How Heat Pump Hot Water Heater Cold Climate Work in Winter?
The heat pump water heater can efficiently provide hot water to the home.
What about in the cold winter? Can heat pump hot water heater cold climate work
well? Yes, it can.
Cold air has heat
The heat pump hot water heater cold climate is specifically designed to
work at temperatures as low as -25C (-15F) below the freezing point. Few people
realize that the air below the freezing point has almost the same relative
energy as the air above the freezing point. By understanding the concept that
air contains energy, we can begin to understand the working principle of cold
climate heat pumps. Only in a space with a temperature of -273 C (absolutely
zero), there is no energy in the air.
Warm always turns to cold
This is the next principle used in cold climate heat pumps. Compared
with cold air, warm air has more energy and more molecular collisions, and will
naturally migrate into cold air until equilibrium is established. Therefore,
using a colder liquid, such as freon, which will not freeze before -50, we can
make the warm -25 C air transfer its energy to the colder freon in the heat
pump.
Pressure determines boiling point
Different substances have different boiling points, which can be changed
by increasing or removing pressure. The water boils at 100 C and 14.69 Psi (sea
level). However, when we lower the pressure, it will boil faster. On Mount
Everest, where the pressure is only 4.89 psi, the boiling temperature of water
is about 71 degrees Celsius. This is because the pressure is less. The
refrigeration cycle uses Freon, which changes from liquid to gas at a lower (cooler)
temperature than water. By adjusting the pressure of Freon, we can control when
this phase change occurs. Our heat pump uses a refrigerant called R410a, which
is more suitable for storing energy in colder conditions. By reducing the
pressure in the heat pump, the temperature of this refrigerant can reach -50°C.
The cold -50 Freon passes through the heat exchanger, and the warm
energy of the outside air (-25 degrees Celsius) is naturally transferred to the
colder Freon through the heat exchanger. This causes Freon to absorb energy.
When it heats up, Freon begins to evaporate (boils) and becomes a gas, and then
the Freon gas is brought to the compressor for compression, so that its
temperature increases greatly as the volume decreases. This hot gas is then
transferred through another heat exchanger, where the colder water/glycol is on
the other side, and the energy is again transformed from hot to cold, and heats
the water/glycol circuit in the home. The refrigerant loses heat, cools it back
to liquid, and starts the cycle again.
This is the basis of the refrigeration cycle. If you understand these basic principles, you can master the working principle of the heat pump even at -25 C (-15 F). A heat pump is just a means of transferring energy from one source to another. This is the same principle used in geothermal, which extracts warm energy from the ground and transports it to the house through a series of heat exchange processes.