TY - CONF A1 - Schlegel, Moritz-Caspar A1 - Simo, Anne A1 - Palkowski, Carsten A1 - Kniechewski, Arno A1 - Akkerman, Floris T1 - Following the evidence – How quality of appliance components can hint at non-compliance with efficiency requirements N2 - Improving the energy efficiency of products was identified as the most important short-term opportunity to decrease energy consumption and therefore CO2-emission worldwide. More efficient products are created due to technical innovation. Restricting market access to efficient products only and making the most efficient products stand out by energy labelling are legislative approaches to encourage this development. Market surveillance authorities’ checks are fundamental to protect the consumer from wrongly declared goods on the market and ensure fair competition between manufacturers. However, the activities of market surveillance authorities are limited by their financial resources. Testing all product efficiency parameters in an accredited laboratory is very time consuming and cost intensive. In this article, a theoretical concept is presented which can be used to develop screening tests enabling market surveillance authorities to perform product tests with less financial resources. The concept identifies components which lead to non-compliance or make a product less energy efficient with minimum effort. The principle is based on a combination of random product tests, disassembling specific products and comparing components. This represents a new approach in product testing procedures beyond the current market surveillance activities. The concept is being tested within a research project funded by the German government. T2 - EEDAL'17 CY - Irvine, CA, USA DA - 13.09.2017 KW - Methodology KW - Market surveillance KW - Ecodesign PY - 2018 UR - http://publications.jrc.ec.europa.eu/repository/handle/JRC109209 SN - 978-92-79-77173-6 U6 - https://doi.org/10.2760/68449 SN - 1018-5593 VL - 3 SP - 1113 EP - 1116 PB - Publications Office of the European Union CY - Luxembourg AN - OPUS4-43925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris A1 - Simo, Anne T1 - Telling the truth - Validity of energy efficiency values of heat pumps determined under laboratory conditions N2 - In this study, the test method EN 14825 for testing heat pumps is validated by verifying the sensitivity of the seasonal space heating energy efficiency ηs,(declared on the energy Efficiency label) in relation to the nominal heating capacity Pdesign. Therefore, the two major parts of the test method, the measurement part and the calculation part, were investigated. The calculation part was subjected to a sensitivity analysis in order to identify the properties of a heat pump which have a strong influence on ηs. The analysis revealed that the energy consumption in Special operating states, the duration in active-mode and seasonal performance values in active-mode (SCOPon) significantly affect the sensitivity of ηs. Especially short operating times, in which the heat pump is in active-mode, lead to large changes in ηs with varying Pdesign. In addition, the range of power of Pdesign turned out to have an increasing impact on ηs with decreasing Pdesign. For Pdesign values ≤10 kW, the sensitivity of ηs increases tremendously. Especially the determination of the ηs for devices with short operating times in active-mode (1400 h) and low values for Pdesign (≤10 kW)cannot be reproduced anymore. T2 - 9th international conference on energy efficiency in domestic appliances and lighting (EEDAL '17) CY - Irvine, CA, USA DA - 13.09.2017 KW - Circumvention KW - Energy efficiency KW - Energy labelling KW - Heat pumps KW - Test method standard optimization PY - 2017 SN - 978-92-79-77174-3 U6 - https://doi.org/10.2760/113534 SN - 1831-9424 VL - 2017 IS - Part III SP - 1104 EP - 1112 AN - OPUS4-43833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Simo, Anne T1 - Quick Seasonal Performance Testing for Heat Pumps N2 - To determine the seasonal performance of heat pumps for energy labelling this study proposes a two-point-method that could conceivably be an alternative to the European standard EN 14825 and similar test standards such as ISO 13256. Heat pumps were tested in line with the EN 14825. The reduction of measurement points, from between five to seven (EN 14825) to only two (two-point-method), leads to 60 % savings in cost and time. It is shown that the shortened method can be used to determine the seasonal energy efficiency of heat pumps with the same degree of precision compared to EN 14825. T2 - ECEEE Summer Study 2019 CY - Hyerès, France DA - 03.06.2019 KW - Heat pump KW - Energy label KW - Testing KW - Coefficient of performance KW - Screening PY - 2019 AN - OPUS4-48274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Simo, Anne T1 - Quick Seasonal Performance Testing for Heat Pumps N2 - To determine the seasonal performance of heat pumps for energy labelling this study proposes a two-point-method that could conceivably be an alternative to the European standard EN 14825 and similar test standards such as ISO 13256. Heat pumps were tested in line with the EN 14825. The reduction of measurement points, from between five to seven (EN 14825) to only two (two-point-method), leads to 60 % savings in cost and time. It is shown that the shortened method can be used to determine the seasonal energy efficiency of heat pumps with the same degree of precision compared to EN 14825. T2 - ECEEE Summer Study 2019 CY - Hyerès, France DA - 03.06.2019 KW - Heat pump KW - Energy label KW - Testing KW - Coefficient of performance KW - Screening PY - 2019 SP - 1547 EP - 1552 AN - OPUS4-48275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Test methods for air conditioners N2 - Comparison of test methods for air conditioners that are currently discussed in standardization. The limitations of the current standard are shown and different options for the further development of the standard are presented T2 - Arbeitsgruppensitzung des Fachverbands Gebäude-Klima CY - Online meeting DA - 28.05.2020 KW - air conditioner KW - test method KW - Load-based testing KW - energy label PY - 2020 AN - OPUS4-50829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Wachau, André A1 - Simo, Anne T1 - Test methods for heat pumps N2 - Comparison of different test methods for the determination of the seasonal performance of heat pumps: 1) The current test standard EN14825, 2) the compensation test method and 3) the dynamic test method. T2 - Impact Assessment / Consultation Space and Water Heaters WG2 Testing CY - Online meeting DA - 02.04.2020 KW - Heat pump KW - Energy label KW - Seasonal performance KW - Compensation method KW - Dynamic method PY - 2020 AN - OPUS4-50713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Technical Meeting BAM RRT for Heat Pumps N2 - Kickoff meeting for the BAM round robin test for load-based heat pump testing T2 - Kickoff meeting BAM RRT for heat pumps CY - Online meeting DA - 26.03.2020 KW - Heat pump KW - Round robin test KW - Load-based testing KW - Compensation method KW - Energy efficiency PY - 2020 AN - OPUS4-50715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Technical Meeting BAM RRT for Air Conditioner N2 - Kickoff meeting for the BAM round robin test for load-based air conditioner testing. T2 - Kickoff meeting BAM RRT for air conditioner CY - Online meeting DA - 26.03.2020 KW - Air conditioner KW - Round robin test KW - Load-based testing KW - Compensation method KW - Energy efficiency PY - 2020 AN - OPUS4-50716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Dynamic Test Method - an Update N2 - An update about the dynamic test method for the determination of the seasonal performance of heat pumps given at the CEN/TC 113/WG 7 meeting. T2 - Meeting of CEN/TC 113/WG 7 CY - Courbevoie, France DA - 14.01.2020 KW - Heat pump KW - Dynamic test method KW - Seasonal performance KW - Coefficient of performance PY - 2020 AN - OPUS4-50579 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Dynamic Test Method for Heat Pumps and Air Conditioners N2 - Die bisher üblichen Verfahren zur Bewertung der Effizienz einer Wärmepumpe durch Labormessungen berücksichtigen kaum transiente Zustände. Können dynamische Bewertungsverfahren im Labor ein realistischeres Verhalten im Feld wiederspiegeln und damit zu sinnvolleren Entscheidungen führen? N2 - The commonly used methods for evaluating the seasonal performance of heat pumps in the laboratory do not consider transient conditions. Will dynamic test methods be able to better reflect real-life behavior in the field and thus lead to more appropriate decision-making? T2 - EHPA MCO CY - Brussels, Belgium DA - 10.10.2019 KW - Heat pump KW - Inverter-type air conditioner KW - Seasonal performance KW - Energy label PY - 2019 AN - OPUS4-49270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - von Schwarzenberg, Stefan A1 - Simo, Anne T1 - Dynamic testing of air conditioners to better reflect real use N2 - In this contribution, a dynamic test method to determine the seasonal performance of invertertype air conditioners has been developed and verified. In comparison to current test standards, where test modes for fixing the compressor speed are required, a dynamic approach is applied with unfixed compressor speed and thus better reflects the performance of air conditioners under real operating conditions. The dynamic tests are conducted in two calorimeter chambers. The indoor chamber is kept at a constant temperature whereas the outdoor chamber is subjected to a temperature profile based on the climate BIN-distribution, representing the reference cooling demand. The proposed dynamic test considers the dynamic control of an air conditioner and delivers results which could indicate the units’ performance in the field. T2 - 25th International Congress of Refrigeration 2019 CY - Montréal, Canada DA - 25.09.2019 KW - Seasonal Performance Factor KW - Inverter-type Air Conditioner KW - Dynamic Test Method KW - Real Use Behavior PY - 2019 AN - OPUS4-48864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - von Schwarzenberg, Stefan A1 - Simo, Anne T1 - Dynamic testing to better reflect real use for the seasonal performance of air conditioners N2 - In this contribution, a dynamic test method to determine the seasonal performance of invertertype air conditioners has been developed and verified. In comparison to current test standards, where test modes for fixing the compressor speed are required, a dynamic approach is applied with unfixed compressor speed and thus better reflects the performance of air conditioners under real operating conditions. The dynamic tests are conducted in two calorimeter chambers. The indoor chamber is kept at a constant temperature whereas the outdoor chamber is subjected to a temperature profile based on the climate BIN-distribution, representing the reference cooling demand. The proposed dynamic test considers the dynamic control of an air conditioner and delivers results which could indicate the units' performance in the field. T2 - 25th International Congress of Refrigeration 2019 CY - Montréal, Canada DA - 25.09.2019 KW - Seasonal Performance Factor KW - Inverter-type Air Conditioner KW - Dynamic Test Method KW - Real Use Behavior PY - 2019 SN - 978-2-36215-035-7 SN - 1025-9031 SP - 672, 3891 EP - 3899 PB - International Institute of Refrigeration IIR CY - Paris AN - OPUS4-48865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Palkowski, Carsten A1 - Schwarzenberg, S. A1 - Simo, Anne T1 - Seasonal cooling performance of air conditioners: The importance of independent test procedures used for MEPS and labels N2 - Minimum energy performance standards and labels are commonly used tools to reduce the household energy use thus mitigating greenhouse gas emissions. However, the technical foundation for minimum energy performance standards and labels are test procedures for rating and testing of appliances. To de- termine the seasonal cooling performance of air conditioners, the current test standards require fixing of the compressor speed of the units to achieve steady-state conditions; this way of operation, how- ever, differs from real-life use. To make the seasonal cooling performance testing better reflect the real use conditions, this study proposes a compensation method which can be conducted independently from manufacturer data and still allows modulation of the tested units. Our results show that the tested units behave differently under part-load conditions, which results in a lower energy efficiency rating for some of the tested devices. KW - Air conditioner KW - Independent test method KW - Real use behavior KW - Seasonal energy efficiency ratio KW - Minimum energy performance standards KW - Energy label PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-485813 SN - 0140-7007 VL - 104 SP - 417 EP - 425 PB - Elsevier AN - OPUS4-48581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Dynamic Test Method for Heat Pumps N2 - Vorstellung der Dynamischen Wärmepumpenprüfung beim CEN/TC 113/WG 7 N2 - Presentation of the dynamic test method for the determination of the seasonal performance of heat pumps at CEN/TC 113/WG 7. T2 - Meeting of CEN/TC 113/WG 7 CY - Stockholm, Sweden DA - 23.04.2019 KW - Heat pump KW - Energy label KW - Seasonal performance KW - Coefficient of performance PY - 2019 AN - OPUS4-48308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - BAM Round Robin Test for Heat Pumps and Air Conditioners N2 - Preliminary results of the BAM RRTs are given in this presentation. T2 - VHK Meeting CY - Online meeting DA - 11.11.2020 KW - Heat Pumps KW - Air Conditioners KW - Round Robin Test KW - Load-Based Test Method KW - Energy Label PY - 2020 AN - OPUS4-51969 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris A1 - Simo, Anne T1 - How cool? - Energy label for air conditioners and possibilities for circumvention N2 - In this study, the test method EN 14825 for testing air conditioners is validated by verifying the sensitivity of the seasonal energy efficiency ratio SEER (declared on the energy efficiency label) in relation to the nominal cooling capacity Pdesign. Therefore, the two major parts of the test method, the measurement part and the calculation part, were investigated. Measurements were conducted on several single-split units. The calculation part was subjected to a sensitivity analysis in order to identify the properties of an air conditioner which have a strong influence on the SEER. The analysis revealed that the measurement procedure delivers reproducible results. However, the energy consumption in special operating states, the duration in active-mode and seasonal performance values in active mode (SEERon) significantly affect the sensitivity of the SEER. Especially assumption of short operating times for a cooling active mode leads to large changes in the SEER with varying Pdesign. In addition, the range of power of Pdesign turned out to have an increasing impact on the SEER with decreasing Pdesign. For Pdesign values ≤10 kW, which is the most popular type of ACs in the EU, the sensitivity of the SEER increases tremendously. Especially the determination of the SEER for devices with short operating times in cooling active-mode (350 h) and low values for Pdesign (≤10 kW) cannot be reproduced anymore. In consequence, manufacturer could use the sensitivity of the SEER on Pdesign to artificially “increase” the energy efficiency of their air conditioner for the Energy label about 10 %. T2 - World Sustainable Energy Days CY - Wels, Austria DA - 28.02.2018 KW - Air Conditioner KW - Energy Efficiency KW - Circumvention KW - Energy Label PY - 2018 AN - OPUS4-47480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Dynamische Methode für die Energieeffizienzprüfung von Wärmepumpen N2 - Vorstellung der Dynamische Wärmepumpenprüfung beim DIN NA-044-00-06 AA T2 - Gremiunssitzung des NA 044-00-06 AA CY - Munich, Germany DA - 19.02.2019 KW - Wärmepumpen KW - Energieeffizienz KW - Dynamische Prüfung PY - 2019 AN - OPUS4-47414 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris A1 - Simo, Anne T1 - EU Energy Label for heating appliances - Optimization of test standards for heat pumps N2 - The European Standards EN14511 and EN14825 are representing standardized procedures for testing the energy efficiency of heat pumps and air conditioners with electrically driven compressors for both space heating and cooling. In this study, these standards are analyzed and validated. It was figured out that the currently used methods implicate high complexity and high financial effort. In order to clarify the circumstances and to identify the deficits more in detail, a round robin test with independent and accredited laboratories was initiated. The aim is to develop an optimized test procedure that improves the feasibility of the testing procedure and finally its application. This study should lead to a repeatable and reproducible testing procedure, which is also compatible with the state of the art in heat pump technology and real operation conditions. T2 - ECEEE Summer Study 2017 CY - Hyères, France DA - 29.05.2017 KW - Climate change KW - Energy efficiency KW - Energy labelling KW - Heat pumps KW - Test method standard optimization PY - 2017 SN - 978-91-983878-1-0 SN - 2001-7960 SP - 1551 EP - 1555 AN - OPUS4-41287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Zottl, A. T1 - Dynamische Energieeffizienzprüfung von Wärmepumpen N2 - Die bisher üblichen Verfahren zur Bewertung der Effizienz einer Wärmepumpe durch Labormessungen berücksichtigen kaum transiente Zustände. Können dynamische Bewertungsverfahren im Labor ein realistischeres Verhalten im Feld wiederspiegeln und damit zu sinnvolleren Entscheidungen führen? T2 - Chillventa 2018 CY - Nuremberg, Germany DA - 15.10.2018 KW - Wärmepumpen KW - Energieeffizienz KW - Dynamische Prüfung KW - Methodenentwicklung KW - Energielabel PY - 2018 AN - OPUS4-46343 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris A1 - Simo, Anne T1 - Telling the truth - Validity of energy efficiency values of heat pumps determined under laboratory conditions N2 - In this study, the test method EN 14825 for testing heat pumps is validated by verifying the sensitivity of the seasonal space heating energy efficiency ηs, (declared on the energy efficiency label) in relation to the nominal heating capacity Pdesign. Therefore, the two major parts of the test method, the measurement part and the calculation part, were investigated. The calculation part was subjected to a sensitivity analysis in order to identify the properties of a heat pump which have a strong influence on ηs. The analysis revealed that the energy consumption in special operating states, the duration in activemode and seasonal performance values in active-mode (SCOPon) significantly affect the sensitivity of ηs. Especially short operating times, in which the heat pump is in active-mode, lead to large changes in ηs with varying Pdesign. In addition, the range of power of Pdesign turned out to have an increasing Impact on ηs with decreasing Pdesign. For Pdesign values ≤10 kW, the sensitivity of ηs increases tremendously. Especially the determination of the ηs for devices with short operating times in active-mode (1400 h) and low values for Pdesign (≤10 kW) cannot be reproduced anymore. T2 - 9th International Conference on Energy Efficiency in Domestic Appliances and Lighting (EEDAL 2017) CY - Irvine, CA, USA DA - 13.09.2017 KW - Energy labelling KW - Heat pumps KW - Air conditioner KW - Test method standard optimization KW - Circumvention PY - 2017 AN - OPUS4-42110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Simo, Anne T1 - Technical and economical evaluation of energy efficiency testing for heat pumps N2 - In order to increase the total amount of energy savings to be reached in 2020 and 2050 the German government launched a number of initiatives. One of the associated projects aims to support market surveillance authorities in the field of Ecodesign and Energy Labelling, thereby increasing confidence in these instruments. The surveillance of heating appliances is of great importance as the energy consumed by space heaters accounts for a significant share of the total energy demand in the European Union. In this study heat pumps are analyzed as a high efficiency technology and prospective candidate for large energy savings. It is focused on both validating the current measurement standards for heat pumps and further developing these methods for the benefit of market surveillance authorities. The test method standards, EN 14511 and EN 14825, for testing heat pumps regarding their performance and energy efficiency are validated by conducting round robin tests in independent and accredited test laboratories. Based on these tests the reproducibility and repeatability of the standardized test methods and the laboratories in Europe are assessed. Identifying deficiencies in the methods is a fundamental step towards a sustained improvement process. Optimization proposals will be developed based on these fundamental investigations and brought to the attention of standardization bodies. It was figured out that the currently used test methods exhibit high complexity, high financial effort and reveal significant deviations of testing results depending on whether they were determined under laboratory or field test conditions. New testing and calculation methodologies are developed to simplify the process with the aim to increase the accuracy and affordability of the energy efficiency testing of heat pumps. T2 - 9th Asia-Pacific Power and Energy Engineering Conference (APPEEC 2017) CY - Chengdu, China DA - 15.04.17 KW - Heat pump KW - Energy efficiency KW - Test method standard optimization KW - Energy labelling KW - Climate change PY - 2017 AN - OPUS4-40800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris A1 - Simo, Anne T1 - EU Energy Label for heating appliances - Optimization of test standards for heat pumps N2 - The European Standards EN14511 and EN14825 are representing standardized procedures for testing the energy efficiency of heat pumps and air conditioners with electrically driven compressors for both space heating and cooling. In this study, these standards are analyzed and validated. It was figured out that the currently used methods implicate high complexity and high financial effort. In order to clarify the circumstances and to identify the deficits more in detail, a round robin test with independent and accredited laboratories was initiated. The aim is to develop an optimized test procedure that improves the feasibility of the testing procedure and finally its application. This study should lead to a repeatable and reproducible testing procedure, which is also compatible with the state of the art in heat pump technology and real operation conditions. T2 - ECEEE Summer Study 2017 CY - Hyerès, France DA - 29.05.2017 KW - Heat pump KW - Energy efficiency KW - Test method standard optimization KW - Energy labelling KW - Climate change PY - 2017 AN - OPUS4-40801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Palkowski, Carsten A1 - Zottl, A. A1 - Malenkovic, I. A1 - Simo, Anne T1 - Fixing efficiency values by unfixing compressor speed: Dynamic test method for heat pumps N2 - The growing market penetration of heat pumps indicates the need for a performance test method that better reflects the dynamic behavior of heat pumps. In this contribution, we developed and implemented a dynamic test method for the evaluation of the seasonal performance of heat pumps by means of laboratory testing. Current standards force the heat pump control inactive by fixing the compressor speed. In contrast, during dynamic testing, the compressor runs unfixed while the heat pump is subjected to a temperature profile. The profile consists of the different outdoor temperatures of a typical heating season based on the average European climate and also includes temperature changes to reflect the dynamic behavior of the heat pump. The seasonal performance can be directly obtained from the measured heating energy and electricity consumption making subsequent data interpolation and recalculation with correction factors obsolete. The method delivers results with high precision and high reproducibility and could be an appropriate method for a fair rating of heat pumps. KW - Heat pump KW - Dynamic test method KW - Seasonal performance factor KW - Variable frequency drive KW - Energy label PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-476944 SN - 1996-1073 VL - 12 IS - 6 SP - 1045, 1 EP - 16 PB - MDPI CY - Basel, Switzerland AN - OPUS4-47694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -