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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.
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.
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.
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 %.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Test methods for heat pumps
(2020)