COST, DESIGN AND PERFORMANCE OF SOLAR HOT WATER IN COLD-CLIMATE HOMES

摘要

As part of the Department of Energy's Building America initiative to research home energy systems, Steven Winter Associates (SWA) has monitored long-term performance of two solar domestic water heating systems in northern climates. Both homes are occupied by 4-person families that consume 60-80 gallons of hot water daily. The prices of the systems were between USD6,000 and USD8,000. The evaluation of both systems uncovered issues that seriously compromised performance. Once repaired and commissioned, both systems collected an average of 25,000 - 30,000 Btu of solar energy daily with solar fractions near 90% during summer months and over 60% year-round. The evaluations resulted in better understanding of good design - and possible drawbacks - when incorporating auxiliary tankless water heaters. The evaluations also highlighted the cost effectiveness of such solar systems: even with rising energy prices, the cost of solar hot water in homes with efficient water heating can be hard to justify.