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Heat pumps can be defined as a “thermal machine that, using a refrigerant gas in a closed thermodynamic cycle, transfers heat from the natural environment—air, water, or ground—to a building or industrial applications by reversing the natural flow of heat so that it flows from a lower temperature to a higher one.”
Consequently, heat pumps are devices capable of transferring heat between two media at different temperatures, effectively “pumping” heat between them, which grants these units a series of benefits:
- They are devices capable of heating spaces by harnessing available heat from an external medium (air, water, or ground) at a lower temperature, and inversely, by reversing the cycle, they can cool those spaces by expelling heat to a higher temperature external medium.
- By capturing available heat from external sources, they utilize energy from renewable sources: air (aerothermal), water (hydrothermal), or ground (geothermal).
- With the drive energy of the equipment, they transfer a much higher amount of thermal energy, giving them a “multiplier” effect that makes them highly efficient.
- They allow for the utilization of residual energy sources available in our environment to heat or cool spaces, whether from climate systems (like ventilation) or from processes inherent to human activity (wastewater, industrial processes, etc.).
HOW DOES A HEAT PUMP WORK?
To transfer heat, heat pumps make use of refrigerants that release heat when changing from gas to liquid, and absorb heat when doing the opposite. By altering the thermodynamic properties of the refrigerant within a closed thermodynamic cycle, heat is transferred in the desired direction, adding or removing heat from a space.
This cycle is known as the “Compression Refrigeration Cycle”, depicted in the following image, which shows the four defining processes:
- Evaporation Process: heat absorption (cooling) occurs as the refrigerant evaporates at low pressure within a heat exchanger called the Evaporator.
- Compression Process: gas pressure and energy content are increased by a Compressor.
- Condensation Process: heat is released (heating) as the gas condenses at high pressure within another heat exchanger, the Condenser, where the refrigerant becomes liquid.
- Expansion Process: refrigerant pressure is reduced through an Expansion Valve or Device, turning it into a mix of liquid and vapor.
WHAT ARE THE COMPONENTS OF HEAT PUMPS?
These processes are carried out by the main components already mentioned: Evaporator, Compressor, Condenser and Expansion Device. To these must be added, in the case of reversible heat pumps, the reversing valve or 4-way valve, which reverses the direction of the refrigeration cycle, so that the internal exchanger that acts as “Evaporator” in the cold production cycle, becomes the “Condenser” in the heat production cycle, and the external exchanger that acts as “Condenser” in the cold production cycle, becomes the “Evaporator” in the heat production cycle.
Indoor Heat Exchanger <-> installation side (space to be air-conditioned)
Outdoor Heat Exchanger <-> source side (air, water or ground).
This means that the reversible heat pumps have a power that no other air conditioning technology has. The same equipment can produce heating and/or domestic hot water (DHW) or cooling, simply by activating the desired cycle.
INSTALLATION CONSIDERATIONS
In the last decade, heat pump technology has evolved significantly. They are more efficient, thanks to the improvement in their components and design. They have a greater capacity of regulation and communication with other systems. This evolution has led to greater possibilities of selection and operation of this equipment. Therefore, the requirements, in terms of selection, assembly and operation, are more extensive.
It is essential that the selection and installation of the heat pump are adequate to ensure that it will operate according to the specifications of the air conditioning installation. And also that it will meet the needs and expectations of it. This requires that the equipment is installed by a qualified professional who has the appropriate means to do so. This applies both to the refrigeration part and to the mechanical, electrical and control elements.
A qualified installer, who has a fluid relationship with the manufacturer, will have a deep knowledge of the heat pump to be installed. In addition, he will have the necessary technical documentation and will have access to training courses provided by the manufacturers. All this will allow you to make a correct installation, taking advantage of the performance of the heat pump, making it work in its best conditions, which will mean that it will work in its maximum efficiency zone, having a longer life cycle.
BENEFITS OF HEAT PUMPS
Heat pumps offer numerous benefits thanks to their advanced technology. Key advantages include:
- Comfort. They generate a healthy environment by maintaining an optimal ambient temperature, and many types include filters for high air quality.
- Efficiency. They multiply the electric or thermal energy they consume with free energy from external sources.
- Savings. Only part of the generated thermal energy corresponds to the consumed energy, reducing operating costs.
- Reliability. Heat pumps are widely used in commercial and industrial sectors with high HVAC needs due to their advanced yet mature technology.
- Simplicity. They require minimal maintenance and, with closed refrigerant circuits, no gas refills.
- Sustainability. By using renewable energy sources, they reduce indirect CO2 emissions, thanks to their high efficiency.
- Versatility. They can provide heating, cooling, and hot water year-round, with a variety of models for different needs.
CONCLUSION
The Heat Pump, the best choice for climate control. Heat pumps extract energy from the natural environment (air, water, or ground) to warm indoor spaces. Optimizing the design of the refrigeration circuit elements (including refrigerant selection) is essential to maximize efficiency and minimize heating costs. It is ideal to have a heat pump designed for each specific service—fan-coil water heating, pool water heating, high-temperature applications, etc., to achieve maximum performance.
This information has been provided by the Asociación de Fabricantes de Equipos de Climatización – AFEC, which developed a Heat Pump Promotion Plan in collaboration with 21 of its member companies to promote the use of heat pumps as a reliable, efficient, and renewable energy-based technology for HVAC and domestic hot water.
Borealis Thermal Energy designs and manufactures climate control and refrigeration equipment aimed at energy savings, reduced installation costs, and industrial and architectural integration, specializing in Geothermal Heat Pumps and dehumidifiers for indoor pools.
