vpmia conf april 2010

8/8/2019 VPMIA Conf April 2010

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The Residential HVAC

To comply with the IR



[email protected]

J ac k Bar t e l lDirector, Service & TrainingDirector, Service & Training

VIRGINIA AIR DISTRIBUTORS



I n t roduc t ion – Provides the

the reality

• Reference:

– o s ouse – ACCA



I n t roduc t ionPlan Ex am iners Form

• Developed by ACCAo es omm ee

• Permit application process• Completed by the HVAC

contractor

• o ware n epen en• Simple over-arching view



I n t roduc t ion

(M1401.3 and M1601.1)

• Applicable

• Fast

• Expandable



I n t roduc t ion• Keep It SIMPLE

• Skimming

• Digging



anua : oa



Manual J8Manual J8AE

For additional informationon ACCA, click on the logo



Unders izing Equipm ent

• Slightly undersizing equipment will

the time

– pace con ons w r w en ex remes n

weather occur.• re era e o overs z ng e equ pmen .

The result is increased energy efficiency

w a m nor oss o com or .• This must be explained to the owner.



What are t he benef i t s o f a det a i led

and ac c urat e load ca lc u lat ion?

May Not

Will NotWhat are t he i t f al ls and c onse uenc esof an inac c urat e load c a lcu lat ion?



Six Ingred ient s o f Forc ed Ai r

1. Even temperature

2. Filtration3. Noise

4. Outdoor air

.

6. Air circulation

A Properly Designed Comfort System “Simultaneously controls the temperature, humidity, air quality and air movement in a

manner that is not noticeable to the occupants”



Manual J 8t h

Edi t ion – Infiltration Load

• Accounts for air in-take needed for people andequipment

– Solar Gains

• Variation of solar gain through the day• The impact of reflection on solar gains

• The loads for skylight including the curbs

– Adds Loads for the affect of equipment,piping, and humidification



Choosing Procedures

One procedure – Average Load for Winter Conditions

Average or Peak Procedure for Summer Conditions

• Average Load Procedure

– When there is a constant

• Peak Load Procedure

– When there is a spike inload through the day

– Or effect of solar gain s isn’t

e coo ng oa

– When the effect of the

solar ain causes

hour to hour within a roomor space

differences from hour tohour



Lack of AED

Adequate

v yE

xposureDiversity

N S

E

WN SCondo A Condo B Condo C

W Peak LoadConditions

An excursion adjustment is addedto the avera e fenestration ain when the application does not

have AED.



Adequat e Ex posure Divers i t y



Ex c urs ion Ad jus t m ent Requ ired

Need to use manual



Ade uat e Ex osure Divers i t

•

Appendix 3

have AED if: – ,

skylight assemblies does not exceed 15 percent of

the associated floor area. – The dwelling has four exposures.

– Each exposure is equipped with a representative.



Limitations and Guidelines



Fig. 3-5 Heat Loss & Gain Tables

Cont ent Com ar ison



Com ponent Heat Loss



Com onent Heat LossCalcu la t ions

• Heat loss calculations.• .

• Opaque panel heat loss.• Radiant floor.

• Block infiltration load for heating.

• Room infiltration load for heating.



Com onent Heat Loss

•

Calcu la t ions

.

• Engineered ventilation load for heating.

• n er um ca on oa .

• Hydronic piping loss.• Equipment sizing.



Com ponent Heat Gain



• Heat gain calculations•

• Opaque panel heat gain• Block infiltration load for cooling

• Room infiltration load for coolin

• Internal gain



Com ponent Heat Gain

Calcu la t ions

• uc oa or coo ng

• Engineered ventilation load for cooling

• Blower heat

•

• Total cooling load

• qu pmen s z ng



Phys ic a l Pr inc iples & Mat hem at ic s

u

measurements protocols.

– .

– Areas of building.

– Perimeters and.



Preparat ion of Form s and Work sheet s

– Worksheet A: design conditions – Worksheet B – C: window lass doors & sk li ht loads

– Worksheet D: opaque surface loads

– Worksheet E: infiltration loads – or s ee : n erna oa s

– Worksheet G: duct loads

– Worksheet H: ventilation loads

– Form J1ae: room load estimates



Manual J do ’s(mandatory requ i rements)

Use outdoor desi n conditions recommended

by table 1 manual J.Use the default indoor design conditions

recommended by manual J.

Consider orientation of the structure on the site.Verify all construction details prior to calculating

loads.

Take full credit for all internal shading devicesand external overhangs.



Manual J do ’s(m andatory requ i rement s)

with the type of room.

specified.

Take full credit for rated performance of construction materials, insulation and constructionfeatures.

construction.

ventilation.



Manual J do ’s(m andatory requ i rement s)

insulation.Match location as close as possible when

selecting a duct load table.

Match duct supply and return system geometry.

Use the correct R-values for duct wallinsulation.

equipment performance data is not adjusted for blower heat.



Whic h has m ore heat ,

a pound of w at er a t 212ºF or a ound of s t eam at 212ºF?

Sensible heat

• , ,temperature. Expressed as dry bulb temperature.

• Heat, which when added to a material, changes its.

pound of material.



144 32°

ce32°

BTU/LB

Latent heat

32° 212°

BTH/LB

SENSIBLE HEAT

WATER WATER

970BTU/LB

212°STEAM

212°WATER

Heat m oves in t h ree w ays :



Heat m oves in t h ree w ays :

nv i nconduc t ion



The Sensib le Heat Equat ion

• Q = 1.08 x CFM x TD – Q = Sensible heat in Btuh

– 1.08 = is a constant (Properties of air at sea level)

– CFM = Cubic Feet per minute of Air

– TD = is the change (temperature difference) in air temperature in ºF. Referred to as the Delta T.

– .076 (pounds of air in a cubic foot) X – .24 (specific heat of standard air at sea level) X

– 60 (number of minutes in an hour)



the remaining by algebraic re-arrangementof the e uation.

• =• CFM = BTUH/(1.1 x TD) CFM = Load

1.08 X TD.



Manual J : Load Calc u lat ions

Resul t s of Over-Sizing• Results of Oversizing

– More consumer expense

• Equipment• Materials

•

– More starts and stops• Wear and tear on

equipment• g er energy usage

– Poor comfort• Less humidity control

• Stagnant air pockets

• Stratified air temperatures

– Marginalized part-load



What fac t o rs de t e rm ine

t he heat ing and c ool ing

home?




Heat Loss



• What factors determine a

house’s heating and cooling

requirements: –

• Orientation

• Latitude

•

Heat Loss

– Building components• Windows

• Insulation

Heat Gain

– Occupants and Plants – Appliances

–

– Etc…




’

Locat ion Fac t ors

heating and cooling load calculation: –

• Indoor Conditions

• Winter Design Temp.• Summer Design Temp.

• Moisture Difference

–

– Altitude

– Orientation Heat Gain

Heat Loss




• Factors that determine a house’s

heating and cooling load calculation: – Desi n Conditions


-, ,“Use of this set of conditionsis mandatory, unless

Heat Loss °

superceded by a code,regulation, or documented

Heat Gain

70°F

ea t requ rement.




Design Condi t ions

Design Conditions•

– Indoor: 70°F

•

70

– Indoor: 75°F75




’

Locat ion Fac t ors





–

– Altitude

– Orientation Heat Gain

Heat Loss




Design Condi t ions




Design Condi t ions

• Design Conditions

– Winter Design Temp. – Summer Design

Temp.

–

Manual J : Load Calc ulat ions





– Outdoor: 2°F

•

702

– Outdoor: 91°F

– OD Grains: 37∆ Gr 75

91

37

50






– Outdoor: -11°F

•

70-11

– Outdoor: 88°F

– OD Grains: 24∆ Gr 75

88

24

50




Bui ld ing Com ponent s




Chica o1,299 Btu/h

1,578 Btu/h




’

Locat ion Fac t ors





–

– Latitude

– Altitude Heat Gain

Heat Loss





Orientation





OrientationSouth

Fron t Door

observation with an arrow or directional rosette that points

north.





Bedrooms South

1

3





South

ccupan s

Manual J8: Occu ants3

1800produce sensible and

latent loads. Thenumber of occupantsshall e ual the number

of bedrooms plus one.

C




Occupants

• ’

heating and coolingoa ca cu a on:

– Occupants

M l J L d C l l t i





South

ccupan s

Manual J8: Occu ants3

1800produce sensible and

latent loads. The1number of occupantsshall e ual the number 3 +1 = 4

of bedrooms plus one.

M l J L d C l l t i





SouthManual J8: 3.10 (Page 14)

3

1800

4

Infiltration load estimatesshall be based on one of the tightness categories(tight, semi-tight, average,

- ,

provided by Table 5A and

.

M l J L d C l l t i





Envelope TightnessSouth•

3

1800

4

•Walls

•Windows and Doors •Engineered Openings•Exhaust s stems

Average

•Duct systems•Overall

M l J L d C l l t i





Ventilation SouthSouth

Manual J8: §3.13 (Page 19)

• Ventilation Requirement

3

1800

4

3

1800

4

• o c en a ex aus• ERV and HRV•

Average

0

• Fireplace/stove operation




(Window s, Sk y l ights , Frenc h doors, e tc )


heating and cooling

– Building components

• Windows – Rough opening

– Orientation

–North?

– Internal shading – Bug screen (or not)

–Southwest?

ou





• ’

heating and coolingu :

– Windows

Boston

Phoenix

• at tu e






heating and cooling

– Building components

• Windows – Rough opening

– Orientation

–North?

– Internal shading – Bug screen (or not)

–Southwest?

ou






SouthSouth

Manual J8: §3.13 (Page 19)

• Eave overhang

3

1800

4

3

1800

4• n erna s a e• Skylights•

Avg

0

°one

Drapes, Light ½ Closed





Ot her fac t ors

•

houses heating and coolingrequ remen s:

– Appliances

– Duct Loads

– AED - Zoning House A

House B





270

South

31,800

91

4

Average

075

37 None

rapes, g t, ose

None




270

South

31,800

91

4

Average

0

51,838

75

37 None

rapes, g t, ose

None

21,423

4,684

26 107




15:0014:0013:0012:0011:0010:009:007:008:005:004:003:006:002:001:000:300:150:00



• Heatin

– Load

– Output Capacity

– Target Airflow

– Design airflow

–• Cooling

– Load

– Sensible / Latent Capacity – Target airflow

– es gn a r ow

– Altitude adjustments

Manual S : Equipm ent Selec t ion



q p

• Heating

–56,000 Btu/h

103°F - 133°F

– Output Capacity – Tar et Airflow = 51,838 Btu/h

,

Out ut ca acit° 56 000°56,000°

– Design airflow

– Altitude adjustments 68°F

CFM × 1.08 × ACF1,000 × 1.08 × ACF1000 × 1.08 × ACF

-

60,000 Btu/h-

Air Delivery – CFM (With Filter)

Unit Size SpeedExternal Static Pressure (inches water column)

0.1 0.2 0.3 0.4 0.5 0.6 0.7

High 1075 1040 995 945 895 840 760

Med – Hi 50 25 8 5 845 7 5 740 660FU60 - 024

Med – Lo 850 825 780 740 685 635 560

Low 740 700 650 620 565 515 455

FU60 - 036

High 1470 1415 1400 1285 1215 1120 995

Med – Hi 1315 1280 1235 1298 1115 1035 930

Med – Lo 1125 1110 1085 1045 1000 915 830

Low 930 9256 910 850 830 770 705

FU60 - 048

High 1700 1685 1640 1580 1545 1450 1380

Med – Hi 1500 1465 1435 1385 1255 1300 1250

Med – Lo 1325 1295 1265 1230 1190 1150 1105Low 1205 1170 1145 1110 1080 1035 990




• Cooling

– Load

= 26,107 Btu/h




• Cooling

– Sensible / Latent Capacity

= 26,107 Btu/h

Total Heat = Sensible + Latent= += + ,, , ,




• Cooling

– Sensible Load

– Latent Load =+ 4,684 Btu/h (Latent)

21,423 Btu/h (Sensible)

– Target airflow

– Design airflow


21 423 Btu/h SensibleSensible Btu/hSensible Heat Ratio

26,107 Btu/h (Total).

Airflow (CFM) =1,044 CFM =

1.08 x (∆T from SHR Table) x ACF

1.08 x ∆T x ACF

ersus

Manual S page 3-4

SHR ∆T1.08 x 19°F x ACF

e ow .

0.80 – 0.85 19

Above 0.85 17




• Cooling

26,107 Btu/h


+ 4,684 Btu/h (Latent)

– Sensible Load

– Latent Load 4,684 Btu/h,


= , – Target airflow

– Design airflow

Sensible Heat Ratio

26,107 Btu/h (Total).

ersus

Manual S page 3-4

SHR ∆T

,

1.08 x 19°F x ACF

1,044 CFM

e ow .

0.80 – 0.85 19

Above 0.85 17




vs.




• oo ng – Total Load 26,107 Btu/h

– Sensible Load 21,423 Btu/h

– Latent Load 4,684 Btu/h

– Target airflow 1,044 CFM




Summer OD

°

Target

airflow1,044 CFM

EWB

63°F

Total Load

26,107 Btu/h

Sensible Load

21,423 Btu/h

Latent Load

4,684 Btu/h




Summer OD

91°F

EWB

63°F

o a o a

26,107 Btu/h

Sensible Load

,

Latent Load

4,684 Btu/h

Target airflow

1,044 CFM



+ ,

- 63

,

+ 5,401

+ , - ,



-

Air Delivery – CFM (With Filter)

Unit Size Speed External Static Pressure (inches water column)0.1 0.2 0.3 0.4 0.5 0.6 0.7

Targetairflow

FU60 - 024

High 1075 1040 995 945 895 840 760

Med – Hi 950 925 895 845 795 740 660

Med – Lo 850 825 780 740 685 635 560

1,044CFM

ow

FU60 - 036

High 1470 1415 1400 1285 1215 1120 995

Med – Hi 1315 1280 1235 1298 1115 1035 930

Med – Lo 1125 1110 1085 1045 1000 915 830

Low 930 9256 910 850 830 770 705

FU60 - 048

High 1700 1685 1640 1580 1545 1450 1380

Med – Hi 1500 1465 1435 1385 1255 1300 1250

Med – Lo 1325 1295 1265 1230 1190 1150 1105

Low 1205 1170 1145 1110 1080 1035 990



ABC System Capacity

995 CFM, 91°F ODT, 63°F EWB and 75°F EDB

ABC

Manual J

LoadHeating Cooling

Heatin Btu/h 51,838 56,000Cooling Btu/h 26,107 29,180

Sensible Btu/h 21,423 21,360

Latent Btu/h4,684 7,820



•

the various styles of residential duct.

• Following each slide will be listed some of

.



Ex t ended Plenum Syst em

D i



DesignPr

• The most common residential duct system

• Eas to fabricate and install.

Cons

or est resu ts ower must e centra ylocated.

Long duct runs make it difficult to turn airinto branch runs near the fan.

Reduc ing Plenum Syst em

D i



Design

Reduc ing Plenum Syst em

D i



DesignPr

• Improves performance over end mounted

blower, extended plenum systems. .

Historically, duct design manuals arbitrarily

’

ns

blower, resulting in less that maximum.



Pr

• Less material used to fabricate duct

system.• Good air distribution if designed properly.

Cons

equ res more wor to a r cate an nstabecause each takeoff requires its own

sect on.

Each section is a different size and requires

a transition to reach the next size.

Radia l or Oc t opus Syst em

Design



Design

Radia l or Oc t opus Syst em



• One of the most cost effective systemsPr

o ns a .

• Easy to fabricate and install.

Cons

or est resu ts ower must e centra ylocated.

Installers tend to use long flex duct runsresulting poor performance due to high

resistance.



Pr

• Effective in cold climates with slab floor construction.

• Maintains comfort at the floor level in heatingseason.

Cons

cu t to es gn.

Expensive to install.

What c an be c ons idered t he best

use of Duc t Tape?



use of Duc t Tape?

Manual D : Duc t Dis t r ibut ion Syst em



-



-• ,

the HVAC equipment and peripheral

requirements.

pressure limitations of the duct system.

-



- .

room.

• e urn n e s cap ure e re urn a r.• Dampers and junction boxes control air

volume in the duct system.

-



-

• Diffusers typically introduce supply air

.

.

• Supply Registers and Grilles typically

the wall. Registers are grilles that have.

• Return Registers and grilles are the

side.

OCCUPIED ZONE



The occupied zone consists of the space between theoor an ee a ove e oor n e ver ca rec on an

the space that is more than 2 feet from the wall in thehorizontal direction.

It is within the occupied zone that comfortconditions must be maintained.

Therefore, do not distribute conditioned



•

or 75 fpm, depending on the particular

a lication, it reaches terminal velocit .

• velocity of the air stream at the end of the throw.

.



.

Throw(20’)

Terminal velocity

The horizontal distance that an air stream travels after leaving a

horizontal sidewall outlet before maximum velocity is reduced toterminal velocity.

.



.

stream falls by the time the air reaches the end of its throw.

.



the point of terminal velocity.

Induction (Aspiration) he process of drawing room air into theprojected air stream due to the velocity of the projected air stream.



Secondary air

Primary air

from the outlet.from the outlet.

Secondary air

room air (can be 10 to 20 timesroom air (can be 10 to 20 timesgreater than the primary airgreater than the primary airuantit .uantit .

Ceiling or Wall Effect The tendency of an air stream moving along a.

Term s used in Duc t

• IWC - Inches of Water Column - A unit used to



measure ressure

• CFM - Cubic Feet per Minute - A unit used to

measure air flow• ESP - External Static Pressure - A unit used to

measure resistance outside of the fan

• ASP – Available Static Pressure of a blower after deducting all component loses

• Pressure Drop - is equal to the pressure lossthat occurs between any two points in a ductsystem

erm s use n uc

• Friction Rate - is equal to the pressure loss



q p

system that are separated by a specific.

• Equivalent Length - A term used to describe

pressure oss roug a ng.• TEL - Total Effective Length - A term used to

describe the friction losses through a duct andall of its fittings and air-side devices.

VELOCITY is measured in feet per minute (fpm)

V = CFM CFM = A x VA



A

The area of the duct (A) must always be stated in. ,

dimensions (w x h) by 144.

” ”

V = CFM 1200 120 = 900 fpm

A 24x8/144 1.3

Pressure

Measured in inches of water column (“w.c.)



1 psig = 27.72” w.c.

Velocity pressure is movement, dynamic pressure.

Static pressure is a bursting pressure. It lacksmovement.

Total pressure is static pressure plus velocity.



Item Static pressure

drop in “w.c.

upp y ucsystem

.

Return ductsystem

.10

Eva orator .20

Furnace

(Coil)

Air cleaner .20

Supply registers .03

Return grilles .03

Volume

dampers

.03

Total external .69

Furnace blower must be able to deliver the required volume of air(CFM) against an external static pressure of .69” water column.

s a c pressure

Tot a l St a t ic Pressurec w o po n s w m easure

Tota l St a t ic p ressure on t he furnace?



D

Furnace

B

C

A


• Duct system design and overview



y g

–Calc each rooms CFM

–Sketch on the blue print• Notes with approx lengths

• Show CFM for each supply and return

• ow or eac run• ID fittings

–

–Use EL calc sheet


• Calculate



• Calculateeach

room’s


Sketch duct geometry




Assign CFM




Determine the duct run with thelongest Total Effective Length




Assign CFM



4I=10EL =

’

= 35 EL’

5J=15EL6L=20 EL8’ 15’

1P=20EL

2Q=10 EL 15’


Determine the duct run with thelongest Total Effective Length



10510155

35

20

20

10

20

10

20

10

5

20

50

6040404040

1259080100120




Determine the

. ,

0.16

Friction Rate 0.10-0.05

0.03

0.30

0.030.03

0.50 0.30 0.20




Determine theFriction Rate

. . .

120 125 225

FR = (ASP × 100 ) ÷ TELFR = (0.20 × 100 ) ÷ 225FR = 20 ÷ 225 = .0888 ≈ 0.09


0.50 0.30 0.20



Determine the

120 125 225

0.09

Friction Rate

0.5 1000

0.16



-0.050.10

0.03

0.030.03

0.20

0.3 0.20.5

0.9


0.5 1000

0.16

1,0000.50

0.50 1,000

0.160.50 0.30 0.20

-



-0.050.10

0.030.030.03

120 125 2250.10

- .

0.030.030.03

120 125 225

0.20

0.3 0.20.5

0.30

0.20

.

0.50 0.30

0.30

0.20

.

0.9

120 125 225




1,000

0.50 120

0.30

0.20

125

225

0.09

Sheetmetal, Flex


2

South

3

70 1 800



70

91

1,8004

Average

0

51,838

7537 None

Drapes, Light, ½ Closed21,423

50

None4,68426,107

,

0.500.30

120

125.

0.09Sheetmetal, Flex

Resident ia l HVAC Syst em Design



Resident ia l HVAC Syst em Design



•

• Questions???

vpmia conf april 2010

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