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.