A heat pump is a device that operates on aerothermal energy, a renewable energy source, to transfer heat from one place to another. Depending on how it is used, it can either transfer heat into a building or, conversely, remove heat from inside a building, which is a typical function of air conditioning.
Aerothermal energy is a process that harnesses the energy stored in the surrounding air in the form of heat to meet the heating, hot water, and cooling needs in our homes. It utilizes the environmental energy provided by the air, which is renewable, clean, and ensures significant energy savings compared to other heating and cooling systems.
In this article, we will explore the types of aerothermal systems that can be found. We will analyze how they operate and what their applications are.
Classification of aerothermal systems that can be found
Air-to-air aerothermal systems
Heat transfer is done directly to the ambient air. When it comes to heating, heat is extracted from the air and delivered directly to the air in the area that needs to be heated. If we’re talking about a reversible heat pump for air conditioning, the process is reversed. Heat is extracted from the room and expelled outside.
The aerothermal heat pump operates based on the principles of thermodynamics. It transports heat energy from one environment to another, a process accomplished by changing the state of a refrigerant fluid from gas to liquid using ambient temperature and a compressor.
These air-to-air aerothermal systems are used in air conditioning installations such as split or multisplit systems, ducted systems, VRF systems, among others.
Air-to-water aerothermal for generating domestic hot water
Here, heat is extracted from the air and transferred to a water circuit.
In the case of aerothermal systems for domestic hot water and heating, the heat released in the condenser is transferred to the water through a heat exchanger. The hot water is stored in a tank, ready for use for several hours before it cools down.
The Technical Building Code (CTE) in Spain requires new buildings to use renewable energy sources to generate domestic hot water. However, in its basic document DB HE4, it specifies that solar thermal energy can be replaced by other renewable energy sources if the CO2 emissions and non-renewable primary energy consumption of the alternative installation are equal to or lower than those of the solar thermal installation. Equipment using aerothermal energy as the main source of energy (heat pumps) meets this criterion.
Air-to-water aerothermal for air conditioning
With air-to-water aerothermal systems, heat exchange is achieved using a water circuit that cools down, and this water is what cools the ambient air. This exchange can be done through two systems: radiant floor or fan coils.
In a radiant floor system, the machine circulates cold water through the floor. It is suitable for areas with low humidity and not extremely hot conditions.
The fan coil unit receives cold water from the outdoor unit. A fan drives the air and passes it through the tubes through which cold water circulates, causing a change in temperature. After passing through the filter, the cooled air is released, conditioning the environment.
Hybrid aerothermal systems with photovoltaic solar energy
Although it is not a specific variety of aerothermal energy, we want to make a special mention of the ability of aerothermal heat pumps to operate in a hybrid manner with a photovoltaic solar panel system. Recent changes in legislation regarding electricity self-consumption, which improve the conditions for connecting photovoltaic installations, make their installation very attractive.
The combination of air-to-water aerothermal heat pumps, radiant cooling systems, and photovoltaic solar energy, when correctly sized, can provide high levels of comfort, minimal CO2 emissions, and very low maintenance costs.
The ideal installation is one that, through the photovoltaic system, generates the energy needed to cover most of the electricity consumption of the residence, including that of the aerothermal system.
Advantages of aerothermal heat pumps
They are highly efficient systems, easy to install, safe, and have reduced maintenance costs.
Aerothermal heat pumps deliver more useful energy (in the form of heat) than they consume for their operation (electricity), potentially resulting in savings of approximately 40% compared to traditional heating systems such as gas, electricity, or diesel.