HomeMy WebLinkAboutAmbler_Heat_Recovery_Case_Study_Aug_2015_REF_Grant_2195453Ambler, Alaska
Water plant displaces nearly 100% of diesel fuel with heat recovery
Quick Facts
Total Project Costs: $501,588
Design: $65,250
Construction: $436,338
Equipment
Generator Makes/Models
Detroit Diesel Series 60 DDEC3 (low kW loads)
Cummins KTA19 (high kW loads)
Heat Output
Detroit Diesel: 1,260 BTUH/kW
Cummins KTA19: 2,255 BTUH/kW
Diesel Fuel Offset
Estimated Annual: 8,864 gallons
Actual Annual: 4,000 gallons
Oct. 2013-Dec. 2014: 5,000 gallons
Fuel Savings
Estimated Annual: $56,020
Actual Annual: $48,000
Oct. 2013-Dec. 2014: $59,000
Benefi t/Cost Ratio: 1.34
Ambler Heat Recovery Project
Project Overview
Using funds from the Alaska Energy Authority (AEA),
the City of Ambler partnered with the Alaska Village
Electric Cooperative (AVEC) and the Alaska Native
Tribal Health Consortium (ANTHC) to construct a
heat recovery system. Th e project installed buried pip-
ing, pumps, heat exchangers, and other system com-
ponents to capture heat generated by the AVEC power
plant. Upon capture, the recovered heat is purchased
by and transferred to the city’s water plant via under-
ground arctic piping. Prior to this project, waste heat
was emitted to the atmosphere by radiators.
Objectives
Th e main objectives of this project were to recover
waste heat from the existing AVEC power plant and
transfer this energy to the city’s water treatment plant.
Th e system reduces the release of combustion emis-
sions to the atmosphere and allows community mem-
bers to reduce monthly water and sewage costs.
Heat Recovery-How it Works
As a rule of thumb, engines are 30 percent effi cient.
Th at is, of the fuel energy input, 30 percent each goes
to horsepower, jacket water heat, and exhaust heat. 10
percent goes to radiation and other losses. Jacket wa-
ter cools the engine by dissipating almost 28 percent
of the heat it generates. Th is low grade heat is sent
to the atmosphere using radiators or cooling tow-
ers. Heat recovery is a unique system that takes heat
captured in the jacket water and harnesses it for space
heating. A heat exchanger isolates the jacket water
loop from the building heating loop so that the heat
recovery system does not impact engine performance.
Heat Sales Agreement
To displace diesel fuel, the City of Ambler entered into
a heat sales agreement with AVEC. Th e city’s water
Entry/Exit point of
heat recovery loop
at the Ambler Water
Treatment Plant, photo
courtesy of ANTHC.
h heat recovery
“As a result of this
project, Ambler
residents pay
approximately 13
percent less on
their monthly water
and sewage bills.”
treatment plant agreed to purchase recovered heat
from AVEC for 50 percent of the treatment plant’s nor-
mal fuel purchase price. In this way, all organizations
benefi t; AVEC reduces emissions and makes money
by selling recovered heat to the water treatment. Th e
water treatment plant reduces their emissions and
fuel costs by using recovered waste heat. Community
members also have a reduced water and sewage bill.
Economic Feasibility
Th e system became operational in October 2013. Since
its inception it has provided 516 MMBtu of thermal
energy and displaced 5,000 gallons of diesel fuel. Th is
displacement has saved the community $59,000 in
energy costs. Over its 20-year lifespan, the project has
a calculated benefi t/cost ratio of 1.34, meaning that the
project will see a 134 percent return on investment.
Allocation of Funding
Th e Renewable Energy Fund contributed $434,928 for
the purchase and installation of the piping, pumps,
heat exchangers, and other components. Local matches
contributed $66,659.
Relevant Information
Th e heat recovery system is designed to reduce the
amount of fuel consumed at the end user building and
is not intended to serve as a primary heat source. Th e
heating system in the end user building must be fully
operational, maintained, and set to operate at appro-
priate temperatures to allow the heat recovery system
to function. Th e amount of heat available for recovery
varies with the electrical load on the generators.
Learning Experiences/Challenges
Th e City of Ambler originally estimated that their an-
nual fuel displacement would be about 8,864 gallons.
Since the system’s inception in October 2013, it has
displaced about 5,000 gallons. Although the number is
smaller than they originally anticipated, the system is
operating as designed and is displacing the majority of
the water treatment plant’s heating fuel.
A second learning experience was that the construc-
tion phase was planned for August 2009 through April
2010. Because of the threat of freeze-up, the window
for trenching and installation of underground piping
was very short. Project scheduling was critical.
Community Benefi ts
1. By using the heat sales agreement, AVEC, the water
treatment plant, and community members all benefi t
from reduced energy costs and cleaner air. Before this
project, community households were suff ering as a re-
sult of high water and sewage costs. Now that the water
treatment plant has lowered their operating costs,
they can aff ord to pass this savings onto community
members. Residents now pay 13 percent less on their
monthly bill than what they paid prior to this project.
2. In the winter of 2014, Ambler’s average fuel price
was approximately $11/gallon. Th is project has dis-
placed nearly 100 percent of the water plant’s fuel oil,
letting them avoid high prices and allocate more funds
to maintenance. Because of this project’s success, the
community is looking into other renewable energy
alternatives, including biomass.
Project Contact Information
Parties Involved:
Eric Hanssen, project engineer ANTHC
Email: echanssen@anthc.org
Phone: 907-729-3620
Carl Remley, energy coordinator ANTHC
Email: cremley@anthc.org
Phone: 907-729-3543
Case Study Author:
Zoe Tressel, AEA
Website: Akenergyauthority.org
Phone: 907-771-3000
Ambler, Alaska, photo courtesy of Nana.com
Ambler Heat Recovery Project
Published August, 2015