Coefficient of performance of heat pumps with and without vapor injection (EVI)

Heat pumps are a modern and environmentally friendly solution for heating homes and buildings. industrial, being increasingly chosen instead of traditional gas or electricity systems. One of the main indicators that determines the efficiency of these systems is performance coefficient (COP)In this article, we will compare heat pumps without EVI technology with those equipped with it. vapor injection (EVI), highlighting the significant advantages that this technology brings.

What is the coefficient of performance (COP)?

Performance coefficient is the ratio of the thermal energy delivered to the electrical energy consumed by the pump. In other words, the COP indicates how many kilowatts of heat are generated for every kilowatt of electrical energy consumed. A COP of 4 means an efficiency of 400%, which makes heat pumps very cost-effective and environmentally friendly.

It is worth noting that the COP value varies depending on the outdoor temperature and the type of technology used in the pump.

Heat pumps without vapor injection: limitations and coefficient of performance

Traditional heat pumps, without EVI technology, work well at moderate temperatures, but as the outside temperature drops, their efficiency drops rapidly. This is because at very low temperatures the compressor has to work harder to maintain the necessary pressure in the refrigerant circuit, which leads to increased electricity consumption and a decrease in COP.

For example, at –15°C, the COP of a standard system can drop to values ​​between 1.7 and 2.5, which means reduced efficiency and higher costs for the user.

EVI technology: what is it and how does it work?

Technology Enhanced Vapor Injection (EVI) is an innovation that allows heat pumps to operate efficiently even at extreme temperatures, down to –30°C or lower with a high coefficient of performance. EVI consists of injecting an additional jet of superheated vapor into the compressor's compression chamber, through a special injection system.

This process increases the temperature and pressure in the compressor, which leads to a significant improvement in the thermal and electrical coefficient of performance of the pump. EVI also reduces the risk of freezing and ensures stable operation in harsh winter conditions.

Advantages of vapor injection pumps (EVI)

• Superior performance coefficient at low temperatures — EVI pumps maintain a high COP down to –30°C, ensuring efficient heating in cold areas.
• Longer lifespan — The compressor is less stressed, which reduces wear and maintenance costs.
• Stable and safe operation — The system avoids frequent shutdowns and protects components against freezing.
• Increased yield — Increasing the condensing temperature leads to increased energy efficiency and significant savings.
• Compatibility with green technologies — Works great with photovoltaic solar panels or other renewable sources.

Performance coefficient. Detailed comparison with and without EVI

Outside air temperature (°C)	COP without EVI	COP with EVI
+7	4.0–4.2	4.6–4.9
0	3.4	4.3
–7	2.8	3.9
–15	2.1	3.5
–25	1.4–1.8	3.1–3.3
–30	1.3–1.5	2.8–3.0

A clear difference is observed: pumps with EVI technology offer a COP approximately 30-50% higher in low temperature conditions, which translates into significant savings on energy bills and constant thermal comfort during the cold season.

Additional technical aspects and recommendations

It is important to note that EVI technology requires special components, an advanced control system and an optimized design for the refrigerant circuit. Thus, EVI pumps may have a higher initial price, but the additional cost is quickly amortized by the savings achieved in operation.

It is also recommended that EVI heat pumps be installed and maintained by specialized companies, to guarantee maximum performance coefficient and durability.

Why choose ALTAL GRUP for the installation of EVI pumps?

ALTAL GRUP offers a complete range of modern heat pumps, including models with EVI technology, adapted to any type of building and climate. Benefit from:

• Free consultation and correct assessment of thermal needs;
• Customized design and professional installation;
• High-quality technical support and after-sales service;
• Energy-efficient and environmentally friendly products, with international certifications.

Contact us now to benefit from a personalized offer and discover the advantages of EVI technology for your heat pump!

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