• 1985 Alaska Field Survey of Part-Loading of Diesel-Electric Generators

      Johnson, Ronald; Gray, John (1986-03)
      By conducting a survey by mail, by phone and in person, we obtained information on 356 diesel electric generator sets in Alaska in 1985. User groups surveyed included the Alaska Village Electric Cooperative (AVEC), public school districts, those certified by the Alaska Public Utilities Commission, the Tanana Chiefs, and the Alaska Department of Transportation and Public Facilities. Our survey focused on part-load operation. We found that a lack of detailed site-specific data precludes making a general quantitative statement about part loading. The most detailed data, by far, are those collected by AVEC. Those data plus some other information indicate that many gensets (some for good reasons) are underloaded, especially in the summer. The simple algebraic average July and January loadings for the 44 AVEC systems surveyed are close to 35% and 50%, respectively. Minimum loads as low as 15% occurred in the summer. AVEC recognizes the potential for improvement and has increased its system-wide efficiency by 25% from 1980 to 1985.
    • Air-Flow Dindows - an Evaluation of Their Potential for use in Arctic and Sub-Arctic Environments

      Lemon, Frank L. (1986-06)
      Air-flow windows, developed in Scandinavia, are being considered for application in arctic and sub-arctic environments. Air-flow windows consist of a double or triple-glazed outer sash and a single glazed inner sash. Room air is returned to the building heating, ventilating and air-conditioning system through the window every cavity existing between the inner and outer sashes, thus warming the inner pane of glass. Air-flow windows have the potential of improving room comfort and reducint building heat losses, particularly if the outdoor air requirement is greater than or at least can be matched to the air extracted through the windows. A sample air-flow window was tested in a guarded hot box at various air flow rates at cold side temperatures ranging from -50(degrees)F to +10(degrees)F. Based on the test results, U-values were calculated for winter night time conditions. The economics of this window system are discussed. The energy balance of an air-flow window is established.
    • Air-to-Air Heat Recovery Devices for Small Buildings

      Zarling, John P. (1981-01)
      With the escalation of fuel costs, many people are turning to tighter, better insulated buildings as a means of achieving energy conservation. This is especially true in northern climates, where heating seasons are long and severe. Installing efficient well sealed vapor barriers and weather stripping and caulking around doors and windows reduces cold air infiltration but can lead to damaging moisture buildup, as well as unpleasant and even unhealthy accumulations of odors and gases. To provide the necessary ventilation air to maintain air quality in homes while holding down energy costs, air-to-air heat exchangers have been proposed for residential and other simple structures normally not served by an active or forced ventilation system. Four basic types of air-to-air heat exchangers are suited for small scale use: rotary, coil-loop, heat pipe, and plate. The operating principles of each of these units are presented and their individual advantages and disadvantages are discusses. A test program has been initiated to evaluate the performance of a few commercial units as well as several units designed and/or built at the University of Alaska. Preliminary results from several of these tests are presented along with a critique on their design.
    • Air-to-Air Heat Recovery Devices for Small Buildings

      Zarling, John P. (1982-05)
      With the escalation of fuel costs, many people are turning to tighter, better insulated buildings as a means of achieving energy conservation. This is especially true in norther climates, where heating seasons are long and severe. Installing efficient well sealed vapor barriers and weather stripping and caulking around doors and windows reduces cold air infiltration but can lead to damaging moisture buildup, as well as unpleasant and even unhealthy accumulations of odors and gases. To provide the necessary ventilation air to maintain air quality in homes while holding down energy costs, air-to-air heat exchangers have been proposed for residential and other simple structures normally not served by an active or forced ventilation system. Four basic types of air-to-air heat exchangers are suited for small scale use: rotary, coil-loop, heat pipe, and plate. The operating principles of each of these units are presented and their individual advantages and disadvantages are discussed. A test program has been initiated to evaluate the performance of a few commercial units as well as several units designed and/or built at the University of Alaska. Preliminary results from several of these tests are presented along with a critique on their design.
    • Report Supplement: Thermal and Cost Analysis of Thermal Envelopes for a Small Rural School

      Zarling, John; Strandberg, James S.; Maynard and Partch; HMS, Inc. (1983-01)