This project will assess the feasibility of solar hot water heating systems on residential units in the NANA Region of Kotzebue. The Kotzebue Community Energy Task Force (CETF) has identified up to ten Elders homes which are most in need of home heating assistance. These homes will serve as test sites. Six solar-thermal heating systems, some using flat plate and some using evacuated tubes, have been installed. If the technology proves feasible above the Arctic Circle, these systems could be installed in homes throughout the region and serve as a model for alternative methods to heat homes without the use of fossil fuels.
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Table of Contents
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Project Outline
Solar thermal systems are not a new technology, but the technology is not widespread in Alaska. Using solar thermal power to actively supplement other methods of water and space heating has many benefits; however the deployment in northern Alaska has been nearly non-existent for several reasons, primarily economic. The benefits of solar thermal will become increasingly obvious as fossil fuel prices continue to rise. Initial modeling done in ReScreen showed a payback on these systems in less than 8 years-finance depending-but this payback must first be demonstrated in order to streamline the design of these systems using off-the-shelf technology. It is important to note that in the time between the initial grant application and the following award, the price structures of the equipment and labor increased.
Objectives
The objective of this project is to mitigate the rising costs of home heating in rural Alaska. Kotzebue Electric Association (KEA) has installed six solar-thermal heating systems, each in different homes, to assess the feasibility of this technology above the Arctic Circle. To our knowledge, not very many people have experimented with this technology at this latitude; however, Alaska Battery Systems has installed one system in Nome, and the Cold Climate Housing Research Center has installed both an evacuated tube space heating solar thermal system and a glazed panel water heating system in Fairbanks. Each system has its advantages and disadvantages; the purpose of this project is to determine the most efficient combination for home space and/or water heating.
Technology
Solar Thermal
Solar thermal technology converts energy from the sun into thermal energy. There is a wide array of technology types and applications, but all types primarily produce heat as opposed to electricity, like PV systems.
Solar heating technology converts solar energy for heating applications such as water heating, space heating and space cooling. One main component of a solar-heating system is the solar collector, which converts the sun's radiation into heat and conducts the heat to a heat transfer fluid such as water, air or ethylene glycol. Other components include storage, heat exchangers, pumps and controls.
There are several common types of active solar collector systems, which rely on pumps or controls to circulate heat transfer fluid through a collector. A flat-plate solar collector is comprised of a flat absorbing surface that is heated by sunlight. A heat transfer fluid such as water or ethylene glycol passes through the collector by a series of tubes, and heat is transferred from the absorbing surface to the heat transfer fluid. While typically inexpensive, these types of collectors can be hindered in cold-weather applications as their performance can be strongly influenced by the ambient temperature.
Another common active solar collector system is an evacuated-tube collector. In this system, tubes of transparent, evacuated glass are attached to piping at either end, filled with a heat transfer fluid. Metal conduction material inside the tubes conducts heat to the fluid, while the vacuum reduces heat loss to radiation and convection. Although evacuated-tube systems are typically more expensive than flat-plate collectors, they have an advantage in cold-weather application as the amount of energy they absorb is not strongly dependent on the ambient temperature.
Cold Climate Housing Research Center found an interesting phenomenon: while flat panel collectors are less efficient than evacuated-tube collectors in cold weather, the heat that was released from the flat panel collectors caused snow to melt off of the panels. This allowed solar thermal…
Arctic Applications
The solar resource in Alaska is significant, but utilization of solar technology has been limited. Historically, major challenges to using solar energy technology in Alaska are its seasonal variability and its dependence on weather conditions. In general, the solar resource is most abundant in the summer, when it is least needed. However, there is a reasonable resource available for seven to eight months of the year for all but the most northern areas of the state. Technological advances, particularly in solar thermal technology, could bridge this gap between availability of the resource and energy needs. There is a large amount of research currently under way focusing on bridging this gap, with aspirations of elevating solar energy to a viable Alaskan renewable resource.
20% of the total heating fuel in the Northwest Arctic Borough is used to heat water. Solar thermal hot water heating could be practical for up to nine months out of the year, ultimately displacing 50% of annual hot water heating needs. There are numerous ways to design a solar hot water heating system: with flat plates or evacuated tubes, tracking mount or fixed mount, large or small storage tanks. Each installed system will have a different configuration so that a comparison can be made for each home and recommendations will be made accordingly.
A typical 2,000 square foot house, rated at R20 with an indoor design temp of 65°F, will require 768 Btu/hr-F. This comes out to an annual requirement of 289 MMBtu based on Kotzebue monthly temperature averages. If heated with #2 diesel at $6.00 per gallon, this home will cost $15,606.
Work Plan
Site Identification
KEA has coordinated with the Kotzebue CETF to identify homes that are suitable for this demonstration project. KEA and CETF had over 25 applicants and 10 met the following criteria: Elders status in Kotzebue, full-time Elders residence, and currently on State Energy Assistance. KEA then worked with CETF and Susitna Energy Systems (SES) designers to identify the homes with the least amount of equipment needed in order to demonstrate the most systems. After careful review, and pricing evaluations, 6 homes where selected for solar collectors.
Planning and Design
Several of the 6 homes selected for this demonstration project utilize hydronic base board heating to heat the homes. In this type of home heating system, a glycol based fluid is heated by the same boiler that heats domestic hot water. It is therefore possible to allow a solar thermal collector to pre-heat both systems. This requires slightly more complex plumbing and more advanced, thus more expensive, storage tanks.
In order to best demonstrate the capacity of solar thermal collectors to reduce fossil fuel consumption, and therefore energy cost, KEA deemed it necessary to install both DHW (domestic hot water) systems as well as combined DHW and hydronic base board heating capacity. Again, the selection of which homes would receive DHW or combined systems was based on costs of installation and space within the home’s utility room to accommodate the necessary equipment.
Final System Selection
Additionally, this demonstration project needed to evaluate the production differences between flat plate and evacuated tube solar collectors. There are several manufacturers with respectable reputations that make both types of collectors, but only two that are well-represented with installation companies here in Alaska: Viessmann Manufacturing Company Inc., represented by Gensco Alaska and installed by Susitna Energy Systems (SES), and Heliodyne Inc, represented and installed by Alaska Battery Systems (ABS). KEA elected to split the 6 homes between the two manufacturing and installation companies as well as to purchase both flat plates and evacuated tubes from each.
Generally, evacuated tube solar thermal collectors have performed slightly better than flat plate collectors in the lower 48. However, evacuated tubes are more expensive and have the capacity to be more troublesome and fragile. In the interest of installing and testing the most systems, KEA elected to install 2 evacuated tube and 4 flat plat systems as follows:
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The specific angle of each solar collector was also considered. Generally, a solar collector is south-facing with an angle approximate to the latitude on site. This is the case with 4 of the collectors. The two Viessmann flat plate collectors were installed at the angle of the roof (approximately 29 degrees) for two reasons: 1) reduced wind resistance (lowering the possibility of damage to the unit), and 2) to determine if the DHW-only systems would benefit from increased production during summer months when the sun in Kotzebue stays high in the sky for 18-24 hours and the boiler systems in the homes are generally not running to produce space heating.
Funding Outline
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Funding Goals
This project is a Denali Commission EETG Program project. The funding goal of the EETG program is to develop emerging energy technology that has the potential of widespread deployment in Alaska and has the long-term goal of reducing energy costs for Alaskans.
Project Recipient
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Kotzebue Electric Association is a rural electric utility cooperative, based in Kotzebue, Alaska. KEA has 840 members, and generates over 18 million kilowatt hours per year. |
Grant Management
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The Alaska Center for Energy and Power (ACEP), an energy research group housed under the Institute of Northern Engineering at the University of Alaska, Fairbanks, is serving as the program manager of the EETG solicitation. As the projects deal with emerging energy technology and by nature are high risk, high reward, ACEP’s technical knowledge and objective academic management of the projects, specifically for data collection, analysis, and reporting, is a vital component to the intent of the solicitation, i.e., providing lessons learned and recommendations. |
Project Partnerships
Community Energy Task Force
The citizens of Kotzebue have created a Community Energy Task Force committee, made up of leaders of the community of Kotzebue who meet regularly to find ways to alleviate the ongoing energy crisis. In particular, the CETF has focused its efforts on helping the elders. CETF was formed and recommended by the participants of the Northwest Arctic Energy Summit that was held in June 2008 in Kotzebue.
NANA Regional Corporation
NANA Regional Corporation, Inc. (NANA) is a Regional Alaska Native corporation formed in 1971 under the Alaska Native Land Claims Settlement Act (ANCSA). The NANA region is located in northwest Alaska. It encompasses an area that is 38,000 square miles, most of which is above the Arctic Circle. There are 11 villages in the region. They are: Ambler, Buckland, Deering, Kiana, Kivalina, Kobuk, Kotzebue, Noatak, Noorvik, Selawik and Shungnak.
ABS Alaska
Since its inception in 1988, ABS Alaska, Inc. has continued a thirty-year tradition of excellence to establish itself as the premier source in Alaska for batteries, alternative energy, and remote or mobile power products. ABS has two distribution centers in Alaska: its Fairbanks headquarters and Alaska Battery Mfg. in Anchorage.
Susitna Energy
Susitna Energy Systems is Alaska's premier source for alternative energy systems and other energy saving solutions. Susitna Energy Systems has solar, wind, hydroelectric, diesel generators, batteries and more for Alaskans' energy needs.
Project Documents
Included below are quarterly reports, project photos, and supplementary documentation. Check back quarterly for updates!
Project Information
Supplementary Information
Quarterly Reports
Milestone Reports
Data and Analysis
Check back quarterly for project results
Photos
KEA Site Visit, November 2010
Video
EET Forum 2-14-11 Presentation
EET Forum 2-14-11 Q&A
