seminar 5 free cooling for water source heat pump systems v2 · 2017-01-03 · 60°f ewt 12 gpm...
TRANSCRIPT
1
Brian MeneghanSpecifying EngineeringCarrier Corporation
© Carrier Corporation 20157/10/15 / SEM005 Ver. 1.1
In order to receive a certificate and professional development hoursfor this symposium you must:
1. Sign the symposium attendance sheet, which demonstrates that youhave attended the symposium.
This will be passed around the room at the start of the symposium.
Certificates cannot be issued without your signature on this sheet.Print legibly so that information can be easily verified.
2. During the symposium, demonstrate participation by answering theassessment questions. These are self-graded.
3. Complete the EvaluationAt the end of the symposium, you must also complete the evaluation.
4. If you are a P.E. in New York, North Carolina, or Florida, sign theappropriate sheet with your P.E. number for that state.If your P.E. is in North Carolina, fill out the additional NC evaluation form.
Turn in the Evaluation to the moderator.Certificates will be delivered to you after the symposium.
PROFESSIONAL DEVELOPMENT CREDITS
2
OBJECTIVES
At the end of this seminar you should be able to:
1. Select from a list of options the types of WSHPsystems
2. Identify the difference in integrated and non-integrated economizers
3. Select the benefits of waterside economizers forenergy savings
4. Select the application conditions for whenwaterside economizer should be used
5. Identify for a given climate zone if watersideeconomizer is required
3
AGENDA
4
• Water Source Heat Pump (WSHP) SystemOverview
• WSHP Waterside Economizer Overview
• WSHP Waterside Economizer DesignConsiderations
• ASHRAE 90.1 and Waterside Economizers
• Summary
INTRODUCTION TO WSHP
6
Water Source Heat Pump OverviewWater to Air Heat Pump: packaged air to water unit that provides bothheating and cooling of air by absorbing heat from or rejecting heat to awater loop.
INTRODUCTION TO WSHP
7
Water Source Heat Pump Overview
Cooling Mode Heating ModeHeat Absorbed from Supply Air
Heat from Air Rejected to Condenser LoopCompressor Heat Rejected to Condenser Loop
Heat Absorbed from Condenser LoopHeat from Loop Rejected to Supply Air
Compressor Heat Rejected to Supply Air
INTRODUCTION TO WSHP
8
Water Source Loop Overview
Adds Heat
Adds HeatRemoves
Heat
Removes Heat
Ideal System: Heat Added = Heat Removed
Sometimes Heat Added > Heat Removed
Sometimes Heat Added < Heat Removed
Photo Source: Carrier HAP v4.9
INTRODUCTION TO WSHP
9
Water Loop Heat Adders and Rejecters
Photo Source: FHP Manufacturing
Boiler and Fluid Cooler
• Boiler adds heat, Fluid Cooler reject heat
• 68°F - 86°F typical loop temperature(Standard Range)
Geothermal
• Ground absorbs or adds heat to loop
• Ground or Lake/Pond Loop (Closed Loop)
• Ground Water Loop (Open Loop)
• Hybrid with Boiler or Tower
Hybrid System (Geo and Tower)
INTRODUCTION TO WSHP
10
Boiler and Tower Loop Overview
Photo Source: Carrier HAP v4.9
Rejects Heat from Loop
Adds Heat to Loop
Typical Loop Temp:Heating: 68°FCooling: 86°F
When Heat Added > Heat Removed
When Heat Removed > Heat Added
Standard Range Loop
INTRODUCTION TO WSHP
11
Typical Geothermal Loop (Ground Loop)
Photo Source: Carrier HAP v4.9
Absorbs Heat from Loop
Adds Heat to Loop
When Heat Added > Heat Removed
When Heat Added > Heat Removed
Typical Loop Temp:Depends on
Location
Extended Range Loop
QUESTION #1
12
A Water Source Heat Pump provides heating by:
A. Absorbing heat from a water loop and rejecting it to thesupply air stream
B. Absorbing heat from the supply air stream andrejecting it to the water loop
C. Hot gas reheat
D. None of the above
INTRODUCTION TO WSHP
13
Warm Weather Loop Overview
Photo Source: FHP Manufacturing
Cooling Loop Temperature:
*Cooling Loop Temperature:
86ºF
* Loop temperature depends on location
Heat Added > Heat removed
INTRODUCTION TO WSHP
14
Cold Weather Loop OverviewHeating Loop Temperature:
*Heating Loop Temperature:
68ºF
Heat Removed > or ≤ Heat RemovedPhoto Source: FHP Manufacturing* Loop temperature depends on location
INTRODUCTION TO WSHP
15
Cold Weather Loop: Cooling Dominant Building
Photo Source: FHP Manufacturing
Heat Added ≥ Heat Removed(Cooling Load > Heating Load)
INTRODUCTION TO WSHP
16
Cold Weather Loop: Cooling Dominant Building
Photo Source: FHP Manufacturing
Cooling Load Exceeds or Equals Heating Load• Typically core vs. perimeter zones• Specialty (high load) cooling load areas
Heating Systems to Absorb from Loop• Perimeter zones during cold months• WSHP DOAS unit during cold months (if equipped)
Water Cooled System and Cool Environment• Heat is easily rejected to environment• Cold air can absorb heat and some moisture• Cool earth can absorb heat
INTRODUCTION TO WSHP
17
Cold Weather Loop
Photo Source: FHP Manufacturing
Maintain Low Loop Temperature40°F-60°F
WSHP WATERSIDE ECONOMIZER
19
What is a Waterside Economizer?
• Economizer, water or waterside: asystem by which the supply air of acooling system is cooled indirectly withwater that is itself cooled by heat ormass transfer to the environmentwithout the use of mechanical cooling.
• -ASHRAE 90.1-2013
Source: ASHRAE Standard 90.1-2013
WSHP WATERSIDE ECONOMIZER
20
Waterside Economizer Types
Chiller Bypass Supply Air Precooling
Water Precooling
Water to Water Systems Water to Air Systems
Source: ASHRAE 90.1 Users Guide
WSHP WATERSIDE ECONOMIZER
21
WSHP Waterside Economizer Overview
Photo Source: Carrier Corporation
WSHP with Supply Air Precooling Economizer Package:
• An air to water coil, mounted upstream of the DX coil
• A water control valve and piping, to direct water to the economizer coil
• An aquastat or other water control device to control the water valve
• Condensate drain pan
Economizer Coil
Control Valve
Aquastat & ValveActuator
Airflow Extended Range Kit(Insulated externaland internal piping)
Economizer WaterPiping
WSHP WATERSIDE ECONOMIZER
22
WSHP Waterside Economizer Operation• When possible, the environment is
allowed to absorb enough heat toproduce cold loop water
• When the loop temperature is lowenough, the chilled loop water isdirected to the economizer coil
• The cold loop water passing through thecoil and absorbs heat from air passingthrough the coil
• Reduces or eliminates the mechanicalcooling load, providing a “free” cooling Water Cooled System with Supply
Air Precooling Economizer
Source: ASHRAE 90.1 Users Guide
QUESTION #2
23
Which type of Waterside Economizer is typically used inWater Source Heat Pump systems?
A. Chiller bypass
B. Supply air pre-cooling
C. Water pre-cooling
D. Fan cycling
WSHP WATERSIDE ECONOMIZER
24
Waterside Economizer Capacity
Waterside Economizer Coil Capacity• Coils typically sized to provide 90% capacity at 45°F EWT
• Entering water temperature greatly impacts capacity
• Integrated economizers allow for higher water temps to be utilized
Economizer Airside Pressure Drop• Constant airside pressure drop
• Adds to fan energy consumption
Economizer Waterside Pressure Drop• Variable waterside pressure drop
Photo Source: Carrier Corporation
WSHP WATERSIDE ECONOMIZER
25
Waterside Economizer Capacity
Numbers based on the average of three industries manufacturers
Unit Size 1 Ton 2 Ton 3 Ton 4 Ton 5 Ton
Avg. Capacity (Tons) 0.99 1.98 2.65 4.08 4.79
Unit Size 1 Ton 2 Ton 3 Ton 4 Ton 5 Ton
Avg. P.D. (in. wg.) 0.11 0.15 0.16 0.18 0.24
Unit Size 1 Ton 2 Ton 3 Ton 4 Ton 5 Ton
Avg. P.D. (ft. wt.) 0.99 3.09 4.65 4.21 5.06
Average Economizer Waterside Pressure Drop
Average Economizer Airside Pressure Drop
Average Economizer Capacity
All data based on 80°F/67°F entering coil air temperature at 400 CFM/tonand 45°F entering water temperature at 3 GPM/ton
WSHP WATERSIDE ECONOMIZER
26
Waterside Economizer Capacity
Source: Carrier Corporation 50PC Performance Data
2To
nU
nit
Entering WaterTemperature (°F)
Total CoolingCapacity (MBH)
% of NominalCapacity
40 26.6 114%
45 22.1 94%
50 17.5 75%
60 10.8 46%
4To
nU
nit
Entering WaterTemperature (°F)
Total CoolingCapacity (MBH)
% of NominalCapacity
40 52.9 110%
45 43.2 90%
50 34.1 71%
60 20.16 42%
All data based on: 400 CFM/Ton airflow, 80.6°F/66.2°F entering coilair temperature and 3 GPM/Ton condenser water flow.
90+% of nominal capacity at 45°F EWT 40%+ Capacity with 60°F Water
WSHP WATERSIDE ECONOMIZER
27
WSHP Waterside Economizer TypesIntegrated Economizer
• Allows mechanical cooling wheneconomizer is enabled, economizeracts as a cooling stage
• Economizer piped in series withcondenser
• Multi-stage control
Non-Integrated Economizer
• Mechanical cooling isdisabled when economizer isenabled
• Economizer may be piped inseries or parallel
• Single stage control
Photo Source: Carrier Corporation
WSHP WATERSIDE ECONOMIZER
28
Waterside Economizer Capacity
Source: Carrier Corporation 50PC Performance Data
2To
nU
nit
Entering WaterTemperature (°F)
Total CoolingCapacity (MBH)
% of NominalCapacity
40 26.6 114%
45 22.1 94%
50 17.5 75%
60 10.8 46%
4To
nU
nit
Entering WaterTemperature (°F)
Total CoolingCapacity (MBH)
% of NominalCapacity
40 52.9 110%
45 43.2 90%
50 34.1 71%
60 20.16 42%
All data based on: 400 CFM/Ton airflow, 80.6°F/66.2°F entering coilair temperature and 3 GPM/Ton condenser water flow.
No
n-
Inte
gra
ted
Inte
gra
ted
Inte
gra
ted
No
n-
Inte
gra
ted
DESIGN CONSIDERATIONS
29
Waterside Economizer Example
Non-Integrated EconomizerIntegrated Economizer
ExampleNominal 4 Ton Unit, Standard Efficiency
1400 CFM, 0.4” ESP, PSC Fan80°F/67°F EAT
60°F EWT12 GPM
Economizer Capacity: 16.4 MBHEconomizer LAT: 69.6°F/63.2°F
Mechanical Cooling Capacity: 50.4 MBHMechanical Cooling LAT: 49.1°F/48.1°F
Total Capable Capacity: 66.8 MBH
Example:Nominal 4 Ton Unit, Standard Efficiency
1400 CFM, 0.4” ESP, PSC Fan80°F/67°F EAT
60°F EWT12 GPM
Economizer Capacity: 16.4 MBHEconomizer LAT: 69.6°F/63.2°F
Mechanical Cooling Capacity: 0 MBHMechanical Cooling LAT: 69.6°F/63.2°F
Total Capable Capacity: 16.4 MBH
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
WSHP WATERSIDE ECONOMIZER
30
WSHP Economizer Waterflow Diagram
Economizer Disabled
Shut Off Solenoid (Optional)Temperature Bulb
WatersideEconomizer Coil(Water to Air)
Loop Water In
Aquastat
3 WayMotorized
Control Valve
Condenser Coil(Refrigerant to
Water)
Loop Water Out
45°
50°F
WSHP WATERSIDE ECONOMIZER
31
WSHP Economizer Waterflow Diagram
Economizer Enabled
45°
Shut Off Solenoid (Optional)Temperature Bulb
WatersideEconomizer Coil(Water to Air)
Loop Water In
Aquastat
3 WayMotorized
Control Valve
Condenser Coil(Refrigerant to
Water)
Loop Water Out
45°F
WSHP WATERSIDE ECONOMIZER
32
Waterside Economizer Airflow Diagram
Loop Water In
Loop Water Out
Loop Water In
Loop Water Out
Loop Water In
Loop Water Out
Mechanical Cooling Mode
(Economizer Disabled)
Economizer Only Mode(Integrated or Non-
Integrated)
Economizer andMechanical Cooling
(Integrated Only)
Airflow Airflow Airflow
QUESTION #3
33
An Integrated Economizer allows for the simultaneousoperation of the following:
A. Economizer and mechanical cooling
B. Economizer and exhaust fan
C. Mechanical cooling and heating
D. Mechanical cooling and exhaust fan
WSHP WATERSIDE ECONOMIZER
34
Waterside Economizer System Example
Photo Source: Carrier Corporation
ExampleBuilding CoreGeothermal Loop(6) 2 Ton WSHPsECM Fan Motors800 CFM Each6 GPM Each45°F Loop Temperature
Fan Hours: 500Cooling Hours: 500Pump Hours: 1000
Compare systems with WSEand without WSE
1 2
3 4
5 6
WSHP WATERSIDE ECONOMIZER
35
Example System without Waterside Economizer
System Performance withoutWaterside Economizer
Zone Fan Energy(kWh)
Compressor(kWh)
1 100 337
2 100 337
3 100 337
4 100 337
5 100 337
6 100 337
Total: 600 2022
Unit AirsidePressure Drop
Unit WatersidePressure Drop
Pump Energy(kWh)
0.4 8.4 117555°F45°F
5 6
3 4
1 2
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
WSHP WATERSIDE ECONOMIZER
36
Example System with Waterside Economizer
System Performance withWaterside Economizer
Zone Fan Energy(kWh)
Compressor(kWh)
1 120 0
2 120 0
3 120 0
4 120 0
5 120 0
6 120 0
Total: 720 0
Unit AirsidePressure Drop
Unit WatersidePressure Drop
Pump Energy(kWh)
0.6” 12.6 ft. 125052°F45°F
1 2
3 4
5 6
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
WSHP WATERSIDE ECONOMIZER
37
Waterside Economizer Benefits
Cost Savings• Energy savings from reduced mechanical cooling load
• Energy savings from reduced heat rejection system range
• Eliminate head pressure control (extended range systems)
• Potential to extended mechanical equipment life
Code Compliance• Local codes requirements
• ASHRAE 90.1
• LEED ® (energy efficiency)
Photo Source: Green IT LEED® is a registered trademark of the U.S. Green Building Council ®.
QUESTION #4
38
What is the main benefit of using Waterside Economizerson WSHP systems?
A. Energy savings
B. Reduced fan energy usage
C. Reduced waterside pressure drop
D. Reduced airside pressure drop
WSHP WATERSIDE ECONOMIZER
39
Waterside Economizer Impacts
Increased Airside Pressure Drop
• Waterside economizer adds to pressure drop at all times
• Increased ESP means higher fan energy consumption
• Supply fan may need to be upsized
Increased Waterside Pressure Drop
• Waterside economizer coil adds to waterside pressure drop,when active
• When inactive, the WSE controls also add to watersidepressure drop
• Increased waterside pressure means higher pump energyconsumption
• Pumps may need to be upsized
WSHP WATERSIDE ECONOMIZER
40
Waterside Economizer System Impacts
Photo Source: FHP Manufacturing
Potential Increase in System Heating Energy Consumption• Low loop temperature decreases WSHP heating capacity
• Unit may need to be upsized or add ancillary heating
• Heat of compressor is not added to loop from mechanical cooling
Potential Increase in Water Usage• Evaporation from Evaporative Fluid Cooler
• Minimized by using Dry Cooler when possible
WSHP WATERSIDE ECONOMIZER
41
Economizer Comparison (on WSHP System)
Airside Economizer
IAQ Negative• Can introduce poor quality air into the
space
• Will reduce indoor RH levels during lowambient conditions
High Cost Impact• High installation cost (not typically
available factory installed on WSHP units)
• High installation cost
• Complex control equipment
Waterside Economizer
IAQ Neutral• Does not introduce poor quality air
into the space
• Does not reduce indoor RH levelsduring low ambient conditions
Low Cost Impact• Typically low/medium cost (when
factory installed)
• Minimal additional installation cost
• Simple control equipment
Ideal Application: Waterside Economizer Energy Savings isGreater than Energy Increase• Must be able to take advantage of economizer
• Airside and waterside energy increase
• Heating energy increase (if any)
Water Loop Low Temperature Capability
Waterside Economizer Operating Hours
Minimize System Impact• Airside, waterside, and heating
APPLICATION CONSIDERATIONS
43Photo Source: dreamstime.com
Waterside Economizer Application
44
Water Loop Low Temperature Capability
Photo Source: FHP Manufacturing
APPLICATION CONSIDERATIONS
Ideal Waterside Economizer Loop Temperature• 50 - 100% of nominal capacity
• Integrated economizer: 40-60°F
• Non-integrated economizer 40-45°F
Geothermal Systems• Location solar load determines loop temperature capability
• Local factors and loop sizing impact loop temperature
Fluid Cooler Systems• Evaporative fluid cooler (cooling towers) or dry coolers
• Local climate determines loop temperature capability
45
Geothermal Water Loop Temperature
Photo Source: Don Penn Consulting, 2002
Zones 1-3Low Loop Temperatures
Rare
Zones 4-5Low Loop Temperatures
Some of the Year
Zones 6-7Low Loop Temperatures
Most of the Year
APPLICATION CONSIDERATIONS
7
6
5
3
4
2
1
46
Fluid Coolers Overview
Photo Carrier Corporation
APPLICATION CONSIDERATIONS
Dry Cooler (Fluid Cooler)
• Heat Transfer• Loop temperature depends on
ambient dry bulb temperatureand selected dry-cooler range
• No evaporation = no water loss
Evaporative Cooling Tower
• Mass & Heat Transfer• Loop temperature depends on
ambient wet bulb temperatureand selected tower approach
• Low loop temperature approachmay differ from design approach
• Evaporation = water loop loss
47
Fluid Cooler Loop Temperature Capability
Photo Source: US Department of Energy
APPLICATION CONSIDERATIONS
Zones 1-2Loop Temperature Too
High for WatersideEconomizer
Zones 3-5Acceptable Loop
Temperature For WSE withCooling Tower
Zones 6-7Ideal Loop Temperature forWSE with Cooling Tower or
Dry Cooler
Assumes appropriately sized equipment forapplication range and approach
48
Low Loop Temperature HoursRecommend 20%+ Annual Hours at Low Loop Temperatures
• Offset airside & waterside pressure drop
• Offset heating energy increase for standard range (boiler & tower)
• Achievable in Mild and Cold Climates
• Dependent on loop type, heat rejecter type, and economizer type
Photo Source: FHP Manufacturing
APPLICATION CONSIDERATIONS
49
Sample Economizer Operating Hours
Photo Source: US Department of Energy
Chicago, IL
Charlotte, NC
Miami, FL
Typical Annual Operating Hours: 4000
APPLICATION CONSIDERATIONS
Zones 1-3Low Loop Temperatures
Rare
Zones 4-5Low Loop Temperatures
Some of the Year
Zones 6-7Low Loop Temperatures
Most of the Year
GrandRapids
50
Potential Waterside Economizer Hours (Chicago, IL)
Good application for Waterside Economizer with Cooling Tower or Dry Cooler
Loop Temp < 45°F: 1274 Hours (32%)
Loop Temp < 60°F: 1761 Hours (44%)
Dry Cooler (10°F Range)
Loop Temp < 45°F: 1761 Hours (32%)
Loop Temp < 60°F: 2573 Hours (65%)
Cooling Tower (7°F Approach)
0
50
100
150
200
250
300
350
400
-7°F
-2°F
2°F
7°F
12
°F
17
°F
22
°F
27
°F
32
°F
37
°F
42
°F
47
°F
52
°F
57
°F
62
°F
67
°F
72
°F
77
°F
82
°F
87
°F
92
°F
Dry Bulb Bin Hours
0
50
100
150
200
250
300
350
400
-8°F
-0°F
0°F
5°F
10
°F
14
°F
19
°F
24
°F
29
°F
33
°F
37
°F
42
°F
45
°F
50
°F
53
°F
59
°F
61
°F
66
°F
69
°F
71
°F
74
°F
Wet Bulb Bin Hours45°F 60°F
45°F 60°F
Loop Temp < 45°F: 2000 Hours (50%)
Loop Temp < 60°F: 4000 Hours (100%)
Geothermal
APPLICATION CONSIDERATIONS
51
Potential Waterside Economizer Hrs. (Charlotte, NC)
Good application for Waterside Economizer with Cooling Tower
Loop Temp < 45°F: 304 Hours (7%)
Loop Temp < 60°F: 983 Hours (24%)
Dry Cooler (10°F Range)
Loop Temp < 45°F: 799 Hours (20%)
Loop Temp < 60°F: 1737 Hours (43%)
Cooling Tower (7°F Approach)
Loop Temp < 45°F: 500 Hours (25%)
Loop Temp < 60°F: 2000 Hours (50%)
Geothermal0
100
200
300
400
500
600
Dry Bulb Bin Hours
45°F 60°F
0
100
200
300
400
500
600
Wet Bulb Bin Hours
45°F 60°F
APPLICATION CONSIDERATIONS
52
Potential Waterside Economizer Hours (Miami, FL)
Poor application for Waterside Economizer
Loop Temp < 45°F: 0 Hours (0%)
Loop Temp < 60°F: 160 Hours (3.4%)
Dry Cooler Performance
Loop Temp < 45°F: 0 Hours (0%)
Loop Temp < 60°F: 136 Hours (3.4%)
Cooling Tower Performance
Loop Temp < 45°F: 0 Hours (0%)
Loop Temp < 60°F: 0 Hours (0%)
Geothermal Performance0
200
400
600
800
1000
1200
1400
47°F 52°F 57°F 62°F 67°F 72°F 77°F 82°F 87°F 92°F
Dry Bulb Bin Hours
45°F 60°F
0
200
400
600
800
1000
1200
1400
43°F 47°F 51°F 56°F 61°F 65°F 70°F 73°F 76°F 77°F
Wet Bulb Bin Hours
45°F 60°F
APPLICATION CONSIDERATIONS
0
100
200
300
400
500
Wet Bulb Bin Hours
0
100
200
300
400
500
Dry Bulb Bin Hours
Good application for Waterside Economizer with Cooling Tower, Dry Cooler, or Geothermal
45°F 60°F
45°F 60°F
Loop Temp < 45°F: 1202 Hours (30%)
Loop Temp < 60°F: 1874 Hours (47%)
Dry Cooler (10°F Range)
Loop Temp < 45°F: 1552 Hours (39%)
Loop Temp < 60°F: 2495 Hours (62%)
Cooling Tower (7°F Approach)
Loop Temp < 45°F: 1750 Hours (43%)
Loop Temp < 60°F: 3000 Hours (75%)
Geothermal
APPLICATION CONSIDERATIONS
Potential Waterside Economizer Hours (Grand Rapids)
54
Potential Economizer Operating Hours (Variable)
APPLICATION CONSIDERATIONS
Slide data depends on presentation location
Loop Temp < 45°F: Hours (0%)
Loop Temp < 60°F: Hours (0.04%)
Dry Cooler Performance
Loop Temp < 45°F: Hours (0.04%)
Loop Temp < 60°F: Hours (7%)
Cooling Tower Performance
Loop Temp < 45°F: Hours (0%)
Loop Temp < 60°F: Hours (0.05%)
Geothermal Performance0
200
400
600
800
1000
1200
1400
47°F 52°F 57°F 62°F 67°F 72°F 77°F 82°F 87°F 92°F
Dry Bulb Bin Hours
45°F 60°F
0
200
400
600
800
1000
1200
1400
43°F 47°F 51°F 56°F 61°F 65°F 70°F 73°F 76°F 77°F
Wet Bulb Bin Hours
45°F 60°F
55
Waterside Economizer Operating Hours
APPLICATION CONSIDERATIONS
Photo Source: Carrier HAP v4.9
Waterside Economizer Is Only Effective if it Can Be Used• Requires cooling load during cool periods
• More economizer operating hours provide greater savings
Depends on Building Load Profile• Core vs. perimeter zoning
• Specialty areas
Depends on Economizer Type• Integrated Economizer allows for wider water temperature range
56
Building Load Profile
APPLICATION CONSIDERATIONS
Photo Source: Carrier HAP v4.9
Ideal Waterside Economizer Applications are Cooling Dominant(standard range systems)
• During cool months, cooling load ≥ the building heating load
• Depends on building usage and zone layouts (core vs. perimeter)
• Minimized impact of heating efficiency decrease for standard range systems
Cooling DominantBuilding
Heating DominantBuilding
Cooling(Core Zones)
Perimeter Zones
Heating
Heating(Perimeter Zones)
Cooling (Core Zones)
57
Building Load Profile
APPLICATION CONSIDERATIONS
Cooling Dominant Building (Cooling > Heating)
• High operating hours for Waterside Economizer
• Good application for WSE (cooling savings > heating increase)
Standard Range Heating Dominant Building
• WSHP heating efficiency decreases at low loop temperatures
• Poor application for WSE (heating increase > cooling savings)
Extended Range Heating Dominant Building
• WSE may still be beneficial (if cooling savings > heating increase)
58
Minimize Economizer System Impact
Photo Source: FHP Manufacturing
APPLICATION CONSIDERATIONS
Airside Pressure Drop
• Waterside Economizer coil mounted on unit returnadds to constant fan pressure
Waterside Pressure Drop
• When active, Waterside Economizer coil adds to thepump head pressure
Heating Impact
• Low loop temperatures may impact WSHP heatingperformance
59
Airside and Waterside Pressure Drop
Minimize Airside Pressure Drop• Use high efficiency fan motors (ECM)
• Use variable speed fan speed control
• Use intermittent fan operation
• If the unit rarely enters cooling mode duringlow ambient conditions, don’t use a WSE
Minimize Waterside Pressure Drop• Use high efficiency pump motors
• Use variable speed pumps
APPLICATION CONSIDERATIONS
Photo Source: Carrier Corporation
60
Heating System Impact
APPLICATION CONSIDERATIONS
Photo Source: Carrier HAP v4.9
Waterside Economizer Requires Low Loop Temperature• WSE effectiveness reduced at loop temperatures above 60°F
WSHP Heating Efficiency Drops at Low Loop Temperatures• May require upsizing units or experience longer run times
• Minimal/no impact on Extended Range (Geothermal) systems
• Impacts Standard Range (Boiler & Tower) systems
• Reduced boiler load reduces boiler energy consumption
61
Heating System Impact
APPLICATION CONSIDERATIONS
Data Source: Carrier WSHP Builder v6.0 All data based on: 2 ton base unit, 400 CFM/Tonairflow, 68°F entering coil air temperature and 3 GPM/Ton condenser water flow.
82°F
84°F
86°F
88°F
90°F
92°F
94°F
96°F
98°F
100°F
102°F
3
3.2
3.4
3.6
3.8
4
4.2
4.4
4.6
40°F 42°F 44°F 46°F 48°F 50°F 52°F 54°F 56°F 58°F 60°F 62°F 64°F 66°F 68°F
Su
pp
lyA
irT
em
pera
ture
CO
P
Entering Water Temperature
Entering Water Temperature vs. Supply Air Temperature
COP LAT
3.7 COP92°F SAT
4.2 COP98°F SAT
4.5 COP101°F SAT
StandardRange Heating
Loop Temp
GeothermalHeating Loop
Temp
62
Heating System Impact
APPLICATION CONSIDERATIONS
Data Source: Carrier WSHP Builder v6.0 All data based on: 2 ton base unit, 400 CFM/Tonairflow, 68°F entering coil air temperature and 3 GPM/Ton condenser water flow.
°F
1°F
2°F
3°F
4°F
5°F
6°F
7°F
8°F
5,000
6,000
7,000
8,000
9,000
10,000
11,000
12,000
40°F 45°F 50°F 55°F 60°F 65°F 70°F
WS
HP
Wate
rTem
pera
ture
Dro
p
Bo
iler
Lo
ad
per
WS
HP
To
n(B
TU
)
Water Loop Temperature
Effect of Water Loop Temperature on Boiler Load
Boiler Load WSHP ΔT
11,100 BTU7.4°F ΔT
7,800 BTU5.2°F ΔT
9,750 BTU6.5°F ΔT
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Waterside Economizer System Example
APPLICATION CONSIDERATIONS
ExampleOffice Building(10) 2 Ton WSHPsBoiler & Tower68°F Loop Temp (No WSE)45°F Loop Temp (No WSE)ECM Fan Motors800 CFM Each6 GPM EachElectric Boiler
Fan Hours: 500Cooling Hours: 500 (Core)Heating Hours 500 (Perimeter)
Compare systems with WSEand without WSE
Photo Source: Carrier Corporation
1 2
3 4
5 6
7
810
9
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WSHP System without Waterside Economizer
APPLICATION CONSIDERATIONS
System Performance withoutWaterside Economizer
Zone Energy Consumption (kWh)
1 570
2 570
3 570
4 570
5 570
6 570
7 638
8 638
9 638
10 638
Tower 305
Boiler 0
Pump 1950
Total: 8227 kWh
71°F68°F
8
5 6
3 4
1 2
7
10
9
10
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
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WSHP System with Waterside Economizer
APPLICATION CONSIDERATIONS
System Performance withWaterside Economizer
Zone Energy Consumption (kWh)
1 120
2 120
3 120
4 120
5 120
6 120
7 788
8 788
9 788
10 788
Tower 275
Boiler 0
Pump 2000
Total: 6145 kWh
1 2
3 4
5 6
7
810
9
47°F45°F
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
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Energy Consumption
APPLICATION CONSIDERATIONS
No Waterside Economizer
Zone Energy Consumption (kWh)
1 570
2 570
3 570
4 570
5 570
6 570
7 638
8 638
9 638
10 638
Tower 305
Boiler 0
Pump 1950
Total: 8227 kWh
With Waterside Economizer
Zone Energy Consumption (kWh)
1 120
2 120
3 120
4 120
5 120
6 120
7 788
8 788
9 788
10 788
Tower 275
Boiler 0
Pump 2000
Total: 6145 kWh
HVAC Energy Savings: 25.3%
Source: Carrier Corporation 50PC Performance Data 50PC-09PD
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Summary
APPLICATION CONSIDERATIONS
When Should a Waterside Economizer be Used?
• If code requires economizer use
• Great fit for Geothermal (Extended Range) Systems (loop temps low by design)
• Good fit for standard range, but location dependent and may need to lower heating loop temps
• Constant cooling load in cold months (e.g. core cooling load)
• >20% low loop temp hours
• If Cooling Energy Savings > Airside + Waterside + Heating energy increase
Energy Savings Factors:
• Geographic Location
• Building Load Profile
• Heating System Impact
• Economizer Type
• Airside & Waterside Pressure Drop
Photo Source: Carrier Corporation
QUESTION #5
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Which of the following should be considered whenapplying Waterside Economizers to WSHP?
A. Condenser loop temperature range capability
B. Local climate/ambient temperature
C. Heating system impact
D. All of the above
ASHRAE 90.1 ENERGY STANDARD
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Overview
Source: ASHRAE Standard 90.1-2013 Purchased stock graphics BLDCM022 by permission
ASHRAE 90.1 is a standard that provides minimum guidelines for buildingenergy efficiency design for buildings (except low rise).
ASHRAE 90.1 ENERGY STANDARD
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Waterside Economizers
Source: ASHRAE Standard 90.1-2013
Waterside Economizers are in Prescriptive Path• WSE with WSHP systems are not required on certain systems
• WSE with WSHP may not meet some requirements of 90.1 (heatingimpact)
Waterside Economizer Beneficial to Energy Cost Method
ASHRAE 90.1 AND WSE
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Prescriptive Path
Derived from: ASHRAE 90.1
Required Based on Climate Zone• Not required in Zone 1
Required Based on Unit Size• Not required on systems under 4.5 tons
WSE Requirement Can Be Waived• Increase unit efficiency based on
Climate Zone
• Zone operating hours
(less than 20 hours/Week)
ClimateZone
EfficiencyImprovement
2a 17%
2b 21%
3a 27%
3b 32%
3c 65%
4a 42%
4b 49%
4c 64%
5a 49%
5b 59%
5c 74%
6a 56%
6b 65%
7 72%
8 77%
ASHRAE 90.1 AND WSE
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Waterside Economizer Requirements
Minimum Capacity Requirements (6.5.1.2.1)• Provide 100% design capacity at 50°F/45°F ambient
Coil Waterside Pressure Drop Limited to 15 Ft. (6.5.1.2.3)• Limit pressure drop during non-economizer operation, if exceeded
Must be an Integrated Economizer (6.5.1.2.3)• Allow mechanical cooling with economizer operation
ASHRAE 90.1 AND WSE
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Waterside Economizer Requirements
Economizer Must Not Increase Heating Energy Use (6.5.1.2.4)HVAC system design and economizer controls shall be such that
economizer operation does not increase the building heating
energy use during normal operation.
Heating Energy Consumption = Boiler Energy + Heat Pump Heating Energy
Source: Interpretation IC 90.1-2010-15 of ANSI/ASHRAE/IES Standard 90.1-2010
QUESTION #6
75
In ASHRAE 90.1, which of the following impacts theWaterside Economizer prescriptive requirement?
A. Unit capacity
B. Geographic location
C. Unit operating hours
D. All of the above
SUMMARY
• Waterside Economizers can be a great fit forWater Source Heat Pump systems
• Waterside Economizers are a powerful tool forenergy savings, when properly applied
• The negative impacts of Waterside economizerscan easily be overcome with smart designchoices
• Energy savings and code compliance are drivingforces behind Waterside Economizer use
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WSHP Waterside Economizers
SUMMARY
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REMEMBER TO FILL OUT AND TURN IN THE EVALUATION FORM
Reminder: If you are registered in Florida, New York, or North Carolina,you must also sign the sheets in the back at the end of the session.
Please print your name, include your registration number, and sign the sheet.
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