The Ecology, Economy, and EMC of Heat Pumps
By Marcel Consée
In recent years, there has been a growing focus on energy efficiency and environmental sustainability in various industries, including the heating, ventilation, and air conditioning (HVAC) sectors. Heat pumps, in particular, have gained significant attention as highly efficient heating and cooling solutions for residential, commercial, and industrial applications. Specific solutions and directives need to be considered to ensure the seamless operation of heat pumps and mitigate electromagnetic compatibility (EMC) issues.
How does a Heat Pump work?
A heat pump is an energy-efficient HVAC system that can both heat and cool a building. It transfers heat from one location to another, using refrigerant to absorb and release heat as it cycles through the system. In heating mode, the heat pump extracts heat from the outdoor air (even in cold temperatures) or from the ground (using geothermal technology) and then transfers that heat into the building through a network of ducts or pipes. In cooling mode, the process is reversed, with the heat pump absorbing heat from inside the building and releasing it outdoors.
Figure 1: Heat Pump Applications (Source: IEA)
The major types of Heat Pumps are:
- Air-Source Heat Pump: uses the outside air as a heat source in winter and as a heat sink in summer.
- Ground-source, or geothermal, Heat Pump: extract heat from the ground and transfer it indoors to heat a building, and vice versa in summer to provide cooling.
- Water-Source Heat Pump: uses a nearby water source.
- Hybrid Heat Pump: combines a traditional furnace with an air-source heat pump.
- Ductless Mini-Split Heat Pump: consists of an outdoor unit and one or more indoor units that can be mounted on walls or ceilings.
EMC Standards for Heat Pumps
EMC regulations specify the maximum amount of electromagnetic interference (EMI) that a heat pump can emit and the minimum level of immunity to external EMI. These standards help ensure that heat pumps can operate without causing interference to other electronic devices and can withstand external interference without malfunctioning.
The EMC standards that apply to heat pumps vary depending on the country or region in which they are sold. In the United States, heat pumps must comply with the Federal Communications Commission (FCC) Part 15 regulations, limiting radiated and conducted emissions. In the European Union, heat pumps must comply with the EMC Directive 2014/30/EU, which sets out requirements for emissions and immunity.
- Radiated Emissions: The electromagnetic energy that is radiated into the surrounding environment. EMC standards specify limits for the level of radiated emissions.
- Immunity: The ability of the heat pump to withstand external electromagnetic interference without malfunctioning. EMC standards specify the minimum level of immunity.
- Conducted Emissions: The electromagnetic energy conducted along power and signal cables. EMC standards specify limits for the level of conducted emissions.
Choosing an EMC Filter
An EMC filter is designed to reduce electromagnetic interference generated by electrical equipment and prevent it from affecting other devices. Regarding a heat pump, the EMC filter is essential to ensure that the device operates smoothly and without interfering with other electronic equipment in the vicinity.
When selecting an EMC filter for a heat pump, it is essential to consider factors such as the size of the filter, its frequency range, and its overall effectiveness in suppressing electromagnetic interference. It’s also important to ensure the filter is properly installed and grounded to prevent potential electrical hazards.
Choosing the right EMC filter for a heat pump depends on several factors, including the specific application, the level of electromagnetic interference generated by the heat pump, and the EMC standards that must be met.
- Identify the Type of Interference: Conducted or radiated EMI? This will help you determine the type of EMC filter required.
- Determine the Frequency Range: This will help you choose an EMC filter with the appropriate frequency response.
- Consider the Load: This will affect the type and size of the needed EMC filter. For example, a three-phase heat pump will require a three-phase EMC filter.
- Check EMC Standards: What’s applicable in your country or region? This will help you choose an EMC filter that meets the required standards.
- Consider Environmental Factors: Temperature, humidity, and vibration may affect the heat pump’s operation, so a suitable filter will be necessary.
- Consult with a Professional: Expertise in EMC filters can be helpful.
Schaffner EMC/RFI Filters for Heat Pumps
Schaffner, now part of TE Connectivity, offers filters that are commonly used in heat pumps to ensure compliance with EMC regulations and improve the reliability and performance of the equipment.
The Single-phase Filter FN2080 provides a high differential and common-mode attenuation and includes good low-frequency attenuation with a current range of up to 16A. FN2090 filters offer an optimized filter range for enhanced performance AC and DC applications up to 30A.
The high-performance EMC/EMI filter series FN2500 and Single-phase Filters FN2520 provide selectable attenuation performance with rated currents up to 32A.
The 3-phase filter series FN3287 / FN3288 provides state-of-the-art EMI attenuation based on an innovative filter topology. The 10A to 230A filters are designed for the most diverse applications worldwide, including heat pumps. FN3287 offers standard attenuation performance, and FN3288 offers even higher attenuation performance.
3-phase filters with neutral are very commonly used in high residential heat pump applications. FN3256 combines high attenuation performance with low leakage current. The current ranges from 8A to 160A are suitable for residential heat pump installations. The series FN3280 should be chosen for commercial heat pump application and is available up to 600A.