A, 

### ~ -~ 

### ~EERMISTD-984 4

## 0 

# 7 3 

# LL EAE-A/STD- q IY V 

# COMMENTS ON DOE'S PROPOSED MINIMUM EFFICIENCY STANDARDS FOR RESIDENTIAL CENTRAL AIR CONDITIONERS AND HEAT PUMPS

November 16, 2000

Comments by John Proctor. P.E.. President Proctor Engineering Group, Ltd. San Rafael, California Cited by Pacific Gas and Electric Company in their submission on February 4, 2000.

9 13doe.doc Page 1 

# ·**~** 

## EE_RM/STD-98-440 

# :#-13lL E.E 

### -IU'II.jSTD- q

## 1-

## YIf0 

# COMMENTS ON DOE'S PROPOSED MINIMUM EFFICIENCY STANDARDS FOR RESIDENTIAL CENTRAL AIR CONDITIONERS AND HEAT PUMPS

November 16, 2000

Comments by John Proctor. P.E.. President Proctor Engineering Group. Ltd. San Rafael, California Cited by Pacific Gas and Electric Company in their submission on FebnJary 4.2000. '"

9113doe.doc Page 1 

# ·**~** 

## EE_RM/STD-98-440 

# :#-13lL E.E 

### -IU'II.jSTD- q

## 1-

## YIf0 

# COMMENTS ON DOE'S PROPOSED MINIMUM EFFICIENCY STANDARDS FOR RESIDENTIAL CENTRAL AIR CONDITIONERS AND HEAT PUMPS

November 16, 2000

Comments by John Proctor. P.E.. President Proctor Engineering Group. Ltd. San Rafael, California Cited by Pacific Gas and Electric Company in their submission on FebnJary 4.2000. '"

9113doe.doc Page 1

### EE-RM/STD-98-440 

# 1 To state the obvious, TXVs improve SEER.
Ifthat alone were their effect, they should be an option that could be traded offagainst other methods ofobtaining a specified performance. 

# But TXVs do far more than that TXVs or their equivalent should be required because they provide substantial in field benefits that are not reflected in SEER.
The primary advantages ofthe TXV are that they perform better than the short tube orifice when the airflow across the inside coil is low and when the amount ofrefrigerant in the unit is different from that specified by the manufacturer.

911 3doe.doc Page 2 

### EE-RM/STD-98-440-

# Jf

# 'l?J..-LlTo state the obvious, TXVs improve SEER.
Ifthat alone were their effect, they should be an option that couldbe traded offagainst other methods ofobtaining a specifiedperformance. 

# ButTXVs do far more than that TXVs or their equivalent should be required because they provide substantial in field

benefits that are not reflected in SEER.
The primary advantages ofthe TXV are that they perform better than the short tube orifice when the airflow across the inside coil is low and when the anlount ofrefrigerant in the unit is different from that specified by the manufacturer.

q I I)doe.doc Page 2 

### EE-RM/STD-98-440-

# Jf

# 'l?J..-LlTo state the obvious, TXVs improve SEER.
Ifthat alone were their effect, they should be an option that couldbe traded offagainst other methods ofobtaining a specifiedperformance. 

# ButTXVs do far more than that TXVs or their equivalent should be required because they provide substantial in field

benefits that are not reflected in SEER.
The primary advantages ofthe TXV are that they perform better than the short tube orifice when the airflow across the inside coil is low and when the anlount ofrefrigerant in the unit is different from that specified by the manufacturer.

q I I)doe.doc Page 2

### EE-RMISTD-98-440-- 

# 13. 

# L 

# New Field Data
New field data confirms widespread mischarge and low airflow.
There is new, clear, and overwhelming evidence from more than 4000 units tested in California in this year that 62% are mischarged by more than 5%. This evidence further quantifies the distribution of the mischarge.

9113doe.doc Page 3 < .•

# EE-RM/STD-98-44(}"'1Y'J~- L-L

# New Field Data

New field data confirms widespread mischarge and low airflow.
There is new, clear, and overwhelming evidence from more than 4000 units tested in California in this year that 62% are mischarged by more than 5%. This evidence further quantifies the distribution of the mischarge.

91 Udoe.doc Page :< < .•

# EE-RM/STD-98-44(}"'1Y'J~- L-L

# New Field Data

New field data confirms widespread mischarge and low airflow.
There is new, clear, and overwhelming evidence from more than 4000 units tested in California in this year that 62% are mischarged by more than 5%. This evidence further quantifies the distribution of the mischarge.

91 Udoe.doc Page :<

# 62% of Population Mischarged 40%

- 

# 5_-- Correct Charge
35%
. -- ____ ___________ 

# *. 30%
_ _ _ _ 

## _ _ __ 

## _ _ 

# 35% a 25% _-___

_ 

### a., 

# 20%
o 15% Q) 

# 1Undercharge Overcharge m

5% -------- ---- -_-__. 

# g
0.2 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.8 Refrigerant Charge (fraction of correct charge) v 

# charge) -.. c: 

# o

...... (1l 

### ::J 

# a. 

# o a. (1l


# ...... 

# o t-'to

# o

...... 

# c: Q) 

# o r... Q) 

# a. 25% 20% 15% 10%

5% - 0% - 

# 62% of Population Mischarged

- Correct Charge

------- ------ --- ------- ------------------

- - ------- - -- ------------------------**--------~** ---------



# Undercharge Overcharge

0.2 0.3 

# 0.5 

# 0.7 0.9 1.1 1.3 

# Refrigerant Charge (fraction of correct charge) 1.5 1.8 

# \ 

# \' c: 

# o

...... (1l 

### ::J 

# a. 

# o a. (1l


# ...... 

# o t-'to

# o

...... 

# c: Q) 

# o r... Q) 

# a. 

# 62% of Population Mischarged

- Correct Charge

._------------ 

# 30% -.**---~** 

# ---**----------------~---- ------.-~**  

## -_ ..

_--- 

# 25% 20% 15% 10%

5% - 0% -0.2 

# Undercharge Overcharge

0.3 0.5 

# 0.7 0.9 1.1 1.3 1.5 

# 1.8 Refrigerant Charge (fraction of correct charge)

## $ 1 co 009 g ° 90.9


### ue 0 0.8 

## E E 0.7 u E 

## u o 0.6 0.5 TXV '" 

## / Short Tube Orifice E u

## w 0.4 

# z 14 0

. 

### 0.3 

## 0.2 0.1
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 

# Refrigerant Charge (fraction of manufacturer's recommendation) \

# ~**'~** 

## d**~ ~**  

## • co m



## ,

# ~

# ~ a:



## , w 

## w 1.1 

## 1



# -**~** 

## 0.9 L.. n:J 

### .c u 

### 0.8 "t:J 

# »Q) u"t:J t: t: 

### 0.7 Q) Q) 

## '0 E 

# H: E 

# w 

# 8 0.6 "t:J Q) Q) L..

### ~ 

## rt; 0.5 

# effi 

# oW 

## 0.4 

# Z'O c: 

## o 0.3**~** 

### o n:J 

## .:: 02 

# -

. 

## 0.1 

# o 

# )K-i-XV U

--- U

--- - 

# ----mu,l • Short Tube Orifice**-~--------------------~------- ---.~--** 



### 0.5 0.6 

## 0.7 0.8 

## 0.9 1.0 1.1 1.2 1.3 

## 1.4 Refrigerant Charge (fraction of manufacturer's recommendation) \

# ~**'~** 

## d**~ ~**  

## • co m



## ,

# ~

# ~ a:



## , w 

## w 1.1 

## 1



# -**~** 

## 0.9 L.. n:J 

### .c u 

### 0.8 "t:J 

# »Q) u"t:J t: t: 

### 0.7 Q) Q) 

## '0 E 

# H: E 

# w 

# 8 0.6 "t:J Q) Q) L..

### ~ 

## rt; 0.5 

# effi 

# oW 

## 0.4 

# Z'O c: 

## o 0.3**~** 

### o n:J 

## .:: 02 

# -

. 

## 0.1 

# o

0.5**~------.~---** 

# -------------,------------------.

0.6 

## 0.7 0.8 

## 0.9 1.0 

# )K-i-xv-

--- U

----

# -----,1
• Short Tube Orifice**-~--------------------~------- ---.~--** 



## 1.1 1.2 Refrigerant Charge (fraction of manufacturer's recommendation) 

## 1.3 

## 1.4

## 0.98 oda 0.96
I-



### . , 0.92 >. ,, 0.88 9 

### " E 

# .a t 0.88 w I 0.86 N| (0.84
Er 0.8 z 0 

### z C 0.8 0¢ 

### -""- TXV u 0.78

_ 

## 7--Short Tube Orifice 0.76 

## 0.74 0.72

0.7 - --- 

## 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Air Flow (fraction of 400 cfm per ton) 

# j
\

### ~ 

## t:-

## ~

\ 

## o 

# l**~** Q 

# t; 

# - :i 

## a:

• w 

## w 

# - 0_98 0.96 0.94 

# g 0.92 +oJ L. 

### >-**~** 0.9 

# g E**.~** 

### 't; 0.88**.~** 0 

# ffi**~** 0.86 -0 +oJ

# ~**~** 0.84 

# =w raw 

## E
.... 0.82 

# o 0 

# z c 0.8 o

## ~ ra 0.78
. 

# .:: 

# - 0.76 - 0.74 0.72 

# ------..-----..---------------------------------- -----------.--..**---._---_---_----.----.----:~;;;-;;;;;;;;;;;;;;;;-=ii)Klll-~==-'** 

## =-;t(-**-----~ -.----~-----**  M( 

### TXV • Short Tube Orifice



### 0.7**.~----_4------_+------_r------~------+_----~~----~------_+------~----~** 

## 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 

### Air Flow (fraction of 400 cfm per ton) 

# j
\

### ~ 

## t:-

## ~

\ 

## o 

# l**~** Q 

# t; 

# - :i 

## a:

• w 

## w 

# - 0_98 0.96 0.94 

# g 0.92 +oJ L. 

### >-**~** 0.9 

# g E**.~** 

### 't; 0.88**.~** 0 

# ffi**~** 0.86 -0 +oJ

# ~**~** 0.84 

# =w raw 

## E
.... 0.82 

# o 0 

# z c 0.8 o

## ~ ra 0.78
. 

# .:: 

# - 0.76 - 0.74 0.72 

# ------..-----..---------------------------------- -----------.--..**---._---_---_----.----.----:~;;;-;;;;;;;;;;;;;;;;-=ii)Klll-~==-'** 

## =-;t(-**-----~ -.----~-----**  M( 

### TXV • Short Tube Orifice



### 0.7**.~----_4------_+------_r------~------+_----~~----~------_+------~----~** 

## 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 

### Air Flow (fraction of 400 cfm per ton)

## EE-RM/STD-98-440" / 7/--L 

# Analysis When the field data is combined with the difference in performance between TXVs and short tube orifices the overall effect ofrequiring TXVs is shown. There are numerous national studies that repeatedly show that over halfthe units in the field are running at low airflow.

9113doe.doc Page 4 

## · 

# . EE-RM/STD-98-440if-13.-

# ~. 

# Analysis When the field data is combined with the difference in performance between TXVs and short tube orifices the overall effect ofrequiring TXVs is shown.
There are numerous national studies that repeatedly show that over halfthe units in the field are running at low airflow.

9113doe.doc Page ..) 

## · 

# . EE-RM/STD-98-440if-13.-

# ~. 

# Analysis When the field data is combined with the difference in performance between TXVs and short tube orifices the overall effect ofrequiring TXVs is shown.
There are numerous national studies that repeatedly show that over halfthe units in the field are running at low airflow.

9113doe.doc Page ..)

### EE-RM/STD-98-440

-- r 

### 73/ 

# Result

All this evidence combined shows an average field savings of 11% when TXVs are used on all units
This is equivalent to the difference between SEER 12 and SEER 13.5.

9113doe.doc Page 5 

## EE-RM/STD-98-440··

# 11 

# 16-[L 

# Result
All this evidence combined shows an average field savings of 11% 

# when TXVs are used on all units
This is equivalent to the difference between SEER 12 and SEER 13.5.

q 113doe.doc Page 5 

## EE-RM/STD-98-440··

# 11 

# 16-[L 

# Result
All this evidence combined shows an average field savings of 11% 

# when TXVs are used on all units
This is equivalent to the difference between SEER 12 and SEER 13.5.

q 113doe.doc Page 5

## EE-RM/STD.98-440

- 

## /_
- 

# C 

# Equivalency Any device that ensures performance in the field by tolerating incorrect charge and low airflow will achieve the necessary effect. A simple performance criteria can be written that allows devices other than TXVs to prove that they have equivalent or better tolerance to incorrect charge and low airflow.

91 13doe.doc Page 6 

### EE-RM/STD-98-440

# -1/

# 13
_ L,

# Lr 

# Equivalency Any device that ensures performance in the field by tolerating incorrect charge and low airflow will achieve the necessary effect. A simple performance criteria can be written that allows devices other than TXVs to prove that they have equivalent orbetter tolerance to incorrect charge and low airflow.

9113doe.doc Page 6 

### EE-RM/STD-98-440

# -1/

# 13
_ L,

# Lr 

# Equivalency Any device that ensures performance in the field by tolerating incorrect charge and low airflow will achieve the necessary effect. A simple performance criteria can be written that allows devices other than TXVs to prove that they have equivalent orbetter tolerance to incorrect charge and low airflow.

<) 113doe.doc Page 6

# EE-RM/STDg98-4 40 

# - 

# 7- Potential Specification

The performance specification could be along these lines: Each unit must have a device or combination of devices that produces 1) an EER95 at 90% and 120% offull charge with no more than a 4% difference from EER95 at full charge and 2) EER95 at 80% offull (certification test) air flow within 2% ofEER95 at certification test airflow. Ifthe unit has a TXV, the performance is assumed to meet these specifications.

911 3doe.doc Page 7 

## · 

# . EE-RM/STO
..

# 98-440-1f·7s./L/"--- 

# Potential Specification
The performance specification could be along these lines: Each unit must have a device or combination of devices thatproduces 1) an EER95 at 

# 90% and 120% offull charge with no more than a 4% difference from EER95 at full charge and 2) EER95 at 800/0 

# offull (certification test) air flow within 2% 

# ofEER95 at certification test airflow. Ifthe unit has a TXV, the performance is assumed to meet these specifications.

91 13doe.doc Page 7 

## · 

# . EE-RM/STO
..

# 98-440-1f·7s./L/"--- 

# Potential Specification
The performance specification could be along these lines: Each unit must have a device or combination of devices thatproduces 1) an EER95 at 

# 90% and 120% offull charge with no more than a 4% difference from EER95 at full charge and 2) EER95 at 800/0 

# offull (certification test) air flow within 2% 

# ofEER95 at certification test airflow. Ifthe unit has a TXV, the performance is assumed to meet these specifications.

91 13doe.doc Page 7

## EE-RM/STD-98-440 

# -'73-- 

# Reliability of TXVs

We know ofno evidence that TXVs are less reliable or subject to tampering any more than other components ofthe air conditioner. TXVs are regularly used in higher efficiency units and commercial rooftop units. They are installed and the units serviced daily all across the United States. The installation and service technicians in the field today are familiar with and work on both types ofunits. It is certainly feasible for manufacturers to produce TXVs that are not adjustable.

91 13doe.doc Page 8 

### EE-RM/STD-98-440

# "'#73-- LL 

# Reliability of

# TXVs

We know ofno evidence that TXV

# s are less reliable or subject to tampering any more than other components ofthe air conditioner. TXV

# s are regularly used in higher efficiency units and commercial rooftop units. They are installed and the units serviced daily all across the United States. The installation and service technicians in the field todav are familiar with and .; 

# work on both types ofunits. It is certainly feasible for nlanufacturers to produce TXVs that are not adjustable.

C) 11**~doe.doc** Page 8 

### EE-RM/STD-98-440

# "'#73-- LL 

# Reliability of

# TXVs

We know ofno evidence that TXV

# s are less reliable or subject to tampering any more than other components ofthe air conditioner. TXV

# s are regularly used in higher efficiency units and commercial rooftop units. They are installed and the units serviced daily all across the United States. The installation and service technicians in the field todav are familiar with and .; 

# work on both types ofunits. It is certainly feasible for nlanufacturers to produce TXVs that are not adjustable.

C) 11**~doe.doc** Page 8

## EE-RM/STD-98-440-t 

# .,5 

# -L Reliability of CurrentRatings

The current SEER ratings are unreliable as estimators offield performance. When these units operate their true efficiency usually does not meet the advertised efficiency. This situation is made much better when TXVs are used across the board. For $8 to $11 you have bought an insurance policy on the efficiency ofyour unit.

91 1 doe.doc Page 9 

## · 

# . EE.RM/STO.98.440
...

# :tF~**13-~** 

# Reliability ofCurrent Ratings

The current SEERratings are unreliable as estimators offield performance. When these units operate their true efficiency usually does not meet the advertised efficiency. This situation is made much better when TXVs are used across the board. For $8 to $11 you have bought an insurance policy on the efficiency ofyour unit.

l) 11 :<doc.doc Page 9 

## · 

# . EE.RM/STO.98.440
...

# :tF~**13-~** 

# Reliability ofCurrent Ratings

The current SEERratings are unreliable as estimators offield performance. When these units operate their true efficiency usually does not meet the advertised efficiency. This situation is made much better when TXVs are used across the board. For $8 to $11 you have bought an insurance policy on the efficiency ofyour unit.

l) 11 :<doc.doc Page 9

## EE-RM/STD-98-440-- 

# 713- 

# Reliability ofTXVs II

On July 24, 2000 Trane Company supported the mandatory use ofthermal expansion valves on all new central air conditioners and heat pumps.

91 13doe.doc Page 10 

### EE.RM/STD.98-440
....

# 1F

# 13.--L

# I--- 

# Reliability of

# TXVs 

# II

On July 24, 2000 Trane Company supported the mandatory use ofthermal expansion valves on all new central air conditioners and heatpumps.**911~doe.doc** Page 10 

### EE.RM/STD.98-440
....

# 1F

# 13.--L

# I--- 

# Reliability of

# TXVs 

# II

On July 24, 2000 Trane Company supported the mandatory use ofthermal expansion valves on all new central air conditioners and heatpumps.**911~doe.doc** Page 10

## EE-RM/STD-98-440/ ?5- 

# 7 L

# Options in Achieving Higher Efficiencies
There are numerous ways to obtain higher SEERs and/or EERs in air conditioners and heat pumps. These include: * Increased coil face area * Increased tube rows * Increased fin density ®Improved inside fan/motor efficiency (e.g. ECM motors) * Improved heat exchanger efficiency (e.g. rifling) e 

# TXVs * Compressor efficiency * Relative compressor size (multi speed or multiple compressor)

91 I3doe.doc Page 1 

### EE-RM/STD-98-440-<tt

# 7.?·- LL/ 

# Options in Achieving HigherEfficiencies
There are numerous ways to obtain higher SEERs and/or EERs in air conditioners and heatpumps. These include:

., Increased coil face area • Increased tube rows
., Increased fin density • Improved inside fan/motor efficiency (e.g. ECM motors)

., Improved heat exchanger efficiency (e.g. rifling) 

# "* TXVs • Compressor efficiency • Relative compressor size (multi speed or multiple compressor)

() 113doe.doc Page 11 

### EE-RM/STD-98-440-<tt

# 7.?·- LL/



# Options in Achieving HigherEfficiencies
There are numerous ways to obtain higher SEERs and/or EERs in air conditioners and heatpumps. These include:

., Increased coil face area • Increased tube rows
., Increased fin density • Improved inside fan/motor efficiency (e.g. ECM motors)

., Improved heat exchanger efficiency (e.g. rifling) 

# "* TXVs • Compressor efficiency • Relative compressor size (multi speed or multiple compressor)

() 113doe.doc Page 11

## EE-RM/STD-98-440 

## ' 93 

# L L DRAFT

OVERVIEW
DescriptionofTechnology A thermostatic expansion valve (TXV) is a refrigerant-metering device used in residential and commercial air conditioners. The TXV is one oftwo common metering devices, the other being a short tube orifice. Compared to the short tube orifice, TXVs are more costly and more effective in controlling refrigerant flow under varying conditions. 

### Function ofa Metering Device The area ofthe inside coil (evaporator) used in phase change from liquid refrigerant to vapor substantially effects the capacity and efficiency of an air conditioner. The larger portion ofthe coil used for phase change, generally the higher the capacity. The refrigerant-metering device controls the amount ofrefrigerant liquid flowing into the inside coil and thus the phase change area. If too much liquid flows into the inside coil not all the refrigerant changes phase in the coil and some liquid may reach the compressor. This can damage the compressor. Iftoo little refrigerant flows into the coil the phase change area ofthe coil is less than ideal and the refrigerant vapor returning to the compressor is superheated. Some superheat is considered desirable because it protects the compressor from liquid refrigerant. Too much superheat however represents wasted evaporator coil area and the superheat energy must be rejected later in the cycle at the outside coil. The durability ofthe compressor can be compromised by too much superheat as well. The compressor is cooled by the refrigerant vapor returning from the inside coil. High superheat provides less cooling to the compressor. The idealized system provides exactly 0 degrees of superheat and no liquid to the compressor. Such a system would protect the compressor without wasting coil area on producing superheat. The refrigerant metering device must work under a variety of conditions: inside temperature and humidity, outside temperature, as well as "off-design" operation (incorrect airflow across the inside coil and incorrect amount ofrefrigerant in the air conditioner). 

### Metering Device Description The short tube orifice is the least costly metering device and the most common. The short tube orifice has a small hole, which meters the flow ofrefrigerant based only on the pressure difference across the hole. Thermostatic expansion valves are more complex. They consist of a temperature sensor, pressure diaphragm, and a variable orifice. The TXV dynamically responds to more than the pressure difference. The TXV is a "constant superheat valve". It meters refrigerant flow to maintain a nearly constant temperature difference between the saturated refrigerant in the evaporator coil and the refrigerant leaving the evaporator coil. TXVs are generally set to provide between 10 °F and 15 °F of superheat.

PG&ETXV Impact Review DRAFT Oct. 23, 2000 Page 1-1 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440

# "*7E>L L DRAFT

OVERVIEW

Description 

## of Technology A thermostatic expansion valve (TXV) is a refrigerant-metering device used in residential and commercial air conditioners. TheTXV is one of two commonmetering devices, the other being a shorttube orifice. Compared to the shorttube orifice, TXVs are more costly and more effective in controlling refrigerant flow under varying conditions. 

### Function ofa Metering Device The area ofthe inside coil (evaporator) used in phase change from liquid refrigerant to vapor substantially effects the capacity and efficiency ofan air conditioner. The larger portion ofthe coil used for phase change, generally the higher the capacity. The refrigerant-metering device controls the amount ofrefrigerant liquid flowing into the inside coil and thus the phase change area. Iftoo much liquid flows into the inside coil not all the refrigerantchanges phase in the coil and some liquid may reach the compressor. This can damage the compressor. Iftoo little refrigerant flows into the coil the phase change area ofthe coil is less than ideal and the refrigerantvapor returning to the compressor is superheated. Some superheatis considered desirablebecause itprotects the compressor from liquid refrigerant. Too much superheathowever represents wasted evaporator coil area and the superheatenergy must be rejected later in the cycle at the outside coil. The durability ofthe compressor can be compromised by too much superheat as well. The compressor is cooled by the refrigerantvapor returning from the inside coil. High superheatprovides less cooling to the compressor. The idealized system provides exactly 0 degrees of superheat and no liquid to the compressor. Such a system would protectthe compressor withoutwasting coil area onproducing superheat. The refrigerant metering device mustwork under a variety ofconditions: inside temperature and humidity, outside temperature, as well as "off-design" operation (incorrectairflow across the inside coil and incorrect amount ofrefrigerant in the air conditioner). 

### Metering Device Description The short tube orifice is the least costly metering device and the mostcommon. The shorttube orifice has a small hole, which meters the flow ofrefrigerantbased only on the pressure difference across the hole. Thermostatic expansion valves are more complex. They consist of a temperature sensor, pressure diaphragm, and a variable orifice. TheTXV dynamically responds to more than the pressure difference. TheTXV is a "constantsuperheatvalve". Itmeters refrigerantflow to maintain a nearly constanttemperature differencebetween the saturated refrigerantin the evaporator coil and the refrigerant leaving the evaporatorcoil. TXVs are generally setto provide between 10 OF and 15 OF of superheat.

PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-1 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440

# "*7E>L L DRAFT

OVERVIEW

Description 

## of Technology A thermostatic expansion valve (TXV) is a refrigerant-metering device used in residential and commercial air conditioners. TheTXV is one of two commonmetering devices, the other being a shorttube orifice. Compared to the shorttube orifice, TXVs are more costly and more effective in controlling refrigerant flow under varying conditions. 

### Function ofa Metering Device The area ofthe inside coil (evaporator) used in phase change from liquid refrigerant to vapor substantially effects the capacity and efficiency ofan air conditioner. The larger portion ofthe coil used for phase change, generally the higher the capacity. The refrigerant-metering device controls the amount ofrefrigerant liquid flowing into the inside coil and thus the phase change area. Iftoo much liquid flows into the inside coil not all the refrigerantchanges phase in the coil and some liquid may reach the compressor. This can damage the compressor. Iftoo little refrigerant flows into the coil the phase change area ofthe coil is less than ideal and the refrigerantvapor returning to the compressor is superheated. Some superheatis considered desirablebecause itprotects the compressor from liquid refrigerant. Too much superheathowever represents wasted evaporator coil area and the superheatenergy must be rejected later in the cycle at the outside coil. The durability ofthe compressor can be compromised by too much superheat as well. The compressor is cooled by the refrigerantvapor returning from the inside coil. High superheatprovides less cooling to the compressor. The idealized system provides exactly 0 degrees of superheat and no liquid to the compressor. Such a system would protectthe compressor withoutwasting coil area onproducing superheat. The refrigerant metering device mustwork under a variety ofconditions: inside temperature and humidity, outside temperature, as well as "off-design" operation (incorrectairflow across the inside coil and incorrect amount ofrefrigerant in the air conditioner). 

### Metering Device Description The short tube orifice is the least costly metering device and the mostcommon. The shorttube orifice has a small hole, which meters the flow ofrefrigerantbased only on the pressure difference across the hole. Thermostatic expansion valves are more complex. They consist of a temperature sensor, pressure diaphragm, and a variable orifice. TheTXV dynamically responds to more than the pressure difference. TheTXV is a "constantsuperheatvalve". Itmeters refrigerantflow to maintain a nearly constanttemperature differencebetween the saturated refrigerantin the evaporator coil and the refrigerant leaving the evaporatorcoil. TXVs are generally setto provide between 10 OF and 15 OF of superheat.

PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-1 Proctor Engineering Group, Ltd.

## EE-RMISTD-98-440 

# /'73
- Overview A short tube orifice provides a varying amount of superheat from 0 °F to over 30 °F. Performance Influences of the Metering Device The performance ofthe air conditioner is influenced by the interaction of the metering device with the following parameters: * Differing outdoor temperatures

· Differing indoor conditions of humidity and temperature * Differing air flows across the inside coil * Differing amounts ofrefrigerant in the air conditioner The primary advantages ofthe TXV are that they perform better than the short tube orifice when the airflow across the inside coil is low and when the amount ofrefrigerant in the unit is different from that specified by the manufacturer. The effects of these parameters for a short tube orifice and for a TXV are shown in Figures 1and 2.

0.98 0.96

_ 0.94 ( 0 92

, i 0.9

't 0.88 U' 0.86 E N 0.84 E 0.82 Z = 0.8 ·- TXV X 078
- =-Short Tube Orifice 0.76 0.74 0.72

0.7 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 AirFlow (fraction of 400 cfm per ton) 

### Figure 1. Air ConditionerEfficiency vs. Evaporator Coil Air Flow (derived generic relationship from multiple units at a variety ofindoor and outdoor conditions

- see Appendix A)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-2 Proctor Engineering Group, Ltd. 

## EE-RM/STO-9S-44o-1113

---

# 1-

# v OvenJiew A shorttube orifice provides a varying amount ofsuperheatfrom 0 OF to over 30 OF. 

### Performance Influences ofthe Metering Device The performance ofthe air conditioner is influenced by the interaction ofthe metering device with the following parameters: • Differing outdoor temperatures • Differing indoor conditions ofhumidity and temperature • Differing air flows across the inside coil • Differing amounts ofrefrigerantin the air conditioner The primary advantages oftheTXV are thattheyperform better than the shorttube orifice when the airflow across the inside coil is low and when the amountofrefrigerantin the unitis different from that specified by the manufacturer. Theeffects ofthese parameters for a shorttube orifice and for a TXV are shown in Figures 1 and 2.

'2 0.98

0.96 0.94· .£ 0.92· Q; ()' Q. 0.9 c E**.~** 't 0.88

.- 0 

## ffi**~** 0.86**~«i** N c:: 0.84· :=UJ**~ ~**  0.82 

# o 0 z § 0.8·**~ ~**  0.78· 0.76 0.74 072 I---TXV 

# l i-Short Tube Orifice I

-----------------

0.7**.~----~-----+------~----+-----~----~------+-----~-----+----~** 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Air Flow (fraction of 400 cfm perton) Figure 1. Air Conditioner Efficiencyvs. Evaporator Coil AirFlow (derived generic relationship from multipleunits at a variety ofindoor and outdoor conditions

- seeAppendix A)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-2 Proctor Engineering Group, Ltd. 

## EE-RM/STO-9S-44o-1113

---

# 1-

# v OvenJiew A shorttube orifice provides a varying amount ofsuperheatfrom 0 OF to over 30 OF. 

### Performance Influences ofthe Metering Device The performance ofthe air conditioner is influenced by the interaction ofthe metering device with the following parameters: • Differing outdoor temperatures • Differing indoor conditions ofhumidity and temperature • Differing air flows across the inside coil • Differing amounts ofrefrigerantin the air conditioner The primary advantages oftheTXV are thattheyperform better than the shorttube orifice when the airflow across the inside coil is low and when the amountofrefrigerantin the unitis different from that specified by the manufacturer. Theeffects ofthese parameters for a shorttube orifice and for a TXV are shown in Figures 1 and 2.

'2 0.98

0.96 0.94· .£ 0.92· Q; ()' Q. 0.9 c E**.~** 't 0.88

.- 0 

## ffi**~** 0.86**~«i** N c:: 0.84· :=UJ**~ ~**  0.82 

# o 0 z § 0.8·**~ ~**  0.78· 0.76 0.74 072 I---TXV 

# l i-Short Tube Orifice I

-----------------

0.7**.~----~-----+------~----+-----~----~------+-----~-----+----~** 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Air Flow (fraction of 400 cfm perton) Figure 1. Air Conditioner Efficiencyvs. Evaporator Coil AirFlow (derived generic relationship from multipleunits at a variety ofindoor and outdoor conditions

- seeAppendix A)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-2 Proctor Engineering Group, Ltd.

## EE-RM/STD-98-440--1 

# L7 - Overview 1.1

x ~0.9

o 0.8

E ^*Short Tube Orifice 5 E 0.4

0.3 E0.2

0.1
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 13 1.4 Refrigerant Charge (fraction of manufacturer's recommendation) 

### Figure 2. Air ConditionerEfficiency vs. Refrigerant Charge (derived generic relationship from multiple units ata variety ofconditions

- see Appendix A) 

### Secondary Performance Influence of the Metering Device The ability ofthe installing or servicing technician to determine whether the refrigerant level is correct is influenced by the metering device. The primary recommendation of most manufacturers is to check refrigerant charge on fixed metering devices by measuring superheat and comparing that against a target value. The target superheat varies with outdoor temperature (condenser air entering temperature) and the indoor wet bulb temperature (evaporator air entering wetbulb). When the outdoor conditions are hot and the indoor conditions are cool and dry, the target superheat is indeterminate. This means that short tube orifice air conditioners cannot be easily checked for overcharge under common conditions in the sunbelt states. On the other hand, the primary recommendation ofmost manufacturers is to check refrigerant level on TXVs by measuring subcooling and comparing it against a target value. There are few limitations to the conditions under which this comparison can be made. Because ofthis difference there is a potential for more air conditioners and heat pumps to be charged properly when a TXV is installed. 

## Market Characteristics Residential air conditioning is expanding into coastal and moderate climate areas. In addition air conditioners are now the rule rather than the exception in new construction. The US Department of Commerce reports that 84% ofnew single family homes completed in 1999 were equipped with central air conditioning (U. S. DOE, 1999).

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-3 Proctor Engineering Group, Ltd. 

### Overuiew
1.1**~** 0.9 

## "'**~** 0.8 "g >,111 

### g 

### -g 0.7
. III III .;:; E iEE06' w 0 . <> "g III III
..**~** 1U 0.5
. "'It: Ew OW 0.4 z- o c**~** 0.3 <>

### ~ 0.2

0.1



### o

0.5 0.6 0.7 0.8 0.9 1.0 

### EE-RM/STD-98-440-

# 11

# 7?/**L--~**



# --**~TXV** 

# -----1**-ShortTube~**

!--------1 --.---.1 1.1 1.2 1.3 1.4 Refrigerant Charge (fraction of manufacturer's recommendation) Figure 2, Air Conditioner Efficiencyvs. Refrigerant Charge (derived generic relationship from multiple units ata variety ofconditions

- see Appendix A) 

### Secondary Performance Influence ofthe Metering Device The ability ofthe installing or servicing technician to determine whether the refrigerant level is correctis influenced by the metering device. The primary recommendation ofmost manufacturers is to check refrigerantcharge onfixed metering devices by measuring superheatand comparing that against a targetvalue. The target superheatvaries with outdoor temperature (condenser air entering temperature) and the indoor wetbulb temperature (evaporator air entering wetbulb). When the outdoor conditions are hot and the indoor conditions are cool and dry, the targetsuperheatis indeterminate. This means that shorttube orifice air conditioners cannotbeeasily checked for overcharge under common conditions in the sunbeltstates. On the other hand, the primary recommendation ofmostmanufacturers is to check refrigerant level onTXVs by measuring subcooling and comparing it against a targetvalue. There arefew limitations to the conditions under which this comparison canbe made. Because ofthis difference there is a potential for more air conditioners and heatpumps to be charged properly when a TXV is installed. 

### Market Characteristics Residential air conditioning is expandinginto coastal and moderate climate areas. In addition air conditioners are now the rule rather than the exception innew construction. The US Department ofCommerce reports that 84% ofnew single family homes completed in 1999were equipped with central air conditioning (U. S. DOE, 1999).

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 1-3 Proctor Engineering Group, Ltd. 

### Overuiew
1.1**~** 0.9 

## "'**~** 0.8 "g >,111 

### g 

### -g 0.7
. III III .;:; E iEE06' w 0 . <> "g III III
..**~** 1U 0.5
. "'It: Ew OW 0.4 z- o c**~** 0.3 <>

### ~ 0.2

0.1



### o

0.5 0.6 0.7 0.8 0.9 1.0 

### EE-RM/STD-98-440-

# 11

# 7?/**L--~**



# --**~TXV** 

# -----1**-ShortTube~**

!--------1 --.---.1 1.1 1.2 1.3 1.4 Refrigerant Charge (fraction of manufacturer's recommendation) Figure 2, Air Conditioner Efficiencyvs. Refrigerant Charge (derived generic relationship from multiple units ata variety ofconditions

- see Appendix A) 

### Secondary Performance Influence ofthe Metering Device The ability ofthe installing or servicing technician to determine whether the refrigerant level is correctis influenced by the metering device. The primary recommendation ofmost manufacturers is to check refrigerantcharge onfixed metering devices by measuring superheatand comparing that against a targetvalue. The target superheatvaries with outdoor temperature (condenser air entering temperature) and the indoor wetbulb temperature (evaporator air entering wetbulb). When the outdoor conditions are hot and the indoor conditions are cool and dry, the targetsuperheatis indeterminate. This means that shorttube orifice air conditioners cannotbeeasily checked for overcharge under common conditions in the sunbeltstates. On the other hand, the primary recommendation ofmostmanufacturers is to check refrigerant level onTXVs by measuring subcooling and comparing it against a targetvalue. There arefew limitations to the conditions under which this comparison canbe made. Because ofthis difference there is a potential for more air conditioners and heatpumps to be charged properly when a TXV is installed. 

### Market Characteristics Residential air conditioning is expandinginto coastal and moderate climate areas. In addition air conditioners are now the rule rather than the exception innew construction. The US Department ofCommerce reports that 84% ofnew single family homes completed in 1999were equipped with central air conditioning (U. S. DOE, 1999).

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 1-3 Proctor Engineering Group, Ltd.

## EE-RM/STD-98-440 -;l 

# 7 Overview Only about 20% ofnew air conditioners use TXV metering devices and these are predominantly used on replacement units as opposed to new construction (Personal Communication, Alco Controls, 2000). The exceptions to this are the higher efficiency units with SEER 13 and above, which generally use TXV metering (Manufacturers' Product Performance Data). These figures are in substantial agreement with DOE's reverse engineered equipment data. TXVs are rare in residential sized package units and lower efficiency heat pumps. They can be used in these applications and are quite common on commercial rooftop package units. The overall market penetration ofTXVs in existing residences in California is approximately 13% based on a database of4,232 homes serviced in the year 2000 (CheckMe!®Database 2000). Residential air conditioners generally operate at off design conditions (Neme et al. 1999). That is, most units operate with low airflow across the inside coil, an incorrect amount of refrigerant, or both. Various studies (ibid.) show a near normal distribution of airflows with a standard deviation of 80 cfm per ton. Data on existing construction show a mean airflow between 270 and 350 cfm per ton. The CheckMe! database has information on the distribution of refrigerant charge. These data (Figure 3) show 62% ofthe units mischarged. This figure is exactly the same as the average of earlier studies summarized in Neme et al. 62% of Population Mischarged 4 0% .................... . ...... . ....... .... ........ l
......... ... . ..... . ...... 

### Correct Charge 35%

- 30%
o 25% 

### 20%_ I --

_i15% 

### °S Undercharge Overcharge



### 15% _l l ,___ 

# O r g 0% 0.2 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.8 Refrigerant Charge (fraction of correct charge) 

### Figure 3. Refrigerant Charge Distribution (from CheckMe! Database) 

### Cost The retail cost of TXVs is between $45 and $50 from parts supply houses (Personnel Communications, 2000). Residential service/installation companies surveyed quoted $100 for a TXV installed. According to one TXV manufacturer (ibid.) the differential price to an air conditioner manufacturer would bebetween $8 and $11.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-4 Proctor Engineering Group, Ltd. 

## EE-RM/STO-9S-440""1r1?:>,

# L~ Overview Only about 20% ofnew air conditioners use TXV metering devices and these are predominantly used on replacementunits as opposed to new construction (Personal Communication, Alco Controls, 2000), The exceptions to this are the higher efficiency units with SEER 13 and above, which generally use TXV metering (Manufacturers' ProductPerformance Data), Thesefigures are in substantial agreement with DOE's reverse engineered equipmentdata, TXVs are rare in residential sized package units and lower efficiency heatpumps, They can be used in these applications and are quite commonon commercial rooftop package units, The overall marketpenetration ofTXVs inexisting residences in California is approximately 13% based on a database of4,232 homes serviced in the year 2000 (CheckMe!® Database 2000), Residential air conditioners generally operate at off design conditions (Neme etaL 1999), Thatis, mostunits operate with low airflow across the inside coil, an incorrect amount ofrefrigerant, or both, Various studies (ibid,) show a near normal distribution of airflows with a standard deviation of 80 cfm per ton, Data on existingconstruction show a mean airflow between 270 and 350 cfm per ton. The CheckMe! database has information on the distribution ofrefrigerantcharge, These data (Figure 3) show 62%ofthe units mischarged, This figure is exactly the same as the average of earlier studies summarized in Neme et aL 62% of Population Mischarged 40% ------------- --- ----------------------- ------------------- "- -1 35% --------------------- -- Correct Charge
c: ,2 30% -1--------------- --------------! 

### n; :; 

## g. 25%- c..

### ~ 20% -------------1 I- 

# - o "E 15% ------------------ Q) (.) iii c.. 10% 5%-1-------- 0_2 0_3 0,5 0.7 0.9 _IHI
_____________

### i :li!l: ' l!tt Overcharge -I,,",,· --.---------;



## --**'~** 

## __I i ;- I' f I , 1.1 1.3 1.5 1.8 Refrigerant Charge (fraction of correct charge) Figure 3. Refrigerant Charge Distribution (from CheckMe! Database) 

### Cost The retail cost ofTXVs is between $45 and $50 from parts supply houses (Personnel Communications, 2000). Residential service/installation companies surveyed quoted $100 for a TXV installed. According to oneTXV manufacturer (ibid.) the differential price to an air conditioner manufacturer would bebetween $8 and $11.

PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-4 ProctorEngineering Group, Ltd, 

## EE-RM/STO-9S-440""1r1?:>,

# L~ Overview Only about 20% ofnew air conditioners use TXV metering devices and these are predominantly used on replacementunits as opposed to new construction (Personal Communication, Alco Controls, 2000), The exceptions to this are the higher efficiency units with SEER 13 and above, which generally use TXV metering (Manufacturers' ProductPerformance Data), Thesefigures are in substantial agreement with DOE's reverse engineered equipmentdata, TXVs are rare in residential sized package units and lower efficiency heatpumps, They can be used in these applications and are quite commonon commercial rooftop package units, The overall marketpenetration ofTXVs inexisting residences in California is approximately 13% based on a database of4,232 homes serviced in the year 2000 (CheckMe!® Database 2000), Residential air conditioners generally operate at off design conditions (Neme etaL 1999), Thatis, mostunits operate with low airflow across the inside coil, an incorrect amount ofrefrigerant, or both, Various studies (ibid,) show a near normal distribution of airflows with a standard deviation of 80 cfm per ton, Data on existingconstruction show a mean airflow between 270 and 350 cfm per ton. The CheckMe! database has information on the distribution ofrefrigerantcharge, These data (Figure 3) show 62%ofthe units mischarged, This figure is exactly the same as the average of earlier studies summarized in Neme et aL 62% of Population Mischarged 40% ------------- --- ----------------------- ------------------- "- -1 35% --------------------- -- Correct Charge
c: ,2 30% -1--------------- --------------! 

### n; :; 

## g. 25%- c..

### ~ 20% -------------1 I- 

# - o "E 15% ------------------ Q) (.) iii c.. 10% 5%-1-------- 0_2 0_3 0,5 0.7 0.9 _IHI
_____________

### i :li!l: ' l!tt Overcharge -I,,",,· --.---------;



## --**'~** 

## __I i ;- I' f I , 1.1 1.3 1.5 1.8 Refrigerant Charge (fraction of correct charge) Figure 3. Refrigerant Charge Distribution (from CheckMe! Database) 

### Cost The retail cost ofTXVs is between $45 and $50 from parts supply houses (Personnel Communications, 2000). Residential service/installation companies surveyed quoted $100 for a TXV installed. According to oneTXV manufacturer (ibid.) the differential price to an air conditioner manufacturer would bebetween $8 and $11.

PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-4 ProctorEngineering Group, Ltd,

## EE-RM/STD-98-440- -. L OvervZiew 

## Benefit Methodology The benefit ofTXVs on the average SEER ofunits was determined by examining the published performance data for identical matched indoor and outdoor units with orifice and with TXV metering devices. The benefits ofTXVs in the performance of air conditioners in off design conditions were estimated in a three-step process. First, laboratory test data for TXV and short tube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existing field data on "off-design" conditions were analyzed and distributions of airflow and amount of charge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole population were estimated. 

## Benefits Replacement of short tube orifices with TXVs would have a number of energy and peak electrical consumption benefits. Using data from laboratory tests reported in the bibliography as well as the distribution of incorrect charge and airflow from the reports and CheckMe! database, replacement of short tube orifices will have the following effects:

· Reduced energy consumption of approximately 4.7% as reflected in an improved SEER 1



### .

· An additional reduced energy consumption of approximately 11% or more due to the TXVs tolerance of incorrect refrigerant charge and low airflow.

· An average peak load reduction of 5.7% or more due to the TXVs tolerance to low airflow and undercharge.
o 

### A simplified charge checking methodology that is applicable over a wider range of conditions.

Note that this improvement will be integrated into the reported SEER and is not additive to SEER.
PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 1-5 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440
..

# 1(**1~·-** 

# tLOverview BenefitMethodology The benefitofTXVs on the average SEER ofunits was determined by examiningthe published performance data for identical matched indoor and outdoor units with orifice and withTXV metering devices. The benefits ofTXVs in the performance of air conditioners in offdesign conditions were estimated in a three-step process. First, laboratory test data for TXV and shorttube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existingfield data on "off-design" conditions were analyzed and distributions of airflow and amountofcharge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole populationwereestimated. 

### Benefits Replacement ofshorttube orifices withTXVs would have a number ofenergy and peak electrical consumption benefits. Using data from laboratory tests reported in the bibliography as well as the distribution ofincorrectcharge and airflow from the reports and CheckMe! database, replacement ofshorttube orifices will have the following effects: • Reduced energy consumption of approximately 4.7% as reflected in an improved SEERl. • An additional reduced energy consumption of approximately 11 %or more due to theTXVs tolerance ofincorrectrefrigerantcharge and low airflow. • An average peak load reduction of5.7% or more due to the TXVs tolerance to low airflow and undercharge. • A simplified charge checkingmethodology thatis applicable over a wider range of conditions.

1 Note thatthis improvementwill be integrated into the reported SEER and is not additive to SEER.
PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-5 ProctorEngineering Group, Ltd. 

### EE-RM/STD-98-440
..

# 1(**1~·-** 

# tLOverview BenefitMethodology The benefitofTXVs on the average SEER ofunits was determined by examiningthe published performance data for identical matched indoor and outdoor units with orifice and withTXV metering devices. The benefits ofTXVs in the performance of air conditioners in offdesign conditions were estimated in a three-step process. First, laboratory test data for TXV and shorttube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existingfield data on "off-design" conditions were analyzed and distributions of airflow and amountofcharge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole populationwereestimated. 

### Benefits Replacement ofshorttube orifices withTXVs would have a number ofenergy and peak electrical consumption benefits. Using data from laboratory tests reported in the bibliography as well as the distribution ofincorrectcharge and airflow from the reports and CheckMe! database, replacement ofshorttube orifices will have the following effects: • Reduced energy consumption of approximately 4.7% as reflected in an improved SEERl. • An additional reduced energy consumption of approximately 11 %or more due to theTXVs tolerance ofincorrectrefrigerantcharge and low airflow. • An average peak load reduction of5.7% or more due to the TXVs tolerance to low airflow and undercharge. • A simplified charge checkingmethodology thatis applicable over a wider range of conditions.

1 Note thatthis improvementwill be integrated into the reported SEER and is not additive to SEER.
PG&E TXV Impact Review DRAFT Oct. 23,2000 Page 1-5 ProctorEngineering Group, Ltd.

# DRAFT EE-RM/STD-98-440-' 

# 7

- L L 

# CONCLUSIONS

Proctor Engineering Group concludes that building residential air conditioners with thermostatic expansion valves as opposed the more common short tube orifice will save energy and reduce the diversified electrical power load on peak. These effects are largely due to the improved tolerance to common field problems of incorrect refrigerant charge and low airflow across the evaporator coil. The cost ofbuilding units to this specification will depend on whether it is done at the factory (shipped already attached to the evaporator coil) or installed by the contractor in the field. The low side differential cost is $15 at the factory. The high side differential cost is $100 in the field.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 2-1 Proctor Engineering Group, Ltd. 

# DRAFT EE-RM/STD-98-440-:#

# 13-' LL 

# CONCLUSIONS

Proctor Engineering Group concludes thatbuilding residential air conditioners with thermostatic expansionvalves as opposed the more common shorttube orifice will save energy and reduce the diversified electrical power load on peak. Theseeffects are largely due to the improved tolerance to common field problems ofincorrectrefrigerant charge and low airflow across the evaporator coil. The costofbuildingunits to this specification will depend on whether itis done atthe factory (shipped already attached to the evaporator coil) or installed by the contractor in the field. The low side differential costis $15 atthe factory. The high side differential cost is $100 in the field.

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 2-1 Proctor Engineering Group, Ltd. 

# DRAFT EE-RM/STD-98-440-:#

# 13-' LL 

# CONCLUSIONS

Proctor Engineering Group concludes thatbuilding residential air conditioners with thermostatic expansionvalves as opposed the more common shorttube orifice will save energy and reduce the diversified electrical power load on peak. Theseeffects are largely due to the improved tolerance to common field problems ofincorrectrefrigerant charge and low airflow across the evaporator coil. The costofbuildingunits to this specification will depend on whether itis done atthe factory (shipped already attached to the evaporator coil) or installed by the contractor in the field. The low side differential costis $15 atthe factory. The high side differential cost is $100 in the field.

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 2-1 Proctor Engineering Group, Ltd.

# DRAFT EE-RM/STD-98-440f- ['" 

# BIBLIOGRAPHY

ALCO Controls Division, Emerson Electric Company, St. Louis, Missouri, "Refrigeration and Air Conditioning Flow Control", Catalogue 28, p. 298

- 310, "Fundamentals ofThermo®Expansion Valves". ARI Directory ofCertified Unitary Equipment Standards 210/240/270. Published by AirConditioning Refrigeration Institute (ARI) twice each year. Bain, Joel A., Dennis L. O'Neal, Michael A. Davis, Angel G. Rodriquez, "The Effect of Hardware Configuration on the Performance ofResidential Air Conditioning Systems At High Outdoor Ambient Temperatures", EPRI Final Report, November 1995, prepared by Energy Systems Laboratory, Texas A&M University. CheckMe!®Database, Electronic recorded data for 4,232 California homes serviced in the year 2000, Proctor Engineering Group Energy Design Update, "Inadequate Air Flow Torpedoes Air Conditioner and Heat Pump Performance", June 1998, p. 11-12. Farzad, Mohsen, "Modeling The Effects ofRefrigerant Charging on Air Conditioner Performance Characteristics For Three Expansion Devices", pH Thesis, Mechanical Engineering, Texas A& M University, August 1990. Farzad, Mohsen and Dennis L. O'Neal, "An Evaluation of Improper Charge on the Performance ofa Split System Air Conditioner with Capillary Tube Expansion", ESL/CON/88-1, July 1988, Texas A&M University. Farzad, M. and D. L. O'Neal, "Influence ofthe Expansion Device on Air-Conditioner System Performance Under a Range of Charging Conditions" ASHRAE Paper 3622, ASHRAE Transactions, January 1993, p. 3

- 13. Manufacturers Product Performance Data from

- o 

### Air Pro/Coleman (Evcon Industries) * Amana Corporation * Carrier Corporation o 

### Lennox Industries * Rudd (Rheem Corporation) * Tempstar/Heil (International Comfort Products Corporation) * The Trane Company, Unitary Products Group * York Corporation

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 3-1 Proctor Engineering Group, Ltd. 

# DRAFT BIBLIOGRAPHY

ALCO Controls Division, Emerson Electric Company, St. Louis, Missouri, "Refrigeration and Air Conditioning Flow Control", Catalogue28, p. 298

- 310, "Fundamentals ofThermo®Expansion Valves". ARI Directory ofCertified Unitary EquipmentStandards 210/240/270. Published by AirConditioning Refrigeration Institute (ARI) twice each year. Bain, Joel A., Dennis L. O'Neal, Michael A. Davis, Angel G. Rodriquez, "The Effect ofHardware Configuration on the Performance ofResidential Air ConditioningSystems AtHigh Outdoor AmbientTemperatures", EPRI Final Report, November 1995, prepared by Energy Systems Laboratory, Texas A&M University. CheckMe!® Database, Electronic recorded data for 4,232 California homes serviced in the year 2000, Proctor Engineering Group Energy Design Update, "Inadequate Air FlowTorpedoes Air Conditioner and HeatPump Performance",June 1998, p. 11-12. Farzad, Mohsen, "ModelingThe Effects ofRefrigerant Charging on Air Conditioner Performance Characteristics ForThree Expansion Devices", pHThesis, MechanicalEngineering,Texas A& M University, August 1990. Farzad, Mohsen and Dennis L. O'Neal, "AnEvaluation ofImproper Charge on the Performance ofa Split System Air Conditioner with Capillary Tube Expansion", ESL/CON/88-1,July 1988, Texas A&M University. Farzad, M. and D. L. O'Neal, "Influence ofthe Expansion Device on Air-Conditioner System Performance Under a Range ofChargingConditions" ASHRAE Paper 3622, ASHRAE Transactions, January 1993, p. 3 -13. Manufacturers ProductPerformance Data from

- • Air Pro/Coleman (Evcon Industries) • Amana Corporation • Carrier Corporation • Lennox Industries • Rudd (Rheem Corporation) • Tempstar/Heil (InternationalComfortProducts Corporation) • TheTrane Company, Unitary Products Group • York Corporation

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 3-1 Proctor Engineering Group, Ltd. 

# DRAFT BIBLIOGRAPHY

ALCO Controls Division, Emerson Electric Company, St. Louis, Missouri, "Refrigeration and Air Conditioning Flow Control", Catalogue28, p. 298

- 310, "Fundamentals ofThermo®Expansion Valves". ARI Directory ofCertified Unitary EquipmentStandards 210/240/270. Published by AirConditioning Refrigeration Institute (ARI) twice each year. Bain, Joel A., Dennis L. O'Neal, Michael A. Davis, Angel G. Rodriquez, "The Effect ofHardware Configuration on the Performance ofResidential Air ConditioningSystems AtHigh Outdoor AmbientTemperatures", EPRI Final Report, November 1995, prepared by Energy Systems Laboratory, Texas A&M University. CheckMe!® Database, Electronic recorded data for 4,232 California homes serviced in the year 2000, Proctor Engineering Group Energy Design Update, "Inadequate Air FlowTorpedoes Air Conditioner and HeatPump Performance",June 1998, p. 11-12. Farzad, Mohsen, "ModelingThe Effects ofRefrigerant Charging on Air Conditioner Performance Characteristics ForThree Expansion Devices", pHThesis, MechanicalEngineering,Texas A& M University, August 1990. Farzad, Mohsen and Dennis L. O'Neal, "AnEvaluation ofImproper Charge on the Performance ofa Split System Air Conditioner with Capillary Tube Expansion", ESL/CON/88-1,July 1988, Texas A&M University. Farzad, M. and D. L. O'Neal, "Influence ofthe Expansion Device on Air-Conditioner System Performance Under a Range ofChargingConditions" ASHRAE Paper 3622, ASHRAE Transactions, January 1993, p. 3 -13. Manufacturers ProductPerformance Data from

- • Air Pro/Coleman (Evcon Industries) • Amana Corporation • Carrier Corporation • Lennox Industries • Rudd (Rheem Corporation) • Tempstar/Heil (InternationalComfortProducts Corporation) • TheTrane Company, Unitary Products Group • York Corporation

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 3-1 Proctor Engineering Group, Ltd.

## EE-RM/STD-98-440--: 

# 1'9 LK. Bibliography Neal, C. Leon, P. E., "Field Adjusted SEER [SEERFA]

- Residential Buildings: Technologies, Design, and Performance Analysis", Proceedings of 1998 ACEEE Summer Study on Energy Efficiency in Buildings, Vol. 1, p. 1.197

- 1.209. Neme, Chris,John Proctor, and Steve Nadel, "National Energy Savings Potential From Addressing Residential HVAC Installation Problems", February 1999, Prepared as a part of the U. S. Environmental Protection Agency's Energy Star Program. Palami, Manivannan, Dr. Dennis O'Neal, and Dr. Jeff Haberl, "The Effect ofReduced Evaporator Air Flow on the Performance of a Residential Central Air Conditioner", Proceedings ofthe Eighth Annual Symposium on Improving Building Systems in Hot and Humid Climates, Texas A&M University, May 13

- 14, 1992, p. 20

- 26. Parker, Danny S., John R. Sherwin, Richard A. Ranstad, and Don B. Shirey III, "Impact of Evaporator Coil Airflow in Residential Air-Conditioning Systems", ASHRAE BN-97-2-1, ASHRAE Transactions 1997, v. 103, pt. 2. Patenaude, Andre, "Refrigeration Fluid Flow Controls and System Troubleshooting Guide", ALCO Controls Division, Emerson Electric Company, December 1990. Personal Communications * Sporlan Valve Company * Alco Controls, Buzz Schaeffer, May 30, 2000 * Alco Controls, Buzz Schaeffer, May 31, 2000 Proctor, J. P., "Field Measurement ofNew Residential Air Conditioners in Phoenix, Arizona", ASHRAE BN-97-2-2, also ASHRAE Transactions 1997, vol. 103, Pt. 2, p. 406

- 415. Proctor, J. and P. Albright, "Sizing Air Conditioners: IfBigger Is Not Better, What Is?", Home Energy Magazine, Sept./Oct. 1996, p. 13

- 18. Proctor, John, Tom Downey, Curtis Boecker, Zinoviy Katsnelson, George Peterson, and Dennis O'Neal., "Investigation ofPeak Load Impacts ofHigh SEER Residential HVAC Units

- Assembly, Testing, and investigation ofa Reduced Peak Load Air Conditioner", Pacific Gas and Electric Company, Research and Development Department June, 1996 Rodriquez, Angel Gerardo, "Effect ofRefrigerant Charge, Duct Leakage, and Evaporator Air Flow on the High Temperature Performance ofAir Conditioners and Heat Pumps", M S Thesis, Mechanical Engineering Department, Texas A&M University, August 1995. Rodriquez, Angel G., Dennis L. O'Neal, Joel A. Bain, and Michael A. Davis, "The Effect of Refrigerant Charge, Duct Leakage, and Evaporator Air Flow on the High Temperature Performance ofAir Conditioners and Heat Pumps", May 1995, Draft Final Report, [Submitted to EPRI] Sporlan Valve Company, 206 Lange Drive, Washington, Missouri 63090, (a) Educational Bulletin 10-9 Thermostatic Expansion Valves

- Theory ofOperation, Application and Selection, October 1995, (b) Educational Bulletin 10-11 Thermostatic Expansion Valves

- Installation, Field Service and Assembly, September 1996.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 3-2 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440

# --J):

# 10.-LL/ Bibliography Neal, C. Leon, P. E., "Field Adjusted SEER [SEERFA]

- Residential Buildings: Technologies, Design, and Performance Analysis", Proceedings of 1998 ACEEE Summer Study on Energy Efficiency in Buildings, Vol. 1, p. 1.197 -1.209. Neme, Chris,John Proctor, and Steve Nadel, "NationalEnergy Savings Potential From AddressingResidential HVAC Installation Problems", February 1999, Prepared as a partof the U. S. Environmental ProtectionAgency's Energy StarProgram. Palami, Manivannan, Dr. Dennis O'Neal, and Dr. JeffHaberl, "The Effect ofReduced Evaporator Air Flow on the Performance of a Residential Central Air Conditioner", Proceedings ofthe Eighth Annual Symposium on Improving BuildingSystems in Hot and Humid Climates, Texas A&M University, May 13 -14, 1992, p. 20

- 26. Parker, Danny S., John R. Sherwin, Richard A. Ranstad, and DonB. Shirey 

### IIt "Impactof Evaporator Coil Airflow in Residential Air-Conditioning Systems", ASHRAE BN-97-2-1, ASHRAE Transactions 1997, v. 103, pt. 2. Patenaude, Andre, "RefrigerationFluid FlowControls and SystemTroubleshooting Guide", ALCO Controls Division, EmersonElectric Company, December 1990. Personal Communications • Sporlan Valve Company • Ako Controls, Buzz Schaeffer, May 30, 2000 • Ako Controls, BuzzSchaeffer, May 31, 2000 Proctor,

### J. P., "Field MeasurementofNew Residential Air Conditioners inPhoenix, Arizona", ASHRAE BN-97-2-2, also ASHRAE Transactions 1997, vol. 103, Pt. 2, p. 406

- 415. Proctor,J. and P. Albright, "Sizing Air Conditioners: IfBigger Is NotBetter, WhatIs?", Home Energy Magazine, Sept./Oct. 1996, p. 13 -18. Proctor,John, Tom Downey, Curtis Boecker, Zinoviy Katsnelson, George Peterson, and Dennis O'Neal., "InvestigationofPeak Load Impacts ofHigh SEER Residential HVAC Units

- Assembly, Testing, and investigation ofa Reduced Peak Load Air Conditioner", Pacific Gas and Electric Company, Research and DevelopmentDepartmentJune, 1996 Rodriquez, Angel Gerardo, "EffectofRefrigerant Charge, DuctLeakage, and Evaporator Air Flow on the High Temperature Performance ofAir Conditioners and HeatPumps", M SThesis, Mechanical Engineering Department, Texas A&M University, August 1995. Rodriquez, Angel G., Dennis L. O'Neal,Joel A. Bain, and Michael A. Davis, "TheEffect of RefrigerantCharge, DuctLeakage, and Evaporator Air Flow onthe HighTemperature Performance ofAir Conditioners and HeatPumps", May 1995, DraftFinal Report, [Submitted to EPRI] Sporlan Valve Company, 206 Lange Drive, Washington, Missouri 63090, (a) Educational Bulletin 10-9Thermostatic Expansion Valves

- Theory ofOperation, Application and Selection, October 1995, (b) EducationalBulletin 10-11 Thermostatic ExpansionValves

- Installation, Field Service and Assembly, September 1996.

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 3-2 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440

# --J):

# 10.-LL/ Bibliography Neal, C. Leon, P. E., "Field Adjusted SEER [SEERFA]

- Residential Buildings: Technologies, Design, and Performance Analysis", Proceedings of 1998 ACEEE Summer Study on Energy Efficiency in Buildings, Vol. 1, p. 1.197 -1.209. Neme, Chris,John Proctor, and Steve Nadel, "NationalEnergy Savings Potential From AddressingResidential HVAC Installation Problems", February 1999, Prepared as a partof the U. S. Environmental ProtectionAgency's Energy StarProgram. Palami, Manivannan, Dr. Dennis O'Neal, and Dr. JeffHaberl, "The Effect ofReduced Evaporator Air Flow on the Performance of a Residential Central Air Conditioner", Proceedings ofthe Eighth Annual Symposium on Improving BuildingSystems in Hot and Humid Climates, Texas A&M University, May 13 -14, 1992, p. 20

- 26. Parker, Danny S., John R. Sherwin, Richard A. Ranstad, and DonB. Shirey 

### IIt "Impactof Evaporator Coil Airflow in Residential Air-Conditioning Systems", ASHRAE BN-97-2-1, ASHRAE Transactions 1997, v. 103, pt. 2. Patenaude, Andre, "RefrigerationFluid FlowControls and SystemTroubleshooting Guide", ALCO Controls Division, EmersonElectric Company, December 1990. Personal Communications • Sporlan Valve Company • Ako Controls, Buzz Schaeffer, May 30, 2000 • Ako Controls, BuzzSchaeffer, May 31, 2000 Proctor,

### J. P., "Field MeasurementofNew Residential Air Conditioners inPhoenix, Arizona", ASHRAE BN-97-2-2, also ASHRAE Transactions 1997, vol. 103, Pt. 2, p. 406

- 415. Proctor,J. and P. Albright, "Sizing Air Conditioners: IfBigger Is NotBetter, WhatIs?", Home Energy Magazine, Sept./Oct. 1996, p. 13 -18. Proctor,John, Tom Downey, Curtis Boecker, Zinoviy Katsnelson, George Peterson, and Dennis O'Neal., "InvestigationofPeak Load Impacts ofHigh SEER Residential HVAC Units

- Assembly, Testing, and investigation ofa Reduced Peak Load Air Conditioner", Pacific Gas and Electric Company, Research and DevelopmentDepartmentJune, 1996 Rodriquez, Angel Gerardo, "EffectofRefrigerant Charge, DuctLeakage, and Evaporator Air Flow on the High Temperature Performance ofAir Conditioners and HeatPumps", M SThesis, Mechanical Engineering Department, Texas A&M University, August 1995. Rodriquez, Angel G., Dennis L. O'Neal,Joel A. Bain, and Michael A. Davis, "TheEffect of RefrigerantCharge, DuctLeakage, and Evaporator Air Flow onthe HighTemperature Performance ofAir Conditioners and HeatPumps", May 1995, DraftFinal Report, [Submitted to EPRI] Sporlan Valve Company, 206 Lange Drive, Washington, Missouri 63090, (a) Educational Bulletin 10-9Thermostatic Expansion Valves

- Theory ofOperation, Application and Selection, October 1995, (b) EducationalBulletin 10-11 Thermostatic ExpansionValves

- Installation, Field Service and Assembly, September 1996.

PG&E TXV ImpactReview DRAFT Oct. 23, 2000 Page 3-2 Proctor Engineering Group, Ltd.

## EE-RM/STD-98.4404 

## 1'5- 

# Lb Bibliography U. S. Department of Energy, Technical Support Document: Energy Efficiency Standards For Consumer Products: Residential Central Air Conditioners and Heat Pumps, November 1999, p. 2

- 3. 

### U. S. Government, Federal Register, Vol. 64, No. 226, Wednesday, November 24, 1999, Proposed Rules Department ofEnergy, Office ofEnergy Efficiency and Renewable Energy, 10CFR Part 430 [Docket No. EE-RM/STD-98-440], pp. 66306

- 66340. www.ari.org/ pr/2000/080700ships.html, "Hot Shipments For Air Conditioning Manufacturers", Ed Dooley, Air-Conditioning &Refrigeration Institute, Koldfax, August 2000.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 3-3 Proctor Engineering Group, Ltd. 

## Bibliography 

## u. S. DepartmentofEnergy, Technical SupportDocument: Energy Efficiency Standards For Consumer Products: Residential Central Air Conditioners and HeatPumps, November 1999, p. 2

- 3. 

## u. S. Government, Federal Register, Vol. 64, No. 226, Wednesday, November 24, 1999, Proposed Rules DepartmentofEnergy, Office ofEnergy Efficiency and Renewable Energy, 10CFRPart430 [DocketNo. EE-RMjSTD-98-440], pp. 66306

- 66340. www.ari.org/pr/2000/080700ships.html. "HotShipments For Air ConditioningManufacturers", Ed Dooley, Air-Conditioning & Refrigeration Institute, Koldfax, August 2000.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 3-3 Proctor Engineering Group, Ltd. 

## Bibliography 

## u. S. DepartmentofEnergy, Technical SupportDocument: Energy Efficiency Standards For Consumer Products: Residential Central Air Conditioners and HeatPumps, November 1999, p. 2

- 3. 

## u. S. Government, Federal Register, Vol. 64, No. 226, Wednesday, November 24, 1999, Proposed Rules DepartmentofEnergy, Office ofEnergy Efficiency and Renewable Energy, 10CFRPart430 [DocketNo. EE-RMjSTD-98-440], pp. 66306

- 66340. www.ari.org/pr/2000/080700ships.html. "HotShipments For Air ConditioningManufacturers", Ed Dooley, Air-Conditioning & Refrigeration Institute, Koldfax, August 2000.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 3-3 Proctor Engineering Group, Ltd.

# DLRAFT U S



## -^ L^ 

### ~DRAFT 1 

## EE-RM/STD-98-440 

# _3o LL 

# GLOSSARY OF TERMS

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page 4-1 Proctor Engineering Group, Ltd. 

# DRAFT GLOSSARY OF TERMS

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page4-1 Proctor Engineering Group, Ltd. 

# DRAFT GLOSSARY OF TERMS

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page4-1 Proctor Engineering Group, Ltd.

# DRAFT EE-RM/STD.98.44 0 

# LL 

# APPENDIX A. METHODOLOGY

Effecton SEER The benefit ofTXVs on the average SEER ofunits was determined by examining the published performance data for identical matched indoor and outdoor units with orifice and with TXV metering devices. 

## Effectat fieldconditions The benefits of TXVs in the performance of air conditioners in off design conditions were estimated in a three-step process. First, laboratory test data for TXV and short tube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existing field data on "off-design" conditions were analyzed and distributions of airflow and amount ofcharge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole population were estimated. 

### Laboratory Test Data for Both Metering Devices There are a limited number of data sets for air conditioners run at incorrect charge, low airflow, and a variety oftest conditions. Available data includes Bain et al. 1995, Proctor et al. 1996, and Rodriquez et al. May 1995. In all cases the largest compilation of data was used to produce the performance equations used in the analysis. In all cases the EER was normalized to the EER at correct charge, normal airflow (taken as 400 cfm per ton wet coil), and the specified indoor / outdoor conditions. Charge Effect on TXV Units The effect of charge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following least squares fit to the data includes 27 observations and all three regression coefficients are significant at the 95% level. EERnorml = 2.289767

- 1.294853 *perchg +1.356132 *LN(perchg) where: EERnorml is the ratio ofthe EER and the maximum EER at those outdoor and air flow conditions perchg is the ratio ofthe installed charge to the correct charge Charge Effect on Short Tube Orifice Units The effect of charge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following least squares fit to the data includes 21 observations and all three regression coefficients are significant at the 95% level. EERnorml =5.082403

- 4.100056 *perchg + 4.619659 *LN(perchg)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-' Proctor Engineering Group, Ltd. 

# DRAFT APPENDIX A. METHODOLOGY

Effect

## on SEER The benefitofTXVs on the average SEER ofunits was determined by examining the published performance data for identical matched indoor and outdoor units with orifice and withTXV metering devices. 

### Effectat 

### field conditions The benefits ofTXVs in the performance of air conditioners in off design conditions were estimated in a three-step process. First, laboratory test data for TXV and shorttube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existing field data on "off-design" conditions were analyzed and distributions of airflow and amount ofcharge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole population were estimated. 

### Laboratory Test Data for Both Metering Devices There are a limited number of data sets for air conditioners run atincorrectcharge, low airflow, and a variety of testconditions. Available data includes Bainet al. 1995, Proctor et al. 1996, and Rodriquez et al. May 1995. In all cases the largestcompilation of data was used to produce the performance equations used in the analysis. In all cases the EER was normalized to the EER at correctcharge, normal airflow (taken as400 dm per ton wet coil), and the specified indoor / outdoor conditions. Charge Effect onTXV Units The effect ofcharge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following least squares fit to the data includes 27 observations and all three regression coefficients are significant at the 95% level. EERnorm1 = 2.289767 -1.294853 

### * perchg +1.356132 

### * LN(perchg) where: EERnorml is the ratio ofthe EER and the maximum EER atthose outdoor and air flow conditions perchg is the ratio ofthe installed charge to the correctcharge Charge Effect on ShortTube Orifice Units The effect ofcharge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following leastsquares fit to the data includes 21 observations and all three regression coefficients are significant at the 95% level. EERnorml =5.082403

- 4.100056 * perchg + 4.619659 

### *LN(perchg)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-I Proctor Engineering Group, Ltd. 

# DRAFT APPENDIX A. METHODOLOGY

Effect

## on SEER The benefitofTXVs on the average SEER ofunits was determined by examining the published performance data for identical matched indoor and outdoor units with orifice and withTXV metering devices. 

### Effectat 

### field conditions The benefits ofTXVs in the performance of air conditioners in off design conditions were estimated in a three-step process. First, laboratory test data for TXV and shorttube orifice equipped air conditioners were analyzed and generalized performance maps were developed. Second, existing field data on "off-design" conditions were analyzed and distributions of airflow and amount ofcharge were determined. Third, the distributions were applied to the performance maps and the resultant differences over the whole population were estimated. 

### Laboratory Test Data for Both Metering Devices There are a limited number of data sets for air conditioners run atincorrectcharge, low airflow, and a variety of testconditions. Available data includes Bainet al. 1995, Proctor et al. 1996, and Rodriquez et al. May 1995. In all cases the largestcompilation of data was used to produce the performance equations used in the analysis. In all cases the EER was normalized to the EER at correctcharge, normal airflow (taken as400 dm per ton wet coil), and the specified indoor / outdoor conditions. Charge Effect onTXV Units The effect ofcharge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following least squares fit to the data includes 27 observations and all three regression coefficients are significant at the 95% level. EERnorm1 = 2.289767 -1.294853 

### * perchg +1.356132 

### * LN(perchg) where: EERnorml is the ratio ofthe EER and the maximum EER atthose outdoor and air flow conditions perchg is the ratio ofthe installed charge to the correctcharge Charge Effect on ShortTube Orifice Units The effect ofcharge on normalized EER was found to be only mildly effected by airflow and outdoor temperatures. The following leastsquares fit to the data includes 21 observations and all three regression coefficients are significant at the 95% level. EERnorml =5.082403

- 4.100056 * perchg + 4.619659 

### *LN(perchg)

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-I Proctor Engineering Group, Ltd.

### EE-RM/STD-98-440.-v 

# /a - L L&- 

### Methodology where: EERnorml is the ratio ofthe EER and the maximum EER at those outdoor and air flow conditions perchg is the ratio of the installed charge to the correct charge Airflow Effect on TXV Units The effect of airflow on normalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equation has been tentatively adopted by ASHRAE 152P committee as describing the effect oflow airflow on normalized EER for TXV units. EERnorm2 = 1.6198

- 0.6198*flowratio + 0.647*LN(flowratio) 

### where: EERnorm2 is the ratio ofthe EER and the maximum EER at those outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 cfm per ton Airflow Effect on Short Tube Orifice Units The effect of airflow on normalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equation has been tentatively adopted by ASHRAE 152P committee as describing the effect oflow airflow on normalized EER on these units. EERnorm2 = 0.65 + 0.35 *flowratio 

### where: EERnorm2 is the ratio of the EER and the maximum EER atthose outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 cfm per ton 

### Field Data on Charge and Airflow Charge Distribution The most extensive data on charge are in the CheckMe!® database. This database is generated from data called into the Proctor Engineering Group offices from technicians working on units in the field. The CheckMe technicians have the following:

· A day of one-on-two field training including measurements for superheat, subcooling, and approach. * Accurate and calibrated tools including a digital electronic refrigerant scale, a two channel digital thermometer, and refrigerant gauges. * Immediate access to technical expertise via a toll free number.

· Immediate checks of the readings and their potential accuracy using a computerized expert system. * Immediate results of charge tests via the computerized expert system.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-2 Proctor Engineering Group, Ltd. 

### EE-RM/STD-98-440..

# it1,5·-**L~** Methodology where: EERnorm1 is the ratio ofthe EER and the maximum EER atthose outdoor and air flow conditions perchg is the ratio ofthe installed charge to the correctcharge Airflow Effect on TXV UnitsTheeffect of airflow onnormalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equation has been tentatively adopted by ASHRAE 152P committee as describing the effect oflow airflow onnormalized EER for TXV units. EERnorm2 = 1.6198

- 0.6198*flowratio + 0.647*LN(flowratio) where: EERnorm2 is the ratio ofthe EER and the maximum EER atthose outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 dm per ton Airflow Effect on ShortTube Orifice UnitsThe effect of airflow on normalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equationhas been tentatively adopted by ASHRAE 152Pcommittee as describing the effect oflow airflow on normalized EER on theseunits. EERnorm2 

### =0.65 + 0.35 *flowratio where: EERnorm2 is the ratio ofthe EER and the maximum EER atthose outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 dm per ton 

### Field Data on Charge and Airflow Charge DistributionThe mostextensive data oncharge are in the CheckMe!® database. This database is generated from data called into the Proctor Engineering Group offices from technicians working on units in the field. The CheckMe technicians have the following: • A day of one-on-two field training including measurements for superheat, subcooling, and approach. • Accurate and calibrated tools including a digital electronic refrigerant scale, a two channel digital thermometer, and refrigerant gauges. • Immediate access to technical expertise via a toll free number. • Immediatechecks ofthe readings and their potential accuracy using a computerized expertsystem. • Immediate results ofcharge tests via the computerized expert system.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-2 ProctorEngineering Group, Ltd. 

### EE-RM/STD-98-440..

# it1,5·-**L~** Methodology where: EERnorm1 is the ratio ofthe EER and the maximum EER atthose outdoor and air flow conditions perchg is the ratio ofthe installed charge to the correctcharge Airflow Effect on TXV UnitsTheeffect of airflow onnormalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equation has been tentatively adopted by ASHRAE 152P committee as describing the effect oflow airflow onnormalized EER for TXV units. EERnorm2 = 1.6198

- 0.6198*flowratio + 0.647*LN(flowratio) where: EERnorm2 is the ratio ofthe EER and the maximum EER atthose outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 dm per ton Airflow Effect on ShortTube Orifice UnitsThe effect of airflow on normalized EER was found to be only mildly effected by charge and outdoor temperatures. The following equationhas been tentatively adopted by ASHRAE 152Pcommittee as describing the effect oflow airflow on normalized EER on theseunits. EERnorm2 

### =0.65 + 0.35 *flowratio where: EERnorm2 is the ratio ofthe EER and the maximum EER atthose outdoor and charge conditions flowratio is the ratio ofthe actual airflow to 400 dm per ton 

### Field Data on Charge and Airflow Charge DistributionThe mostextensive data oncharge are in the CheckMe!® database. This database is generated from data called into the Proctor Engineering Group offices from technicians working on units in the field. The CheckMe technicians have the following: • A day of one-on-two field training including measurements for superheat, subcooling, and approach. • Accurate and calibrated tools including a digital electronic refrigerant scale, a two channel digital thermometer, and refrigerant gauges. • Immediate access to technical expertise via a toll free number. • Immediatechecks ofthe readings and their potential accuracy using a computerized expertsystem. • Immediate results ofcharge tests via the computerized expert system.

PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-2 ProctorEngineering Group, Ltd.

## EE-RM/STD-98-440 

# 4I 

# ' U-. Methodology The initial tests are recorded, and when charge corrections are completed, the amount of refrigerant weighted in (or out) is reported along with the post repair test results. The database contains thousands of tests. These data were analyzed for both initial tests and postrepair tests. The initial tests for non-TXV units showed 30% undercharge, 32% overcharge, and 38% correct charge based on actual superheat within 5°F of the target superheat for the conditions 2



### . Post-repair tests were used to determine the amount ofmischarge for each unit that was offcharge by more than 5%. This produced the distribution of refrigerant charge shown in Figure 3. The initial test data and the post-repair data show the same percentage of correct charge as the average in the Neme (Neme et al. 1999) nationwide analysis. This dataset is the most comprehensive data set available to determine the distribution of refrigerant charge. Airflow Distribution There is less comprehensive data on the distribution of airflow on residential air conditioners and heat pumps. The Neme study summarizes fourteen studies that have some information about airflow across the inside coil. Proctor Engineering was able to analyze data from six studies to determine the standard deviation ofthe airflows. The standard deviations ranged between 16 and 22%. Data from seven studies (some new construction, some existing construction) showed a range of airflows across the coil averaging between 352 and 270 cfm per ton. For existing construction the data points were 270, 300, and 350 cfm per ton (wet coil). This analysis is based on a normal distribution with a standard deviation of 80 cfm per ton and a mean flow of 300 cfm per ton.

2

### Units where the test conditions produced a target superheat of less than 5°F were excluded from the analysis.
PG&E TXV Impact Review DRAFT Oct. 23, 2000 Page A-3 Proctor Engineering Group, Ltd. 

## .... EE-RM/STD-98-440

# -tt

# 13/'L1-- Methodology The initial tests are recorded, and when charge corrections are completed, the amount of refrigerantweighted in (or out) is reported along with the postrepair testresults. The database contains thousands oftests. These data were analyzed for both initial tests and postrepair tests. The initial tests for non-TXV units showed 30% undercharge, 32% overcharge, and 38% correctcharge based on actual superheatwithin 5°F ofthe target superheatfor the conditions2 Post-repair tests were used to determine the amount ofmischarge for each unitthat was offcharge by more than 5%. This produced the distribution ofrefrigerant charge shown in Figure 3. The initial test data and the post-repair data show the same percentage ofcorrectcharge as the average in the Neme (Neme et al. 1999) nationwide analysis. This datasetis the most comprehensive data set available to determine the distribution ofrefrigerantcharge. Airflow DistributionThere is less comprehensive data on the distribution of airflow on residential air conditioners and heatpumps. The Neme study summarizes fourteen studies that have some information about airflow across the inside coil. Proctor Engineering was able to analyze data from six studies to determine the standard deviation ofthe airflows. The standard deviations ranged between 16 and 22%. Datafrom seven studies (somenew construction, some existingconstruction) showed a range of airflows across the coil averaging between 352 and 270 cfm per ton. Forexisting construction the data points were 270, 300, and 350 cfm per ton (wet coil). This analysis is based on a normal distribution with a standard deviation of 80 cfm per ton and a mean flow of300 cfm per ton.

2 Units where the testconditions produced a target superheat of less than 5°F were excluded from the analysis.
PG&E TXV lmpactReview DRAFT Oct. 23, 2000 Page A-3 ProctorEngineering Group, Ltd. 

## .... EE-RM/STD-98-440

# -tt

# 13/'L1-- Methodology The initial tests are recorded, and when charge corrections are completed, the amount of refrigerantweighted in (or out) is reported along with the postrepair testresults. The database contains thousands oftests. These data were analyzed for both initial tests and postrepair tests. The initial tests for non-TXV units showed 30% undercharge, 32% overcharge, and 38% correctcharge based on actual superheatwithin 5°F ofthe target superheatfor the conditions2 Post-repair tests were used to determine the amount ofmischarge for each unitthat was offcharge by more than 5%. This produced the distribution ofrefrigerant charge shown in Figure 3. The initial test data and the post-repair data show the same percentage ofcorrectcharge as the average in the Neme (Neme et al. 1999) nationwide analysis. This datasetis the most comprehensive data set available to determine the distribution ofrefrigerantcharge. Airflow DistributionThere is less comprehensive data on the distribution of airflow on residential air conditioners and heatpumps. The Neme study summarizes fourteen studies that have some information about airflow across the inside coil. Proctor Engineering was able to analyze data from six studies to determine the standard deviation ofthe airflows. The standard deviations ranged between 16 and 22%. Datafrom seven studies (somenew construction, some existingconstruction) showed a range of airflows across the coil averaging between 352 and 270 cfm per ton. Forexisting construction the data points were 270, 300, and 350 cfm per ton (wet coil). This analysis is based on a normal distribution with a standard deviation of 80 cfm per ton and a mean flow of300 cfm per ton.

2 Units where the testconditions produced a target superheat of less than 5°F were excluded from the analysis.
PG&E TXV lmpactReview DRAFT Oct. 23, 2000 Page A-3 ProctorEngineering Group, Ltd.