January 2012 1
January 2012
ASHRAE Winter Conference 2012
Track: HVAC& R System & Equipment Seminar 4 Learning Objectives
ASHRAE Technical Seminar 22nd January 2012 Water-cooled Variable Refrigerant Flow Systems - An Introduction
1. Describe the water-source VRF heat pump and heat recovery concept as applied to commercial buildings. 2. Describe the application potential for both heat pump and heat recovery water source VRF systems across a range of building types. 3. Describe how to ensure optimal annual performance levels through effective design strategies.
Dermot McMorrow MSc CEng PEng
4. Understand field data on the annual operating performance of heat recovery VRF geothermal systems. 5. Describe basis design guidance on the implementation of water-source VRF systems in buildings. 6. Understand case study reference documentation and further reading publication listings on the application of water-source VRF systems.
DEFINITION –
ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA members. Certificates of Completion for nonAIA members are available on request.
What is Variable Refrigerant Flow?
ASHRAE Journal April 2007 The term “Variable Refrigerant Flow refers to the capability of a HVAC system to control the amount of refrigerant flowing to each of the indoor units/evaporators, enabling the use of multiple evaporators of differing capacities and configurations, individualized comfort control, simultaneous heating and cooling in different zones with heat recovery from one zone to another”
This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
AHRI Standards & Policy Committee June 2009 Variable Refrigerant Flow (VRF) System is an engineered direct exchange (DX) multi- split system incorporating at least one variable capacity compressor distributing refrigerant through a piping network to multiple indoor fan coil units each capable of individual zone temperature control, through a zone temperature control devices and common communications network. Variable refrigerant flow implies three or more steps of control on common, inter-connecting piping
Variable Refrigerant Flow – Typical System Elements
Typical Pressure Enthalpy Diagram Pressure
4 Way Valve – Changeover Heating to Cooling
Condensing COOLING MODE
Expansion Cycle
Sub-cooled refrigerant
High psi
Indoor Units
Heat Rejected
Refrigerant in liquid and gaseous states
Heat Exchanger
Low psi TH 22
Compressor
Condenser
Evaporating
TH 23
Superheat Differential
Operating Parameters
HEAT SINK
Accumulator
Inverter Variable speed control
WATER LOOP
Enthalpy
Linear Expansion Valve
GROUND
T
WCU T1
T2
1
January 2012
Variable Refrigerant Flow – Typical System Elements
Cooling Mode IU
IU
IU
IU
4 Way Valve – Changeover Heating to Cooling
WCU Header Water-source condensing units must be placed indoors
WCU
WCU
HEATING MODE
Indoor Units
Heat Input Thru Compression
Heat Absorbed
HEAT SINK
Compressor
WATER
Reject Heat to Cooling Tower
Accumulator
GROUND
Inverter Variable speed control
50 gpm Nominal Flow Rate Cooling Tower
Linear Expansion Valve
23 - 113 F Loop Temperature
T Heating Injection
Refrigerant Flow
T1
T2
Heating Output will vary based on cooling load
Heating Mode IU
IU
IU
Water-source VRF Heat Pump Heat recovery in water loop only
IU
Header Cooling
WCU
WCU
Water-source condensing units must be placed indoors
PQHY Unit “A”
Heat is recovered between the WCU within the water loop
Cooling
System “A” in COOLING Mode (refrigerant absorbing heat)
Cooling
Cooling Heating PQHY Unit “B”
Heating
50 gpm Nominal Flow Rate Cooling Tower
23 - 113 F Loop Temperature
System “B” in HEATING Mode (refrigerant discharging heat)
Heating Heating Injection
Heating Output will vary based on cooling load
Water Circuit
Variable Refrigerant Flow System Layout – Heat Recovery Mode 4 Way Valve – Changeover Heating to Cooling
4 Way Valve – Changeover Heating to Cooling
VSD
Condenser
WCU
HEAT SINK
WCU
WATER
WATER GROUND
Compressor
Compressor
Accumulator
Heat Exchanger
VSD
Accumulator
Less Heat Absorbed
Heat Gain from CHW Circuit
Condenser HEAT SINK
BC
HEATING COOLING MODE
Heat Rejected Reduced
More Heat Recovered
Variable Refrigerant Flow System - Heat Recovery Mode
BC
COOLING MODE
Heat Exchanger
Heating
GROUND
T T1
T2
T T1
T2
2
January 2012
Cooling & Heating IU
IU
IU/AU
IU/AU
Water-source VRF Heat Recovery Heat recovery on refrigerant and water-side – Double Heat Recovery BC
Heat recovery on the direct expansion side. Indoor units could be used to heat and cooling Zones simultaneously or we could heat domestic hot water via Refrigerant to water modules.
Heating
Heat recovery WCU
Heat is recovered between the WCUs within the water loop
WCU
Cooling
PQRY
Cooling
Indoor units
Heat recovery Cooling
No heat rejection to Tower when in balanced heating/cooling mode.
Heating PQRY
Heating
50 gpm Nominal Flow Rate Water-source condensing units must be placed indoors
Cooling Tower
Heating
Heating Injection
Water circuit
Zone Load Report – Peak Heating/Cooling
Indoor units
Cooling
DOE Report – Annual Hours of Heat Recovery
EnergyPro 5 DOE 2 Print Out
Nom CLG kW Output
Factor
Actual CLG kW Output
Nom CLG Input kW
Factor
Actual CLG input kW
CLG COP
WCU
6T
21.3
1
21.3
3.85
0.66
2.54
8.38
WCU
8T
26.2
1
26.2
5.61
0.66
3.70
7.08
WCU
10 T
35.2
1
35.2
7.51
0.66
4.96
7.10
WCU
12 T
42.6
1
42.6
7.94
0.66
5.24
8.13
WCU
14 T
49.6
1
49.6
9.73
0.66
6.42
7.72
WCU
16 T
56.4
1
56.4
11.55
0.66
7.62
7.40
WCU
18 T
63.3
1
63.3
13.5
0.66
8.91
7.10
WCU
20 T
70.3
1
70.3
15.47
0.66
10.21
6.89
4 Way Valve – Changeover Heating to Cooling
COOLING MODE
Heat Rejected to CWT
Heat Exchanger
Compressor
Reduced Heat Rejection
10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00
Domestic Hot Water
COP
Variable Refrigerant Flow System – Heat Recovery – Cooling Dominant
Accumulator
ECWT @ 50 F
VSD
Condenser HEAT SINK
WCU
WATER 32 F
50 F
70 F
113F
GROUND Cooling Mode
T
Heating Mode T1
T2
ECWT
3
January 2012
Variable Refrigerant Flow System – Heat Recovery (Heating Dominant)
Mixed Use – Residential & Commercial - Qty 87 Residential Suites with 50,000 ft2 Retail & 20,000 ft2 Office
4 Way Valve – Changeover Heating to Cooling
HEATING COOLING MODE
Chilled Water System
Heat Gain from CHW Circuit
Heat Exchanger
Compressor
Accumulator
Less Heat Absorbed
VSD
Condenser
WCU
HEAT SINK WATER
T
GROUND
T1
High Rise Residential
Water-source Heat Recovery c/w future integration with district Cooling/heating via lake water
T2
SENIORS RESIDENCE APPLICATION - Qty 109 Suite - Seniors Residence – 100% Geothermal
- 30 Storey – 272 Suites
Application Overview 1. 100% Geothermal Heating & Cooling 2. Geothermal Heat Recovery System distributed mechanical rooms 3. Ceiling Cassette & Ceiling Concealed Indoor Units 4. Individual Suite by Suite comfort control & BACNET BMS integration 5. NC25-30 Sound Levels in each space
WCU Geothermal Heat Recovery
WCU Geothermal Heat Recovery
Variable Refrigerant Flow System Layout – Open Loop Geothermal
Coupled to a Lake or Pond Closed Loop
Coupled to Ground Water Closed Loop
HX
HX
YES Heat Exchanger Isolation
Variable Refrigerant Flow System Layout – Closed Loop Geothermal Coupled to Earth Vertical Closed Loop
YES
Coupled to Earth Horizontal Closed Loop
YES
YES Heat Exchanger Isolation Closed Piping Loop Closed Piping Loop
4
January 2012
IU
IU
IU
Commercial Office & Retail Building
IU
Heating Mode Stage 2
WCU
Cooling Mode Bypass WWHP
WWHP
WCU
Water-source VRF Heat Recovery system c/w Domestic Hot Water Generation via refrigerant side heat recovery
Heating Mode Stage 1
Geothermal Loop/District Heating/Cooling
THANK YOU!
5
ASHRAE Winter Conference 2012
Track: HVAC& R System & Equipment Seminar 4 Learning Objectives
ASHRAE Technical Seminar 22nd January 2012 Water-cooled Variable Refrigerant Flow Systems - An Introduction
1. Describe the water-source VRF heat pump and heat recovery concept as applied to commercial buildings. 2. Describe the application potential for both heat pump and heat recovery water source VRF systems across a range of building types. 3. Describe how to ensure optimal annual performance levels through effective design strategies.
Dermot McMorrow MSc CEng PEng
4. Understand field data on the annual operating performance of heat recovery VRF geothermal systems. 5. Describe basis design guidance on the implementation of water-source VRF systems in buildings. 6. Understand case study reference documentation and further reading publication listings on the application of water-source VRF systems.
DEFINITION –
ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA members. Certificates of Completion for nonAIA members are available on request.
What is Variable Refrigerant Flow?
ASHRAE Journal April 2007 The term “Variable Refrigerant Flow refers to the capability of a HVAC system to control the amount of refrigerant flowing to each of the indoor units/evaporators, enabling the use of multiple evaporators of differing capacities and configurations, individualized comfort control, simultaneous heating and cooling in different zones with heat recovery from one zone to another”
This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
AHRI Standards & Policy Committee June 2009 Variable Refrigerant Flow (VRF) System is an engineered direct exchange (DX) multi- split system incorporating at least one variable capacity compressor distributing refrigerant through a piping network to multiple indoor fan coil units each capable of individual zone temperature control, through a zone temperature control devices and common communications network. Variable refrigerant flow implies three or more steps of control on common, inter-connecting piping
Variable Refrigerant Flow – Typical System Elements
Typical Pressure Enthalpy Diagram Pressure
4 Way Valve – Changeover Heating to Cooling
Condensing COOLING MODE
Expansion Cycle
Sub-cooled refrigerant
High psi
Indoor Units
Heat Rejected
Refrigerant in liquid and gaseous states
Heat Exchanger
Low psi TH 22
Compressor
Condenser
Evaporating
TH 23
Superheat Differential
Operating Parameters
HEAT SINK
Accumulator
Inverter Variable speed control
WATER LOOP
Enthalpy
Linear Expansion Valve
GROUND
T
WCU T1
T2
1
January 2012
Variable Refrigerant Flow – Typical System Elements
Cooling Mode IU
IU
IU
IU
4 Way Valve – Changeover Heating to Cooling
WCU Header Water-source condensing units must be placed indoors
WCU
WCU
HEATING MODE
Indoor Units
Heat Input Thru Compression
Heat Absorbed
HEAT SINK
Compressor
WATER
Reject Heat to Cooling Tower
Accumulator
GROUND
Inverter Variable speed control
50 gpm Nominal Flow Rate Cooling Tower
Linear Expansion Valve
23 - 113 F Loop Temperature
T Heating Injection
Refrigerant Flow
T1
T2
Heating Output will vary based on cooling load
Heating Mode IU
IU
IU
Water-source VRF Heat Pump Heat recovery in water loop only
IU
Header Cooling
WCU
WCU
Water-source condensing units must be placed indoors
PQHY Unit “A”
Heat is recovered between the WCU within the water loop
Cooling
System “A” in COOLING Mode (refrigerant absorbing heat)
Cooling
Cooling Heating PQHY Unit “B”
Heating
50 gpm Nominal Flow Rate Cooling Tower
23 - 113 F Loop Temperature
System “B” in HEATING Mode (refrigerant discharging heat)
Heating Heating Injection
Heating Output will vary based on cooling load
Water Circuit
Variable Refrigerant Flow System Layout – Heat Recovery Mode 4 Way Valve – Changeover Heating to Cooling
4 Way Valve – Changeover Heating to Cooling
VSD
Condenser
WCU
HEAT SINK
WCU
WATER
WATER GROUND
Compressor
Compressor
Accumulator
Heat Exchanger
VSD
Accumulator
Less Heat Absorbed
Heat Gain from CHW Circuit
Condenser HEAT SINK
BC
HEATING COOLING MODE
Heat Rejected Reduced
More Heat Recovered
Variable Refrigerant Flow System - Heat Recovery Mode
BC
COOLING MODE
Heat Exchanger
Heating
GROUND
T T1
T2
T T1
T2
2
January 2012
Cooling & Heating IU
IU
IU/AU
IU/AU
Water-source VRF Heat Recovery Heat recovery on refrigerant and water-side – Double Heat Recovery BC
Heat recovery on the direct expansion side. Indoor units could be used to heat and cooling Zones simultaneously or we could heat domestic hot water via Refrigerant to water modules.
Heating
Heat recovery WCU
Heat is recovered between the WCUs within the water loop
WCU
Cooling
PQRY
Cooling
Indoor units
Heat recovery Cooling
No heat rejection to Tower when in balanced heating/cooling mode.
Heating PQRY
Heating
50 gpm Nominal Flow Rate Water-source condensing units must be placed indoors
Cooling Tower
Heating
Heating Injection
Water circuit
Zone Load Report – Peak Heating/Cooling
Indoor units
Cooling
DOE Report – Annual Hours of Heat Recovery
EnergyPro 5 DOE 2 Print Out
Nom CLG kW Output
Factor
Actual CLG kW Output
Nom CLG Input kW
Factor
Actual CLG input kW
CLG COP
WCU
6T
21.3
1
21.3
3.85
0.66
2.54
8.38
WCU
8T
26.2
1
26.2
5.61
0.66
3.70
7.08
WCU
10 T
35.2
1
35.2
7.51
0.66
4.96
7.10
WCU
12 T
42.6
1
42.6
7.94
0.66
5.24
8.13
WCU
14 T
49.6
1
49.6
9.73
0.66
6.42
7.72
WCU
16 T
56.4
1
56.4
11.55
0.66
7.62
7.40
WCU
18 T
63.3
1
63.3
13.5
0.66
8.91
7.10
WCU
20 T
70.3
1
70.3
15.47
0.66
10.21
6.89
4 Way Valve – Changeover Heating to Cooling
COOLING MODE
Heat Rejected to CWT
Heat Exchanger
Compressor
Reduced Heat Rejection
10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00
Domestic Hot Water
COP
Variable Refrigerant Flow System – Heat Recovery – Cooling Dominant
Accumulator
ECWT @ 50 F
VSD
Condenser HEAT SINK
WCU
WATER 32 F
50 F
70 F
113F
GROUND Cooling Mode
T
Heating Mode T1
T2
ECWT
3
January 2012
Variable Refrigerant Flow System – Heat Recovery (Heating Dominant)
Mixed Use – Residential & Commercial - Qty 87 Residential Suites with 50,000 ft2 Retail & 20,000 ft2 Office
4 Way Valve – Changeover Heating to Cooling
HEATING COOLING MODE
Chilled Water System
Heat Gain from CHW Circuit
Heat Exchanger
Compressor
Accumulator
Less Heat Absorbed
VSD
Condenser
WCU
HEAT SINK WATER
T
GROUND
T1
High Rise Residential
Water-source Heat Recovery c/w future integration with district Cooling/heating via lake water
T2
SENIORS RESIDENCE APPLICATION - Qty 109 Suite - Seniors Residence – 100% Geothermal
- 30 Storey – 272 Suites
Application Overview 1. 100% Geothermal Heating & Cooling 2. Geothermal Heat Recovery System distributed mechanical rooms 3. Ceiling Cassette & Ceiling Concealed Indoor Units 4. Individual Suite by Suite comfort control & BACNET BMS integration 5. NC25-30 Sound Levels in each space
WCU Geothermal Heat Recovery
WCU Geothermal Heat Recovery
Variable Refrigerant Flow System Layout – Open Loop Geothermal
Coupled to a Lake or Pond Closed Loop
Coupled to Ground Water Closed Loop
HX
HX
YES Heat Exchanger Isolation
Variable Refrigerant Flow System Layout – Closed Loop Geothermal Coupled to Earth Vertical Closed Loop
YES
Coupled to Earth Horizontal Closed Loop
YES
YES Heat Exchanger Isolation Closed Piping Loop Closed Piping Loop
4
January 2012
IU
IU
IU
Commercial Office & Retail Building
IU
Heating Mode Stage 2
WCU
Cooling Mode Bypass WWHP
WWHP
WCU
Water-source VRF Heat Recovery system c/w Domestic Hot Water Generation via refrigerant side heat recovery
Heating Mode Stage 1
Geothermal Loop/District Heating/Cooling
THANK YOU!
5
