Post on 26-Feb-2018
7/25/2019 VRF Systems presentation
1/194
VRF Systems: The
Good, The Bad and TheUgly
Mark Hydeman, PE, Principal
Hwakong Cheng, SeniorMechanical Designer
Taylor Engineering, LLC
http://www.taylor-engineering.com
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
7/25/2019 VRF Systems presentation
2/194
Logistics
Safety
Restrooms
Recycling
Cell phone etiquette
Lunch
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 2
Review forms
Webinar etiquette
PG&E Resources
Rebates Tool Lending Library
Marlene Vogelsang (mxv6@pge.com)
7/25/2019 VRF Systems presentation
3/194
Agenda
Topic Speaker(s)
Intro and Overview M Hydeman
BREAK
VRF Manufacturer Perspective R Wilmarth & S Khayatian
BREAK
VRF Design Perspective H Cheng & M Hydeman
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 3
LUNCH
VRF Owner's Perspective T Rabiah
BREAK
VRF Cx Perspective D Sellers
BREAK
Discussion and Wrapup All
7/25/2019 VRF Systems presentation
4/194
Handouts
You can get a copy of the handouts in PDF format asfollows:
Type the following link into your web browser:
http://www.taylor-engineering.com/ftp/PECClassHandouts.html
Click on the link for VRF Systems to download the
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 4
Acrobat file of the presentation.
7/25/2019 VRF Systems presentation
5/194
Speakers
Mark Hydeman, PE, Principal, Taylor Engineering, LLCmhydeman@taylor-engineering.com
Ruben Willmarth, Mitsubishi Electric HVACrwillmarth@HVAC.mea.com
Sherwin Khayatian, Norman S. Wrightskhayatian@norman-wright.com
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 5
Hwakong Cheng, Senior Mechanical Designer, TaylorEngineering, LLChcheng@taylor-engineering.com
Tal Rabiah, PE, Sr. Mechanical Engineer, UCSC
trabiah@ucsc.edu David Sellers, PE, Facility Dynamics
DSellers@FacilityDynamics.com
7/25/2019 VRF Systems presentation
6/194
Introduction
Who are you?
Facility Operations or Engineering
Design Consultant
Contractor
Vendor
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 6
Other
What brings you here?
7/25/2019 VRF Systems presentation
7/194
VRF Systems: The
Good, The Bad and TheUgly
Ruben Willmarth, Regional Mgr.
Mitsubishi Electric, HVAChttp://www.mitsubishipro.com
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
7/25/2019 VRF Systems presentation
8/194
VRF Systems- The Good, The Bad & The Ugly
Two kinds of VRF
The Value of Heat Recovery
Piping
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 2
Economizers & Ventilation
7/25/2019 VRF Systems presentation
9/194
Applications The Bad
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 33
7/25/2019 VRF Systems presentation
10/194
Applications The Ugly
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 44
7/25/2019 VRF Systems presentation
11/194
Two kinds of VRF
Heat Pump or Heat Recovery?
Who do you serve?
Would a 2-pipe Hydronic work here? Or not?
Is it a cooling only application?
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 5
Small zones?
Hotel or Assisted Living?
7/25/2019 VRF Systems presentation
12/194
VRF Heat Pump Technology
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 6
7/25/2019 VRF Systems presentation
13/194
VRF Heat Recovery Technology
Simultaneous cooling and heating
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 7
7/25/2019 VRF Systems presentation
14/194
The Value of Heat Recovery
Comfort = Productivity
The lesser of Heat or Cool is essentially free
Most often occurs between 35F-65F, or with special
applications
New o tions to recover heat for DHW or HHW
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 8
Must always remember it is an applied benefit
7/25/2019 VRF Systems presentation
15/194
VRF Systems Heat Recovery Operation
The Value of Heat Recovery
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 9
7/25/2019 VRF Systems presentation
16/194
What Makes Heat Recovery DifferentSample Building in Part Load: OA Temp 50oF
3000 BTU
3000 BTU
Elect
Janitor
Break RoomLobby/
Waiting Room
ConferenceRoom
Cubicle Area
Open WorkRoom
6000 BTU
12000 BTU
6000 BTU
3000 BTU
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 10
Simultaneous Load:
Cooling: 27000 BTU
Heating: 21000 BTU
3000 BTU
6000 BTU
3000 BTU
Office #1 Office #23000 BTU WomenMen
6 Ton Heat Recovery System
7/25/2019 VRF Systems presentation
17/194
What Makes Heat Recovery Different
Cooling Power Input PURY-P72
5.00
6.00
7.00 72,000
B
6.48
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 11
0.00
1.00
2.00
3.00
4.00
0 12000 24000 36000 48000 60000 72000 84000
System Load BTUH
PowerInputKW
27,000
B
2.38
7/25/2019 VRF Systems presentation
18/194
What Makes Heat Recovery Different
Outdoor Temperature Power Input Correction
(For a 68 Indoor WB Temperature)
2.1000
2.2000
2.3000
2.4000
2.38
95
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 12
1.5000
1.6000
1.7000
1.8000
1.9000
2.0000
0 10 20 30 40 50 60 70 80 90 100
OA Temperature FDB
PowerInputKW
1.87
50
7/25/2019 VRF Systems presentation
19/194
What does this mean
Getting 27,000 BTUH of cooling and 21,000 BTUH of
heating, while providing only 1.87 KW to the outdoor unit.
This savings cannot be realized without the ability to do
simultaneous heating and cooling.
VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
SLIDE
13
,C 25.7
7/25/2019 VRF Systems presentation
20/194
Value of Heat Recovery to Hot Water
72 . C $10,000
A:
C C, B A
72,000 B/=21.1 *8760=184,836 / 100%
VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
SLIDE
14
184,836 $0.10/ 1/1.00 = $18,484 /
.
72,000 B/ 8760/100000 /=6,307.2 /
80%
6,307.2 $1.25/ 1/0.80 = $9,855 /
7/25/2019 VRF Systems presentation
21/194
Piping with VRF Systems
1. Always use type ACR copper piping
2. Always specify brazing with dry Nitrogen
3. Always specify pressure test with dry Nitrogen(550psi)
4. Always specify triple evacuation to
7/25/2019 VRF Systems presentation
22/194
Piping with VRF Systems
A Good installation
VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
SLIDE
16
7/25/2019 VRF Systems presentation
23/194
Piping with VRF Systems
A Good installation
VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
SLIDE
17
7/25/2019 VRF Systems presentation
24/194
Piping The Bad
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1818
7/25/2019 VRF Systems presentation
25/194
Piping The Bad
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1919
7/25/2019 VRF Systems presentation
26/194
Piping The Ugly
No accommodation
for thermal expansion
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 2020
7/25/2019 VRF Systems presentation
27/194
VRF Controls
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 21
7/25/2019 VRF Systems presentation
28/194
VRF Controls- Which to Use?
. &
.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 22
7/25/2019 VRF Systems presentation
29/194
Central Controllers
2000 AC /
VRF Controls- Which to Use?
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 23
CB
Consider when 5-10 Zones or more for easier scheduling
Use for remote access, alerts, IPhone, etc.
40
C C
7/25/2019 VRF Systems presentation
30/194
VRF Controls- Which to Use?
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 24
7/25/2019 VRF Systems presentation
31/194
VRF Controls- Which to Use?
1. B,
, C,
2. A C B,
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 25
. .
C
7/25/2019 VRF Systems presentation
32/194
Economizers with VRF
They are available, but are they a benefit?
Offsets Heat
Recovery energy
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 26
Can increase
fan energy
Can Model in
Energy Pro
7/25/2019 VRF Systems presentation
33/194
Economizers with VRF
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 27
7/25/2019 VRF Systems presentation
34/194
15% Distributed OSA
Pair of 12 Dia. Ducts
Ventilation with VRF Systems
1. C C/
2. C/ (DA)
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 28
Air
30 Diameter
Ductwork
15% Central OSA
Single 16Dia Duct
1200 CFM
Space required to deliver 20 tons of cooling
7/25/2019 VRF Systems presentation
35/194
.
Ventilation with VRF Systems
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 29
7/25/2019 VRF Systems presentation
36/194
( !)
Ventilation with VRF Systems
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 30
7/25/2019 VRF Systems presentation
37/194
Questions
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 31
7/25/2019 VRF Systems presentation
38/194
VRF Systems: The
Good, The Bad and TheUgly
Sherwin Khayatian, MBA
Norman S. Wright MEC
http://www.norman-wright.com
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
7/25/2019 VRF Systems presentation
39/194
VRF Design Pitfalls
1. Over Zoning the Floor Plan One Fan Coil, Separate Point of Changeover per Room
2. Heat Pump versus Heat Recovery Applications
Picking the Right # of Changeover Points
Grouping Fan Coils on a Common Point of Changeover3. Heat Recovery: Establishing Cooling Only Zones
Comfort Cooling and Process Cooling
4. Zone Controller Application and Misconceptions
5. Centralized Controller. The Best Money you ever spent. Is a Separate BAS even required?
If so, what functions should a 3rd party BAS provide?
7/25/2019 VRF Systems presentation
40/194
VRF Design Pitfalls - Over Zoning the Floor Plan
One Fan Coil, Separate Point of Changeover per Room This is the Most Expensive Configuration possible
o This is usually a requirement for Hotel Guest Rooms
Multiple Fan Coils on a Common Point of Changeover
This can shave some costs and in some cases is an appropriatesolution for Office Spaces .
o This can be done so long as the Capacity of the ChangeoverDevice is not exceeded (i.e. No more than 8 Tons of Fan Coils perPoint of Changeover; Heat Pumps Points can be even bigger)
o This is good design practice when you have multiple fan coils
serving a common zone (i.e. Fan Coils should change over fromHeat to Cool and vice versa together as a group)
o Can also be considered for fan coils serving partitioned spaces thatshare a common load profile (i.e. Individual offices on sameexposure). This will reduce equipment costs.
7/25/2019 VRF Systems presentation
41/194
Single Floor Office Example 10,000 ft office space
4 open plan office spaces, 8 single offices & a server room Office Space has a peak load of 26 tons & block load of 20 tons
Server room has a 2 ton load
Engineer assumes that customer needs individual temperature control in each room
*
.
.
.
.
.
.
.
.
7/25/2019 VRF Systems presentation
42/194
Typical Office Example
As the customer is looking for temperature control per zone this would mean
a fan coil & branch selector box per indoor unit
This is an effective, efficient solution but can increase first cost
Approximate VRV installed cost 110%
0
BSVQ36
BSVQ
36
BSVQBSVQBSVQBSVQ
60606060BSVQBSVQBSVQBSVQ
36363636
BSVQ
36
BSVQ
36
BSVQ
36
BSVQ
36
7/25/2019 VRF Systems presentation
43/194
Typical Office Example
Combining indoor units in the same heat/cool changeover zone onto a common branch selector box
provides the most cost effective solution and meet the customers needs This reduces overall equipment and installation costs
Approximate VRV installed cost 78%
0
BS
BSVQ
96
7/25/2019 VRF Systems presentation
44/194
Typical Office Example
The most cost effective solution for this would be to zone the system as you would a VAV system
This reduces overall equipment and installation costs Approximate Installed Cost 73%
This does not meet the customers requirements of temperature control per zone
BSVQ
36
BSVQ
60BSVQ
0
7/25/2019 VRF Systems presentation
45/194
VRF Design Pitfalls
Heat Pump versus Heat Recovery Applications Picking the Right # of Changeover Points Grouping Fan Coils on a Common Point of Changeover
For Grouping, similar concept as Fan Coils on a CommonBSVQ for a Heat Recovery System
Heat Pump Systems can be up to 30% lower cost than Heat
Recovery Systems e care u no o cross zones; n o as a or pe
o Do not serve both Interior and Perimeter on the Same System
o Each System is a Point of Changeover; Changeover Routineshould be discussed before hand to insure customer buy-in
o Smaller Systems allow for more points of changeover and easier
retrofits Heat Pumps are typically used for Cool Only Applications
Heating Operation Mode can be locked using Dip Switch Settingsor with Controls
7/25/2019 VRF Systems presentation
46/194
VRF Design Pitfalls Cool Only Zones
Heat Recovery: Establishing Cooling Only Zones Comfort Cooling and Process Cooling
Process Cooling
Do you really want your 2 Ton Server Room on your 20 TonHeat Recovery System? Think about your House VAV, CW
o Benefit: Can Potentially Recover Heat Absorbed in Process Areao Benefit: Less Equipment
For Colder Ambient Climates, add BSVQ as PRD
Not a given; Each Design and System is Unique
What if majority of Comfort Zones are Interior? After Hours?
o Cons: Significant Additional Run Hours on Expensive HouseSystem
Would a separate Split System, VRF, or RTU with Economizerbe a better option with VRF Fan Coil as backup only?
7/25/2019 VRF Systems presentation
47/194
VRF Design Pitfalls Cool Only Zones
Heat Recovery: Establishing Cooling Only Zones Comfort Cooling and Process Cooling
Comfort Cooling
Is the Makeup Air Tempered or does the Design incorporate
Heat Reclaim Ventilation? If so, ventilation loads are fully or
present for certain occupied zones.
Potential for Design without Point of Heat/Cool Changeover
o Design can eliminate BSVQ Box and save costs, reduce units
o With VRF technology, the Expansion Valve can shut in Coolingso that there is no Coil Capacity when satisfied
o This is quite different from the typical Single Duct VAV
installation
7/25/2019 VRF Systems presentation
48/194
Single Floor Office Example
The most cost effective way is to design around heat pumps, right?
This project consists of 4 main heat cool changeover zones
This would mean 3 VRV heat pump outdoor units & a Split System
Approximate VRV Installed Cost = 100% (this will be used as the baseline cost)
A heat recovery system best suits this project as one outdoor unit can be utilized to match the loads
Does this mean we can now connect the server room to the VRV system?
No, this should be connected to a single split system (this is true of all VRV/VRF systems!)
o A VRV indoor unit can however be used as a back up
*
7/25/2019 VRF Systems presentation
49/194
Typical Office Example
Eliminating Unnecessary BSVQs reduces costs and equipment
Just Branch off Liquid and Suction Main Only
BSVQ
36
BSVQ
60BSVQ
0
7/25/2019 VRF Systems presentation
50/194
VRF Design Pitfalls - Controls
Zone Controller Application and Misconceptions
Zone Controller is Not Necessary
o Yes, Control can be strictly centralized
o However, it is Better to use a Zone Controller (Service Functions)
Functionality can be restricted from the Centralized Device
o BAD Idea: Trying to use 3rd Party Zone Controls
This is possible and has been done successfully
o Most Instances required additional coordination
Unnecessary Costs; Requires Skilled Programmer
Zone Controller is Point of Temperature Sensing
o Not Always the Case; This is Configurable on Some models
Grouping Fan Coils onto a Common Point of Zone Controlo Simplifies Control and Eliminates Unnecessary Costs
o Considerations: How to View at Central Level, How to Sense andReport Zone Temperature for Control and Monitoring Purposes
7/25/2019 VRF Systems presentation
51/194
VRF Design Pitfalls - Controls
Centralized Controller. The Best Money you ever spent. Is a Separate BAS even required? It really depends.
o 3rd Party BAS is very costly especially if full control integration isrequired
o Can a Central Controller provide enough functionality?
3rd
Party Equipment Start/Stop Scheduling, Status, Interlocks en ra on ro er s es gne y qu pmen anu ac urer so
you get all the controllable points and some basic routines
If a requirement, what functions should 3rd party BAS provide?
o Scheduling, Monitoring Only? Custom Routines? Interlocks?
Centralized Controllers can provide many beneficial features Zone Controller Restrictions, More Custom Changeover
Routines, Remote Monitoring/Control and Alarm Reporting
7/25/2019 VRF Systems presentation
52/194
Other Things to Watch Out For When Designing A
VRV Solution
Things that can lead to Poor Comfort Poor zoning
Over connecting capacity to an outdoor unito Is there diversity in the building?
Wrong type of indoor units
Over sizin units oor tem erature control
Return air sensor positiono Is outside air integrated to the indoor unit?
Things that can lead to a Project going Over Budget
Too many, or wrong indoor unit type. Too many zones on heat recovery unit
Oversized units
7/25/2019 VRF Systems presentation
53/194
Questions
7/25/2019 VRF Systems presentation
54/194
VRF Systems: The
Good, The Bad and TheUgly
Hwakong Cheng
Senior Mechanical Designer
Taylor Engineering, LLC
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
7/25/2019 VRF Systems presentation
55/194
Designer Perspective
Agenda System Selection Zoning and system layout Pipe Sizing and Layout
Refrigerant Management
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 2
Code Compliance Controls Integration
Limitations Photos
7/25/2019 VRF Systems presentation
56/194
System Selection
Ducted vs Ductless(but still need ventilation)
Heat Pum vs Heat
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 3
Recovery Systems
Air vs Water-cooledcondensing units
7/25/2019 VRF Systems presentation
57/194
Heat Pump System Type
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 4
7/25/2019 VRF Systems presentation
58/194
Simultaneous Heating & Cooling
Cool Morning
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 5
N
7/25/2019 VRF Systems presentation
59/194
Simultaneous Heating & Cooling
Cool Afternoon
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 6
N
7/25/2019 VRF Systems presentation
60/194
Pipe Sizing and Layout
Pipe length, effective pipelength, vertical height, and
overall system pipe length
limitations
Reduced capacity with longer
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 7
Prescriptive pipe sizing from
manufacturer (selection
software)
7/25/2019 VRF Systems presentation
61/194
Pipe Sizing and Layout
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 8
0
7/25/2019 VRF Systems presentation
62/194
Pipe Sizing and Layout
Pressure testing
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 9
7/25/2019 VRF Systems presentation
63/194
Refrigerant Management
VRF lots of refrigerant
ASHRAE Stds 15/34, CMC Ch 11
R-410A: Safety group A1
25 lb / 1000 cubic feet410
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 10
7/25/2019 VRF Systems presentation
64/194
Refrigerant Management
Example:
Ductless fan coils operable
windows
System charge: 48.3 lb R410A
Normal room: 16x15x10 = 2400 cf
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 11
Smallest room: 16x10x10 = 1600 cf
Catastrophic discharge into
smallest room:
48.3 lb / 1600 cf = 30.1 lb / 1000 cf
Above limit of 25 lb / 1000 cf!
7/25/2019 VRF Systems presentation
65/194
Refrigerant Management
Possible solutions:
Permanent openings
Door louver/undercuts
Transfer air grilles
Transfer fan
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 12
Connected duct systems
7/25/2019 VRF Systems presentation
66/194
Refrigerant Management
LEED EAc4 Enhanced Refrigerant Management
R-410 high global warming potential GWP =1890(GWP of CO2 = 1)
Look at: Lbs/ton, GWP, leakage rate, lifespan
LEED Credit EAc4 difficult to achieve
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 13
Refrigerant in rated corridors
7/25/2019 VRF Systems presentation
67/194
Coordination with other trades
Electrical power to each:
fan coil
branch controller / branch selector
condensing unit
Plumbin :
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 14
condensate from eachfan coil, branchcontroller
may be over sensitive
ceilings, electricalequipment
piping may need to besloped
7/25/2019 VRF Systems presentation
68/194
Code Compliance
24 ( 6)
1230
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 15
/
7/25/2019 VRF Systems presentation
69/194
Controls Integration
Stand-alone controls
Scheduling
Setpoint control
Monitoring / Feedback
Web access
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 16
BMS system integration
BACnet/LonWorks
7/25/2019 VRF Systems presentation
70/194
Limitations
Humidity control
Fan pressure
Limited control of airside pressure drop
Watch PD for ducted systems
Standard filters ~ MERV 4
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 17
Sound
7/25/2019 VRF Systems presentation
71/194
Limitations
Airside Economizer
35
40
45
110
120
130
140
150
160
170
Hu
35
40
45
120
130
140
150
160
170
H
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 18
Weather Hours
0 to 1
0 to 1
0 to 1
0 to 1
0 to 1
0 to 1
0 to 1
0 to 1
0 to 1
-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110
0
5
10
15
20
25
30
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
10
20
30
40
50
60
70
80
90
100
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
idityRatio,grains/lbofdryair
Dry-Bulb Temperature, F
NOYES
Return Air
Supply Air
Return Air
Supply Air
Weather Hours
117 to 105
104 to 92
91 to 79
78 to 66
65 to 53
52 to 40
39 to 27
26 to 14
13 to 1
-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110
0
5
10
15
20
25
30
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
10
20
30
40
50
60
70
80
90
100
Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com
umidityRatio,grains/lbofdryair
Dry-Bulb Temperature, F
Return Air
San Francisco
Weather
7/25/2019 VRF Systems presentation
72/194
Limitations
Airside Economizer
aftermarket option forducted systems
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 19
7/25/2019 VRF Systems presentation
73/194
Photos
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 20
7/25/2019 VRF Systems presentation
74/194
Photos
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 21
7/25/2019 VRF Systems presentation
75/194
Questions
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 22
7/25/2019 VRF Systems presentation
76/194
VRF Systems: The
Good, The Bad and TheUgly
Tal Rabiah, PE
Physical Planning & Construction
UC Santa Cruz
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 1VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
7/25/2019 VRF Systems presentation
77/194
Overview
1. Existing Installations
2. Pros and Cons
3. Outdoor
4. Indoor
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 2
.
Plumbing
HVAC
Maintenance
Design
7/25/2019 VRF Systems presentation
78/194
1. Existing Installations (past 7 years)
University of Michigan (Ann Arbor, MI)
N. Campus Recreational Sports Building
o 2-story building; 32 tons
Central Campus Printing Building
o 3-story building; 64 tons
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 3
Central Campus Recreational Building
o 3-story building; 24 tons
7/25/2019 VRF Systems presentation
79/194
1. Existing Installations (past 7 years)
University of California-Santa Cruz
Communication Building
o Cell phone areas; 16 tons
Communication Building
o Computer areas; 16 tons
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 4
UC Santa Cruz Extension
o Santa Clara Computer Labs; 8 tons
7/25/2019 VRF Systems presentation
80/194
2. Pros and Cons of VRF Systems
Pros:
A VRF system is possibly more suitable for coolingupgrades in existing buildings than chilled water system
since the VRF has less than 1/4th the pipe size. The VRF
system may even be a preferable alternative to the
extension of an existin chilled water s stem to a new
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 5
building or building addition.
VRF is possibly the best option for systems with fewer than100 tons of cooling capacity.
7/25/2019 VRF Systems presentation
81/194
2. Pros and Cons of VRF Systems
Pros (con't) :
The new 100% outside air fan coil unit for VRFs is asignificant advancement in the application of VRF system
in make-up air and laboratory HVAC applications where
100% outside air is required.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 6
simpler to design, operate and maintain by eliminating
cooling tower, boiler, pumps and chemical treatment.
7/25/2019 VRF Systems presentation
82/194
2. Pros and Cons of VRF Systems
Pros (con't) :
VRF offers simultaneous cooling and heating on the samepiping network through the use of heat pump and heat
recovery systems with automatic changeover.
All brazed cooper piping system for more corrosion and
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 7
.
Long refrigerant piping lengths to accommodate manytypes of applications.
7/25/2019 VRF Systems presentation
83/194
2. Pros and Cons of VRF Systems
Pros (con't) :
Low operating sound levels-58 dB at full load for outdoorunit and 25dB for indoor unit.
Water balancing is eliminated and air balancing issimplified.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 8
u a e or cre s on energy e c ency an ecompliant.
Capacities are AHRI certified.
7/25/2019 VRF Systems presentation
84/194
2. Pros and Cons of VRF Systems
Cons: VRF is a proprietary system. Mixing of parts from different
VRF manufacturers is not possible.
Operates at 530 psig which is considered very highpressure piping system inside a building, which makes leak
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 9
.
Is suitable for certain heights and sizes of buildings.
7/25/2019 VRF Systems presentation
85/194
2. Pros and Cons of VRF Systems
Cons (con't) : Occupancy sensors are not provided as part of the
system.
Maintenance accessibility for Branch Selectors andBranch Controllers is required.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 10
an on y e ns a e an ma n a ne y ra nepersonnel.
Few manufacturers are available which leads to lessercompetition.
7/25/2019 VRF Systems presentation
86/194
2. Pros and Cons of VRF Systems
Cons (con't) : System lifetime is not yet as predictable as the hydronic
systems.
Is not widely known by U.S. HVAC designers.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 11
7/25/2019 VRF Systems presentation
87/194
3. Outdoor Installation
For roof installation provide spring-type vibration isolatorswith lateral restraints. Bolt isolators onto a 4 thick
concrete pad and onto bottom of condensing unit.
Do not use wooden or sheet metal roof curbs under
units.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 12
On grade, install unit on a 4 concrete curb with
neoprene or cork isolators bolted to bottom of unit and to
concrete curb.
7/25/2019 VRF Systems presentation
88/194
Outdoor Installation cont
- Use vibration isolators
Roof: spring-type
Grade: neoprene
Bolt to concrete pad
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 13
NO wood curbs
NO sheet metal curbs
Units shall be braced so that they will not
7/25/2019 VRF Systems presentation
89/194
Units shall be braced so that they will not
laterally tilt due to high winds.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 14
Pi i th h f h ld b
7/25/2019 VRF Systems presentation
90/194
Piping through roof should be run
through a pipe roof curb with flashing
around it.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 15
7/25/2019 VRF Systems presentation
91/194
Flexible Connection
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 16
When vibration isolators are provided,
provide 6 long flexible braided copper
connector on refrigerant piping that connectsto the unit. Do not bend flexible connectors
excessively.
7/25/2019 VRF Systems presentation
92/194
Provide a services ball-type shut-off valve
with a charging port at the connection to the
unit.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 17
Insulation refrigeration lines with
7/25/2019 VRF Systems presentation
93/194
Insulation refrigeration lines with
thick closed-cell foam insulation.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 18
Piping should be supported every 6 feet or
7/25/2019 VRF Systems presentation
94/194
Piping should be supported every 6 feet or
less without pinching insulation.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 19
H. Follow manufacturers instructions regarding the amount of
7/25/2019 VRF Systems presentation
95/194
g g
required open space around the units to allow for adequate air
movement.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 20
7/25/2019 VRF Systems presentation
96/194
Do not allow suspension rods, ducts, or conduits
to touch the piping (to avoid electrolysis).
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 21
7/25/2019 VRF Systems presentation
97/194
Weather coat the outdoor insulation of piping with a
weather-resistant PVC coating. Valves should have
removable and re-installable covers.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 22
7/25/2019 VRF Systems presentation
98/194
Labeling
Label piping on roof with weather-resistant
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 23
pipe labels including directional arrows. Alsolabel condensing units with the equipmentnumbers of the indoor evaporator units thatthey serve. Follow ANSI A13.1 standards.
Clean condenser fins where there is vegetation
7/25/2019 VRF Systems presentation
99/194
Clean condenser fins where there is vegetation
buildup on the condenser tubing fins.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 24
I d I t ll ti
7/25/2019 VRF Systems presentation
100/194
Indoor Installation
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 25
7/25/2019 VRF Systems presentation
101/194
Connect the ceiling supported unit to duct through a 4
long flexible connection. Do not allow kinks in the flexible
connection.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 26
7/25/2019 VRF Systems presentation
102/194
Seismic Supports
See manufacturer instructions
See local codes
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 27
7/25/2019 VRF Systems presentation
103/194
Condensate Waste
Prefer gravity flow
Use a trap
Provide secondary
drain i e
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 28
Or: heavy-duty withredundant pump
Connect the ceiling supported unit to duct through a 4
7/25/2019 VRF Systems presentation
104/194
long flexible connection. Do not allow kinks in the flexible
connection.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 29
7/25/2019 VRF Systems presentation
105/194
Condensate Drain Pan
Provide drain pan
under unit separate
from the evaporator
unit drain pipe.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 30
If condensate pumps
are used put in drain
pan.
Example of unit discharge ductwork from a
7/25/2019 VRF Systems presentation
106/194
Example of unit discharge ductwork from a
plenum box.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 31
Assure that filters, unit control panel, and fan
7/25/2019 VRF Systems presentation
107/194
, p ,
motor are all easily accessible for periodic
maintenance or replacement.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 32
Recommendations
7/25/2019 VRF Systems presentation
108/194
Recommendations
Plumbing HVAC
Maintenance
Design
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 33
Plumbing Recommendations
7/25/2019 VRF Systems presentation
109/194
Plumbing Recommendations
Read the fine print with regard to limitations of pipinglength. The length specified is the total equivalent pipe
length.
Confirm pressure testing of pipes at 600 psig for 24
hours.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 34
3. The VRF system typically operates in the 300-400 psig
range, making leak protection essential.
HVAC Recommendations
7/25/2019 VRF Systems presentation
110/194
HVAC Recommendations
A BacNet or Lonworks device is required to connect theVRF controls to the rest of your building or campus
control system. This device will allow you to monitor the
VRF system, but not control it.
If there are many confined spaces served by the VRF
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 35
,
alarms may be required in order to meet ASHRAE
standards 15 and 34.
Maintenance Recommendations
7/25/2019 VRF Systems presentation
111/194
Maintenance Recommendations
The VRF system is a complete proprietary packagedsystem, including its own related controls, except for the
refrigerant piping.
You cannot intermix parts from the different
manufacturers of the VRF system.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 36
System maintenance requires an experienced refrigerant
technician who is familiar with applicable codes related to
refrigerants, leak detection, and ventilation requirements.
Maintenance Recommendations
7/25/2019 VRF Systems presentation
112/194
Maintenance Recommendations
When selecting a VRF system for your building, selectcontractors that are trained and qualified to install this
system. Select a contractor who has experience
pressure testing refrigerant piping which has been
pressurized up to 600 psig.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 37
- ,
therefore quality of brazing, evacuating, and pressure
testing can affect the VRF system performance
Maintenance Recommendations
7/25/2019 VRF Systems presentation
113/194
Maintenance Recommendations
Provide easy access to units on roof (not through anaccess hatch or a catwalk).
For the maintenance program, allow inspection of units
every three (3) months.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 38
Design Recommendations
7/25/2019 VRF Systems presentation
114/194
Design Recommendations
When comparing a VRF system to other air conditioningsystems, compare it to the 4-pipe fan coil system, or to a
water source heat pump system. Keep in mind the
systems lifetime and maintenance costs.
If outdoor installation is within a mile of the ocean, or if
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 39
,
coatings on unit exterior finish and on condenser copper
tubing and fans.
Coordinate unit color selection with the architect.
Aesthetics can be especially important at someinstallations.
Questions
7/25/2019 VRF Systems presentation
115/194
Questions
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY SLIDE 40
VRF Systems: The David Sellers, PE, Senior
7/25/2019 VRF Systems presentation
116/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY JUNE 2 2011
VRF Systems: The
Good, The Bad and The
Ugly
The Commissioning
Perspective
Engineer
Facility Dynamics Engineering
NW Satellite Office
www.FacilityDynamics.com
The Commissioning Providers Perspective
http://www.facilitydynamics.com/http://www.facilitydynamics.com/7/25/2019 VRF Systems presentation
117/194
Corporate Perspective
Limited VRF Exposure Some Daikin and some Mitsubishi
No tests developed in our
commissioning database
One system designed by a senior
engineer in a past life (about 15years ago in the Air Force)
Several people can hardly wait to
get inside a branch controller/point
of change-over
On person about to take factory
training
Early Commissioning Providers
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 2
The Commissioning Providers Perspective
7/25/2019 VRF Systems presentation
118/194
Personal Perspective
One new construction and oneretrocommissioning project with
Mitsubishi VRF equipment (both
current projects)
Exposure to built up direct
expansion systems since 1976
o Dual mode system serving anice rink in winter and building
loads in the summer (See
Mentoring Field Technicians; A
Learning Experience for
Everyone Involved;
Proceedings - NCBC 2009)
o Various commercial and
process projects
Early Commissioning Providers
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 3
Commissioning Process Goals
7/25/2019 VRF Systems presentation
119/194
New Construction
s
Verify:
Installed performance
Design intent achieved
Enable persistence
o Documentation
Commissioning record
System Manual
o Train the staff
Try not to go crazy
Have fun
Retrocommissioning* (MBCx
program context)
Develop facility baselines
Identify and assess energy
efficiency opportunities
Coordinate with the Owner to
implement improvements
Verify goals are achieved
Enable persistence
Documentation
o Pre and post baseline reports
o Train the staff
Have Fun
A.K.A. Existing Building Commissioning, EBCx, RCx,
Recommissioning, Monitoring Based Commissioning,
Building Tune-up, and, when I first started, operating the
building properly
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 4
Typical Issues
7/25/2019 VRF Systems presentation
120/194
Cx/EBCx
Access/Serviceability
Occupant satisfaction
Installation does not comply with
Manufacturer or industry standards
Implementation of complex
technology difficult to achieve inreal world environments
Installation does not reflect design
intent
Integration
Optional/2nd party equipment Other HVAC processes
Control systems
Persistence
VRF Experience to Date
Access/Serviceability
Occupant satisfaction
Installation does not comply with
Manufacturer or industry standards
Implementation of complex
technology difficult to achieve inreal world environments
Installation does not reflect design
intent
Integration
Optional/2nd party equipment Other HVAC processes
Control systems
Persistence
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 5
Access and ServiceabilityDuring Construction
7/25/2019 VRF Systems presentation
121/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 6
Access and ServiceabilityAfter Construction
7/25/2019 VRF Systems presentation
122/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 7
Simple Constant Volume AHU System Diagram
7/25/2019 VRF Systems presentation
123/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 8
VRF System Diagram
7/25/2019 VRF Systems presentation
124/194
Electronic expansion valve, variable speed
fan, filters, economizer dampers and related
controls above a 10 foot semi-hard ceiling
Ceiling plenum, shafts, and other
building structure provide reliefpath
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 9
The Actual VRF System Diagram
7/25/2019 VRF Systems presentation
125/194
10
To existing constant
volume reheat
zones
Filter Access
7/25/2019 VRF Systems presentation
126/194
Filter Access Door:Typical access interval
Open once every
6 to 12 months to
change filters
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 11
Filter Access
7/25/2019 VRF Systems presentation
127/194
DDC Panel:Typical rewire and/or
recommission interval
Once every 6 to
12 months if
mounted on filter
access door
Once every 6 to
12 years if
mounted
somewhere else
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 12
Branch Controller Technologyhttp://www.mylinkdrive.com/CityMulti/Software/CM_Refrigerant_Flow/
7/25/2019 VRF Systems presentation
128/194
Image courtesy Mitsubishi Refrigerant Flow
Demonstrator; Used with Permission
13
Branch Controller Technologyhttp://www.mylinkdrive.com
7/25/2019 VRF Systems presentation
129/194
Image courtesy Mitsubishi PRUY Service
Instruction; Used with Permission
14
Branch Controller Technology
http://www.mylinkdrive.com
7/25/2019 VRF Systems presentation
130/194
Recommended
access opening
nominally 18 x
18 Small to mediumtechnical person - 20
Image courtesy
Mitsubishi
PRUY Service
Instruction;
Used with
Permission
15
Branch Controller Installed Location
7/25/2019 VRF Systems presentation
131/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 16
Branch Controller Installed Location
7/25/2019 VRF Systems presentation
132/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 17
Branch Controller Installed Location
7/25/2019 VRF Systems presentation
133/194
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 18
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
134/194
Image courtesy Mitsubishi PRUY Service Instruction; Used with Permission
19
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
135/194
20
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
136/194
21
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
137/194
Image courtesy Mitsubishi PRUY Service Instruction;
Used with Permission
22
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
138/194
Typical service welding equipment
Image courtesy Mitsubishi PRUY Service Instruction;
Used with Permission
23
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
139/194
Image courtesy Mitsubishi PRUY Service Instruction;
Used with Permission
24
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
140/194
Image
courtesy
Mitsubishi
PRUY
Service
Instruction;
Used with
Permission 25
Branch Controller Service Procedures
7/25/2019 VRF Systems presentation
141/194
Image
courtesy
Mitsubishi
PRUY
Service
Instruction;
Used with
Permission26
Installation Practices
7/25/2019 VRF Systems presentation
142/194
Refrigerant piping installation practice critical to short and
long term system integrity General requirements no different from those employed
with any built up refrigeration system
Details associated with R410 systems may vary from
standard practice in the field at this point in time
27VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Cleanliness Is EssentialCleaned and Capped
7/25/2019 VRF Systems presentation
143/194
Cleaned to an ASTM
established limit for residue
Purged with dry nitrogen Sealed with rubber plugs with
positive nitrogen pressure
inside the tuber
Continuous nitrogen purge
necessary during installation
Maintains factory cleanedand capped integrity
Prevents contamination by
the oxides and residuals
produce by brazing
Mitsubishi recommendsbrazing temporary caps on
pipes that are not connected at
the end of the day
Used to be Cleaned
and Capped
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 28
Cleanliness Is Essential
7/25/2019 VRF Systems presentation
144/194
Moisture and refrigerant dont work welltogether
Corrosion Ice
Refrigerant oil problems
Motor problems
Cleaned and Capped
Used to be Cleaned
and Capped
29VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Cleanliness Is Essential
7/25/2019 VRF Systems presentation
145/194
Dirt and precision machinery dont workwell together
Moving parts in compressors Small orifices in metering and control
valves and lubrication system
Chemical reactions with oil andrefrigerant
Cleaned and Capped
Used to be Cleaned
and Capped
30VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Field Joints
7/25/2019 VRF Systems presentation
146/194
Field joints are made using a frustum of right circular
cone
31
Image
courtesy
Mitsubishi
PRUY
Service
Instruction;
Used with
Permission
Field Joints
7/25/2019 VRF Systems presentation
147/194
Field joints are made using a 45SAE Flare joint
Operating Pressures
Refrigerant Low Side High Side
R22 55-70 psig 180 - 260 psig
R410 95 - 135 psig 305 - 410 psig
32
Image
courtesy
Mitsubishi
PRUY
Service
Instruction;
Used with
Permission
Field Joints
7/25/2019 VRF Systems presentation
148/194
33VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Field Joints
7/25/2019 VRF Systems presentation
149/194
34VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Flaring Tools; Theyre Not All Created Equal
http://www.ridgid.com/ASSETS/BEDAF5C9AC504029A6264034BF58D1D5/458R_Ratchet_Flaring_Tool_3C.jpg7/25/2019 VRF Systems presentation
150/194
Conventional flaring tools
press the flare onto the end of
the tube
Recommended flaring tool rolls
the flare onto the end of the
tube
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 35
Images courtesy www.ridgid.com/; Used with Permission
Either way: Metal to metal sealing mechanism
Lubricate flare before tightening
Tightening the Connection
http://www.ridgid.com/ASSETS/BEDAF5C9AC504029A6264034BF58D1D5/458R_Ratchet_Flaring_Tool_3C.jpghttp://www.ridgid.com/ASSETS/9F672F49DF3E4A54B01B4361F7D5292B/345_Flaring_Tool_3C.jpg7/25/2019 VRF Systems presentation
151/194
Lubricate with a refrigerant compatible oil
Use two wrenches
Use specified torque values
36VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Torque Wrenches, Flare Nut Wrench and CrowsFoot
7/25/2019 VRF Systems presentation
152/194
37VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Tightening the Connection
7/25/2019 VRF Systems presentation
153/194
Easier accomplished on the bench than in the air
Factory line sets minimize field flares
38VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Vibration and Stress Relief
7/25/2019 VRF Systems presentation
154/194
39VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Flare
Flare
Branch controller support per
Mitsubishi requirements
Rigid support nominally with-in
20 per Mitsubishi requirements
Vibration and Stress Relief
7/25/2019 VRF Systems presentation
155/194
40VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Relative motion still possiblewith out sway bracing
Refrigerant Oil
7/25/2019 VRF Systems presentation
156/194
R22 systems use mineral oil as a lubricant
R410A systems use an ester oil, either ether oil oralkylbenzene
Using the wrong oil can cause sludge and other problemsleading to failure
Tools use on R22 systems can be contaminated withmineral oil and should not be used on R410A systems
Contamination can lead to sludge and other problems
R410 oil is an order of magnitude more hygroscopic than
R22 oil
41VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Connecting to Existing Branch Controllers
7/25/2019 VRF Systems presentation
157/194
Concern on the part of the new project contractor
regarding unknown quality of the previous contractorswork
Pipe installation practice
System evacuation and charging practice
Low charge in existing system due to leakage
Near Azeotropic refrigerant compounds the problem
42VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Azeotrope
7/25/2019 VRF Systems presentation
158/194
A mixture made up of two or more refrigerants with
similar boiling points that act as a single fluid. Thecomponents of azeotropic mixtures will not separate
under normal operating conditions and can be charged
as a vapor or liquid
43VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Definitions from the National Refrigerants web site; http://www.refrigerants.com/frame.htm
Near Azeotrope
7/25/2019 VRF Systems presentation
159/194
A mixture made up of two or more refrigerants with
different boiling points that, when in a totally liquid orvapor state, act as one component. However, when
changing from vapor to liquid or liquid to vapor, the
individual refrigerants evaporate or condense at different
temperatures. Near-azeotropic mixtures have atemperature glide of less than 10 F and should be
charged in the liquid state to assure proper mixture (non-
azeotropic) composition
44VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Definitions from the National Refrigerants web site; http://www.refrigerants.com/frame.htm
Zeotrope
7/25/2019 VRF Systems presentation
160/194
A mixture made up of two or more refrigerants with
different boiling points. Zeotropic mixtures are similar tonear-azeotropic mixtures with the exception of having a
temperature glide greater than 10 F. Zeotropic mixtures
should be charged in the liquid state
45VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Definitions from the National Refrigerants web site; http://www.refrigerants.com/frame.htm
Control Sensor Installation
Damper face velocity = 800 fpm
7/25/2019 VRF Systems presentation
161/194
Damper face velocity 800 fpm
Mixing plenum depth = 39
Do you think the mixed air
Sensor is really measuring
The mixed temperature?
46VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Single Point Mixed Air
Sensor LocationOutdoor
Air
Return
Air
VRF Fan Coil
Dampers
Economizer Outdoor Air Enthalpy Change-over Sensor
7/25/2019 VRF Systems presentation
162/194
47VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Economizer Outdoor Air Enthalpy Change-over Sensor
7/25/2019 VRF Systems presentation
163/194
48VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Economizer Outdoor Air Enthalpy Change-over Sensor
7/25/2019 VRF Systems presentation
164/194
49VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Economizer Outdoor Air Enthalpy Change-over SensorAre there any issues with this enthalpy
7/25/2019 VRF Systems presentation
165/194
y py
sensor installation given:
The duct is the outdoor air duct The sensor is lying
on the bottom ofthe duct,unsecured
50VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
7/25/2019 VRF Systems presentation
166/194
The Improved installationImage courtesy Brian Nixon
51VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
7/25/2019 VRF Systems presentation
167/194
The Improved installationImage courtesy Brian Nixon
52VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
7/25/2019 VRF Systems presentation
168/194
The Improved installationImage courtesy Brian Nixon
53VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
; THE
COMMISSIONING
PERSPECTIVE
VRF Unit Economizer Design Intent
Provide an economizer cycle Position to full return air if the VRF
7/25/2019 VRF Systems presentation
169/194
Provide an economizer cycle
No mechanical cooling until the
economizer is on 100% outdoor air(Code requirement; integratedeconomizer)
Supplement the outdoor air coolingas required (Code requirement;integrated economizer)
Continue to use outdoor air until theoutdoor air is not suitable for cooling(Code requirement; integratedeconomizer)
Use minimum outdoor air if theoutdoor air enthalpy is not suitablefor cooling (Code requirement;
integrated economizer) Do not heat until the economizer is
on minimum outdoor air (i.e. nosimultaneous heating and cooling)
Position to full return air if the VRFsystem is off (critical given the OA
source) Use no outdoor air in warm-up mode
if the space is not occupied
Use outdoor air in the cool-downmode only if outdoor air is suitablefor cooling
Minimum outdoor air flow matchescontract document requirements forminimum occupancy and maximumoccupancy
The demand controlled ventilationsystem can over-ride thetemperature based control of the
economizer cycle if necessary tomaintain adequate ventilation.
VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
; THE
COMMISSIONING
PERSPECTIVE
54
Design Intent Documentation
R i d th VRF it h d l
7/25/2019 VRF Systems presentation
170/194
Required accessory on the VRF unit schedule
Code compliance required
Economizer supplier uses Honeywell W7212 which:
Can perform integrated economizer cycle (but also can doa non-integrated economizer cycle
Can do warm-up/cool down if configured properly
Can close the dampers when the system is off if configuredproperly
Can do either/or demand controlled ventilation cycle
o Minimum occupancy air flow if CO2 below threshold
o Maximum occupancy air flow if CO2 above threshold
55VRF SYSTEMS
: THE
GOOD
, THE
BAD AND
THE
UGLY
; THE
COMMISSIONING
PERSPECTIVE
Design Intent Documentation vs. Intent
Provide an economizer cycle Position to full return air if the VRF
Covered by Documents
7/25/2019 VRF Systems presentation
171/194
y
No mechanical cooling until the
economizer is on 100% outdoor air(Code requirement; integratedeconomizer)
Supplement the outdoor air coolingas required (Code requirement;integrated economizer)
Continue to use outdoor air until theoutdoor air is not suitable for cooling(Code requirement; integratedeconomizer)
Use minimum outdoor air if theoutdoor air enthalpy is not suitablefor cooling (Code requirement;
integrated economizer) Do not heat until the economizer is
on minimum outdoor air (i.e. nosimultaneous heating and cooling)
system is off (critical given the OA
source) Use no outdoor air in warm-up mode
if the space is not occupied
Use outdoor air in the cool-downmode only if outdoor air is suitablefor cooling
Minimum outdoor air flow matchescontract document requirements forminimum occupancy and maximumoccupancy
The demand controlled ventilationsystem can over-ride thetemperature based control of the
economizer cycle if necessary tomaintain adequate ventilation.
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 56
Covered by Code
Covered by Code
Covered by Code
Covered by Code
Covered by W7212 if Implemented
Covered by W7212 if Implemented
Covered by W7212 if Implemented
Covered by Documents; Probably
requires TAB RFI to clarify
Covered by W7212 if Implemented
Economizer Procurement
VRF Fan coil unit provided by Economizer mixing box
7/25/2019 VRF Systems presentation
172/194
VRF Fan coil unit provided by
1st party
Includes wiring harness for
economizer interface
Economizer package provided
by 2nd party
Includes generic wiringdiagram
Capable of a number of
change over strategies
Economizer mixing box and
controls provided by a 3rd party
Includes multiple product
specific data sheets with a
wide range of capability
Economizer mixing box
installed by a 4th party
Economizer controls installed
by a 5th party
Economizer must interface to a
building wide automation
system by a 6
th
party to dodemand controlled ventilation
Verification of design intent by
a independent 7th party
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 57
The Result: The Economizer Doesnt Work
Conf sion regarding the pre f nctional testing
7/25/2019 VRF Systems presentation
173/194
Confusion regarding the pre-functional testing
requirements Must reference:
Contract documents (contractor charged with developingand executing start-up and functional tests with spot
checks by the Cx provider after completion) Economizer package documents (generic in nature)
Economizer controller documents (product specific innature but no project specific details)
Control system submittals (retransmits demand controlledventilation signal and BACnet interface)
California energy code (very thick book)
58VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Generic Economizer Package Documents
7/25/2019 VRF Systems presentation
174/194
No wiring or check out information in one set of instructionsbut a lot of product specific information
Generic wiring and a cut and paste check out procedure in adifferent set of instructions but no product specific information
Both use a clicks on economizer change over switch as abasis of design
59VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Generic Economizer Package Documents
In the normal Berkeley
7/25/2019 VRF Systems presentation
175/194
In the normal Berkeley
climate, it would be
possible for a clicks-onwith the tolerances
shown to disable the
economizer in the
afternoon of the first day
of August and not re-enable it until September
some time
60
Generic Economizer Package Documents
There are many days in
7/25/2019 VRF Systems presentation
176/194
There are many days in
many other months were
the same thing couldhappen (the light green
band on the graphs is
the normal range)
61
Product vs. Project Specific Wiring Information
7/25/2019 VRF Systems presentation
177/194
62
Honeywell documentation includes wiring diagrams for 9
applications None are Mitsubishi systems
None are VRF systems 2010 Honeywell International Inc.; Used with permission
The Actual VRF System Diagram
7/25/2019 VRF Systems presentation
178/194
63
To existing constant
volume reheat
zones
Outdoor air provided by an economizerequipped constant volume reheat system
VRF zones are variable volume and require
system control strategy change
VRF zones potentially interactive with each
other and constant volume zones
Must balance economizer benefits with
reheat penalty
VRF dampers currently not interlocked to
close with VRF shut down
Conflicting Sensor Location Information
Discharge air vs mixed air
7/25/2019 VRF Systems presentation
179/194
Discharge air vs. mixed air
Either will work but discharge airlocation will cause the
economizer to generally
function like a non-integrated
economizer
Bad for maximizing energysavings
Good for compressorreplacement costs in
packaged equipment with
limited or no turn-downcapability
64VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
2010 Honeywell International Inc.; Used with permission
Economizer Controller to VRF Control Integration
W7212 designed
7/25/2019 VRF Systems presentation
180/194
g
to interlock with
the mechanicalcooling and keep
it off until the
economizer has
a chance to work
Economizerpackage wiring
diagram shows
no interlocks
Field wiring for
intelock is there,but wheres it
going?
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 65
Economizer Controller to VRF Control Integration
W7212 is
7/25/2019 VRF Systems presentation
181/194
capable of a
warm-up andcool-down cycle
(design intent)
but currently is
not wired for it
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 66
The Actual VRF System Diagram
7/25/2019 VRF Systems presentation
182/194
67
To existing constant
volume reheat
zones
Main AHU schedules are provided by thebuilding wide control system
VRF schedules are provided by the VRF
control system
Currently no communication of schedules
between the two systems
Occupant Satisfaction
7/25/2019 VRF Systems presentation
183/194
68VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Space temperature
drifts up 2F in about 1
hour and 30 minutes
then is
driven
back down
2F below
set pointin about
20
minutes
Three out of four
zones sampled at
random so far are
doing this
Occupant Satisfaction
7/25/2019 VRF Systems presentation
184/194
69VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Meanwhile the pneumatic and chilled
water technology that is being replacedby the VRF systems floated around with-
in the throttling range of the controller
during the same time period Two out of two
pneumatic zones
sampled atrandom were
working this way
Throttling Range
Technology Can Have its Limitations
VRF systems have turndown capability but not below
7/25/2019 VRF Systems presentation
185/194
VRF systems have turndown capability but not below
about 20-25% of capacity Subject to issues related to over-sizing just like any
other approach
If the peak load potential in a zone is unknown, thenyou know what you dont know
o Consider the minimum load potential
Seasonal load profile
Daily load profile
o
Address the current reality with provisions for thefuture potential
o Make sure you understand the details of thetechnology you are about to embrace
70VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Occupant Satisfaction
7/25/2019 VRF Systems presentation
186/194
71VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Comfort aside, this could
be costing energy in the
form of unnecessary
dehumidification
Note room dew point
dropping below
outdoor air dew point
The Machinery Can Be Made to Work
7/25/2019 VRF Systems presentation
187/194
72VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
But it Requires Attention to Detail
7/25/2019 VRF Systems presentation
188/194
73VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
And Taking the Time to Integrate Things
7/25/2019 VRF Systems presentation
189/194
74VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Integration; The Commissioning Perspective
Integrate the equipment into a
working system
7/25/2019 VRF Systems presentation
190/194
working system
Verify design intent in the shortterm
Ensure its persistence in the
long term
Integrate all the players into a
team to identify and solve
problems
Bring new technology into the
mainstream
Understand how it should work Address prototypical issues
Ensure it things keep working
for the life of the systemEarly Commissioning Providers
VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE 75
National Refrigerantswww.refrigerants.com
7/25/2019 VRF Systems presentation
191/194
76
Principles of Refrigeration by Roy Dossat
Complex principles in understandable terms
7/25/2019 VRF Systems presentation
192/194
77VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Trane Refrigeration Manual
Other Resources
7/25/2019 VRF Systems presentation
193/194
http://www.trane.com/Commercial/Dna/View.aspx?i=492 Copeland Refrigeration Manual
http://www.emersonclimate.com/en-us/brands/pages/copeland.aspx
http://lvhvac.com/cope_bulletins/aeIndex.pdf
Sporlan Valve
http://www.sporlanonline.com/literature.shtml
Mueller Brass
http://www.muellerindustries.com/
ASHRAE Journal
Variable Refrigerant Flow Systems by William Goetzler, April 2007;www.ashrae.org
78VRF SYSTEMS: THE GOOD, THE BAD AND THE UGLY; THE COMMISSIONING PERSPECTIVE
Questions
http://www.trane.com/Commercial/Dna/View.aspx?i=492http://www.emersonclimate.com/en-us/brands/pages/copeland.aspxhttp://lvhvac.com/cope_bulletins/aeIndex.pdfhttp://www.sporlanonline.com/literature.shtmlhttp://www.muellerindustries.com/http://www.ashrae.org/http://www.ashrae.org/http://www.muellerindustries.com/http://www.sporlanonline.com/literature.shtmlhttp://lvhvac.com/cope_bulletins/aeIndex.pdfhttp://www.emersonclimate.com/en-us/brands/pages/copeland.aspxhttp://www.trane.com/Commercial/Dna/View.aspx?i=4927/25/2019 VRF Systems presentation
194/194