Search Results

In 2007 the electrical power consumption of 180 rural Alaska villages was 370,000 MW-h, generated using isolated diesel gensets. From a stationary diesel engine considerable amount of heat energy at an elevated temperature is released into the atmosphere from engine jacket liquid and exhaust gases. In rural Alaska, due to the infrastructure, economic impact and needs of the villages, many of village gensets may not be appropriate for applying heat recovery for the purposes other than electrical power generation. Other appropriate types of heat recovery applications in Alaska may include desalination, refrigeration, and district heating. Also due to the varying sizes and electrical loads of most of the diesel gensets (from 100 kw to 1 MW); small-sized heat recovery power systems (80 kW or less) are preferred instead of industrial scale systems.

This paper presents test results of a 50 kW Organic Rankine Cycle (ORC) system and proposed guidelines for how to effectively apply this system to the rural Alaska power industry. In rural Alaska, approximately 180 villages rely on off-grid diesel generators for power. Most of the generators have capacities of about 1 MW or less. In general, the average operation efficiencies are noticeably less than 40%, with the rest of the fuel energy becoming heat. If the heat is not applied for useful application, it is called waste heat. Most of the wasted heat is contained in engine exhaust and jacket fluid and eventually dissipates into the environment. For rural Alaska, waste heat for heating is most effective; in many cases, waste heat for power may be needed due to a variety of reasons. Many rural Alaskan villages are reluctant to apply exhaust heat recovery due to concerns about corrosion and soot accumulation in the exhaust system and their effect on emissions.