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“Get it while it’s Hot” Sewage Heat Technology Assessment
Presenter
Mike Harvey
2
Milwaukee MSD
Debra Jensen
Credits:
3
Objectives
Discuss Economics and
Triple Bottom Line Analysis
Review Case Studies
Globally
Discuss Sewage Heat
Recovery Technologies
Retrofit Feasibility
Respond to Questions
4
Introduction
• Strong trend toward optimization
of energy utilization within
municipalities in recent year
• Focus has been in water reclamation facilities
• Growing opportunities in collection systems
• Significant number in Europe
• Some in Canada and US
5
Technologies
Five technologies selected for review:
• ThermWin by Huber Technology
• SHARC System by International Water Systems
• PKS-Thermpipe by Frank Der Vorsprung
• TubeWin by Huber Technology
• Rabtherm Series by Rabtherm Energy Systems
Wet Well (Modular)
Heat Exchange Removes wastewater from sewer to
perform heat exchange
7
ThermWin
• Best applied to flows
greater than 150 gpm
• Filters wastewater
using the “ROK 4”
screen
• Utilizes “RoWin”
modular heat
exchanger
• Heating Capacity :
> 200 mBTU/hr
Schematic Drawing of Typical
ThermWin System
8
ThermWin
• Vertically lifts screenings with screw
• Screened wastewater sent to RoWin Heat Exchanger
• Heated water sent to heat pump/boiler for use in facility
RoWin Heat Exchanger RoK 4 Screen
9
SHARC
• Self-contained clog-proof filtering
system
• Reduces odor issues / fouling
• Installed in British Columbia,
Canada
• Seven35 and Sail
Communities
• In design for Seattle, WA (2015)
SHARC Screen
10
SHARC
In-Sewer
Heat Exchange Utilizes heat exchanger within sewer pipe
12
TubeWin
• Heat exchange
modules arranged
in pairs
• Best where 70-500
mBTU/hr is needed
TubeWin System
13
TubeWin
• Comprised of heat
exchange modules
• 4.25 feet long
• Each module transfers
~ 3,400 BTU/hr
• Minimum: 15 pairs
• 10.2 mBTU/hr
• Maximum: 75 pairs
• 500mBTU/hr
• Relatively new technology
TubeWin System
14
• Series E – Heat exchange liners (existing pipe)
• Series I – Integrated heat exchangers (new pipe)
• Common Length:
• 100 to 200 feet
• 350 mBTU/hr
• Anti-fouling System
Rabtherm Series
Rabtherm Series I
15
Rabtherm Series
• Based on ten installations, minimum flow ranges
from 175 gpm to 5,000 gpm
• Series I system contained within pipe wall
• No reduction in flow area
(see schematic)
16
PKS-Thermpipe
• Polyethylene pipe surrounded by
circumfrential loops
• Transfer heat to a boiler and/or
heat pump
• Greater durability
• Draws heat from wastewater
and surrounding soil
• Hybrid sewer heat recovery and
geothermal heat recovery
PKS-Thermpipe
17
PKS-Thermpipe
• 12-inch to 72-inch diameter available
• Expected heat extraction:
• 375 BTU/hr per linear foot (12-inch pipe)
• 1900 BTU/hr per linear foot (72-inch pipe)
• Recommended for consumers less than 100 feet from sewer
• Systems in Germany and France.
• None currently in the U.S. / Canada
18
Technology Assessment
Each technology has individual strengths and
weaknesses:
• Modular systems:
• Limited by wastewater flow, temperature, and area available
for equipment footprint
• In-sewer systems:
• Limited by condition of existing sewers, length of straight
runs, slope, and wastewater flow
19
Economic Analysis
$0
$500,000
$1,000,000
$1,500,000
$2,000,000
$2,500,000
0 2,000 4,000 6,000 8,000 10,000
Insta
lled
Co
st
(In
cl. H
eat
Pu
mp
)
Heating Capacity (mBTU/hr after heat pump)
ThermWin (Modular)
SHARC (Modular)
TubeWin (Liner for Existing Pipe)
Rabtherm Series E (Liner for Existing Pipe)
Rabtherm Series I (Integrated in New Pipe at Invert)
PKS-Thermpipe (Integrated in New Pipe, Circumfrential Loops)
20
Assessment Details
Technical and Environmental elements most disparate
TR
IP
LE
B
OT
TO
M LIN
E
SOCIAL
ELEMENTS
TECHNICAL
AND
ENVIRONMENTAL
ELEMENTS
ECONOMIC
ELEMENTS
1 2 3
21
European examples
France, Germany, Austria, Switzerland
•Extensive number of projects in past several
years
• Condensed residential developments
• Office buildings – esp. government
• District heating projects
• Swimming pools
• Industries
22
Vancouver, British Columbia
Southeast False Creek Neighborhood
23
SoutheastFalse Creek – Compact and Mixed-use
North Shore
Burrard InleDowntown Peninsula
Stanley Park
False Creek
Southeast False Creek
Vancouver, British Columbia
• Facility = $29 Million
• 2010 Olympic Village
• Neighborhood Energy Utility
• Self Funded
• 70% of the heat is recovered
from sewers
• Remainder from natural gas
boilers
24
Vancouver, British Columbia
25
Vancouver, British Columbia
Seven35 Community (60 Units)
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Vancouver, British Columbia
SHARC installation reduced domestic water heating energy
use by 75%.
Previous
830 kWh/day (Natural Gas)
Current
206 kWh/day (Electricity)
27
Philadelphia, Pennsylvania
Southeast Water Pollution Control
Facility (Philadelphia Water Department)
$390,000 capital cost
978,000 BTU’s/hr
Philadelphia-based NovaThermal Energy
Unveiled April 2012
28
Philadelphia, Pennsylvania
Estimated Annual Savings Projected Cost
1 million BTU/hour unit accesses heat from an adjacent sewage channel
$18,000 $390,000 • $150,000 from Grants
• $240,000 from NovaThermal
• No cost to taxpayers
Payback – 22 years
29
• Growing potential for sewage heat recovery
• Customizable, diverse solutions for various needs
• Established technologies in Europe and Canada
• Future planning in the U.S.
• Notable examples/case studies:
• 2010 Olympic Village
(Vancouver)
• Philadelphia (Pilot Phase)
• Seattle (Planned for 2015)
Retrofit
Feasibility Assessment Where might Sewer Heat Recovery Fit?
31
Typical Criteria – from Frank PKS
Dense residential buildings or industry with a
correspondingly high supply of waste water (dry
weather flow ≥ 15 l/s).
Consumers with correspondingly high heat
requirements (≥ 50 - 200 kW).
Schools, Government buildings, shopping
centers, hospitals, hotels, swimming pools,
larger residential complexes
Relatively short distances (approx. 100 m, max.
500 m) between the heating system and the
sewage conduit.
32
Potential Candidate Sewers
33
Candidate Sewers with Candidate Landuse
