Energy efficiency of heat pumps - what is worth knowing?

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Energy Efficiency of Heat Pumps – How Is It Measured and What Does It Mean?

The efficiency of a heat pump is a parameter that defines how much electricity the device consumes in relation to the thermal energy it generates. Ideally, it should be as high as possible, as an efficient heat pump is one that uses little electricity while generating a large amount of heat. When comparing different heat pump models, you may encounter three values used to describe energy efficiency. It’s important to understand these well to compare equivalent indicators. Heat pump efficiency is measured using:

• COP (Coefficient of Power) – This represents the instantaneous ratio of the heat delivered by the heat pump to the energy consumed. For example, if a heat pump uses 1 kWh of electricity to produce 3 kW of heat, the COP will be 3.
• SCOP (Seasonal Coefficient of Power) – While COP refers to efficiency at a specific moment, SCOP indicates the average heating efficiency of the pump throughout the heating season. This makes it a better reflection of the device's real-world capabilities. In practice, SCOP is often slightly lower than COP.
• SPF (Seasonal Energy Efficiency Ratio) – This seasonal efficiency ratio defines the pump’s performance over an entire year, covering both the heating and cooling seasons.

It’s important to note that COP, SCOP, and SPF are not constant values; they depend, among other factors, on weather conditions and the quality of the building’s insulation. Manufacturers are required to declare the device's efficiency under various climatic conditions in accordance with the PN-EN:14511-3:2023 standard.

It is difficult to give a definitive answer as to what COP or SCOP value is "good enough." Much depends on the type of device and the heat demand. High-quality ground-source heat pumps can produce around 4.6–4.9 kW or more of heat per 1 kWh of electricity. When selecting a pump, always compare the same indicators, e.g., COP to COP, not SCOP to COP.

Heat Pump Efficiency – Key Factors Affecting Performance

The efficiency of a heat pump depends on many factors. The most significant include the climatic conditions in a given area and the temperatures of the heat source and the heat sink. The smaller the difference between these, the more efficiently the pump operates.

The design of the device itself also matters. Heat pumps are available in two main types: Split and Monoblock. In Split systems, part of the refrigeration circuit, including refrigerant pipes, is located outside the building. Monoblock systems, on the other hand, house the entire refrigeration circuit within a hermetically sealed outdoor unit. The price of a heat pump can range from several thousand to 40,000–50,000 PLN, depending on its construction and technical parameters.

Monoblock pumps are often praised for their higher energy efficiency due to their compact design. On the other hand, they tend to be slightly more expensive. Split pumps, in contrast, involve lower initial costs, but the heat exchange system may not be as efficient. When preparing a business plan to improve your company’s energy efficiency, consider various solutions and account for both installation and maintenance costs. Economic efficiency encompasses more than just heat generation and electricity consumption!

How to Increase Heat Pump Efficiency – Practical Tips and Advice

Since heat pump efficiency is not a fixed value, let’s explore how you can optimize it. This is important because efficient heat generation translates into lower electricity bills.

1. Implement Building Thermal Modernization – Insulate the building using modern materials. Instead of traditional polystyrene, consider materials like mineral wool, extruded polystyrene (XPS), polyisocyanurate (PIR), or aerogel. Aim for the lowest possible thermal conductivity coefficient. The less heat escapes from the building, the less electricity the pump will use. This will also reduce the device's workload, extending its lifespan. Additionally, proper insulation increases the likelihood of obtaining a "white certificate."

2. Upgrade Windows and Doors – Replace old windows and doors with ones that have good thermal insulation. This eliminates thermal bridges, ensuring heat stays inside the building rather than escaping.

3. Optimize Your Energy Tariff – Choose an electricity tariff that aligns with your company’s usage patterns. For instance, if your business operates mainly at night, consider a tariff like c12b, which offers lower electricity prices during off-peak hours. If your current energy provider doesn’t offer favorable rates, consider switching suppliers.

4. Install Photovoltaic Panels – Increasingly popular in the corporate sector due to rising energy costs, photovoltaic panels can power heat pumps. This approach creates a nearly self-sustaining system. Solar cells generate free electricity, which is then used to drive a technology that produces heat. This allows you to generate both electricity and heat almost for free. Additionally, you may qualify for funding through the Mój Prąd 6.0 program, which began accepting applications on September 2. With a funding pool of 400 million PLN, companies can receive up to 28,000 PLN in support, the same amount as in the previous round. Applications will likely remain open for some time, though the exact duration depends on how quickly the funds are exhausted.

Heat Pump Efficiency – Key Parameters to Consider

When choosing a heat pump, consider several factors. While COP, SCOP, and SPF are important, there are other key parameters to note:

• Energy Class – The most common classes are A+, A++, and A+++. Higher classes indicate lower electricity consumption, resulting in lower operating costs and a better chance of securing subsidies.

• Acoustic Power Level – Measured in decibels, this indicates the noise level of the device, both indoors and outdoors. Lower acoustic power means quieter operation.

• Rated Heating Capacity Across Europe – This is particularly important for companies operating in multiple countries with varying climate conditions.

• Type of Compressor – Inverter compressors are considered the best due to their high operational efficiency and durability. Inverter compressors can be rotary, piston, or scroll types.

Finally, remember that purchasing and installing a heat pump isn’t enough. Regular maintenance is essential, which will also incur additional costs.

Heat pumps are an excellent way to reduce operational costs in businesses. If you’re planning to invest in green technologies, a heat pump is a great complement to photovoltaic panels and other renewable energy systems. However, selecting a heat pump isn’t straightforward, especially since these devices exhibit variable performance.