HomeMy WebLinkAboutAmbler HR Case Study Final - REF Grant 2195453 2015Ambler, Alaska
Ambler Heat Recovery Project
Quick Facts
Total Project Costs: $501,587.62
Design: $65,250
Construction: $436,337.62
Equipment
Generator Makes/Models:
Detroit Diesel Series 60 DDEC3 (low kW loads)
Cummins KTA19 (high kW loads)
Output:
Detroit Diesel: 1,260 BTUH/kW
Cummins KTA19: 2,255 BTUH/kW
Diesel Fuel Offset
Estimated Annual: 8,864
Actual Annual: 5,000 gallons
2013-2014: 5,000 gallons
Fuel Savings
Estimated Annual: $56,020
Actual Annual: $59,000
2013-2014: $59,000
Estimated Payback: 7.7 years
Actual Payback: 8.5 years
CASE STUDY
Project Overview
Th e city of Ambler used grant funds to construct bur-
ied piping, pumps, heat exchangers, and other system
components to install a heat recovery system for the
city. Th e heat recovery system captures heat generated
by the Alaska Village Electric Cooperative (AVEC)
power plant. Upon capture, the recovered heat is pur-
chased by and transferred to the City’s water plant and
washeteria via underground arctic piping. Prior to the
project, waste heat was rejected to the atmosphere by
radiators.
Objectives
Th e main objectives for this project were to recover
waste heat fom the existing Alaska Village Electric
Cooperative power plant and confer this energy to
the new City water plant and washeteria. Doing so
reduces the release of combustion pollutants to the at-
mosphere and allows community members to reduce
electricity costs.
Heat Recovery-How it Works
As a rule of thumb, engines are 30% effi cient. Th at is,
of the fuel energy input, 30% each goes to horsepower,
jacket water heat, and exhaust heat. 10% goes to radi-
ation and other losses. Jacket water cools the engine
by dissipating almost 28% of the heat it generates. Th is
heat is low grade and isn’t of any use, so it is sent to
the atmosphere using radiator or cooling towers. Heat
recovery is a unique system in that it takes heat that is
lost to the jacket water and harnesses it for space heat-
ing. Th e jacket water loop is isolated from the build-
ing heating loop by a heat exchanger so that the heat
recovery system does not impact engine performance.
Heat Sales Agreement
In order to save the community of Ambler money on
expensive diesel fuel, AVEC entered into a heat sales
Entry/Exit
point of heat
recovery loop
at the Ambler
Water Treat-
ment Plant
Photo courte-
sy of ANTHC.
agreement with the city water plant and washeteria.
Th e water plant and washeteria agreed to purchase
the recovered heat from AVEC for 50% of what the
treatment plant would spend on diesel, a price much
lower than what the water plant and washeteria would
pay on their own. In this way, all organizations benefi t;
AVEC reduces their waste heat emissions, saves mon-
ey by reducing their own diesel purchases, and makes
money by selling waste heat to the community facili-
ties. Th e water plant and washeteria save a great deal
of money by removing the need for diesel fuel and also
reduce waste heat emissions.
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, sav-
ing 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 benefi ts outweigh the
costs by 1.34.
Allocation of Funding
Th e Renewable Energy Fund contributed $434,928.09
for the purchase and installation of the piping, pumps,
heat exchangers, and other components. Local matches
contributed $66,659.53.
Equipment & Design
A marine jacket was placed over the exhaust manifold
to recover heat given off during operation. In addition
to this, regulating valves are used so that when one
end-user (the washeteria or city water plant) heat load
is low, more of the available heat will go to the other
end-user that is currently requiring more heat.
Learning Experiences/Challenges
Th e City of Ambler originally estimated that their
annual fuel displacement would be about 8,864 gal-
lons. Since the system’s inception in October 2013, it
has displaced about 5,000 gallons. Th ough the number
is smaller than they originally anticipated, it usually
takes a couple years for the system to become highly
effi cient.
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. Th e primary benefi t of this project is the vast
amount of savings that the community and AVEC
get to experience. By using the heat sales agreement,
AVEC, the washeteria, city offi ce, and community
members all benefi t from both reduced energy costs
and cleaner air.
2. Ambler doesn’t get barge access very oft en and their
fuel last winter was approximately $11.00/gallon. Be-
cause of this project, the water plant has had to use es-
sentially zero fuel oil and they have more funds avail-
able for maintenance. Th e community is now looking
into future energy projects, 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
Email: ztressel@aidea.org
Ambler, Alaska. Photo courtesy of KTUU Channel 2 News.
Ambler, Alaska