Design of a residential air source heat pump for extremely cold climates

Abstract

Air source heat pumps are energy efficient systems suitable for space heating applications, however, their performance drastically degrades in low ambient temperatures. An innovative design is proposed in this thesis that can switch operating modes to allow efficient heating operation in an ambient temperature range of -50 °C to +20 °C. The proposed design is modeled and analyzed in detail, and the system performance is applied to weather data of two northern Canadian cities. The results show remarkable performance improvement, with around 30% annual energy savings compared to similar systems available in the market. The coefficient of performance is above 2.0 and 1.5 for temperatures as low as -30 °C and -50 °C, respectively. In addition, the heating capacity is almost steady despite decreasing lower ambient temperatures, thereby solving one of the biggest challenges of this technology and eliminating the need for auxiliary heating systems, as is the current practice.