Download or read book Development of Environmentally Benign Heat Pump Water Heaters for the US Market written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Improving energy efficiency in water heating applications is important to the nation's energy strategies. Water heating in residential and commercial buildings accounts for about 10% of U.S. buildings energy consumption. Heat pump water heating (HPWH) technology is a significant breakthrough in energy efficiency, as an alternative to electric resistance water heating. Heat pump technology has shown acceptable payback period with proper incentives and successful market penetration is emerging. However, current HPWH require the use of refrigerants with high Global Warming Potential (GWP). Furthermore, current system designs depend greatly on the backup resistance heaters when the ambient temperature is below freezing or when hot water demand increases. Finally, the performance of current HPWH technology degrades greatly as the water set point temperature exceeds 330 K. This paper presents the potential for carbon dioxide, CO2, as a natural, environmentally benign alternative refrigerant for HPWH technology. In this paper, we first describe the system design, implications and opportunities of operating a transcritical cycle. Next, a prototype CO2 HPWH design featuring flexible component evaluation capability is described. The experimental setup and results are then illustrated followed by a brief discussion on the measured system performance. The paper ends with conclusions and recommendations for the development of CO2 heat pump water heating technology suitable for the U.S. market.