Electric heating vs. heat pump

Thanks to its “capacity” to capture energy from natural, inexhaustible and free sources, the heat pump is also considered highly efficient and respectful with the environment, both for air conditioning the house and obtaining hot water.

How does the heat pump work in heating mode?

Heat pumps are one of the most efficient air – conditioning devices s on the market to heat a home. But what is the reason?

It is necessary to explain how this system works in heat mode to understand it.

A heat pump is a thermal machine that allows energy to be transferred from one environment to another in the form of heat. Its operation is based on the 2nd Law of thermodynamics:

“Heat is directed spontaneously from a hot source to a cold one, and not vice versa until their temperatures equalize.”

For this reason, and although the heat pump’s operation can be reversed and also used to cool or obtain hot water, its primary use is heating, which is where it develops high efficiency.

Heat pumps extract heat from the outside environment and transfer it to an indoor space.

Heat pumps have an evaporator, a compressor, a condenser, and an expansion valve. In addition, there is a liquid cooling circuit inside it that absorbs heat from the air (aerothermal), the ground (geothermal), or groundwater (hydrothermal) and turns into steam.

When the heat pump is in heating mode, the objective is to heat the refrigerant by compression to obtain heat.

Once the fluid has absorbed the heat and has become vapor, it passes through a compressor in which its pressure and temperature increase. Later, this same steam, with a significant concentration of energy, gives up its heat to the space it wishes to heat.

Once the refrigerant fluid has given up energy, its temperature drops, this decrease is more significant when, inside the expansion valve, the fluid is decompressed to a point well below that it was before being compressed.

This is how the heat pump extracts heat from one place to spread it to another, and the cycle starts all over again.

Why is the heat pump an efficient heating system?

Heat pumps for heating have high efficiency, up to 400% in some cases. This high percentage is because they can obtain much more helpful energy (in the form of heat) than the energy consumption necessary to drive their operation (electricity). How do we know how efficient a heat pump for heating is?

The efficiency of a heat pump is measured through its coefficient of performance or Coefficient of Performance (COP). This value is calculated as the relationship between the thermal energy released by the system and the energy absorbed by the compressor under specific temperature conditions and with the unit at full load.

The heat pump’s performance may vary depending on the hot spot and the cold spot (in the case of the heat pump of an aerothermal system, the outside air temperature and the characteristics of the room to be heated ) and the power of the equipment.

For this reason, to calculate the performance of a heat pump for heating, in addition to the COP, it is necessary to take into account the average seasonal performance (SPF or SCOP), which is defined as the efficiency of a unit calculated for the heating demand annual reference in a specific geographical area.

An air-water heat pumps, the efficiency of the equipment is also related to the ambient humidity and the inlet temperature of the cold water.

For proper functionality, a heat pump must achieve a COP of between 2 and 6. For practical purposes, a COP 3 implies performance of 300%. This means that for every 1kWh of electricity consumed for the system to work, the heat pump contributes 3 kWh of energy in the form of heat to the accumulation tank.

In addition to its efficiency, other benefits of the heat pump as heating are:

  • It works with renewable energy. Aerothermal harnesses the heat contained in the air, a free and unlimited energy source with enormous potential.
  • It does not generate CO₂ emissions. The heat pump does not produce CO₂; therefore, it contributes to protecting the environment.
  • Save energy and money. The heat pump as heating allows to reduce up to 30% of the energy consumption in the home.
  • It is clean and comfortable. Heat pumps do not generate fumes or ashes that dirty walls, facades, or roofs. Furthermore, they only need electricity to function.

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