Final answer:
To determine the suitable condensation temperature for the heat pump, subtract the desired temperature from the evaporator temperature. Calculate the coefficient of performance (COP) using the temperature differences. The refrigerant mass flow and energy saved cannot be calculated without additional information.
Step-by-step explanation:
To determine the suitable condensation temperature for the heat pump, we need to refer to the temperature range within which it needs to operate. The heat pump is used to heat water from 15°C to 45°C, meaning the temperature difference is 30°C. Since the evaporator temperature is 12°C, the suitable condensation temperature would be around 42°C to achieve the desired temperature difference.
The coefficient of performance (COP) of a heat pump is given by the formula COP = desired temperature difference / temperature difference at the evaporator. In this case, the COP can be calculated as COP = (45 - 15) / (12 - 5), which equals 5. The COP represents the ratio of the desired heat output to the energy input.
The refrigerant mass flow can be calculated using the formula mass flow rate = heat transfer rate / (enthalpy of evaporation - enthalpy of condensation). However, the heat transfer rate is not given in the question, so this calculation cannot be performed.
The energy saved during the day by using the heat pump instead of directly heating the water can be calculated using the equation energy saved = energy consumed by electrical heater - energy consumed by heat pump. However, the energy consumed by the electrical heater and the heat pump are not provided, so this calculation cannot be performed either.