The Working Principle of Heat Pump Hot Water Heater Cold Climate
Speaking of the topic of heat pump hot water, there will inevitably be a
question: but do they work in a cold climate environment?
Yes, it will. Below we explain to you why the heat pump water heater
will work in the cold winter.
Cold air has energy
Cold climate heat pumps are 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 changes to cold
This is the next principle used in 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 is heated, 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 converted from heat 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.
It is determined that the heat pump water heater can be used in the cold
winter. The following are the precautions for buying a cold climate heat pump:
Buy the right equipment
Air source heat pump technology has made great strides in the past 10
years. Even if the outdoor temperature drops to -12 degrees Fahrenheit, a
cold-climate heat pump can heat the house, and only 3% of the time and 10% of
the time require additional resistance heating.
The key is to buy the right equipment for your climate zone from the
start.
The colder the climate, the more important it is to ensure that the
correct equipment is found when power is applied. There are cold climate heat
pumps specially made for cold climates. If you just install a typical heat pump
in a cold climate, then you will not succeed.
The importance of changing building codes
Because heat pumps are now a viable option in cold climates. But you
need to adopt stricter building codes to improve the floors of electrified
buildings. A well-installed all-electric building will greatly reduce your
carbon emission level.
Need more thoughtful design
Properly achieving electrification may require additional
pre-construction planning.
1. In cold climates, heat pump water heaters should be installed in the
home rather than in the garage for best performance.
2. Installing heat pump water heaters indoors requires the builder to
leave more space for the unit, but it also does not require the use of less
efficient backup resistance heating.
3. If you pay attention to the correct selection and installation of
heat pumps, it should help ensure that contractors, builders and homeowners
will not give up heat pumps because of a bad experience.
Use with solar photovoltaic panels
If an air source heat pump or heat pump water heater is installed in a new house, and it is also equipped with a compact building envelope and roof solar photovoltaic panels, electrification is economical even in the harshest winter areas.