Heat Pump Water Heater For Cold Climate – Canada

Abstract

Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

Modelling and Energy Management Control Study for a Net Zero Energy Home

“…Brought forward by extensive research geared towards diminishing DHWH energy consumption, Air Source Heat Pump Water Heater (ASHPWH) have become a promising alternative for cold climate applications. Performing at efficiencies that are 2 to 2.5 times the efficiency of conventional electric water heaters [12], ASHPWH can provide a reduction of 60.3% and 53.2% in DHWH electric energy consumption for a residential building in Canada, during the summer and winter seasons respectively [13]. This study will investigate the performance achieved by the A.O.…”

“…This study will investigate the performance achieved by the A.O. Smith residential hybrid electric ASHPWH, which is installed in the ASH B [13]. The system features four modes of operation, including efficiency mode, hybrid mode, electric mode and vacation mode.…”

“…Energy recovery by the DWHR unit works by extracting heat from drained water released by water fixtures such as showers and faucets, and uses it to heat the house inlet water flowing through the supply line. The effectiveness (ER) of the DWHR, found from the manufacturer data, is stated to be 53.3% by applying the CSA B55.1 testing protocol which specified all required performance measurements be made with flow rate of 2.5 GPM [13,15].…”

“…Unlike electric heaters, heat pump performance is influenced by the average water temperature in storage and the air temperature of the ambient adjacent to the ASHPWH. In a study done by Amirirad [13], energy factor (EF) was defined as the supplied energy, according to the water draw schedule, over the energy required to maintain the water in the tank at the set point temperature. Following this definition, EF were determined for heat pump and electric heaters following draw schedules at ambient air conditions of 15°C and 25°C [13].…”

“…In a study done by Amirirad [13], energy factor (EF) was defined as the supplied energy, according to the water draw schedule, over the energy required to maintain the water in the tank at the set point temperature. Following this definition, EF were determined for heat pump and electric heaters following draw schedules at ambient air conditions of 15°C and 25°C [13]. Assuming the relation between EF versus ambient air temperature to be linear, equations for linear interpolation functions were developed using the data points found in Figure 15 (heat pump) and Figure 16 (electric heater).…”