Cooling system idiosyncrasies 2006

2006 / 2007 Seminar
Cooling Systems
" Idiosyncrasies "

by
e
thos .
or in asies Garth Denison
is hum yncr
e re s
T h g Idio Sr. Product Application Engineer
Co olin Sporlan Valve Division
Parker Hannifin Canada

c:sporlan 2006cooling idiosyncrasies

" Cooling Systems Idiosyncrasies "

A behavioral characteristic unique to an individual or group

The Sporlan Valve Division, Parker Hannifin assumes no obligations or liability for any advice furnished or for
any results, property damage or personal injury including death that may result with respect to the use of this
information. All such advice is given and accepted at users risk. This disclosure of information herein is not a
license to operate under, or a recommendation to infringe any patent of Sporlan Division of Parker Hannifin or
others.

® Registered trademark of Sporlan Valve Division, Parker Hannifin Corporation, Cleveland Ohio USA
© Copyright 2005 by Sporlan Valve Division, Parker Hannifin Inc

Service Guide to Various
System Idiosyncrasies

above 50°F

Split Condensers

H ea ding
Bull

below 5
0°F


above 50°F 0.15 0.20 0.25
SENSIBLE HEAT RATIO = Qs / Qt
0.30 0.35

Split Condensers
55 60

R-410A 90
1.35

Note importance of 50 1.3

ding MO
.028
0.40
sub-cooling

15.
1.25

H ea

0
85 60
85
CT 162 °F, CP 715 psia 1.2

Bull
.026

45 1.15
85
WE .024 0.45
TB 1.1
UL
BT
EM
80 PE 1.05
RA
T UR 80 55
40 E- .022
°F 0.50 1

80 .95
.020

POE .9

VAPOuR PRESSURE - INCHES OF MERCURY
75 0.55

ENTHALPY - BTU PER POUND OF DRY AIR
35 75
R

.85
AI

14.
.018

DEW POINT TEMPERATURE - °F
Y

50
DR

5
0.60
.8
F

75

F
O

-°
D
UN

E
R
70 .016 .75
PO

TU

30 70 0.65
RA
R
PE

PE

.7

HUMIDITY RATIO - POUNDS MOISTURE PER POUND DRY AIR
TU

M
TE

0.70
-B

70
N

.014
PY

.65
O
TI

65
AL

RA

65 45 0.75
TH

TU

25 .6
EN

SA

0.80
.012
65 .55

14.
60 % 0.85
90 60

0V
0.90 .5

OL
% .010

UM
20 55 80 60
0.95
.45

E-
55 1.00
%

CU
40
70 .4

.F
50 .008

T. P
55

SENSIBLE HEAT RATIO = Qs / Qt
% 50
60 .35

RLE
13.

15 45 50

B. D
%
5

50 45 .3
.006

RY
40
45 40 .25
40%
AIR
35
40 35 35 .2
.004
30%
13.

35 30
0

.15
25
20%

be .002 20 .1
HUMIDITY
12.

lo w
TIVE
10% RELA 10
5

.05
0

50
35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 30

AB °F
DRY BULB TEMPERATURE - °F

10 15 20 25

ENTHALPY - BTU PER POUND OF DRY AIR


For 2006


Refrigerant Science of Yester Year

Temp / Press psig
Name Formula Flammable 0°F and 85°F
F-12 CCl2F2 No 9.2 91.7
Sulphur Dioxide SO2 No 8.9” 50.6
Ammonia NH3 Yes (16 to 25) 15.7 151.7
Butane C4H10 Yes (1.6 to 6.5) 15.0” 26.2
Iso Butane C4H10 Yes (1.8 to 8.5) 6.3” 43.9
Carbon Dioxide CO2 No 293.9 1012.3
Methyl Chloride CH3Cl Yes (8.1 to 17.2) 4.1 79.4
Ethyl Chloride C2H5Cl Yes (3.7 to 12) 21.6” 11.9
Methylene Chloride CH2Cl2 Yes (8.1 to 17.2) 27.9” 9.9”
Dichlorotetrafluoroethane C2Cl2F4 No 17.8” 21.0

Source: Frigidaire engineering manual Nov. 15, 1938


Global Warming … Kyoto


" Typical Receiver Types "


Receivers

For receivers having an internal diameter of 6 inches (150 mm) or smaller:
ARI 495, UL listed, steel, brazed, 400 psig (2760 kPa) pressure rating,
with pipe threaded female access fittings for inlet, outlet, and pressure
relief valve.

Receivers larger than 6 inches (150 mm) diameter: ARI 495, welded steel,
tested and stamped according to ASME Boiler and Pressure Vessel Code:
Section VIII; 400 psig (2760 kPa) pressure rating, with pipe threaded female
access fittings for inlet, outlet, pressure relief valves, and a liquid level indicator.

Typical receiver accessories ..
Relief device (valve or fusible plug)
Dual relief valve saddle assembly
Liquid level indicator / alarm
Sight glass
Receiver heater
Insulated receiver
Access / Isolation valves

Typical Receiver Types

From condenser To evaporator
Receiver styles:
vertical
horizontal

Receiver
Minimum refrigerant charge is 15% of receivers Vent line
capacity to ensure a liquid seal at the dip tube. Surge Receiver

Liquid Line
indicates vapour

indicates liquid
No minimum receiver refrigerant charge needed


System with Receiver
Receiver may or may not effect the quantity of sub-cooling depending on
refrigerant’s speed, receivers ambient and system’s refrigerative effect.

The circled area represents a typical receiver installed in the liquid condensate line.


System with Surge Receiver
A surge receiver will not effect the quantity of sub-cooling. Refrigerant
not required to accommodate the load will back into the surge receiver.

The circled area represents a typical surge receiver installed in the liquid line.


Receiver Components & Accessories
Level indicators / Alarm actuators

Typical relief valve
&
Fusible plugs

Poly Tetra Fluoro
Ethylene (Teflon)

Straight-thru
relief valve

Pressure transducer,
gauge and relief valve
Dual relief valve assembly

A typical installation with a pressure vessel having
a maximum working pressure of 400 PSI might be:
Relief
valves

Relief Valves 400 PSI: Set at the design working pressure of the vessel OR
25 % higher than the maximum working pressure of the system.

High / Low: Set at approximately 80 – 85% of relief valve setting. 330 PSI

Relief Valve: Table below for code parameters for a High / Low
400 PSI relief valve. Bypass valve IN

High Pressure
Receiver
Relief Valve Parameters
PSI Suction header
+ 10 % R.V. Full Open 440

Added protection is a High / Low By-
R.V.
pass valve if system pressure nears the
Setting potential relief valve “Seep” Point.
Relief Valve (R.V.) Setting 400
Tolerance
OUT

- 10 % Potential R.V. “Seep” Point 360
Maximum system operating pressure 320

Relief valve parameters as a percent of R.V. set pressure. Source: Henry Technologies


Receiver Components & Accessories

Synthetic ester oil based grease
using a lithium soap.

SKF system grease LGLT-2

Operating temperature range

-55ºC to 110ºC

-65ºF to 230ºF

Indoors Outdoors


Receiver Heaters

Various Heater Types
Strap-on heater
Insertion heater
Emersion heater
Peel & Stick foil backed
Magnetic heater strips
Blanket heater


Thought Provoking !!!

For testing purposes ONLY …
How can a technician change rotation
on a three phase application without
moving a wire ?

" Reversing Fuses "


Reversing Fuses
Uninstalled Fuses
Fuse

Heavy Wire

Blown / Bad Fuse

Blown / Bad Fuse
Fuse

Heavy Wire

EXTREME CAUTION

Reversing Fuses
Installed Fuses

Blown / Bad
Blown / Bad Fuse

Fu
se
se
Fu

Fuse
Heavy Wire

EXTREME CAUTION

" Receivers and their Affects "


Air Cooled Condenser Typical Split Condenser
Summer c/w Standard Receiver

R-22 condenser converted to R-404A,
Liquid lines

approximately a 10% gain in capacity.

Restrictor tube to
low side may be
used to control
To evaporator
pump out rate of
inactive condenser
ORI / OROA

Receiver
Minimum refrigerant charge is 15% of receivers
capacity to ensure a liquid seal at the dip tube.

Typical Split Condenser
Air Cooled Condenser
c/w By-pass Receiver
Summer

Liquid lines

Shown de-energized

Restrictor tube to
low side may be To evaporator
used to control
pump out rate of
inactive condenser
ORI / OROA

8, 12 or 16D

Receiver


Three Way Solenoid

8D, 12D, 16D
Energized

To receiver

From condenser

1. High pressure refrigerant
2. Piston vent line
3. Open to low pressure

To liquid line De-energized

De-energized


Energized


Air Cooled Condenser Typical Split Condenser
Summer c/w Surge Receiver

Liquid lines


Restrictor tube to
low side may be
used to control
Vent to condenser inlet,
pump out rate of check valve installed
inactive condenser in this line.
ORI / OROA
Surge Receiver

“weir”

Liquid Line
receiver
inlet / outlet No minimum receiver refrigerant charge needed

Why Typical Split Condenser Vertical Drop ?


Density Specific. 1 psi Lift in
Ref. lb/ft3 Gravity Lift in ft. inches

R-22 74.5 1.20 1.93 23.2
R-134a 75.1 1.21 1.91 22.9
Liquid lines
R-404A 65.5 1.05 2.20 26.4
**
R-407C 70.8 1.14 2.03 24.4
Typical 6 ft.
R-507A 65.5 1.05 2.20 26.4

R-410A 67.7 1.09 2.12 25.5

Restrictor tube to R-12 81.8 1.31 1.76 21.1
low side may be R-502 76.0 1.22 1.89 22.1
used to control
pump out rate of R-718 62.3 1.00 2.31 27.7
inactive condenser
Densities are at 25ºC or 77ºF
ORIT / OROA
Specific Gravity = Density / 62.31
Split Condenser Circuits 1 psi Lift in ft. = 2.31 / SG

** Note: ARI check valve acceptable leak rate is 750 ml/minute
one US gal = 3.8 liters (1 liter = 1000 ml)


" Multi Receivers and their Affects "


Variances in Lift Verses Density .. @ 1 psi

Refrigerants Water Lubricants Ammonia

one psi one psi one psi one psi

Typical refrigerant Water H2O Typical lubricant Refrigerant R-717
1.8 feet or 21.6 inches 2.31 feet or 27.7 inches 2.5 feet or 30 inches 3.9 feet or 47 inches


Multi Receivers

Series Receivers
Water cooled condensers
Insufficient existing capacity
Normally 2 or 3 in series

Parallel Receivers
Difficult in controlling liquid levels
Possible liquid in one and vapour in other


When Supplemental Receivers
are Needed

Auxiliary receivers may be necessary when refrigerant pumpdown capacity is less than the
proper operational charge of refrigerant in the system. This condition sometimes occurs in
water cooled systems where the condenser-receivers have limited capacity and it can also
occur in any system where large evaporators or long liquid lines are used or where the
pumpdown liquid solenoid valves cannot be located close to the TEV’s. To correct this
condition, an additional receiver with the necessary holding capacity should be installed in
series with and close to the outlet of the main receiver on the compression unit.

The auxiliary receiver should be installed on the same level or below the main receiver on the
compression unit. Both the main and auxiliary receiver must have their own service valves,
fusible plug or relief valve. The liquid line sightglass, drier and the liquid line to the evaporator
should then be connected in the normal manner to the service valve which is installed on the
outlet fitting of the auxiliary receiver.


Supplemental Receivers

Catch-All Solenoid

See-All

Receiver

Catch-All Solenoid

See-All
Main

Auxiliary
" Series " Receivers


Typical Copeland " C " Line Condensing Units

Refrigerants

Liquid In
Outlet
Valve

one psi

Typical refrigerant
2.0 feet or 24 inches

Cross sectional view of two refrigerant receivers in series


" Effects of Sub-cooling "

An Idea Whose Time Has Come


Sub-cooling

Definition:
The reduction of the liquid refrigerant’s temperature
to a point below its saturation temperature.
Sub-cooling is always the removal of sensible heat
only from a liquid phase fluid.

Obtainable:
Up to 20% increase in Btu loading
Decrease in electrical usage as much as 25%
Reducing pull-down time up to 50%
Provide more uniform refrigerating temperatures
Reduces first cost, by permitting down sizing of
compressors in new system.

Understanding Heat in the five Regions
of a Ph Diagram

Gaseous region
Critical Point
Sensible heat
regions
Subcooled " Quality "
Liquid region (% vapour)

Latent heat
t
oin

oint
region
eP

Dew P
bl
b
Bu
…

e …
Superheated
e
lin

Liquid / Vapour Vapour region

our lin
d

mixture region
ui
liq
te d

ap
ra

ated v
tu
Sa

Satur
0.8
0.6

0.9
0.7
0.5
0.3
0.2

0.4
0.1

Solid region Triple point


Increasing Sub-cooling Reduces Flash Gas,
Increases Net Refrigeration Effect.

Consider the Following:
The compressor is a fixed displacement pump. It is pumping
a certain number of CFM (pounds) of refrigerant through the
cycle, and really doesn’t care how many Btu’s are in each one
of those pounds. So by increasing the number of Btu’s per
pound, we can increase the capacity of the system while not
increasing the mass flow of refrigerant.


Sub-cooling can:

1. Increase capacity
2. Decrease electrical usage
3. Reduce equipment maintenance
4. Produce better temperature control
5. Reduce pull-down time after defrost
6. Reduce first costs



What do the headlights on a motor car
and on a bus have to do with you, the
refrigeration and air conditioning
technician ?


MC and B tanks
(acetylene)

" MC " Motor Car
" B " Bus
10 cu ft
40 cu ft

B
MC

Acetylene Headlights
Henry Ford Museum, Dearborn Michigan

" Accomplishing Sub-cooling "


Types of Sub-cooler

Ambient sub-cooling
Air
Water
Refrigerant

Mechanical sub-cooling
Integral part of system
Self contained refrigeration system
Usually brazed plate heat exchangers

Both styles actually refrigerate the refrigerant.

Installation & Mounting ...

ACCEPTABLE

PREFERRED
NEVER

For Single Phase, Liquid-to-Liquid Applications


Effect of Inclination on Two Phase, Refrigerant Applications

0
Evaporator -
5 5
No measurable difference
30
within ± 5º of vertical. 30
45
-2% -3%
-10% 60
45
-9% -16%

60 -15% -38%
90

-37%

90

Based on testing conducted by NIST. R-22 evaporator.

Effect of Inclination on Two Phase, Refrigerant Applications

0
Condenser -
5 5
No measurable difference.
30
Short term limited test. 30
45

45 60

60
90

90

Based on testing conducted by NIST. R-22 evaporator.

Typical Plate to Plate Heat Exchangers,
Sub-coolers

Sub-coolers
Mechanical sub-coolers leaving
liquid refrigerant temperature is
usually controlled by a temperature
The brazed plate heat sensor on the condensers liquid
exchanger is substantially condensate drop leg.
small than other technologies
that could be used.

The EPR valve should normally be set to maintain
desired liquid temperature. This is normally 50°F
but may be as low as 40°F for some systems.


Refrigeration Retrofitting R-22 to R-404A

to
Regaining the Lost Capacity
liquid manifold

TEV’s

solenoids

Plate to Plate
Heat exchanger
Plate to Plate
Heat Exchanger

EPR

from receiver to
suction manifold

Thermodynamic 411

Specific Heat .. the amount of heat needed to raise / lower one
pound of a substance one F°. (Btu/lb. F° sensible heat)

Refrigerant Liquids
Btu/lb F° Btu/lb F°
R-22 Cp 0.300 R-407C Cp 0.368

R-404A Cp 0.367 R-410A Cp 0.440
Source DuPont AG3 and AG2


Sub-cooling Calculation Example

R-22 has a Specific heat (Cp ) of 0.300

Example:
Liquid refrigerant entering sub-cooler is 100ºF
Desired refrigerant temperature leaving sub-cooler 50ºF
Formula used is Mass x Specific heat (Cp) x Delta temperature
Refrigeration effected needed per pound of mass flow is 1 x 0.300 x 50 = 15 btu’s
A system having a mass flow rate of 13 pounds per minute needs 13 x 15 = 195 btu’s or 1 ton
Using the same conditions:
360,000 btu’s (30 ton LT) rack would need approximately 105 lbs/min
Sub-cooling capacity 105 x 0.300 x 50 = 1575 btu’s or 1575 / 200 = 7.9 tons

TEV’s for Sub-cooler .... One three tons and one five ton


Plate to Plate Heat Exchanger
Mechanical Sub-cooler
to
liquid manifold
The brazed plate heat exchanger is substantially smaller than
other technologies that could be used as a liquid sub-cooler.
Typically the rack controller has a temperature sensor
that will sense the refrigerant drop leg (condenser return)
TEV’s line to the receiver. Depending on the refrigerant type and
system design it is quite normal to supply 40 to 50 °F
sub-cooled liquid refrigerant throughout the network.

solenoids An example of a typical Sub-coolers operation is as follows:
no solenoids energized = no additional sub-cooling
Plate to Plate
Heat exchanger
# 1 solenoid energized = 3 additional tons
# 2 solenoid energized = 5 additional tons
# 1 and # 2 solenoids energized = 8 additional tons

The EPR is normally set to maintain the minimum desired
liquid refrigerant supply temperature. This is normally
EPR 50°F but may be as low as 40°F for some systems. A sub-
cooler EPR settings of 68 psig will have a SST of 40°F
for R-22 and 29°F for R-404A.

The liquid line solenoids in front of the sub-cooler expansion
from receiver to valves close when the condensers drop leg temperature gets
suction manifold below the set point thereby shutting off the sub-cooler.


How Sub Cooling Affects System Capacity

R-22 R-404A / R-507

For every 10F° of sub cooling For every 10F° of sub cooling
of R-22 will equal a 6% of R-404A / R-507 will equal
reduction in refrigerant mass a 10% reduction in refrigerant
flow requirements. mass flow requirements.
Example: SCT 100 F SCT 100 F Example: SCT 100 F SCT 100 F
SST – 25 F SST – 25 F SST – 25 F SST – 25 F
SC 0F SC 50F SC 0F SC 50F
SH 25 F SH 25 F SH 25 F SH 25 F
LOAD 5T LOAD 5T LOAD 5T LOAD 5T
BTU/LB 62.6 BTU/LB 77.6 BTU/LB 38.6 BTU/LB 58.4

Summary: Summary:

77.6 / 62.6 = 1.24 58.4 / 38.6 = 1.51
Therefore 2F° SC = 1 % capacity increase Therefore 1F° SC = 1 % capacity increase
Refrigerant circulated 15.9 to 12.9 lb/min Refrigerant circulated 25.9 to 17.2 lb/min
Compressor displacement from 44.1 to 35.5 cfm Compressor displacement from 49.7 to 32.9 cfm

NOTE: the above outlined calculation were determined by the use of DuPrex computer program



What is the controlling capacity
factor of any refrigeration
system ?

The choke point ….
" Evaporator "


" Economizers when Multi Staging "


Open Economizer

refrigerant vapour to
indicates vapour
compressor’s inter-stage

indicates liquid

spray
nozzles

liquid refrigerant
to
liquid refrigerant Evaporator (s)
from condenser
open economizer
saturated refrigerant
at inter-stage pressure

The " Open or Flash " economizer is simply a tank, which is vented to the compressors inter-stage.
The refrigerant flashes, evaporating some of the refrigerant, cooling the remaining liquid to
the saturation temperature corresponding to the inlet pressure of the compressor inter-stage.
The open or flash economizer is an economical, efficient method of cooling liquid refrigerant
en-route to the evaporator (s). Open economizers are generally used when high efficiency is required
as they also reduce the BHP requirements.


Open Economizer

2nd stage

1st stage

" Open or Flash " economizer


Closed Economizer
liquid refrigerant
from condenser

Sub-cooled liquid
refrigerant to
evaporator (s)
indicates vapour

level
indicates liquid
controller

liquid refrigerant vapour to
refrigerant compressors inter-stage

closed economizer
The " Closed " economizer takes the liquid from the condenser and splits the flow into two streams.
Most of the refrigerant flow goes through the tubes of a shell and tube heat exchanger; the remaining
refrigerant goes to the shell side through a control valve to be boiled off to cool the refrigerant in the
tubes. The vapour generated is vented to the inlet of the compressors inter-stage.

Closed Economizer

2nd stage

1st stage

" Closed " economizer


Two Stage A/C Cooling !!

His and Hers ??


Summary

Possible reselection of TEV
and distributor orifice disc needed

Up to 20% increase in Btu loading
Decrease in electrical usage as much as 25%
Reducing pull-down time up to 50%
Provide more uniform refrigerating temperatures
Reduces first cost, by permitting down sizing of
compressors in new system.
Catch-All Solenoid

See-All


Affects of Sub-cooling
on TEV’s Capacity

Refrigerant 100°F 60°F 50°F 40°F
(0°SC) (40°SC) (50°SC) (60°SC)
R-134a 100% 1.29 1.36 1.42
R-401A 100% 1.25 1.31 1.36
R-409A 100% 1.23 1.28 1.34

R-404A 100% 1.43 1.54 1.64
R-408A 100% 1.27 1.34 1.40
R-507 100% 1.40 1.50 1.59

R-22 100% 1.23 1.29 1.34
R-407C 100% 1.28 1.35 1.42


" Accumulators and their Affects "


Accumulator Design
Hold approximately 50% of systems charge in TEV systems

Hold approximately 70% of systems charge in fixed orifice systems

Standard screen in 3 inch Standard screen in 3 through 6 inch
diameter accumulators diameter accumulators

Metering orifice for oil return to the compressor located behind screen
0.055” diameter for 3 through 5 inch diameter accumulators
0.080” diameter for 6 inch diameter accumulators

Accumulator Screens
Original R-22 Screen Enhanced HFC Screen

Mesh 0.001’s Microns

10 = 0.0580 = 1500
30 = 0.0194 = 500
60 = 0.0097 = 250
100 = 0.0058 = 150
140 = 0.0041 = 105
200 = 0.0029 = 74
350 = 0.0017 = 44

60 x 60 mesh of surface area Increased surface area retains more
Smaller mesh can trap POE oils and contaminants without plugging.

additives. 30 x 30 mesh screen prevents POE oils &
additives from becoming trapped due to
surface tension .

Mesh .. Number of openings per linear inch, measured from the centre of one wire to a point one inch distant.



Odors … Bacteria
Odor eaters ..
Charcoal
Baking Soda
FDS (feminine deodorant spray)
foam core insulation, not fiberglass

Personal level ..
Vicks Vapor Rub … your upper lip
Basil … nasal snort c:sporlan 2006cooling idiosyncrasies

Effects of Hydrostatic Pressures ?

Lets Look at it.


Typical Effects of Hydrostatic Pressure
3200

2600

Hydrostatic Pressure
Increase
2200
R-12/R-134a is 40 psi / each F°
R-22 is 60 psi / each F°
R-410A is 45 psi / each Fº
1800
Pressure psig

4BA / 4BW
1400
Burst Pressure
1040
thru
1600
1000

Relief
R-410A Devices
600 R-22 390 psi
thru
800 psi
R-12 & R-134a
200

40 60 80 100 120 140 160 180

R-410A R-22 R-12/R-134a Temperature °F
40°F is 120 psi 40°F is 70 psi 40°F is 37 psi
155°F is 645 psi 180°F is 540 psi 180°F is 330 psi
Receiver to Solenoid ?

Troubled System … 6 TEV’s Replaced
Still High Super Heat ?

System:
R-22, with MO Freezer at
- 25ºF SST - 17ºF
Electric defrost
Pump out system
LP control cutout
1 psig (- 40ºF) Freezer at
- 17ºF
Found a 30Fº ∆ across Tee

Freezer at
Liquid line solenoid
100 feet away.
- 17ºF

“Tee”


Blood Storage Room
critical application
- 30ºC or - 22ºF

Blood Storage Room
Problem: loss of critical temperature
control, in a continuous operation.
Picture is of Hot Gas stabilizer line at
evaporator inlet, solenoid 8 ft above
outside box in a 74ºF ambient.


Fouling !!!!!

Modern Service
Technician


A 0.042" Film of Dirt on a Coil
Equals 21% Loss in
Heat Transfer Efficiency


" Servicing a Winter Charge"


Sporlan
Bulletin
90-30-1


Sporlan Bulletin 90-30-1

Refrigerants listed
R-12 R-22 R-134a R-401A R-401B
R-402A R-402B R-404A R-407C R-408A
R-409A R-502 R-507

Servicing a Winter Charge !!!

To calculate the correct additional winter operational
refrigerant charge needed at winter design follow
the procedure as outlined in Sporlan
bulletin 90-30-1 dated July 1998.

How to calculate the needed additional refrigerant if only a partial charge exists.
1. Calculate the correct added winter refrigerant charge for the winter design conditions. eg: 128 lbs @ - 20ºF.
(follow procedure as outlined in Sporlan bulletin 90-30-1 dated July 1998)
2. Take and record the current outdoor ambient air temperature. eg: + 20ºF
3. Add refrigerant until the sight glass just clears and record the quantity of refrigerant added. eg: 17 lbs
4. Recalculate the added winter charge for the current existing ambient temperature. eg: 98 lbs @ + 20ºF.
(this unit now contains the correct operational winter charge for its current ambient air temperature)
5. Additional refrigerant needed to operate at – 20ºF is 128 – 98 = 30 lbs.
6. In this example the billable refrigerant charge would be 17 + 30 or 47 lbs.


Fin and Tube Heat
Exchangers
FINS Used for both evaporators
Secondary and condensers.
Surface,
usually made
of Aluminum
(Al)

TUBES
Primary Surface, usually
made of copper (Cu).


Coefficient of Expansion

Cu is 0.0000104 of an inch / per inch / per F°

or

1.04E-5 per inch / per F°

Coefficient of Expansion

Al is 0.0000130 of an inch / per inch / per F°

or

1.30E-5 per inch / per F°

Source: American Machinists Handbook, p 33 - 29

2 Lines of Nozzles


Cu vs Al

“Aluminum will creep and move approximately 33% more
than copper. This large movement will eventually lead to
fatigue failure.”

“Through repetitive thermal cycling, aluminum laminations
(fins) can become loose, resulting in early failure.”
Source: elettra technology inc.

H2O (hard or soft) will evaporate AND cause residue (residual) deposits of
either or both mineral and / or oxides to be left behind. This residue
will be deposited on or between the Cu and Al thereby increasing the
heat exchanger’s fouling factor. This increase interferes with the heat
transfer process causing a loss of efficiency and capacity.


Other Considerations

• Continues running of water .. Added costs
water cost / sewer charge

• Roof will not dry off … permanent roof damage

• Loss of head pressure control as temperature changes

• Environmental aspects

• Outdoor installation, freezing prospects

• Repeated calls to start / stop adjust etc:

• Equipment life shortened, rust, motors, belts, drives


And Then There is the
Other Contractor

Modern Service
Technician

Poor Bulb Location = Floodback

Show smashed compressor parts …………….


Built-in Redundancy !!!


10 Units in 48” wide passage !!!


First Rule in Real Estate

Location .. Location .. Location


Residential Split Systems

Typical Cool Climate
Installation ?
Traditional / Standard
Method


Residential Split Systems

Secure top of hairpin only .. Allows opening / closing

Second Alternative, Knee Braces on outside wall.
Preferred Installation Pro’s: Not effected by ground thermo shear.
Method Landscaping not completed .. RNC market.
Con’s: Sound transmission, harmonics through wall.
Isolation pads may be needed ?


Didn’t like the look …
Must hide the Condensing unit


R-410A ? Under the Deck …
unit will die of emphysema !!!

RedRock Clubhouse, prestigious golf course in
South Carolina. Removed 4” of pine needles to
get units in and then only 1” top clearance on
second unit.

Typical Ductless Split Installation


Then There is the Contractor ABC
( Always Bring Cash )


Chicken crates
Safety … !!!!!!

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rt s?
ppo
s su
os
Cr

Entranced way


Attic installation in a Southern
State. Do it yourself installation
dream.

Home on pillars, note condensers discharge duct
on top of unit, complete with turning vane.


Access Ladder to Roof


Three Compressors !!!

FIDO


Cooling system idiosyncrasies 2006

Cooling system idiosyncrasies 2006

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