. is 12 F 1.6 GPM/ton if water temp diff. is 15 F

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Definition of Terms/Concepts Energy/Operating Costs : BHP - > "brake" HP; measure of real fan/pump vitality utilized specifically influences working cost kw/ton - > input control in kw cooling limit in tons therms - > 1 therm = 100,000 btu

Slide 12

Definition of Terms/Concepts Common Energy Efficiency Units : EER/SEER - efficiency rating for cooling prepare: E nergy E fficiency R atio S easonal E nergy E fficiency R atio EER or SEER = cooling limit in "btu/hour" input control utilized as a part of "watts" EER utilized for 3 stage "business" prepare. Soothsayer utilized for 1 stage private consolidating units

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Definition of Terms/Concepts Common Energy Efficiency Units : HEATING EQUIPMENT AFUE - efficiency rating for furnaces/boilers A nnual F uel U tilization E fficiency AFUE = yield btu/hour input btu/hour

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Definition of Terms/Concepts Common Energy Efficiency Units : HEATING EQUIPMENT COP - efficiency of warmth pumps in heating mode C o-effective O f P erformance COP = yield btu/hr input in watts

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Definition of Terms/Concepts "Title-24" Standards : directed by California Energy Comm. Building Envelope imperatives: protection sorts and execution coating sorts and execution penetration Lighting framework requirements: lighting levels (ft.candles, lumens, watts per sq. ft.) installation execution utilization of "day-lighting" and inhabitance sensors

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Definition of Terms/Concepts "Title-24" Standards (cont.): HVAC System limitations: need to legitimize estimating of proposed new hardware by means of load figurings productivity rating of warming/cooling gear ( least levels of EER, AFUE , COP ) sets up gauges for pipe/pipe protection sets up ventilation rates for building tenants

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Definition of Terms/Concepts "Title-24" Standards (cont.): programmed control and shutdown of hardware requirement for "air-side" economizers on bigger frameworks directs utilization of electric resistance warm

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HVAC System Types All-Air frameworks (bundle/split AC units): consistent volume, housetop bundle or split framework units consistent volume, housetop bundle or split framework warm pumps steady volume, classroom bundle terminal warming/cooling units variable volume, roof bundle cooling/just units

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HVAC System Types Air/Water frameworks : focal plant chilled water frameworks focal plant boiling point water frameworks focal plant steam warming frameworks water-source warm pumps air-cooled chilled water frameworks

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HVAC System Types ** Rooftop Package Units** Why are these so Common ? Low first cost Easy to acquire/keep up Simple to utilize/introduce/keep up Excellent ventilation by means of air-side economizers

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HVAC System Types ** Rooftop Package Units** What are their weaknesses ? High working/support cost 12-15 year life expectancy Pre-bundled singular parts "Light business review" segments

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HVAC System Types ** Rooftop Package Units** Gas/Electric; Cooling/just; Heat Pumps Cooling limits: 1 ton = 400 CFM (+/ - 20% adaptability) unit limit = add up to limit NOT sensible capacity sensible cooling limit 70-80% of aggregate limit "ARI" evaluations: 95F encompassing, 80F edb, 67F ewb minimum EER\'s: 8.5 for units up to 10 tons 8.2 for units between 10 - 25 tons

Slide 23

HVAC System Types ** Rooftop Package Units** Heating Capacities: 1) Gas/electric units-Input limit (1 MBH = 1000 btu/hr) Output limit (1 MBH = 1000 btu/hr) Efficiency = output MBH/input MBH Title 24 least efficiency(AFUE)= 80% Typically "low warmth" models utilized as a part of California "Aluminized steel" warm exchangers (SS as option)

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HVAC System Types ** Rooftop Package Units** 2) Package Heat Pumps-warmth is produced by refrigeration compressors switching valve changes capacity of evaporator and condenser warm yield is a component of OSA temperature ARI appraisals @ 47 F surrounding least COP = 3.0 for Title 24 helper electric radiators required for frosty winter A.M. what\'s more, "defrost cycle"

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HVAC System Types ** Split-System Units ** Why are these frameworks introduced ? Littler open air gear can be cushion mounted; no housetop hardware required cooling hardware can be included later limited ducting frameworks consume less upper room

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** Split-System Units ** Continued Disadvantages indoor gear room required indoor AH gear hard to keep up nearby commotion from AH hardware costly refrigeration/condensate funneling frameworks ventilation frameworks/ducting can be hazardous

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HVAC System Types **Package Terminal AC/Heat Pump Units (PTAC)** Why are these frameworks introduced ? Most reduced introduced cost No ducting required numerous control zones simple substitution/access for upkeep

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Package Terminal Continued Disadvantages: low effectiveness/high working costs high neighborhood clamor both inside and outside room short gear life traverse

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HVAC System Types ** VAV Systems ** Common System sorts: Varitrac/VVT-changes over bundle unit to VAV cooling with consistent volume border warm VAV with boiling point water warm Double Duct VAV

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HVAC System Types ** Central Plant ** Central Plant Systems : Why are these frameworks introduced ? Bring down progressing operation/support costs counterbalance higher beginning cost Life Cycle Cost/Present Worth Analysis Longer life expectancy of gear - > 25-30 years Greater adaptability in planning/selecting "engineered" parts Increased unwavering quality of framework

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Central Plant HVAC Systems Air-cooled versus Water-cooled chillers air-cooled : least costly introductory cost higher working cost (1.2-1.6 kw/ton) rated limit in view of T dry globule (i.e. Sacramento- - > 115 F least) water-cooled : higher beginning cost most reduced working cost (0.5-0.8 kw/ton) evaluated limit in view of T wet globule (i.e. Sacramento- - > 72 F) higher upkeep cost (cooling towers)

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HVAC: Building/Energy Management Systems Typical System Features : Time-of-day booking Optimum begin/stop Duty Cycling Load Shedding ASHRAE " ECO " Guidelines "E nergy C onservation O pportunities"

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HVAC: Energy Use & Management Strategies DDC Controls : access to "framework data" expanded observing capacities for client "brilliant" controls ideal begin/quit; morning warm-up; night difficulty remote temporary worker/specialist access for investigating

Slide 34

HVAC: Energy Use & Management Strategies Economizers: use "free cooling" when it is accessible. Bundle units-prudent for frameworks 5 tons and bigger for cost-viability enthalpy versus dry

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