CCHP/V Systems Integration
PhD. Defense
Fred Betz
PhD. Candidate
May 11th, 2009
Carnegie Mellon University
Center for Building Performance and Diagnostics
Dissertation Committee
• Volker Hartkopf – Chair, Architecture
• David Archer – Mechanical Engineering
• John Wiss – Mechanical Engineering
2
Outline
• Problem and Objectives
• Sub-system Overview
– Biodiesel Fueled CHP System
– Steam Driven Double Effect Absorption Chiller
– Enthalpy Recovery Ventilation System with Desiccant
Dehumidification
• TRNSYS Simulations
– Intelligent Workplace (IW)
– Building As Power Plant (BAPP)
• Systems Integration
• Future Work
3
Problem
• According to the Department of Energy the
main barriers to the adoption of the CHP
systems are:
– the high first cost,
– the high operating cost (maintenance,
personnel), and
– the complexity of operation
4
Objectives
• Integrate the biodiesel fueled CHP system
with the steam driven absorption chiller and
enthalpy recovery ventilation system with
desiccant dehumidification.
– To reduce first and operating costs
– To simplify installation and operation
• Cited by DoE as key barrier to adoption
5
Sub-System Overview
• Biodiesel Fueled CHP System
• Steam Driven Double Effect Absorption
Chiller
• Enthalpy Recovery Ventilation System with
Desiccant Dehumidification
6
Biodiesel Fueled CHP System
7
CHP System Flow Diagram
Power to
IW/Grid
ATS / SLC
Exhaust
Muffler
Generator
Absorption
Chiller
Steam
Diesel Engine
Radiator
Exhaust Exhaust Gas
Diversion
Valve
To Condensate Tank
Steam
Generator
Hot Water
Converter
Coolant
Loop
Condensate
Tank
Coolant Heat
Exchanger
Chilled Water Supply
and Return (IW/Grid)
To CMU
Campus
Steam Grid
Hot Water Supply and
Return (IW/Grid)
To CMU Campus
Condensate Grid
Regen Exhaust
Condensate from
Exhaust
Air
Absorption Chiller/Grid
Regen
Coil
Hot Water Supply and
Return (IW/Grid)
Ventilation
System
Regen
Air
Return
Air
Outside Air
Dehumidified Air to IW
8
Biodiesel Fueled CHP Systems
Integration
Coolant
Heat
Exchanger
Biodiesel
Diesel
Fill
Station 2
Fill
Station 1
VFD
Fuel Tank
2
Fuel Tank
1
Motor
Valve 5
Valve 6
Motor
Radiator
Fan
Motor
Motor
Pump
Starter
Valve 4
Motor
Motor
Valve 3
Engine-Generator
Fuel Pump 1 Day Tank 1
Engine
Generator
Fuel Pump 2 Day Tank 2
Air
Turbocharger
Controler
Electric Grid
Automatic
Transfer
Switch
Intelligent Workplace
Mullion
Steam Generator
Bypass
Tee
Muffler
Blowdown
Separator
Steam
Generator
Back
Pressure
Valve
Control
Column
Steam
Converter
Motor
Valve 2
Fan Coil
Supplier/Manf/Integrator
Baldor
John Deere
Stamford
Intelligen
ASCO
Vaporphase
Kickham
Broad
ITT
Pryco
Magnetek
BorgWarner
Belimo
Bell & Gossett
Highland Tank
Marathon
Penn Separator Corp.
Thermoflo
General Electric
Siemens
Nelson
Pomeco OPW
Marathon Electric
Campus
Steam Grid
Motor
Valve 1
Absorption
Chiller
Radiant
Panel
Cool Wave
Feed
Water
Valve
Condensate
Pumps (2)
Motor (2)
Condensate
Receiver w/
Controller
9
Biodiesel Fueled CHP I/O
• Measured Inputs
–
–
–
–
Fuel (Biodiesel or Petrol-Diesel For Engine)
Air (For Engine)
Condensate (For Steam Generator)
Hot Water Return (For Coolant Heat Exchanger)
• Measured Outputs
– Electricity (For IW and Campus Grid)
– Exhaust (For Steam Generator)
– Steam (For Space Heating, Absorption Chiller, or
Campus Grid)
– Hot water Supply (For Space Heating or Desiccant
Regeneration)
10
CHP Results
Winter CHP Soy Based Biodiesel Results
Power
Output
(kWe)
Fuel
Input
(kWc)
Plant
Power
(kWe)
Coolant Heat
Recovered
(kWt)
Exhaust Heat
Recovered
(kWt)
CHP
Efficiency
(%)
25
76
4
18
18
76%
• Evaluated Diesel and soy based biodiesel fuel over
four power levels (6, 12, 18 and 25 kWe)
• Nearly identical performance, except higher
biodiesel fuel consumption.
• Electrical and CHP efficiency drops as power level
decreases.
11
Emissions Results
Averaged Diesel Emissions
Load
(kWe)
%
O2
%
CO
%
CO2
25
9.6
0.1
8.2
UHC
NO
(PPM) (PPM)
12
502
NO2
(PPM)
4
Averaged Biodiesel Emissions
Load
(kWe)
%
O2
%
CO
%
CO2
25
9.7
0.0
8.4
UHC
NO
(PPM) (PPM)
3
498
PPM
(NO2)
9
• Completed 6-gas exhaust gas analysis for both Diesel and
biodiesel fuel.
• Reasonable AFR based on %O2 and %CO2.
• Reduction in %CO and UHC shows improved combustion for
biodiesel fuel consistent with published data.
• NOX doesn’t increase, which is inconsistent with published data.
12
May be due to engine timing.
Steam Driven Double Effect
Absorption Chiller
13
Absorption Chiller I/O
• Measured Inputs
–
–
–
–
High Pressure Steam (From Steam Generator)
Chilled Water Return (From IW)
Electricity (For Pumps, Fan, Controls)
Treated Water (For Cooling Tower)
• Measured Outputs
– Chilled Water Supply (For IW and/or Grid)
– Condensate (For Steam Generator)
– Water Vapor (From Cooling Tower)
14
Absorption Chiller Operation
• Uses approximately 16 kWt of steam at
– 87 psig (6 bar)
– 360oF (160oC)
– 28 kg/hr (65lb/hr)
• Average COP of 1.1
• Reduces water temperature from 57oF to
45oF (14oC to 7oC)
15
Ventilation system with Enthalpy
Recovery and Solid Desiccant
Dehumidification
16
Ref: Images from Chaoqin Zhai, www.cmu.edu/iwess
Ventilation
Operation
Psychrometric Chart of Ventilation System
17
Ventilation System I/O
• Measured Inputs
– Outside Air for Ventilation and Desiccant
Regeneration
– Natural gas (For Desiccant Regeneration)
– Electricity (For fans, wheels and controls)
– Return Air (From Conditioned Space)
• Measured Outputs
– Dehumidified Ventilation Air (For IW)
– Exhaust Air (To atmosphere)
– Exhaust (From Desiccant Regeneration)
18
Ventilation Results
• The desiccant wheel
accounts for 62% of the
operating cost due to
natural gas consumption
for regeneration.
• 95oC heat at 12 GPM
from the engine coolant
can be used to
regenerate the desiccant.
Ventilation System
Operating Cost Breakdown
19
Ref: Slide presented by Dr. Zhai at 2008 ASME Energy Sustainability Conference
TRNSYS Simulations
• An integrated model based on empirical data
collected from the absorption chiller, ventilation
system, and the CHP system has been created.
• Inputs:
– The IW’s heating, cooling, and regeneration load files.
• Outputs:
– A look up table with operational data from the CHP
system including power level, fuel consumption, and
temperatures and flows of the various heat streams
for cooling, heating, and desiccant regeneration.
20
TRNSYS Simulations
• The controller currently can operate in
three different modes:
-Mode 0: Operate at 100% (25 kWe)
-Mode 1: Thermal Load Follow (Cooling,
Heating)
-Mode 2: Regeneration Load Follow
Note:
– The controller prioritizes coolant energy for heating over
steam, which can be exported.
– The engine will not operate below 25% of rated capacity.
21
IWESS Mode Zero Results
Mode Zero Results: Design Operation at 25 kWe
Annual Net Energy Export
1,015,470
MJ
Annual Net Thermal Energy Export
706,442
MJ
Annual Net Electrical Energy Export
309,028
MJ
Hours of Operation
8,760
Hours
Heating Hours Not Met
351
Hours
Cooling Hours Not Met
191
Hours
Regeneration Hours Not Met
265
Hours
Total Energy Used
1,791,999
Total Fuel Consumption
Total Fuel Energy Consumption
19,921
2,712,360
Average Annual Efficiency
MJ
Gallons
MJ
66%
• Only achieves a 66% efficiency
– due to rejection of coolant heat and,
– rejecting high temperature exhaust after heat
recovery.
22
IWESS Model Discussion
• Average annual CHP efficiency is 65% to 68%
depending on the operational mode due to.
– the relatively large amount of coolant heat is rejected,
– the engine operating at an inefficient load, and/or
– due to the relatively high rejected exhaust temperature.
• Low and intermittent loads from high performance
buildings presents a significant controls challenge.
• Potential Solutions:
– Have a larger hot water grid that can absorb the excess coolant
energy.
– Install a single effect absorption chiller to make chilled water and
export it to the grid.
– Use thermal storage to maintain a higher load, and then shut off
the engine.
– Have several smaller engines that can be banked together using
a modular approach.
23
BAPP Simulations
• The BAPP simulations use a modified 200
kWe Diesel engine generator based on a
manufacturer’s specification sheet and data
collected from the 25 kWe engine generator.
• The same CHP controller was utilized for
this simulation with three operational modes.
• Modified IW load files were used as no
BAPP simulation file is available.
24
BAPP Mode One Results
Mode One Results: Thermal Load Follow
Annual Net Energy Import
2,363,485
MJ
Annual Net Thermal Energy Import
2,058,830
MJ
Annual Net Electrical Energy Import
304,655
MJ
Hours of Operation
5,165
Hours
Heating Hours Not Met
5,817
Hours
Cooling Hours Not Met
2,981
Hours
Regeneration Hours Not Met
3,450
Hours
Total Energy Used
Total Fuel Consumption
Total Fuel Energy Consumption
Average Annual Efficiency
5,663,109
54,107
7,366,797
MJ
Gallons
MJ
77%
• The BAPP mode 1 simulation operates about 5,000 hours.
• The efficiency higher than the IWESS results because the
CHP system is under sized, and is a net energy import.
• Turndown ratio is an issue as the load is often below 25%
25
of the engine’s capacity.
BAPP Model Discussion
• The fact that a BAPP load file with cooling,
heating, and regeneration loads does not exist
makes design recommendations difficult.
• A modular approach to the CHP system with
several smaller prime movers will assist in
solving the turn down ratio if a thermal load
follow operational mode is desired.
• Connections to hot water grids in MMCH,
Donner Hall, etc would assist in finding loads for
hot water. Alternately, a single effect absorption
chiller could be used to generate additional
chilled water for export to the campus grid.
26
Systems Integration
• Combine three separate sub-systems
– Steam driven double effect absorption chiller
– Enthalpy recovery ventilation system with
desiccant dehumidification
– Diesel engine generator with heat recovery
27
Energy Cascade
Fuel Energy
Engine
Generator
Electricity
Chilled Water Return
Absorption
Chiller
Chilled Water Supply
Exhaust
Coolant
Exhaust Heat
Recovery (DHW)
Exhaust Heat
Recovery (SH)
Regeneration Heat
Exchanger
Coolant Heat
Exchanger
Domestic Hot
Water Preheat
City Water / Preheated DHW
Domestic Hot Water
Hot Water Return
Hot Water Supply
Outside Air
Regeneration Air
Hot Water Return
Hot Water Supply
City Water
Preheated DHW
28
Sub-Systems to be Integrated
Control
Data
Control
Data
Intelligen
Controls
Automatic
Transfer
Switch /
Soft Load
Controller
Electricity
Engine
Generator
Air
Pneumatic
Controls
Exhaust
Heat
Recovery /
Steam
Generator
ALC Controls
Radiator
Coolant
Heat
Recovery
Fuel Hot Air
Hot
Water
Loop
Compressed
Air
Steam
Control
Data
Hot Exhaust
Condensate
ALC Controls
Exhaust
Air
Enthalpy
Recovery
Module
Desiccant
Module
Heat
Pump
Module
Regen Burner
Return
Natural
Air
Gas Electricity
Outside
Air
Regeneration
Air Exhaust
Control
Data
Broad Controls
Absorption
Chiller
Cooling
Tower
Electricity
Dehumidified
Supply Air
Treated
Water
High Pressure
Low Quality
Steam
Steam
29
Summary of I/O
Existing IWESS Configuration Inputs / Outputs
CHP System
Inputs
Fuel
(Biodiesel)
Outputs
Absorption Chiller System
Inputs
Ventilation System
Outputs
Inputs
Outputs
Exhaust
Fuel (Natural
Gas)
Dehumidified Air
Regeneration
Exhaust Air
Exhaust Air
Electricity
Electricity
Air
Exhaust
High Pressure
Steam
Condensate
Outside and
Return Air
Condensate
High Pressure
Steam
Chilled Water
Return
Chilled Water
Supply
Regeneration
Air
Hot Water
Return
Hot Water
Supply
Makeup Water
(Cooling Tower)
Steam (Cooling
Tower)
Electricity
Compressed
Air
30
IWESS Systems Integration
Control
Data
Automatic
Transfer
Switch /
Soft Load
Controller
Electricity
Control
Data
Intelligen
Controls
ALC Controls
Engine
Generator
Air
Radiator
Coolant
Heat
Recovery
Fuel Hot Air
Dehumidified
Supply Air
Hot
Exhaust
Pump
Exhaust
Air
Enthalpy
Recovery
Module
Desiccant
Module
Broad Controls
High
Pressure
Steam
Hot
Water
Loop
ALC Controls
Control
Data
Pneumatic
Controls
Exhaust
Heat
Recovery /
Steam
Generator
Regeneration
Air Exhaust
Regeneration
Air Supply
Cooling
Tower
Chilled Water
Loop
Heat
Pump
Module
Regen Burner
Regen Coil
Outside
Return
Air
Air
Absorption
Chiller
Control
Data
Electricity
Natural
Gas
Electricity
Terminal
Heating
Units
Pump
City
Water
Domestic
Hot Water
Exhaust
Treated
Water
Low Quality
Steam
Terminal
Cooling
Units
Pump
DHW
31
Natural
Gas
Electricity
Cutting First Costs
• Removed Components
– 1 major component (heat pump)
– 2 minor components (regeneration burner and
cooling tower)
– 7 control systems with their respective interfaces
– 2 heat rejections
• Added Components
– 3 minor components (heating coil, cooling coil,
and DHW preheat heat exchanger)
– 1 supervisory controller that handles all control
features with one interface
32
Packaged System
Supervisory Controller
Electricity
Regeneration
Air Exhaust
Regeneration
Air Supply
Engine
Exhaust
Engine
Exhaust
Regen Coil
Automatic
Transfer
Exhaust
Engine
Switch /
Heat
Generator
Soft Load
Recovery
Controller
Electricity
Coolant
Heat
Recovery
Absorption
Chiller
Radiator
Domestic
Hot Water
Preheat
Air Fuel
Enthalpy
Recovery
Module
Heating
Coil
Cooling
Coil
Desiccant
Module
City Outside Return
Water Air
Air
Hot Air
Pump
Chilled Water
Loop
Dehumidified
Supply Air
Pump
Domestic
Hot Water
DHW
Pump
Hot Water
Loop
Terminal
Heating
Units
Terminal
Cooling
Units
33
Operating Cost Savings
• Regenerating the solid desiccant of the ventilation
system will reduce the operational costs of the
ventilation system by approximately 60%.
• Operating a pump with heating and cooling coils in
place of the compressor on the heat pump.
• Using the reject heat from the cooling tower will
save treated cooling tower water, and will provide a
heat source for preheating domestic hot water.
34
Contributions
• Complete installation, operation, and
evaluation of a biodiesel fueled CHP system.
• A generic preliminary CHP design guide.
• A TRNSYS simulation platform for CHP
systems to test operational strategies.
• An example of systems integration for a CHP
system with an absorption chiller and a
ventilation system.
35
Conclusions
• A biodiesel fueled CHP system performs as well
as a Diesel fueled CHP system.
• If CHP systems and high performance buildings
are to be combined, it is necessary to make
thermal grids available to maintain a high
efficiency.
• The BAPP CHP system should be a modular
system that can achieve a high turndown ratio to
maintain a high CHP efficiency.
36
Future Work
• Automation and Integration
– Complete the automated startup and control
system via Automated Logic software.
– Physically connect the engine coolant system to
the ventilation regeneration system to validate
the simulation.
– Extend exhaust heat recovery to include DHW.
– Link the operation of the engine directly with the
chiller and ventilation operation.
37
Future Work
• Work with researchers and manufacturers on an
integrated system to reduce first costs by a factor
of 10 to 20.
Biodiesel Fueled Engine Generator with Heat Recovery Cost Breakdown
Facilities, $18,692.72, 3%
Instrumentation & Controls, $90,818.85,
13%
Engineering, $48,014.38, 7%
Installation, $397,613.00, 60%
Capital Equipment, $117,756.00, 17%
Other, $2,886.52, 0%
38
Installation
Other
Capital Equipment
Engineering
Instrumentation & Controls
Facilities
Future Work
• Recreate the BAPP simulation file and
determine new loads for the TRNSYS file to
explore design strategies for the mechanical
systems.
– Test additional control strategies.
– Test modular prime mover size options.
– Add DHW and or a single effect chiller to the
model to complete the energy cascade.
– Determine the effect of multiple BAPPs in a
campus grid.
39
Questions?
40
Acknowledgements
Special thanks to my committee and
their tireless efforts supporting and
reviewing my work
Special thanks to Dr. Chris Damm at
the Milwaukee School of
Engineering for getting me involved
in this project
Special thanks to Flore Marion
for her TRNSYS work, which made
this dissertation possible!
41
Preliminary CHP Design Guidelines
1. Determine electrical and thermal loads, load
profiles, and required flow rates and
temperatures of cooling and heating
streams.
2. Determine which fuel types are locally
available, how they are distributed, and their
cost.
3. Determine what energy grids are available,
what their operating conditions and costs
are, and if it is possible to interface with
them.
42
Preliminary CHP Design Guidelines
4. Select a prime mover that best fits the load
profiles, load proportions, and fuel
selection.
5. Select auxiliary and heat recovery
equipment to match the prime mover and
the fluids used to transfer energy.
6. Choose an operating strategy (thermal or
electrical load follow, base load, design,
etc.)
7. Evaluate the options on a capital, operating,
and environmental cost basis.
43
Additional Ventilation System
Results
Moisture Removal Breakdown
Enthalpy Removal Breakdown
44
Computational TRNSYS Model
45
Method
• Phase I
–
–
–
–
Component survey of chiller and ventilation systems.
Analyze existing TRNSYS simulation models.
Complete evaluation of biodiesel fueled CHP system.
Complete CHP TRNSYS model.
• Phase II
– Integrate TRNSYS models into a single model.
– Show potential first cost reductions by creating a packaged
CCHP/V system.
• Phase III
– Apply operating strategies using integrated TRNSYS model.
– Show potential operating cost reductions using a packaged
CCHP/V system.
46
CHP Results
Summer CHP Diesel Results
Power Output
(kWe)
Fuel Input
(kWc)
Plant Power
(kWe)
Coolant Heat
Recovered (kWt)
Exhaust Heat
Recovered (kWt)
CHP
Efficiency
6
25
3
6
3
47%
12
43
3
9
7
59%
18
57
3
12
12
68%
25
76
3
18
18
76%
Winter CHP Diesel Results
Power Output
(kWe)
Fuel Input
(kWc)
Plant Power
(kWe)
Coolant Heat
Recovered (kWt)
Exhaust Heat
Recovered (kWt)
CHP
Efficiency
6
25
4
6
4
49%
12
43
4
11
7
61%
18
57
4
14
12
70%
25
76
4
18
17
74%
Winter CHP Biodiesel Results
Power Output
(kWe)
Fuel Input
(kWc)
Plant Power
(kWe)
Coolant Heat
Recovered (kWt)
Exhaust Heat
Recovered (kWt)
CHP
Efficiency
6
26
4
8
4
54%
12
42
4
10
9
65%
18
59
4
14
13
68%
25
76
4
18
18
76%
47
Emissions Results
Low Sulfur Diesel Emissions Results
Load (kWe)
% O2
% CO
% CO2
UHC (PPM)
NO (PPM)
NO2 (PPM)
6
16.1
0.0
3.7
4
251
4
12
13.9
0.1
5.2
9
424
6
18
11.6
0.1
6.8
11
466
5
25
9.6
0.1
8.2
12
502
4
Soy Based Biodiesel Emissions Results
Load (kWe)
% O2
% CO
% CO2
UHC (PPM)
NO (PPM)
NO2 (PPM)
6
16.3
0.0
3.8
0
224
5
12
13.9
0.0
5.4
1
357
8
18
11.5
0.0
7.1
2
450
10
25
9.7
0.0
8.4
3
498
9
48
Absorption Chiller vs. Vapor
Compression Chiller
Heat Rejection to
Cooling Tower
High Temperature
Heat Source
Condenser
Generator
or Desorber
Electricity
P
Evaporator
Absorber
Heat From Load
(Building)
Heat Rejection to
Cooling Tower
• Absorption Chiller
– COP = 0.6 – 1.1
– Uses heat to generate
cooling
Condenser
Expansion
Valve
Compressor
Expansion
Valve
Heat Rejection to
Cooling Tower
Electricity
Evaporator
Heat From Load
(Building)
• Vapor Compression
Chillers
– COP = 2.0 – 6.0
– Uses electricity to
generate cooling
49
Absorption Chiller Components
High Temperature
Heat Source
Condenser
Steam
supply
Strong LiBr
Refrigerant
solution
Refrigerant
LTRG
condensate
HTRG
Cooling
water
LTHX
HRHX
HTHX
Evaporator
Chilled water loop
Absorber
High
Condenser
Expansion
Valve
Heat Rejection to
Cooling Tower
Electricity
P
Low
Condenser
Expansion
Valve
Dilute
solution
High
Generator
Low
Generator
Electricity
P
Evaporator
Absorber
Heat From Load
(Building)
Heat Rejection to
Cooling Tower
Schematic diagram
50
Ref: Slide presented by Dr. Yin at 2008 ASME Energy Sustainability Conference
Absorption Chiller Construction
•
–
–
–
–
–
Condenser
Steam
supply
Strong LiBr
Refrigerant
solution
Refrigerant
LTRG
condensate
HTRG
Cooling
water
LTHX
HRHX
Evaporator
HTHX
Chilled water loop
Absorber
Dilute
solution
Schematic diagram
5 major heat transfer components
•
4 minor heat exchanger
components
–
–
–
–
•
the evaporator
the absorber
the high temperature regenerator
low temperature regenerator
the condenser
high temperature heat exchanger
low temperature heat exchanger
steam heat recovery exchanger
by-pass heat exchanger
Other associated components
include:
– cooling tower
– pumps
– spray nozzles and valves
51
Ref: Slide presented by Dr. Yin at 2008 ASME Energy Sustainability Conference
Absorption Chiller Results

Vary five operating parameters individually
 chilled water return temperature (cooling load)
 chilled water flow rate
 cooling water supply temperature
 cooling water flow rate
 steam pressure
COP 
Qcooling
Qheat _ input
Qheat _ input  m steam  (hsteam  hcondensate)
Qcooling  m CHW  C p  (Treturn  Tsup ply )
h – enthalpy
m
. – flow rate
Cp – heat capacity of water
T – temperature
52
Ref: Slide presented by Dr. Yin at 2008 ASME Energy Sustainability Conference
• 807 hours or 9% of the year not met. Most of this is
due to near simultaneous heating and cooling in the
data files. The IW’s light weight construction allows
for significant outdoor temperature changes to switch
53
from heating to cooling relatively quickly.
Integrated TRNSYS Model Based
On Look Up Tables
54
IWESS Mode One Results
Mode One Results: Thermal Load Follow
Annual Net Energy Import
104,613
MJ
Annual Net Thermal Energy Export
31,827
MJ
Annual Net Electrical Energy Import
136,440
MJ
Hours of Operation
5,158.5
Hours
Heating Hours Not Met
2,773
Hours
Cooling Hours Not Met
2,986
Hours
Regeneration Hours Not Met
3,184
Hours
Total Energy Used
Total Fuel Consumption
Total Fuel Energy Consumption
Average Annual Efficiency
834,821
9,025
1,228,845
68%
• Operates for ~5,000
hours annually.
MJ
Gallons
MJ
• Has overall highest
efficiency
• Has large number of
hours unmet as most
of the year the IW
loads are less than
25% of the CHP
systems capacity.
• System turndown
ratio is not small
enough.
55
IWESS Mode Two Results
Mode Two Results: Regeneration Load Follow
Annual Net Energy Export
390,334,042
MJ
Annual Net Thermal Energy Import
389,883,120
MJ
Annual Net Electrical Energy Import
450,922
MJ
Hours of Operation
1,042.0
Hours
Heating Hours Not Met
5,486
Hours
Cooling Hours Not Met
2,927
Hours
Regeneration Hours Not Met
7,136
Hours
Total Energy Used
71,217
MJ
Total Fuel Consumption
Total Fuel Energy Consumption
Average Annual Efficiency
800
108,900
65%
• Operates for ~1,000
hours annually.
Gallons
MJ
• Most of the loads
were not met as the
majority of the time
the regeneration
load is below 25% of
the engines
operating capacity.
• Again, the turndown
ratio of the CHP
system is not small
enough.
56
BAPP Mode Zero Results
Mode Zero Results: Design Operation at 200 kWe
Annual Net Energy Export
38,543
MJ
Annual Net Thermal Energy
Import
3,165,375
MJ
Annual Net Electrical Energy
Export
3,203,918
MJ
Hours of Operation
8,760
Hours
Heating Hours Not Met
3,531
Hours
Cooling Hours Not Met
2,050
Hours
Regeneration Hours Not Met
2,956
Hours
Total Energy Used
Total Fuel Consumption
Total Fuel Energy Consumption
Average Annual Efficiency
13,006,500
119,965
16,333,612
80%
MJ
Gallons
MJ
• Achieves the highest
efficiency, however is
undersized for the
estimated BAPP loads.
• The undersized system
allows for more
utilization of the coolant
energy, driving up the
efficiency.
57
BAPP Mode Two Results
Mode Two Results: Regeneration Load Follow
Annual Net Energy Import
7,008,961
MJ
Annual Net Thermal Energy Import
4,146,361
MJ
Annual Net Electrical Energy Import
2,862,600
MJ
Hours of Operation
1,042
Hours
Heating Hours Not Met
5,653
Hours
Cooling Hours Not Met
2,942
Hours
Regeneration Hours Not Met
7,283
Hours
Total Energy Used
Total Fuel Consumption
Total Fuel Energy Consumption
Average Annual Efficiency
504,924
4,706
640,713
MJ
Gallons
MJ
• Most of the loads were
not met as the majority of
the time the regeneration
load is below 25% of the
engines operating
capacity.
• Again, the turndown ratio
of the CHP system is not
small enough.
79%
• Operates for ~1,000
hours annually.
58
Steam Generate T-Q Diagram
1000
900
Temperature (oF)
800
700
Exhaust at 25 kWe
600
500
Exhaust at 6 kWe
400
Saturated Steam
(87psig)
300
Condensate
200
Domestic Hot Water
100
0
0
5
10
15
Heat Transfer (kWt)
20
25
59
Coolant Heat Exchanger T-Q Diagram at 25kWe
210
Temperature (oF)
Coolant (12 GPM)
190
Summer Operation
Water (12 GPM)
170
150
130
Coolant (2 GPM)
110
Water (4 GPM)
Winter Operation
90
0
5
10
Heat Transfer (kWt)
15
20
60
High Performance Building Guidelines
• High performance building guidelines require
that the entire energy supply process from fuel
to terminal units is understood and integrated.
– Separating heating and cooling from ventilation
allows for the use of desiccant regeneration
providing an additional load for a CHP system.
– Using low temperature heating systems influences
the control and the design of the heat recovery
systems and the operation of the engine.
– Understanding the entire energy supply system
informs the design process and the energy
cascade.
61
CHP Results
• Plant overall efficiency through winter: 77%
• Engine brake efficiency:
– 6kWe = 6.8 kWm = 26%
– 12kWe = 13.6 kWm = 32%
– 18kWe = 20.5 kWm = 36%
– 25kWe = 28.4 kWm = 37%
62
Definitions
• Distributed Generation (DG)
– An electrical power source with a capacity of less than
5 MW electrical
• Combined Cooling – Heating and Power (CCHP)
– Burning a single source of fuel to generate electrical
and thermal energy.
– Commonly electricity and heating and/or cooling.
63
Standard Electricity Generation
2002 Electricity Flow, in Quadrillion Btu (1015 Btu) (Conversion: 1 quadrillion Btu = 293 billion kWh)
Total energy consumed to generate electricity in 2002 is 39.56 quadrillion Btu = 11.59 trillion kWh
Source: EIA, Annual Energy Review 2002, Diagram 5.
64
DG & CCHP Generation
2002 Electricity Flow, in Quadrillion Btu (1015 Btu) (Conversion: 1 quadrillion Btu = 293 billion kWh)
Total energy consumed to generate electricity in 2002 is 39.56 quadrillion Btu = 11.59 trillion kWh
Source: EIA, Annual Energy Review 2002, Diagram 5.
65
CHP vs. Conventional Power & Heat
66
Ref: www.microturbine.com